for Journals by Title or ISSN
for Articles by Keywords
help
  Subjects -> AGRICULTURE (Total: 767 journals)
    - AGRICULTURAL ECONOMICS (75 journals)
    - AGRICULTURE (522 journals)
    - CROP PRODUCTION AND SOIL (91 journals)
    - DAIRYING AND DAIRY PRODUCTS (30 journals)
    - POULTRY AND LIVESTOCK (49 journals)

AGRICULTURE (522 journals)

The end of the list has been reached or no journals were found for your choice.
Journal Cover European Journal of Agronomy
  [SJR: 1.488]   [H-I: 75]   [9 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 1161-0301
   Published by Elsevier Homepage  [3039 journals]
  • Climate, soil and land-use based land suitability evaluation for oil palm
           production in Ghana
    • Authors: Tiemen Rhebergen; Thomas Fairhurst; Shamie Zingore; Myles Fisher; Thomas Oberthür; Anthony Whitbread
      Pages: 1 - 14
      Abstract: Publication date: November 2016
      Source:European Journal of Agronomy, Volume 81
      Author(s): Tiemen Rhebergen, Thomas Fairhurst, Shamie Zingore, Myles Fisher, Thomas Oberthür, Anthony Whitbread
      In the past decade, oil palm (Elaeis guineensis Jacq.) has become the world’s most important oil crop. The large demand for palm oil has resulted in a rapid expansion of oil palm cultivation across the globe. Because of the dwindling availability of land in Southeast Asia, most expansion of the industry is expected in Central and South America and sub-Saharan Africa, where land with suitable agro-ecological conditions is available. Using Ghana as a case study, a method for evaluating areas that are both suitable and available for oil palm production is presented. Our assessment used spatial data and GIS techniques, and showed that areas with suitable climatic conditions (annual average water deficit <400mm) is about 20% greater than was previously identified. The observed differences are the result of using different methods to determine suitability, and climate change. A major climatic factor limiting suitability for oil palm production in Ghana is the annual water deficit, with the most suitable areas located in the rainforest and semi-deciduous forest zones with higher rainfall in southern Ghana. Opportunities for large-scale oil palm plantation development is limited, however, because of the lack of availability of large and contiguous tracts of land that are required for commercial plantation oil palm development. A feasible strategy for oil palm expansion is therefore smallholder production, which can make use of smaller parcels of land. Alternatively, oil palm production in Ghana can be increased by yield intensification on land already planted to oil palm. This can also reduce the requirement for further land clearance for new plantations to meet the growing demand for palm oil. Such assessments will be essential for guiding government policy makers and investors considering investments in oil palm development.

      PubDate: 2016-08-25T09:35:43Z
      DOI: 10.1016/j.eja.2016.08.004
      Issue No: Vol. 81 (2016)
       
  • Preanthesis biomass accumulation of plant and plant organs defines yield
           components in wheat
    • Authors: Quan Xie; Sean Mayes; Debbie L. Sparkes
      Pages: 15 - 26
      Abstract: Publication date: November 2016
      Source:European Journal of Agronomy, Volume 81
      Author(s): Quan Xie, Sean Mayes, Debbie L. Sparkes
      The preanthesis period in wheat is critical for growth of plant organs including leaves, stems, spikes and roots. However, the roles of the preanthesis biomass accumulation of plant and plant organs in yield determination are only partially elucidated, and the underlying genetic basis remains largely unknown. This study aimed to understand the physiological and genetic relationships between preanthesis biomass accumulation and yield determination. In a mapping population of bread wheat (Triticum aestivum ‘Forno’) and its relative spelt (Triticum spelta ‘Oberkulmer’) contrasting for biomass, the dry weight of above-ground whole shoots and different organs, and leaf area, were analysed at GS39 (full flag leaf emergence) and anthesis. Yield components (thousand grain weight, grains per spike, final shoot biomass and grain weight per spike) and plant height were measured at maturity, followed by identification of quantitative trait loci (QTL) for all above traits. Field experiments were carried out in UK in 2011–2012 and 2012–2013 seasons, each using a randomised complete block design with three replicates. The results showed that there was a significant variation in biomass and its partitioning to organs at different stages. Consistent with the previous findings, stem water soluble carbohydrates and spike dry weight at anthesis contributed to thousand grain weight and grains per spike, respectively. In addition, this study revealed many other traits positively associated with one or more yield components, including biomass and leaf area at GS39, leaf and structural stem growth as well as whole shoot biomass at anthesis, and higher dry matter accumulation and crop (and spike) growth rates between the two stages. Increasing shoot biomass by removing other tillers at GS39 led to higher grain number and grain weight per spike. These results indicate the importance of the preanthesis growth of plant and plant organs for yield determination. Plant height was only weakly correlated with final biomass at maturity so it is possible to produce high-biomass genotypes without increasing plant height. Genetic analysis revealed 193 QTL associated with biomass and biomass-related traits. Frequent QTL coincidences between biomass and yield traits were observed, mainly on chromosomes 2B, 3A, 4A, 4B, 5A, 6A and 7B, indicating pleiotropy or tight gene linkages, consistent with their phenotypic associations. The preanthesis biomass traits associated with yield components and the underlying QTL, would facilitate the trait-based physiological and molecular breeding in wheat.

      PubDate: 2016-08-25T09:35:43Z
      DOI: 10.1016/j.eja.2016.08.007
      Issue No: Vol. 81 (2016)
       
  • Performance of DSSAT-Nwheat across a wide range of current and future
           growing conditions
    • Authors: Belay T. Kassie; Senthold Asseng; Cheryl H. Porter; Frederick S. Royce
      Pages: 27 - 36
      Abstract: Publication date: November 2016
      Source:European Journal of Agronomy, Volume 81
      Author(s): Belay T. Kassie, Senthold Asseng, Cheryl H. Porter, Frederick S. Royce
      Crop models are widely used in agricultural impact studies. However, many studies have reported large uncertainties from single-model-based simulation analyses, suggesting the need for multi-model simulation capabilities. In this study, the APSIM-Nwheat model was integrated into the Decision Support System for Agro-technology (DSSAT), which already includes two wheat models, to create multi-model simulation capabilities for wheat cropping systems analysis. The new model in DSSAT (DSSAT-Nwheat) was evaluated using more than 1000 observations from field experiments of 65 treatments, which included a wide range of nitrogen fertilizer applications, water supply (irrigation and rainout shelter), planting dates, elevated atmospheric CO2 concentrations, temperature variations, cultivars, and soil types in diverse climatic regions that represented the main wheat growing areas of the world. DSSAT-Nwheat reproduced the observed grain yields well with an overall root mean square deviation (RMSD) of 0.89t/ha (13%). Nitrogen applications, water supply, and planting dates had large effects on observed biomass and grain yields, and the model reproduced these crop responses well. Crop total biomass and nitrogen uptake were reproduced well despite relatively poor simulations of observed leaf area measurements during the growing season. The low sensitivity of biomass simulations to poor simulations of leaf area index (LAI) were due to little changes in intercepted solar radiation at LAI>3 and water and nitrogen stress often limiting photosynthesis and growth rather than light interception at low LAI. The responses of DSSAT-Nwheat to temperature variations and elevated atmospheric CO2 concentrations were close to observed responses. When compared with the two other DSSAT-wheat models (CERES and CROPSIM), these responses were similar, except for the responses to hot environments, due to different approaches in modeling heat stress effects. The comprehensive evaluation of the DSSAT-Nwheat model with field measurements, including a comparison with two other DSSAT-wheat models, created a multi-model simulation platform that allows the quantification of model uncertainties in wheat impact assessments.

      PubDate: 2016-09-03T12:38:30Z
      DOI: 10.1016/j.eja.2016.08.012
      Issue No: Vol. 81 (2016)
       
  • Effects of different soil conservation tillage approaches on soil
           nutrients, water use and wheat-maize yield in rainfed dry-land regions of
           North China
    • Authors: Yunhui Shao; Yingxin Xie; Chenyang Wang; Junqin Yue; Yuqing Yao; Xiangdong Li; Weixing Liu; Yunji Zhu; Tiancai Guo
      Pages: 37 - 45
      Abstract: Publication date: November 2016
      Source:European Journal of Agronomy, Volume 81
      Author(s): Yunhui Shao, Yingxin Xie, Chenyang Wang, Junqin Yue, Yuqing Yao, Xiangdong Li, Weixing Liu, Yunji Zhu, Tiancai Guo
      Excessive tillage compromises soil quality by causing severe water shortages that can lead to crop failure. Reports on the effects of conservation tillage on major soil nutrients, water use efficiency and gain yield in wheat (Triticum aestivum L.) and maize (Zea mays L.) in rainfed regions in the North China Plain are relatively scarce. In this work, four tillage approaches were tested from 2004 to 2012 in a randomized study performed in triplicate: one conventional tillage and three conservation tillage experiments with straw mulching (no tillage during wheat and maize seasons, subsoiling during the maize season but no tillage during the wheat season, and ridge planting during both wheat and maize seasons). Compared with conventional tillage, by 2012, eight years of conservation tillage treatments (no tillage, subsoiling and ridge planting) resulted in a significant increase in available phosphorus in topsoil (0–0.20m), by 3.8%, 37.8% and 36.9%, respectively. Soil available potassium was also increased following conservation tillage, by 13.6%, 37.5% and 25.0%, and soil organic matter by 0.17%, 5.65% and 4.77%, while soil total nitrogen was altered by −2.33%, 4.21% and 1.74%, respectively. Meanwhile, all three conservation tillage approaches increased water use efficiency, by 19.1–28.4% (average 24.6%), 10.1–23.8% (average 15.9%) and 11.2–20.7% (average 15.7%) in wheat, maize and annual, respectively. Additionally, wheat yield was increased by 7.9–12.0% (average 10.3%), maize yield by 13.4–24.6% (average 17.4%) and rotation annual yield by 12.3–16.9% (average 14.1%). Overall, our findings demonstrate that subsoiling and ridge planting with straw mulching performed better than conventional tillage for enhancing major soil nutrients and improving grain yield and water use efficiency in rainfed regions in the North China Plain.

      PubDate: 2016-09-09T12:50:01Z
      DOI: 10.1016/j.eja.2016.08.014
      Issue No: Vol. 81 (2016)
       
  • Delayed permanent water rice production systems do not improve the
           recovery of 15N-urea compared to continuously flooded systems
    • Authors: Terry J. Rose; Dirk V. Erler; Tania Farzana; Lukas Van Zwieten
      Pages: 46 - 51
      Abstract: Publication date: November 2016
      Source:European Journal of Agronomy, Volume 81
      Author(s): Terry J. Rose, Dirk V. Erler, Tania Farzana, Lukas Van Zwieten
      Crop recovery of nitrogen (N) fertiliser in flooded rice systems is low relative to fertiliser N recoveries in aerobic crops, and the N losses have environmental consequences. Recent water shortages across the globe have seen a move towards alternative water management strategies such as delayed permanent water (DPW, also known as delayed flood). To investigate whether N fertiliser regimes used in DPW systems result in greater recovery of N fertiliser than traditional continuously flooded (CF) rice systems, we conducted a multi-N rate field trial using 15N-labelled urea. Around 27% of the 15N-labelled fertiliser was recovered in aboveground biomass at maturity, regardless of water regime or N fertiliser rate, and approximately 20% recovered in the soil to 300mm depth. Plants in the CF system accumulated more total N at each rate of applied N fertiliser than plants in the DPW system due to greater exploitation of native soil N reserves, presumably because the earlier application of N fertiliser in the CF systems led to greater early growth and higher crop N demand. The greater crop biomass production as a result of higher N uptake in the CF system did not increase grain yields above those observed in the DPW system, likely due to cold weather damage. In the following season at the same site, a single N rate (150kgNha−1) trial found no significant differences in crop N uptake, biomass yields, grain yields or 15N-labelled urea recovery in DPW, CF and drill sown-CF (DS-CF) treatments. However, owing to higher 15N fertiliser recovery in the 0–100mm soil horizon, total plant+soil recovery of 15N was significantly higher in the CF treatment (63%) than the DS-CF and DPW treatments (around 50% recoveries). The loss of 40–50% of the applied N (presumably as NH3 or N2) in both seasons regardless of watering regime suggests that new fertiliser N management strategies beyond optimising the rate and timing of urea application are needed, particularly in light of increasing N fertiliser prices.

      PubDate: 2016-09-03T12:38:30Z
      DOI: 10.1016/j.eja.2016.08.009
      Issue No: Vol. 81 (2016)
       
  • A comparison of cardinal temperatures estimated by linear and nonlinear
           models for germination and bulb growth of forage brassicas
    • Authors: M.P. Andreucci; D.J. Moot; A.D. Black; R. Sedcole
      Pages: 52 - 63
      Abstract: Publication date: November 2016
      Source:European Journal of Agronomy, Volume 81
      Author(s): M.P. Andreucci, D.J. Moot, A.D. Black, R. Sedcole
      Forage brassicas are widely used as a supplementary feed in temperate pasture systems but there is a lack of quantitative data about their growth and development. Furthermore, numerous models are available to estimate cardinal temperatures but there is uncertainty about whether linear or nonlinear models should be used. Initially a germination experiment was used to describe the rate response of nine forage brassicas to temperature. Three models were compared to estimate cardinal temperatures and the two best models were used for thermal time (Tt) accumulation for three groups of forage brassicas. Cardinal temperatures, defined as the base (Tb), optimum (Topt) and maximum (Tm), differed among groups of species for the bilinear and Lactin models but were similar within a group of species for these models. In most cases, cardinal temperatures estimated by the bilinear and Lactin models for the B. rapa group ranged from 3 to 4°C for Tb, 31°C for Topt and 41 to 48°C for Tm. For the B. napus and B. napus biennis groups these temperatures ranged from 0 to 3°C for Tb, 29 to 33°C for Topt and 38°C for Tm. The B. oleracea group had temperatures from 0 to 1°C for Tb, 25 to 27°C for Topt and 35°C for Tm. A second data set based on hypocotyl thickening was used to estimate the base temperature (Tb) for bulb growth of turnips and swedes. Both models estimated an average Tb of 4.2°C for bulb turnips and an average of 3.7°C for swedes. The Lactin model was considered the most adequate model to describe temperature responses where as, in some cases, the bilinear model had to be modified to account for changes in the rate of development. More importantly, an appropriate range of test temperatures was crucial for the estimation of reliable cardinal temperatures, independent of the model used.

      PubDate: 2016-09-03T12:38:30Z
      DOI: 10.1016/j.eja.2016.08.010
      Issue No: Vol. 81 (2016)
       
  • The relevance of N fertilization for the amount of total greenhouse gas
           emissions in sugar beet cultivation
    • Authors: Kerrin Trimpler; Nicol Stockfisch; Bernward Märländer
      Pages: 64 - 71
      Abstract: Publication date: November 2016
      Source:European Journal of Agronomy, Volume 81
      Author(s): Kerrin Trimpler, Nicol Stockfisch, Bernward Märländer
      The agricultural sector is highly affected by climate change and it is a source of greenhouse gases. Therefore it is in charge to reduce emissions. For a development of reduction strategies, origins of emissions have to be known. On the example of sugar beet, this study identifies the main sources and gives an overview of the variety of production systems. With data from farm surveys, calculations of greenhouse gas (GHG) emissions in sugar beet cultivation in Germany are presented. Emissions due to the production and use of fertilizers and pesticides, emissions due to tillage as well as field emissions were taken into account. All emissions related to the growing of catch crops during fall before the cultivation of sugar beet were also included. The emissions are related to the yield to express intensity. The median of total GHG emissions of sugar beet cultivation in Germany for the years 2010–2012 amounted to 2626 equivalents of CO2 (CO2eq)kgha−1 year−1 when applying mineral plus organic fertilizer and to 1782kgha−1 when only organic fertilizer was applied. The CO2eq emissions resulting from N fertilization exclusively were 2.5 times higher than those caused by diesel and further production factors. The absence of emissions for the production of organic fertilizers led to 12% less total CO2eq emissions compared to the use of mineral fertilizer only. But by applying organic fertilizer only, there were more emissions via the use of diesel due to larger volumes transported (126l diesel ha−1 vs. 116lha−1 by applying mineral fertilizer exclusively). As there exists no official agreement about calculating CO2eq emissions in crop production yet, the authors conclude that there is still need for further research and development with the aim to improve crop cultivation and crop rotations concerning GHG emissions and the therewith related intensity.
      Graphical abstract image

      PubDate: 2016-09-17T13:00:43Z
      DOI: 10.1016/j.eja.2016.08.013
      Issue No: Vol. 81 (2016)
       
  • Phenological response of spring wheat to timing of photoperiod perception:
           The effect of sowing depth on final leaf number in spring wheat
    • Authors: E.D. Meenken; H.E. Brown; C.M. Triggs; I.R. Brooking; M. Forbes
      Pages: 72 - 77
      Abstract: Publication date: November 2016
      Source:European Journal of Agronomy, Volume 81
      Author(s): E.D. Meenken, H.E. Brown, C.M. Triggs, I.R. Brooking, M. Forbes
      Wheat phenological modelling literature suggests final leaf number (FLN) targets of wheat (Triticum aestivum) will be set only once daylight is perceived and will be based upon environmental and cultivar-specific genetics at that time. Development is thought to proceed relative to thermal time regardless of light perception prior to emergence. Modelled predictions of final leaf number (FLN) and thence anthesis are based on this mechanism. Results did not support this hypothesis, and we suggest and alternative hypothesis based on molecular interactions between vernalization genes Vrn1, Vrn2 and Vrn3.

      PubDate: 2016-09-17T13:00:43Z
      DOI: 10.1016/j.eja.2016.08.008
      Issue No: Vol. 81 (2016)
       
  • Effects of reduced nitrogen input on productivity and N2O emissions in a
           sugarcane/soybean intercropping system
    • Authors: Shasha Luo; Lingling Yu; Yu Liu; Ying Zhang; Wenting Yang; Zhixian Li; Jianwu Wang
      Pages: 78 - 85
      Abstract: Publication date: November 2016
      Source:European Journal of Agronomy, Volume 81
      Author(s): Shasha Luo, Lingling Yu, Yu Liu, Ying Zhang, Wenting Yang, Zhixian Li, Jianwu Wang
      A seven-year (2009–2015) continuous field experiment was established at the South China Agricultural University in order to identify the effects of sugarcane/soybean intercropping and reduced N rate on ecosystem productivity, yield stability, soil fertility, and N2O emissions. The randomized block experiment was designed with four cropping patterns (sugarcane monocropping (MS), soybean monocropping (MB), sugarcane/soybean (1:1) intercropping (SB1), and sugarcane/soybean (1:2) intercropping (SB2)) and two rates of N fertilization (300kghm−2 (N1, reduced rate) and 525kghm−2 (N2, conventional rate)). The results showed that the land equivalent ratio (LER) of all intercropping systems was greater than 1 (between 1.10 and 1.84), and the SB2-N1 optimally improved the land utilization rate among all treatments. The cropping patterns and N applied rates had no significant effect on sugarcane yield. The soybean yield was influenced by different cropping patterns because of different planting densities (4, 8 and 16 rows of soybean were plant under SB1, SB2, and MB, respectively) and was adopted in this experiment. In addition, under the SB2 cropping pattern, the soybean yield at the reduced N application rate was higher than that at the conventional N application rate. Wricke’s ecovalence (Wi 2), the sustainable yield index (SYI) and the coefficient of variation (CV) were used to evaluate yield stability. Different treatments had no significant effects on sugarcane yield stability, as demonstrated by three indicators (Wi 2, SYI and CV), which indicated that intercropping with soybean and reduced N rate had no effect on sugarcane yield. For soybeans, the value of Wi 2 demonstrated that the stability of the intercropping system was higher than its counterpart monocropping system, as SYI and CV values indicated that SB2 had higher stability than SB1. During seven years of experiments, there was no significant difference in the soil fertility between MS and SB patterns. The soybean monocropping had a higher available K, pH and lower available P content than sugarcane inter- and mono-cropping. Different cropping patterns had a slight impact on N2O emissions and the greenhouse gas intensity (GHGI) value. Higher N input promoted N2O emissions and increased GHGI values. In conclusion, the present study observed that a 40% reduced nitrogen input combined with intercropping soybeans could maintain sugarcane yield and soil sustainable utilization, and that higher N fertilizer additions induced negative impacts on greenhouse gases emissions. Sugarcane intercropping with soybeans can reduce chemical fertilizer input and simultaneously maintain crop productivity; thus, it can be considered to be a reasonable practice for field management.

      PubDate: 2016-09-17T13:00:43Z
      DOI: 10.1016/j.eja.2016.09.002
      Issue No: Vol. 81 (2016)
       
  • Screening chickpea for adaptation to water stress: Associations between
           yield and crop growth rate
    • Authors: Lachlan Lake; Victor O. Sadras
      Pages: 86 - 91
      Abstract: Publication date: November 2016
      Source:European Journal of Agronomy, Volume 81
      Author(s): Lachlan Lake, Victor O. Sadras
      Robust associations between yield and crop growth rate in a species-specific critical developmental window have been demonstrated in many crops. In this study we focus on genotype-driven variation in crop growth rate and its association with chickpea yield under drought. We measured crop growth rate using Normalised Difference Vegetative Index (NDVI) in 20 diverse chickpea lines, after calibration of NDVI against biomass accounting for morphological differences between Kabuli and Desi types. Crops were grown in eight environments resulting from the combination of seasons, sowing dates and water supply, returning a yield range from 152 to 366gm−2. For both sources of variation – environment and genotype – yield correlated with crop growth rate in the window 300°Cd before flowering to 200°Cd after flowering. In the range of crop growth rate from 0.07 to 0.91gm−2 °Cd−1, the relationship was linear with zero intercept, as with other indeterminate grain legumes. Genotype-driven associations between yield and crop growth rate were stronger under water stress than under favourable conditions. Despite this general trend, lines were identified with high crop growth rate in both favourable and stress conditions. We demonstrate that calibrated NDVI is a rapid, inexpensive screening tool to capture a physiologically meaningful link between yield and crop growth rate in chickpea.

      PubDate: 2016-09-17T13:00:43Z
      DOI: 10.1016/j.eja.2016.09.003
      Issue No: Vol. 81 (2016)
       
  • A model-based approach to assist variety evaluation in sunflower crop
    • Authors: Pierre Casadebaig; Emmanuelle Mestries; Philippe Debaeke
      Pages: 92 - 105
      Abstract: Publication date: November 2016
      Source:European Journal of Agronomy, Volume 81
      Author(s): Pierre Casadebaig, Emmanuelle Mestries, Philippe Debaeke
      Assessing the performance and the characteristics (e.g. yield, quality, disease resistance, abiotic stress tolerance) of new varieties is a key component of crop performance improvement. However, the variety testing process is presently exclusively based on experimental field approaches which inherently reduces the number and the diversity of experienced combinations of varieties×environmental conditions in regard of the multiplicity of growing conditions within the cultivation area. Our aim is to make a greater and faster use of the information issuing from these trials using crop modeling and simulation to amplify the environmental and agronomic conditions in which the new varieties are tested. In this study, we present a model-based approach to assist variety testing and implement this approach on sunflower crop, using the SUNFLO simulation model and a subset of 80 trials from a large multi-environment trial (MET) conducted each year by agricultural extension services to compare newly released sunflower hybrids. After estimating parameter values (using plant phenotyping) to account for new genetic material, we independently evaluated the model prediction capacity on the MET (relative RMSE for oil yield was 16.4%; model accuracy was 54.4%) and its capacity to rank commercial hybrids for performance level (relative RMSE was 11%; Kendall's τ =0.41, P <0.01). We then designed a numerical experiment by combining the previously tested genetic and new cropping conditions (2100 virtual trials) to determine the best varieties and related management in representative French production regions. Finally, we proceeded to optimize the variety-environment-management choice: growing different varieties according to cultivation areas was a better strategy than relying on the global adaptation of varieties. We suggest that this approach could find operational outcomes to recommend varieties according to environment types. Such spatial management of genetic resources could potentially improve crop performance by reducing the genotype–phenotype mismatch in farming environments.

      PubDate: 2016-09-17T13:00:43Z
      DOI: 10.1016/j.eja.2016.09.001
      Issue No: Vol. 81 (2016)
       
  • Differential effect of regulated deficit irrigation on growth and
           photosynthesis in young peach trees intercropped with grass
    • Authors: Oswaldo Forey; Aurélie Metay; Jacques Wery
      Pages: 106 - 116
      Abstract: Publication date: November 2016
      Source:European Journal of Agronomy, Volume 81
      Author(s): Oswaldo Forey, Aurélie Metay, Jacques Wery
      The effects of a moderate soil water deficit on several shoot growth variables (1st and 2nd order shoot growth and final leaves number, final height and final number of 2nd order shoots) and on net photosynthesis were studied in young peach trees during the two years following plantation (January 2014). Trees were either fully irrigated (C), subjected to moderate water deficit (RDI) or subjected to moderate water deficit and associated with a grass-legume mixture on the entire orchard floor (RDI +G). Irrigation was scheduled according to soil water potential target ranges in order to keep C trees above −0.02MPa, i.e. at field capacity, and RDI and RDI+G trees between −0.04MPa and −0.06MPa. The level of water deficit obtained was moderate but yet significantly reduced by 50% overall tree growth in 2014 in RDI. This reduction was enhanced when water deficit lasted longer and when it was associated with grass in RDI+G. No reduction in growth variables occurred in RDI in 2015 due to the shorter duration of water deficit. Overall reduction was observed in 2015 in RDI+G mostly due to a carry-over effect of the previous year. Net photosynthesis was reduced by the longer and more intense water deficit in 2014, but was not reduced during the soil water deficit in 2015. An indicator of plant process sensitivity to water deficit, taking into account the variable reduction with regards to the control, the water deficit intensity and its duration was used to classify shoot growth variables and net photosynthesis according to their sensitivity to water deficit. Variables could be classified according to the following order of ascending sensitivity: net photosynthesis <1st order final leaf number<final tree height <1st order final shoot length <2nd order final leaf number <2nd order final shoot number <2nd order final shoot length. Applying a moderate water deficit combined with full grass cover drastically reduces overall tree size due to grass competition.

      PubDate: 2016-09-22T13:04:32Z
      DOI: 10.1016/j.eja.2016.09.006
      Issue No: Vol. 81 (2016)
       
  • Effects of irrigation and nitrogen fertilization on the greenhouse gas
           emissions of a cropping system on a sandy soil in northeast Germany
    • Authors: Benjamin Trost; Annette Prochnow; Andreas Meyer-Aurich; Katrin Drastig; Michael Baumecker; Frank Ellmer
      Pages: 117 - 128
      Abstract: Publication date: November 2016
      Source:European Journal of Agronomy, Volume 81
      Author(s): Benjamin Trost, Annette Prochnow, Andreas Meyer-Aurich, Katrin Drastig, Michael Baumecker, Frank Ellmer
      Irrigation induces processes that may either decrease or increase greenhouse gas emissions from cropping systems. To estimate the net effect of irrigation on the greenhouse gas emissions, it is necessary to consider changes in the crop yields, the content of soil organic carbon and nitrous oxide emissions, as well as in emissions from the use and production of machinery and auxiliary materials. In this study the net greenhouse gas emissions of a cropping system on a sandy soil in northeast Germany were calculated based on a long-term field experiment coupled with two-year N2O flux measurements on selected plots. The cropping system comprised a rotation of potato, winter wheat, winter oil seed rape, winter rye and cocksfoot each under three nitrogen (N) fertilization intensities with and without irrigation. Total greenhouse gas emissions ranged from 452 to 3503kg CO2-eqha−1 and 0.09 to 1.81kg CO2-eqkg−1 yield. Application of an adequate amount of N fertilizer led to a decrease in greenhouse gas emissions compared to zero N fertilization whereas excessive N fertilization did not result in a further decrease. Under N fertilization there were no significant differences between irrigation and non-irrigation. Increases in greenhouse gas emissions from the operation, production and maintenance of irrigation equipment were mainly offset by increases in crop yield and soil organic carbon contents. Thus, on a sandy soil under climatic conditions of north-east Germany it is possible to produce higher yields under irrigation without an increase in the yield-related greenhouse gas emissions.

      PubDate: 2016-09-22T13:04:32Z
      DOI: 10.1016/j.eja.2016.09.008
      Issue No: Vol. 81 (2016)
       
  • Radiation interception and radiation use efficiency of potato affected by
           different N fertigation and irrigation regimes
    • Authors: Zhenjiang Zhou; Mathias Neumann Andersen; Finn Plauborg
      Pages: 129 - 137
      Abstract: Publication date: November 2016
      Source:European Journal of Agronomy, Volume 81
      Author(s): Zhenjiang Zhou, Mathias Neumann Andersen, Finn Plauborg
      Three years of field experiments were carried out to explore the response of potato dry matter production, accumulated intercepted photosynthetic active radiation (Aipar) and radiation use efficiency (RUE) to five N levels providing 0, 60, 100, 140 and 180kgNha−1 and three drip irrigation strategies, which were full, deficit and none irrigation. Results showed that, irrespective of years, dry matter production and Aipar were increased by prolonged N fertigation, even though N fertigation was carried out from middle to late growing season. The highest total and tuber dry matter and accumulated radiation interception in all three years were obtained when potatoes were provided with 180kgNha−1. RUE on the other hand was not affected by N regime. Thus, increases in total dry matter production with increasing N levels were essentially caused by higher Aipar. The strongest response to N fertilization occurred when most N was applied early in the growing season and the latest N fertilization should be applied no later than 41–50days after emergence. Deficit irrigation, which received ca.70% of irrigation applied to full irrigation, did not reduce radiation interception and radiation use efficiency.

      PubDate: 2016-09-22T13:04:32Z
      DOI: 10.1016/j.eja.2016.09.007
      Issue No: Vol. 81 (2016)
       
  • Pig slurry fertilization in a double-annual cropping forage system under
           sub-humid Mediterranean conditions
    • Authors: J. Ovejero; C. Ortiz; J. Boixadera; X. Serra; S. Ponsá; J. Lloveras; C. Casas
      Pages: 138 - 149
      Abstract: Publication date: November 2016
      Source:European Journal of Agronomy, Volume 81
      Author(s): J. Ovejero, C. Ortiz, J. Boixadera, X. Serra, S. Ponsá, J. Lloveras, C. Casas
      In areas of Southern Europe with very intensive pig production, most of the pig slurry (PS) is applied as fertilizer. However, in the European Union, no more than 170kgNha−1 year−1 can be applied in nitrate vulnerable zones (NVZs) from livestock manures. In this context, a six-year trial was conducted for a maize-triticale double-annual forage cropping rotation under rainfed conditions. Four different N rates were applied (0, 170, 250 and 330kgNha−1 year−1), to evaluate their effect on crop yield, N uptake, unrecovered N and soil nitrate content. The corresponding PS rates were defined as zero (PS 0), low (PSL) medium (PSM) and high (PSH). The annual average dry matter (DM) yields (maize+triticale) for the PS fertilization treatments PS0, PSL, PSM and PSH were 12.6, 17.7, 20.2 and 22.0MgDMha−1, respectively. Maize DM yield was influenced mainly by weather conditions, and triticale DM yield was clearly influenced by initial soil NO3 −-N and PS fertilization rates. Unrecovered N was affected by PS fertilization rate and initial soil NO3 −-N content. A residual effect of the PS when applied to maize had an important effect on soil NO3 −-N and subsequent triticale DM yield. Moreover, total annual average unrecovered N, considering the sum of both crops (maize+triticale), were 91, 144, and 222kgNha−1 in PSL, PSM and PSH, respectively. In order to avoid part of this unrecovered N, mainly by lixiviation of nitrates, PS fertilization in triticale should be applied as side dressing at tillering. The application of N, in the form of PS, at rates higher than the legally permitted maximum of 170kgNha−1 year−1, may result in better yields. However, high rates of PS fertilization may originate in significantly lower N use efficiency and a higher potential environmental impact in double-cropping systems, practiced in rainfed sub-humid Mediterranean conditions.

      PubDate: 2016-09-27T13:08:20Z
      DOI: 10.1016/j.eja.2016.09.005
      Issue No: Vol. 81 (2016)
       
  • Influence of harvest time and frequency on light interception and biomass
           yield of festulolium and tall fescue cultivated on a peatland
    • Authors: Tanka P. Kandel; Lars Elsgaard; Mathias N. Andersen; Poul E. Lærke
      Pages: 150 - 160
      Abstract: Publication date: November 2016
      Source:European Journal of Agronomy, Volume 81
      Author(s): Tanka P. Kandel, Lars Elsgaard, Mathias N. Andersen, Poul E. Lærke
      In this study, we report efficiencies of light capture and biomass yield of festulolium and tall fescue cultivated on a riparian fen in Denmark under different harvesting managements. Green biomass targeted for biogas production was harvested either as two cuts (2C) or three cuts (3C) in a year. Three different timings of the first cut in the 2C systems were included as early (2C-early), middle (2C-mid) and late (2C-late) cuts corresponding to pre-heading, inflorescence emergence and flowering stages, respectively. The fraction of intercepted photosynthetically active radiation (fPAR) was derived from the canopy reflectance measured on 61 dates throughout a year, and cumulative interception of PAR (IPAR) and radiation use efficiency (RUE) was calculated. The dynamics of fPAR and biomass accumulations was similar for both crops before the first cuts in all managements. Festulolium fPAR in 2C-early and 2C-mid managements declined faster than in 2C-late and 3C managements in the second growth period and thus growing period IPAR of 2C-early and 2C-mid declined by 8% as compared to 3C management where IPAR was 925MJm−2. Annual festulolium dry matter (DM) yield in 2C-early and 2C-mid managements (average 14.1MgDMha−1) decreased by 22% compared to 3C management (18.2 MgDMha−1). The highest and the lowest RUE of festulolium were observed in 3C and 2C-mid managements as 1.97 and 1.59gMJ−1, respectively. For tall fescue fPAR declined rather slowly in the second growing period in all 2C managements, which contributed to similar IPAR (908–919MJm−2), total biomass yield (16.4–18.8MgDMha−1 yr−1) and RUE (1.80–2.07gMJ−1) for all managements. Whereas both crops were highly productive under both 3C management and 2C management with first harvest after flowering (i.e., 2C-late), the 2C-late strategy is recommended as the least intensive of the two management systems.

      PubDate: 2016-10-12T12:36:48Z
      DOI: 10.1016/j.eja.2016.09.010
      Issue No: Vol. 81 (2016)
       
  • Nitrogen use efficiency and residual effect of fertilizers with
           nitrification inhibitors
    • Authors: M. Alonso-Ayuso; J.L. Gabriel; M. Quemada
      Pages: 1 - 8
      Abstract: Publication date: October 2016
      Source:European Journal of Agronomy, Volume 80
      Author(s): M. Alonso-Ayuso, J.L. Gabriel, M. Quemada
      Blending fertilizers with nitrification inhibitors (NI) is a technology to reduce nitrogen (N) losses. The application of NI could increase the soil N supply capacity over time and contribute to an enhancement of N use efficiency (NUE) in some cropping systems. The objectives were to determine in a field experiment located in Central Spain (i) the effect of NI-fertilizers applied to maize (Zea mays L.) during two seasons on yield, N content and NUE compared to conventional fertilizers, (ii) the soil residual effect of NI-fertilizers in a non-fertilized sunflower (Helianthus annuus L.) planted during a third season, and (iii) the possible sources of residual N via laboratory determinations. The maize was fertilized with ammonium sulfate nitrate (ASN) and DMPP (3,4-dimethylpyrazole phosphate) blended ASN (ENTEC®) at two levels (130 and 170kgNha−1). A control treatment with no added N fertilizer was included to calculate NUE. The second year, DMPP application allowed a 23% reduction of the fertilizer rate without decreasing crop yield or grain quality. In addition, the sunflower planted after the maize scavenged more N in treatments previously treated with ENTEC® than with traditional fertilizers, increasing NUE in the cropping systems. After DMPP application, N was conserved in non-ready soil available forms during at least one year and subsequently released to meet the sunflower crop demand. The potential N mineralization obtained from aerobic incubation under controlled conditions of soil samples collected before sunflower sowing was higher for ENTEC® than ASN or control treatments. A higher δ15N in the soil indicated larger non-exchangeable NH4 + fixation in soils from the plots treated with ENTEC® or ASN-170 than from the ASN-130 or the control. These results open the opportunity to increase NUE by designing crop rotations able to profit from the effect of NI on the soil residual N.

      PubDate: 2016-07-11T03:44:32Z
      DOI: 10.1016/j.eja.2016.06.008
      Issue No: Vol. 80 (2016)
       
  • Crop-livestock integration, from single practice to global functioning in
           the tropics: Case studies in Guadeloupe
    • Authors: Fabien Stark; Audrey Fanchone; Ivan Semjen; Charles-Henri Moulin; Harry Archimède
      Pages: 9 - 20
      Abstract: Publication date: October 2016
      Source:European Journal of Agronomy, Volume 80
      Author(s): Fabien Stark, Audrey Fanchone, Ivan Semjen, Charles-Henri Moulin, Harry Archimède
      Agricultural systems will have to produce more and better in a changing world. Mixed crop livestock systems (MCLS) are sound alternative ways to progressively achieve these goals through crop-livestock integration (CLI). CLI exploits the synergies between cropping and livestock systems, for example, through organic fertilization and the use of crop residues to feed livestock, and offers many opportunities to improve productivity, as well as to increase resource use efficiency and improve the resilience of the whole farming system. In the scientific literature, authors advocate the interest of MLCS and CLI, based on theoretical considerations, modelling and empirical evidence from local case studies. But these studies do not clearly identify the respective roles of the diversity of activities and CLI management practices in improving performances at the level of the whole farming system. The aim of this study was thus to assess CLI at farm scale in a range of MCLS and to explain farm performances by analyzing the combination of activities and the level of integration. This study was conducted in Guadeloupe, (French West Indies), where MCLS and CLI are complex but important challenges for local agricultural. Ecological network analysis was used to study the structure, functioning and performance of agrosystems. To this end, a range of eight farms was selected to characterize CLI as practices, and as a network of nitrogen flows at farm level. The land and labor productivity were then assessed along with the resilience, efficiency, productivity and self-sufficiency of the network of flows. Results show that CLI only applies to certain types of production, including feeding pigs with a wide range of crop residues (crop residues provide from 16 to 45% of the N supply to pigs) or organic fertilization of small market gardens and plots used to grow tubers (manure provides 24–100% of the N supply to plots). But at whole system level, CLI remains low: in seven cases, the N circulating within the system – ICR- represent only between 0.7 to 3.5% of the total N circulating through the system; only one farm presents a higher intensity of CLI, with an ICR of 18.9%. Consequently, performances and especially efficiency and productivity, depend more on the nature of the activity than on CLI management practices.

      PubDate: 2016-07-11T03:44:32Z
      DOI: 10.1016/j.eja.2016.06.004
      Issue No: Vol. 80 (2016)
       
  • Girdling and gibberellic acid effects on yield and quality of a seedless
           red table grape for saving irrigation water supply
    • Authors: Pasquale Crupi; Donato Antonacci; Michele Savino; Rosalinda Genghi; Rocco Perniola; Antonio Coletta
      Pages: 21 - 31
      Abstract: Publication date: October 2016
      Source:European Journal of Agronomy, Volume 80
      Author(s): Pasquale Crupi, Donato Antonacci, Michele Savino, Rosalinda Genghi, Rocco Perniola, Antonio Coletta
      Table grapes need of substantial water supply for achieving commercial requirements. Viticulture practices such as girdling (G) and gibberellic acid (GA) application, as well as water supply, can improve table grape quality. The study, which was conducted in two consecutive seasons (2010–2011), aimed to assess the counterbalance effect of these viticulture practices on yield and quality parameters and flavonoids composition in case of a significant and unusual irrigation water reduction (40%) applied to a table grape variety. The data from the two-way ANOVA and PCA analyses indicated that viticulture practices were clearly related to anthocyanins and flavonols variations whereas water management appeared mainly involved in the yield parameters variability. Specifically, the reduced water supply (RWS) decreased the grape yield (−20%) with respect to full water supply (FWS); by contrast GA, G, and G×GA treatments determined an increment of grape production ranging from 10 to 23%, independently from irrigation strategy. Moreover, G, in particular applied to RWS grapes, was able to improve the total soluble solids over titrable acidity (TSS/TA), a ratio strictly related to the quality perception by the consumer. Total anthocyanins were found positively linked to FWS whereas flavanols content was indifferent to water management. Instead viticulture practices seemed to have a greater impact on anthocyanin composition, considering that in RWS grapes under GA condition, higher contents of malvidin and peonidin (mainly responsible for the color stability of the skins) were revealed. Furtheremore, catechins and rutin appeared significantly enhanced by G and G×GA, and GA, respectively. From gathered findings, it can be concluded that suitable viticulture practices can allow a sensible reduction of water supply during table grape growth cycle without detrimental effects on yield and quality.
      Graphical abstract image

      PubDate: 2016-07-11T03:44:32Z
      DOI: 10.1016/j.eja.2016.06.015
      Issue No: Vol. 80 (2016)
       
  • Optimising crop production and nitrate leaching in China: Measured and
           simulated effects of straw incorporation and nitrogen fertilisation
    • Authors: Kiril Manevski; Christen D. Børgesen; Xiaoxin Li; Mathias N. Andersen; Xiying Zhang; Per Abrahamsen; Chunsheng Hu; Søren Hansen
      Pages: 32 - 44
      Abstract: Publication date: October 2016
      Source:European Journal of Agronomy, Volume 80
      Author(s): Kiril Manevski, Christen D. Børgesen, Xiaoxin Li, Mathias N. Andersen, Xiying Zhang, Per Abrahamsen, Chunsheng Hu, Søren Hansen
      The sustainability of growing a maize—winter wheat double crop rotation in the North China Plain (NCP) has been questioned due to its high nitrogen (N) fertiliser use and low N use efficiency. This paper presents field data and evaluation and application of the soil–vegetation–atmosphere transfer model Daisy for estimating crop production and nitrate leaching from silty loam fields in the NCP. The main objectives were to: i) calibrate and validate Daisy for the NCP pedo-climate and field management conditions, and ii) use the calibrated model and the field data in a multi-response analyses to optimise the N fertiliser rate for maize and winter wheat under different field managements including straw incorporation. The model sensitivity analysis indicated that a few measurable crop parameters impact the simulated yield, while most of the studied topsoil parameters affect the simulated nitrate leaching. The model evaluation was overall satisfactory, with root mean squared residuals (RMSR) for simulated aboveground biomass and nitrogen content at harvest, monthly evapotranspiration, annual drainage and nitrate leaching out of the root zone of, respectively, 0.9Mgha−1, 20kgNha−1, 30mm, 10mm and 10kgNha−1 for the calibration, and 1.2Mgha−1, 26kgNha−1, 38mm, 14mm and 17kgNha−1 for the validation. The values of mean absolute deviation, model efficiency and determination coefficient were also overall satisfactory, except for soil water dynamics, where the model was often found erratic. Re-validation run showed that the calibrated Daisy model was able to simulate long-term dynamics of crop grain yield and topsoil carbon content in a silty loam field in the NCP well, with respective RMSR of 1.7 and 1.6Mgha−1. The analyses of the model and the field results showed that quadratic, Mitscherlich and linear-plateau statistical models may estimate different economic optimal N rates, underlining the importance of model choice for response analyses to avoid excess use of N fertiliser. The analyses further showed that an annual fertiliser rate of about 300kgNha−1 (100 for maize and 200 for wheat) for the double crop rotation with straw incorporation is the most optimal in balancing crop production and nitrate leaching under the studied conditions, given the soil replenishment with N from straw mineralisation, atmospheric deposition and residual fertiliser. This work provides a sound reference for determining N fertiliser rates that are agro-environmentally optimal for similar and other cropping systems and regions in China and extends the application of the Daisy model to the analyses of complex agro-ecosystems and management practices under semi-arid climate.
      Graphical abstract image

      PubDate: 2016-07-17T01:02:26Z
      DOI: 10.1016/j.eja.2016.06.009
      Issue No: Vol. 80 (2016)
       
  • The effects of dairy cattle manure and mineral N fertilizer on irrigated
           maize and soil N and organic C
    • Abstract: Publication date: Available online 29 November 2016
      Source:European Journal of Agronomy
      Author(s): E. Martínez, F. Domingo, A. Roselló, J. Serra, J. Boixadera, J. Lloveras
      This work was aimed at providing a sustainable approach in the use of manure in irrigated maize crop under Mediterranean climatic conditions. To this end, the effect of continuous annual applications of dairy cattle manure, combined or not with mineral N fertilizer, on the following parameters was studied: grain yield, grain and plant N concentration, N uptake by plant, N use efficiency, and soil N and organic carbon. The experiment was conducted in a furrow-irrigated sandy soil under dry Mediterranean conditions during seven years. Three different rates of cattle manure (CM): 0, 30 and 60Mgha−1, were applied each year before sowing. These CM rates were combined with four mineral N rates (0, 100, 200 and 300kgNha−1) applied at sidedress. On average, the highest grain yields during the 7 years were obtained with the combination of CM at 30Mgha−1 and mineral fertilizer and with CM at 60Mgha−1 without mineral fertilizer. With CM at 30Mgha−1, mineral fertilizer increased yields during most of the growing seasons, meanwhile with CM at 60Mgha−1, there was not any significant effect of the joint application of mineral fertilizer on yields. Overall, best results were obtained exceeding maximum rates according to present legislation. The mean apparent nitrogen recovery (ANR) fraction during the 7 seasons was 29% for N exclusively applied as CM. Overall, increased N rates applied as CM resulted in decreased ANRs. However, ANR with CM at 30 and 60Mgha−1 increased during the first two seasons. This increased ANR ascribed to mineralization of residual organic N applied in previous seasons explained the increasing yields observed in the treatments along the study. The application of CM during 7 years increased the soil organic carbon in the first 30cm by 5.7 and 9.9Mgha−1 with CM at 30 and 60Mgha−1, respectively, when compared to the initial stock. Thus, manure-based fertilization could be an alternative to mineral fertilizer in order to achieve high maize yields while improving soil quality under dry Mediterranean conditions.

      PubDate: 2016-12-05T09:41:44Z
       
  • Spatial distribution of soil water, soil temperature, and plant roots in a
           drip-irrigated intercropping field with plastic mulch
    • Abstract: Publication date: February 2017
      Source:European Journal of Agronomy, Volume 83
      Author(s): Xianyue Li, Jiří Šimůnek, Haibin Shi, Jianwen Yan, Zunyuan Peng, Xuewen Gong
      Intercropping and drip irrigation with plastic mulch are two agricultural practices used worldwide. Coupling of these two practices may further increase crop yields and land and water use efficiencies when an optimal spatial distribution of soil water contents (SWC), soil temperatures, and plant roots is achieved. However, this coupling causes the distribution of SWCs, soil temperatures, and plant roots to be more complex than when only one of these agricultural practices are used. The objective of this study thus was to investigate the effects of different irrigation treatments on spatial distributions of SWCs, soil temperatures, and root growth in a drip-irrigated intercropping field with plastic mulch. Three field experiments with different irrigation treatments (high T1, moderate T2, and low T3) were conducted to evaluate the spatial distribution of SWCs, soil temperatures, and plant roots with respect to dripper lines and plant locations. There were significant differences (p <0.05) in SWCs in the 0–40cm soil layer for different irrigation treatments and between different locations. The maximum SWC was measured under the plant/mulch for the T1 treatment, while the minimum SWC was measured under the bare soil surface for the T3 treatment. This was mainly due to the location of drippers and mulch. However, no differences in SWCs were measured in the 60100cm soil layer. Significant differences in soil temperatures were measured in the 05cm soil layer between different irrigation treatments and different locations. The soil temperature in the subsoil (1525cm) under mulch was higher than under the bare surface. The overlaps of two plant root systems in an intercropping field gradually increased and then decreased during the growing season. The roots in the 030cm soil layer accounted for about 60%70% of all roots. Higher irrigation rates produced higher root length and weight densities in the 030cm soil layer and lower densities in the 30100cm soil layers. Spatial distributions of SWCs, soil temperatures, and plant roots in the intercropping field under drip irrigation were significantly influenced by irrigation treatments and plastic mulch. Collected experimental data may contribute to designing an optimal irrigation program for a drip-irrigated intercropping field with plastic mulch.

      PubDate: 2016-12-05T09:41:44Z
       
  • Sowing date and N application effects on tap root and above-ground dry
           matter of winter oilseed rape in autumn
    • Abstract: Publication date: February 2017
      Source:European Journal of Agronomy, Volume 83
      Author(s): Klaus Sieling, Ulf Böttcher, Henning Kage
      In many parts of Europe, farmers often replace winter barley by winter wheat as preceding crop for winter oilseed rape (WOSR) resulting in a delayed WOSR sowing and poor autumn growth. Based on data from a field trial running in 2009/10, 2010/1l, and 2012/13, this study aims i) to investigate how a delayed sowing impairs autumnal above-ground and tap root growth of winter WOSR and ii) to test the ability of an additional N supply in autumn to compensate for the negative effects of an unfavorable sowing date. In order to create sufficiently differentiated canopies, 4 sowing dates (first decade of August till the third decade of September) and 4 autumn N treatments (0, 30, 60, and 90kgNha−1) combined. Above-ground and tap root dry matter (DM) as well as green area index (GAI) were determined in autumn. On average of the three years, delaying sowing date significantly decreased above-ground and tap root DM accumulation and GAI of oilseed rape at the end of autumn growth. The reduction in tap root DM was more pronounced compared to that in above-ground DM. N supply in autumn significantly boosted above-ground and tap root DM. However, the N effect was less distinct compared to that of the sowing date. Green area of all autumn N treatments increased according to a logistic function, reaching its maximum at a thermal time (Tbase =3°C) of about 650°d. N supply in autumn significantly enhanced GAI formation. The current results clearly revealed that a delayed sowing date of OSR decreased both the above-ground and tap root DM. An additional N supply was only partly able to compensate for a poor autumn growth, especially that of the tap root.

      PubDate: 2016-11-28T02:21:13Z
       
  • Water and radiation use efficiencies explain the effect of potassium on
           the productivity of cassava
    • Abstract: Publication date: February 2017
      Source:European Journal of Agronomy, Volume 83
      Author(s): K.S. Ezui, A.C. Franke, P.A. Leffelaar, A. Mando, J. van Heerwaarden, J. Sanabria, J. Sogbedji, K.E. Giller
      We studied the effects of potassium (K) and its interactions with nitrogen (N), phosphorus (P) and harvest time on the productivity, water use efficiency (WUE) and radiation use efficiency (RUE) of cassava under rain-fed conditions. A field experiment was conducted during two consecutive years on K-deficient soils in Djakakope and on relatively K-rich soils in Sevekpota in Southern Togo, West Africa. Fifteen fertiliser combinations involving K and N rates of 0, 50 and 100kgha−1 each, and P rates of 0, 20 and 40kgha 1 were tested. Monthly measurements of leaf area index from 3 to 11 months after planting and daily weather data were used to estimate light interception, RUE, potential water transpiration and WUE of cassava. Overall WUE was 3.22g dry matter kg−1 water transpired and RUE was 1.16g dry matter MJ−1 intercepted photosynthetic active radiation (PAR). On the K-deficient soils, application of K increased WUE and RUE by 36–41% compared with 2.81g dry matter kg−1 water transpired and 0.92g dry matter MJ−1 intercepted PAR achieved without K, respectively. However, the effect of K on cassava growth depended on N availability. Applications of N had relatively weak effects on RUE and WUE, but induced a positive correlation between RUE/WUE and K mass fractions in the plant, and increased the cumulative amount of light intercepted by 11–51%, and the cumulative amount of water transpired through increased leaf area by 13–61%. No significant effect of P on WUE and RUE was observed. Increased cassava yields could be achieved under rain-fed conditions in West Africa through enhanced K management to increase RUE and WUE, along with sufficient N supply for improved light interception and water transpiration by the crop.

      PubDate: 2016-11-28T02:21:13Z
       
  • A new method for analyzing agricultural land-use efficiency, and its
           application in organic and conventional farming systems in southern
           Germany
    • Abstract: Publication date: February 2017
      Source:European Journal of Agronomy, Volume 83
      Author(s): Hung-Chun Lin, Kurt-Jürgen Hülsbergen
      Improving the land-use efficiency (LUE) of farming systems could satisfy increasing global food, feed, biomass and bioenergy demand in a sustainable manner. This study presents a new method for calculating LUE, beginning with an overview of different approaches to assessing agricultural LUE. This new method takes into account the quality and function of agricultural products and the relationship between the yield of the assessed farm and the average yield of the reference region with comparable soils, climate and socio-economic conditions. The new approach was tested using data from long-term experiments at the Scheyern Research Farm in southern Germany, which include different farming systems (organic mixed farming, arable farming, and agroforestry; conventional arable farming and agroforestry). In our case studies, the LUE of conventional systems (arable farming: 1.00; improved arable farming: 1.06; agroforestry: 0.98) was higher than those of the organic systems (mixed farming: 0.69; arable farming: 0.33; agroforestry: 0.43) due to different crop rotations, dry matter yields, and biomass usage (harvest ratio). The conversion of high-input arable farming systems (conventional farming) to agroforestry systems is an extensification with negative effects on the dry matter yield and land-use efficiency. Nevertheless, the conversion to agroforestry systems can increase dry matter yield and land-use efficiency in low-input arable farming systems (organic farming). LUE should be used in combination with agri-environmental indicators, in order to ensure both efficient and sustainable land use.

      PubDate: 2016-11-28T02:21:13Z
       
  • Assessment of soybean yield with altered water-related genetic improvement
           traits under climate change in Southern Brazil
    • Abstract: Publication date: February 2017
      Source:European Journal of Agronomy, Volume 83
      Author(s): Rafael Battisti, Paulo C. Sentelhas, Kenneth J. Boote, Gil M. de S. Câmara, José R.B. Farias, Claudir J. Basso
      Water deficit is a major factor responsible for soybean yield gap in Southern Brazil and tends to increase under climate change. An alternative to reduce such gap is to identify soybean cultivars with traits associated to drought tolerance. Thus, the aim of this study was to assess soybean adaptive traits to water deficit that can improve yield under current and future climates, providing guidelines for soybean cultivar breeding in Southern Brazil. The following soybean traits were manipulated in the CSM-CROPGRO-Soybean crop model: deeper root depth in the soil profile; maximum fraction of shoot dry matter diverted to root growth under water stress; early reduction of transpiration under mild stress; transpiration limited as a function of vapor pressure deficit; N2 fixation drought tolerance; and sensitivity of grain filling period to water deficit. The yields were predicted for standard and altered traits using climate data for the current (1961–2014) and future (middle-century) scenarios. The traits with greater improvement in soybean yield were deeper rooting profile, with yield gains of ≈300kgha−1, followed by transpiration limited as a function of vapor pressure deficit and less drought-induced shortening of the grain filling period. The maximum fraction of shoot dry matter diverted to root and N2 fixation drought tolerance increased yield by less than 75kgha−1, while early reduction of transpiration resulted in a small area of country showing gains. When these traits were combined, the simulations resulted in higher yield gains than using any single trait. These results show that traits associated with deeper and greater root profile in the soil, reducing transpiration under water deficit more than photosynthesis, creating tolerance of nitrogen fixation to drought, and reducing sensitivity of grain filling period to water deficit should be included in new soybean cultivars to improve soybean drought tolerance in Southern Brazil.

      PubDate: 2016-11-28T02:21:13Z
       
  • Land use intensification in the Rolling Pampa, Argentina: Diversifying
           crop sequences to increase yields and resource use
    • Abstract: Publication date: Available online 9 November 2016
      Source:European Journal of Agronomy
      Author(s): J.F. Andrade, S.L. Poggio, M. Ermácora, E.H. Satorre
      Increasing and maintaining high productivity levels presents a major challenge facing farmers today and will continue into the near future. More integrative and complex approaches to decision-making, besides adopting new technologies, are necessary for redesigning more productive, stable, and sustainable farming systems. Thus, novel crop sequences should be implemented to improve these properties of farming systems. The aim of our research was to characterize how different preceding crops that open recurrent sequences will impact on the productivity and resource use of the following crops, in order to determine the possibilities of increasing the frequency of double crops in rotations. Three field experiments were conducted under rainfed conditions at three sites in the Rolling Pampas of Argentina. The effects of seven cropping systems on the productivity of succeeding crops were evaluated at each location. The seven cropping systems included five double crops (rapeseed/soybean, wheat/soybean, barley/soybean, field pea/soybean, and field pea/maize) and two single crops (maize and soybean). The seven cropping systems were followed by the same crop sequence: wheat/soybean double crop and maize single crop in the first and second growing seasons, respectively. Radiation use and grain yield, water use and nitrogen uptake were evaluated for each crop in the sequence. Results indicate that repeating cereal crops in the cropping sequence reduces their productivities, while well balanced sequences that include legumes resulted in the highest productivities of cereal crops. Our findings highlight that diversifying cropping systems by adopting different double crops are practical options that can contribute to a more sustainable intensification of cropping systems specialized for grain crops. Increasing crop diversity in sequence influenced nitrogen uptake, among other factors, and may explain the enhanced crop yield in such systems. Our research highlights that crop diversification is critical in designing efficient and sustainable intensified crop sequences.

      PubDate: 2016-11-14T09:49:20Z
       
  • Effect of input management on yield and energy balance of cardoon crop
           systems in Mediterranean environment
    • Abstract: Publication date: Available online 7 November 2016
      Source:European Journal of Agronomy
      Author(s): Paola A. Deligios, Leonardo Sulas, Ester Spissu, Giovanni Antonio Re, Roberta Farci, Luigi Ledda
      Sustainable cardoon (Cynara cardunculus L. var. altilis DC.) production system need to be developed to become a large-scale dedicated energy crop. Two field experiments were carried out in Italy to investigate the effects of management intensities and crop age on yield (biomass and seed), thermochemical traits, and energy efficiency of cardoon crops. The first experiment (Exp. 1) was based on the comparison of two crop management intensities (conventional chemical inputs and tillage, CT; reduced chemical inputs and tillage, LI), and it lasted five years. The second experiment (Exp. 2) lasted three years and evaluated two crop densities (standard density, SD; high density, HD). In Exp. 1, CT system performed better than LI for all analyzed agronomic traits. The average net energy yield of CT (157.7GJha−1) was significantly higher compared with LI (103.1GJha−1). The different crop densities in Exp. 2 did not influence seed yield and plant survival in the first and third year. Higher energy surpluses were found for HD than SD, due to the relatively high energy output. Our results also indicate that in less favorable soils at the Exp. 1, conventional management ensures better crop growth and energy budget, whereas in deep soils (Exp. 2), promising results could be obtained combining no N input with adjusted crop density.

      PubDate: 2016-11-14T09:49:20Z
       
  • Partial root-zone drying irrigation in orange orchards: Effects on water
           use and crop production characteristics
    • Abstract: Publication date: Available online 7 November 2016
      Source:European Journal of Agronomy
      Author(s): S. Consoli, F. Stagno, D. Vanella, J. Boaga, G. Cassiani, G. Roccuzzo
      We have studied the effects of partial root-zone drying (PRD) on plant physiological response, plant-soil water dynamics, yield and fruit quality of young orange trees during the irrigation seasons 2013 and 2014 in an orchard located in Eastern Sicily (Southern Italy). The irrigation treatments included: (i) full irrigation (T1), with trees irrigated by supplying 100% of crop water demand using micro-irrigation systems; and (ii) alternate partial root-zone drying (T4), with trees irrigated at 50% of crop water demand. Minimally invasive electrical resistivity tomography (ERT) was adopted to help quantify root-water-uptake (RWU) processes at the finer (decimetric) spatial scale. Results show that, compared with the full irrigation treatment, PRD at 50% of crop water demand (ETc) increased the fruit yield by 20% in 2013 and 10% in 2014. The PRD irrigation treatment, which induces a reduction of the wetted soil volumes, had also obvious positive effects on water use efficiency (WUE), compared to full irrigation. From the results of this study, we concluded that when water resources are limited, PRD at 50% level of ETc is an efficient water saving strategy to increase WUE, while other physiological and growth parameters are practically unaffected.

      PubDate: 2016-11-14T09:49:20Z
       
  • Growth and yield formation of sugar beet (Beta vulgaris L.) under strip
           tillage compared to full width tillage on silt loam soil in Central Europe
           
    • Abstract: Publication date: Available online 9 November 2016
      Source:European Journal of Agronomy
      Author(s): Daniel Laufer, Heinz-Josef Koch
      On silt loam sites in Central Europe, autumn strip tillage (ST) might offer an option to produce high sugar beet yields at lower costs and improved erosion control compared to full width tillage practices. Three field trials were conducted in 2013/14 and 2014/15 at Göttingen, Lower Saxony, Germany, to investigate the effect of three tillage systems (intensive tillage (IT), reduced tillage (RT), ST) and two fertilizer nitrogen levels (no fertilizer nitrogen (N0), fertilizer nitrogen required for optimum yield (Nopt)) on sugar beet growth. Compared to IT and RT, field emergence period under ST was prolonged by 5-7days, which was presumably caused by a coarse and uneven seedbed. In the early growth stage, chlorophyll present in the leaves (SPAD value) was higher for IT and RT compared to ST, indicating a lower nitrogen supply for ST, especially under N0. This was supported by a slightly higher nitrogen concentration in the plant dry matter and a higher soil mineral nitrogen content in spring under IT and RT compared to ST. Leaf area index of sugar beet was almost equal between IT and RT, while values for ST tended to be lower. As a result, plant dry matter yield and white sugar yield were approximately 7 % higher for IT and RT compared to ST. Plant nitrogen uptake revealed a similar pattern, thus, nitrogen use efficiency was not affected by tillage systems. Penetration resistance and root length density in the top soil revealed no relation to the difference in yield. It was concluded that both, the prolonged field emergence period and the lower nitrogen supply under ST possibly impaired a rapid development of an adequate leaf canopy that facilitates efficient light interception and a high yield.

      PubDate: 2016-11-14T09:49:20Z
       
  • Impact of spatio-temporal shade dynamics on wheat growth and yield,
           perspectives for temperate agroforestry
    • Abstract: Publication date: Available online 8 November 2016
      Source:European Journal of Agronomy
      Author(s): Sidonie Artru, Sarah Garré, Christian Dupraz, Marie-Pierre Hiel, Céline Blitz-Frayret, Ludivine Lassois
      A stumbling block to the adoption of silvoarable agroforestry systems is the lack of quantitative knowledge on the performance of different crops when competing for resources with trees. In North-Western Europe, light is likely to be the principal limiting resource for understorey crops, and most agronomic studies show a systematic reduction of final yield as shade increases. However the intensity of the crop response depends on both the environmental conditions and the shade characteristics. This study addressed the issue by monitoring winter wheat (Triticum aestivum L.) growth, productivity and quality under artificial shade provided by military camouflage shade-netting, and using the Hi-sAFe model to relate the artificial shade conditions to those applying in agroforestry systems. The field experiment was carried out over two consecutive years (2013–14 and 2014–15) on the experimental farm of Gembloux Agro-Bio Tech, Belgium. The shade structures recreated two shade conditions: periodic shade (PS) and continuous shade (CS), with the former using overlapping military camouflage netting to provide discontinuous light through the day, and the latter using conventional shade cloth. The experiment simulated shading from a canopy of late-flushing hybrid walnut leaves above winter wheat. Shading was imposed 16 (2013–14) and 10 (2014–15) days before flowering and retained until harvest. The crop experienced full light conditions until the maximum leaf area index stage (LAImax) had been reached. In both years, LAI followed the same dynamics between the different treatments, but in 2013–2014 an attack of the take-all disease (Gaeumannomyces graminis var. tritici) reduced yields overall and prevented significant treatment effects. In season 2014–15 the decrease in global radiation reaching the crop during a period of 66days (CS: – 61% and PS: – 43%) significantly affected final yield (CS: – 45% and PS: – 25%), mainly through a reduction of the average grain weight and the number of grain per m2. Grain protein content increased by up to 45% under the CS treatment in 2015. Nevertheless, at the plot scale, protein yield (t/ha) did not compensate for the final grain yield decrease. The Hi-sAFe model was used to simulate an agroforestry plot with two lines of walnut trees running either north-south or east-west. The levels of artificial shade levels applied in this experiment were compared to those predicted beneath trees growing with similar climatic conditions in Belgium. The levels used in the CS treatment are only likely to occur real agroforestry conditions on 10% of the cropped area until the trees are 30 years old and only with east-west tree row orientation.

      PubDate: 2016-11-14T09:49:20Z
       
  • Spatial and temporal uncertainty of crop yield aggregations
    • Abstract: Publication date: Available online 31 October 2016
      Source:European Journal of Agronomy
      Author(s): Vera Porwollik, Christoph Müller, Joshua Elliott, James Chryssanthacopoulos, Toshichika Iizumi, Deepak K. Ray, Alex C. Ruane, Almut Arneth, Juraj Balkovič, Philippe Ciais, Delphine Deryng, Christian Folberth, Roberto C. Izaurralde, Curtis D. Jones, Nikolay Khabarov, Peter J. Lawrence, Wenfeng Liu, Thomas A.M. Pugh, Ashwan Reddy, Gen Sakurai, Erwin Schmid, Xuhui Wang, Allard de Wit, Xiuchen Wu
      The aggregation of simulated gridded crop yields to national or regional scale requires information on temporal and spatial patterns of crop-specific harvested areas. This analysis estimates the uncertainty of simulated gridded yield time series related to the aggregation with four different harvested area data sets. We compare aggregated yield time series from the Global Gridded Crop Model Intercomparison project for four crop types from 14 models at global, national, and regional scale to determine aggregation-driven differences in mean yields and temporal patterns as measures of uncertainty. The quantity and spatial patterns of harvested areas differ for individual crops among the four data sets applied for the aggregation. Also simulated spatial yield patterns differ among the 14 models. These differences in harvested areas and simulated yield patterns lead to differences in aggregated productivity estimates, both in mean yield and in the temporal dynamics. Among the four investigated crops, wheat yield (17% relative difference) is most affected by the uncertainty introduced by the aggregation at the global scale. The correlation of temporal patterns of global aggregated yield time series can be as low as for soybean (r=0.28). For the majority of countries, mean relative differences of nationally aggregated yields account for 10% or less. The spatial and temporal difference can be substantial higher for individual countries. Of the top-10 crop producers, aggregated national multi-annual mean relative difference of yields can be up to 67% (maize, South Africa), 43% (wheat, Pakistan), 51% (rice, Japan), and 427% (soybean, Bolivia). Correlations of differently aggregated yield time series can be as low as r=0.56 (maize, India), r=0.05 (wheat, Russia), r=0.13 (rice, Vietnam), and r=−0.01 (soybean, Uruguay). The aggregation to sub-national scale in comparison to country scale shows that spatial uncertainties can cancel out in countries with large harvested areas per crop type. We conclude that the aggregation uncertainty can be substantial for crop productivity and production estimations in the context of food security, impact assessment, and model evaluation exercises.

      PubDate: 2016-11-07T09:30:10Z
       
  • Comparison of regression techniques to predict response of oilseed rape
           yield to variation in climatic conditions in Denmark
    • Abstract: Publication date: Available online 31 October 2016
      Source:European Journal of Agronomy
      Author(s): Behzad Sharif, David Makowski, Finn Plauborg, Jørgen E. Olesen
      Statistical regression models represent alternatives to process-based dynamic models for predicting the response of crop yields to variation in climatic conditions. Regression models can be used to quantify the effect of change in temperature and precipitation on yields. However, it is difficult to identify the most relevant input variables that should be included in regression models due to the high number of candidate variables and to their correlations. This paper compares several regression techniques for modeling response of winter oilseed rape yield to a high number of correlated input variables. Several statistical regression methods were fitted to a dataset including 689 observations of winter oilseed rape yield from replicated field experiments conducted in 239 sites in Denmark, covering nearly all regions of the country from 1992 to 2013. Regression methods were compared by cross-validation. The regression methods leading to the most accurate yield predictions were Lasso and Elastic Net, and the least accurate methods were ordinary least squares and stepwise regression. Partial least squares and ridge regression methods gave intermediate results. The estimated relative yield change for a +1°C temperature increase during flowering was estimated to range between 0 and +6 %, depending on choice of regression method. Precipitation was found to have an adverse effect on yield during autumn and winter. It was estimated that an increase in precipitation of +1 mm/day would result in a relative yield change ranging from 0 to −4 %. Soil type was also important for crop yields with lower yields on sandy soils compared to loamy soils. Later sowing was found to result in increased crop yield. The estimated effect of climate on yield was highly sensitive to the chosen regression method. Regression models showing similar performance led in some cases to different conclusions with respect to effect of temperature and precipitation. Hence, it is recommended to apply an ensemble of regression models, in order to account for the sensitivity of the data driven models for projecting crop yield under climate change.

      PubDate: 2016-11-07T09:30:10Z
       
  • Designing future barley ideotypes using a crop model ensemble
    • Abstract: Publication date: Available online 6 November 2016
      Source:European Journal of Agronomy
      Author(s): Fulu Tao, Reimund P. Rötter, Taru Palosuo, C.G.H. Díaz-Ambrona, M. Inés Mínguez, Mikhail A. Semenov, Kurt Christian Kersebaum, Claas Nendel, Davide Cammarano, Holger Hoffmann, Frank Ewert, Anaelle Dambreville, Pierre Martre, Lucía Rodríguez, Margarita Ruiz-Ramos, Thomas Gaiser, Jukka G. Höhn, Tapio Salo, Roberto Ferrise, Marco Bindi, Alan H. Schulman
      Climate change and its associated higher frequency and severity of adverse weather events require genotypic adaptation. Process-based ecophysiological modelling offers a powerful means to better target and accelerate development of new crop cultivars. Barley (Hordeum vulgare L.) is an important crop throughout the world, and a good model for study of the genetics of stress adaptation because many quantitative trait loci and candidate genes for biotic and abiotic stress tolerance have been identified in it. Here, we developed a new approach to design future crop ideotypes using an ensemble of eight barley simulation models (i.e. APSIM, CropSyst, HERMES, MCWLA, MONICA, SIMPLACE, SiriusQuality, and WOFOST), and applied it to design climate-resilient barley ideotypes for Boreal and Mediterranean climatic zones in Europe. The results showed that specific barley genotypes, represented by sets of cultivar parameters in the crop models, could be promising under future climate change conditions, resulting in increased yields and low inter-annual yield variability. In contrast, other genotypes could result in substantial yield declines. The most favorable climate-zone-specific barley ideotypes were further proposed, having combinations of several key genetic traits in terms of phenology, leaf growth, photosynthesis, drought tolerance, and grain formation. For both Boreal and Mediterranean climatic zones, barley ideotypes under future climatic conditions should have a longer reproductive growing period, lower leaf senescence rate, larger radiation use efficiency or maximum assimilation rate, and higher drought tolerance. Such characteristics can produce substantial positive impacts on yields under contrasting conditions. Moreover, barley ideotypes should have a low photoperiod and high vernalization sensitivity for the Boreal climatic zone; for the Mediterranean, in contrast, it should have a low photoperiod and low vernalization sensitivity. The drought-tolerance trait is more beneficial for the Mediterranean than for the Boreal climatic zone. Our study demonstrates a sound approach to design future barley ideotypes based on an ensemble of well-tested, diverse crop models and on integration of knowledge from multiple disciplines. The robustness of model-aided ideotypes design can be further enhanced by continuously improving crop models and enhancing information exchange between modellers, agro-meteorologists, geneticists, physiologists, and plant breeders.

      PubDate: 2016-11-07T09:30:10Z
       
  • Diversity of methodologies to experiment Integrated Pest Management in
           arable cropping systems: Analysis and reflections based on a European
           network
    • Abstract: Publication date: Available online 31 October 2016
      Source:European Journal of Agronomy
      Author(s): Martin Lechenet, Violaine Deytieux, Daniele Antichi, Jean-Noël Aubertot, Paolo Bàrberi, Michel Bertrand, Vincent Cellier, Raphaël Charles, Caroline Colnenne-David, Silke Dachbrodt-Saaydeh, Philippe Debaeke, Thierry Doré, Pascal Farcy, César Fernandez-Quintanilla, Gilles Grandeau, Cathy Hawes, Lionel Jouy, Eric Justes, Roman Kierzek, Per Kudsk, Jay Ram Lamichhane, Françoise Lescourret, Marco Mazzoncini, Bo Melander, Antoine Messéan, Anna-Camilla Moonen, Adrian C. Newton, Jean-Marie Nolot, Silvia Panozzo, Patrick Retaureau, Maurizio Sattin, Juergen Schwarz, Clotilde Toqué, Vasileios P. Vasileiadis, Nicolas Munier-Jolain
      Integrated Pest Management (IPM) aims to promote physical and biological regulation strategies that help farmers contain populations of pests (pathogens, animal pests and weeds) and to finally reduce the reliance on pesticides. It is based on the holistic combination of multiple management measures rather than on the sum of single methods, each of them having only small effects on pests reduction. Thus, to analyse the interactions between IPM measures and to evaluate the sustainability of their implementation, we require an approach considering the whole cropping system (CS), i.e. a functional entity whose complexity is more than the sum of its parts. A network of European experiments at the CS level was set up recently, and aimed at sharing data and expertise to enhance knowledge of IPM. Comparison of existing methodologies highlighted a diversity of CS designs and experimental layouts. We deduced that the concept of CS itself was viewed differently among scientists, and this affected experimental protocols. Other differences were related to the research context and objectives. Some experiments aimed to explore very innovative strategies and generated knowledge on both their effects on the agroecosystem and their ability to satisfy a set of performance targets, while others aimed to provide quickly adoptable solutions for local farmers in line with the current socio-economic constraints. In some research programmes, the experiment was part of the CS design process — and tested CS were regularly revised based on an continuous improvement loop — while in other cases CS were kept stable across years so as to enable the evaluation of their long-term cumulative effects. A critical aspect contributing to the diversity among CS experiments was the distinction between a factorial design of experimental CS and systemic approaches: factorial experiments allowed quantification of the effects of each IPM component regardless of the consistency between components defining the CS. In contrast, systemic approaches focused on the overall evaluation of CS designed with consideration of their consistency, hence maximising their ability to meet the objectives. Because CS experiments represent a huge investment in terms of economics and time, preliminary reflections of the relevance of the experimental strategy is of critical importance.

      PubDate: 2016-11-07T09:30:10Z
       
  • Separating the confounding effects of farming practices on weeds and
           winter wheat production using path modelling
    • Abstract: Publication date: Available online 27 October 2016
      Source:European Journal of Agronomy
      Author(s): Maude Quinio, Mélanie De Waele, Fabrice Dessaint, Luc Biju-Duval, Marc Buthiot, Emilie Cadet, Ann K. Bybee-Finley, Jean-Philippe Guillemin, Stéphane Cordeau
      Optimal crop yield can be achieved directly by optimizing farming practices to increase crop growth and indirectly by optimizing pest management to decrease pest pressure. The aim of this study was to quantify the indirect effect of farming practices on yield through a change of the weed pressure and, thereby, disentangle the effect of farming practices on yield and weeds. Between 2006 and 2012 in Burgundy, France, 152 winter wheat fields were surveyed for weeds and farmers were interviewed about their farming practices and yields. Data were analysed using partial least square path modelling (PLS-PM). A path model that related farming intensity (fallow management, sowing, chemical pest control and fertilization), crop productivity (yield), and weed pressure was designed and validated. It was then used to assess the relationships between the identified variables (β path coefficients) and compare groups of fields varying in, the preceding crop, herbicide use and weed pressure in the field. Farming intensity had a positive effect on crop productivity (β=0.32). Weed pressure negatively impacted crop productivity (β=−0.12). Farming intensity decreased weed pressure and had a sufficiently negative effect on weeds (β=−0.19) to counteract the negative impact of weeds on crop productivity. Therefore, the indirect effect of farming intensity on crop productivity through a change of weed pressure was positive and accounted for 7% of the total (direct+indirect) effect of farming intensity on crop productivity. The indirect effect of farming intensity on crop productivity varied by preceding crop (3.6% and 23% with a winter and spring/summer preceding crop, respectively) and herbicide use (14.1% and 2.1% when herbicide use was less and more than the regional reference, respectively) and weed pressure (0.5% and 2.6% when the total weed abundance after weeding was less and more than 2 individualsm−2, respectively). From the path model, we quantified the direct and indirect effects of farming intensity on crop productivity to show that effective weed management can sustain crop production in cropping systems with reduced herbicide use.

      PubDate: 2016-10-30T21:49:42Z
       
  • Effect of preceding crop on the agronomic and economic performance of
           durum wheat in the transition from conventional to reduced tillage
    • Abstract: Publication date: Available online 27 October 2016
      Source:European Journal of Agronomy
      Author(s): Laura Ercoli, Alessandro Masoni, Marco Mariotti, Silvia Pampana, Elisa Pellegrino, Iduna Arduini
      Preceding crop greatly affects the agronomic and economic performance of durum wheat, but its interaction with tillage intensity was scarcely investigated at the early transition from conventional to reduced tillage. This work was aimed at studying how preceding crop determines the performance of durum wheat during the early transition from conventional to reduced tillage. To this end, the effect of four preceding crops (sunflower, durum wheat, alfalfa and maize) in interaction with two tillage systems without inversion (RT1 – chisel ploughing, disking twice, and harrowing and RT2 – disking twice and harrowing) and a conventional tillage (CT – mouldboard ploughing, disking twice, and harrowing) was studied on durum wheat in two years of cultivation. The effect of preceding crop on grain yield and yield components of durum wheat was different depending on tillage intensity, and this effect varied depending on the year of cultivation. Grain yield increased by 1.1–4.2tha−1 with the increase of the intensity of tillage in both years and all preceding crops, with the only exception of wheat crop following sunflower in 2009–2010 and following maize in 2010–2011. RT2 decreased wheat grain yield when compared with RT1 only with alfalfa as preceding crop. Differences in grain yield among tillage systems and crops preceding wheat in both years were mainly due to variations of mean kernel weight and number of spikes per unit area. The profitability of durum wheat varied according to the year of cultivation, the preceding crop and the tillage system. Overall, in both years profitability was lowest and negative following wheat under reduced tillage system, while it was highest and positive following alfalfa under CT. Reduced growth of durum wheat with reduced tillage systems was mainly consequence of weeds and volunteers plants development and nitrogen availability in soil resulting from nutrient immobilization. It can be concluded that potential yield penalties in durum wheat in the transition from conventional to reduced tillage can be alleviated by an appropriate selection of preceding crops.

      PubDate: 2016-10-30T21:49:42Z
       
  • Maternal environment and dormancy in sunflower: The effect of temperature
           during fruit development
    • Abstract: Publication date: Available online 25 October 2016
      Source:European Journal of Agronomy
      Author(s): María Paula Bodrone, María Verónica Rodríguez, Sebastián Arisnabarreta, Diego Batlla
      A rapid and uniform germination in the field is an important requirement for commercial hybrid sunflower seed. Persistence of dormancy after harvest can negatively affect this aspect of seed quality, and seed lots with some degree of dormancy cannot be commercialized. Seed dormancy intensity and duration can vary greatly among sunflower genotypes, but it is also subject to strong interactions with the maternal environment. In this paper we report results of investigations into the effect of temperature during sunflower fruit development on the level of dormancy after harvest. After conducting controlled (greenhouse) and field experiments (sowing dates and plastic tents), we found that higher temperatures during later stages of achene development significantly increased the level of dormancy at harvest and its persistence during storage. The impact of the maternal (thermal) environment on embryo and coat-imposed dormancy was also investigated. Results showed that although maturation under warmer environments reduced embryo dormancy, this effect was overcompensated for by the enhancement of inhibition imposed by the pericarp and the seed coat. In addition, the results obtained suggest that observed changes in dormancy in response to the maternal environment could be at least partially explained by changes in achene and/or embryo sensitivity to ABA. Results presented here should be useful when choosing a proper environment for the production of hybrid sunflower seed of high quality, avoiding high temperatures during later stages of fruit development.

      PubDate: 2016-10-30T21:49:42Z
       
  • From grid to field: Assessing quality of gridded weather data for
           agricultural applications
    • Abstract: Publication date: Available online 27 October 2016
      Source:European Journal of Agronomy
      Author(s): Spyridon Mourtzinis, Juan I. Rattalino Edreira, Shawn P. Conley, Patricio Grassini
      High quality measured weather data (MWD) are not available in many agricultural regions across the globe. As a result, many studies that dealt with global climate change, land use, and food security scenarios and emerging agricultural decision support tools have relied on gridded weather data (GWD) to estimate crop phenology and crop yields. An issue is the agreement of GWD with MWD and the degree to which this agreement may influence the utility of GWD for agricultural research. The objectives of this study were: (i) to compare the agreement of two widely used gridded weather databases (GWDs) (Daymet and PRISM) and MWD, (ii) to evaluate their robustness at simulating maize growth and development, and (iii) to examine how GWD compare relative to weather data interpolated from existing meteorological stations for which MWD are available. The U.S. Corn Belt, a region that accounts for 43 and 34% of respective global maize and soybean production, was used as a case of study because of its dense weather station network and high-quality MWD. Historical daily MWD were retrieved from 45 locations across the region, resulting in ca. 1300 site-years. To test the accuracy of GWDs, separate simulations of maize yield and development were performed, separately for the two GWDs and MWD, using a well-validated maize crop model. For both GWDs, small biases were observed for temperature and growing degree-days in relation with MWD. However, accuracy was much lower for relative humidity, precipitation, reference evapotranspiration, and degree of seasonal water deficit. There was close agreement in duration of vegetative and reproductive phases between GWD and MWD, with root mean square error (RMSE) ranging from 3 to 7days for the different crop phases and GWDs. However, robustness of GWDs to reproduce maize yields simulated using MWD was lower as indicated by the RMSE (18 and 24% of average yield for Daymet and PRISM, respectively). There was also a high proportion of site-years (20 and 32% for Daymet and PRISM, respectively) exhibiting a yield deviation >15% in relation to the yield simulated using MWD. Data interpolation using a dense weather station network resulted in lower RMSE% for simulated phenology and yields relative to GWDs. Findings from this study indicate that GWD cannot replace MWD as a basis for field-scale agricultural applications. While GWD appear to be robust for applications that only require temperature for prediction of crop stages, GWD should not be used for applications that depend on accurate estimation of crop water balance, crop growth, and yield. We propose that the evaluation performed in this study should be taken as a routinary activity for any research or agricultural decision tool that relies on GWD.

      PubDate: 2016-10-30T21:49:42Z
       
  • PhenoGlad: A model for simulating development in Gladiolus
    • Abstract: Publication date: Available online 17 October 2016
      Source:European Journal of Agronomy
      Author(s): Lilian Osmari Uhlmann, Nereu Augusto Streck, Camila Coelho Becker, Natalia Teixeira Schwab, Rômulo Pulcinelli Benedetti, Andrea Schwertner Charão, Bruna San Martin Rolim Ribeiro, Waleska Bolson Silveira, Fernanda Alice Antonello Londero Backes, Cleber Maus Alberto, Martina Muttoni, Gizelli Moiano de Paula, Regina Tomiozzo, Leosane Cristina Bosco, Dislaine Becker
      Crop simulation models are important tools to help farmers in planning management practices and flowering time of cut flowers, like Gladiolus (Gladiolus x grandiflorus Hort.). The objective of this study was to develop a robust Gladiolus phenology model, named PhenoGlad, for field applications. The model describes the timing of developmental stages, including harvest point, the vase life of Gladiolus spikes and the low (chilling) and high (heat) temperature effects on spike quality. The Gladiolus developmental model simulates on a daily basis the cumulative leaf number and the phenology using a non-linear temperature response function and genotype-specific coefficients considering three main phases: corms sprouting phase, vegetative phase, and reproductive phase. Data from nine field experiments conducted during five years (2011–2015) in three locations across the Rio Grande do Sul State and in one location in Santa Catarina State, Brazil, were used. These cultivar x planting dates x years x locations experiments provided a rich data set for parameterizing and evaluating the Gladiolus model. The PhenoGlad model accurately simulated the dynamics of leaf development, final leaf number and the timing of developmental stages among cultivars, planting dates, years and locations, with an overall RMSE of 0.5 leaves for leaf development and final leaf number, 6.5days for the date of reproductive developmental stages, and 1.3days for simulating the vase life of harvested spikes. PhenoGlad was also accurate in predicting the effects of chilling and high temperatures damage on florets.

      PubDate: 2016-10-25T00:19:59Z
       
  • Organ-specific approaches describing crop growth of winter oilseed rape
           under optimal and N-limited conditions
    • Abstract: Publication date: Available online 19 October 2016
      Source:European Journal of Agronomy
      Author(s): Wiebke Weymann, Klaus Sieling, Henning Kage
      Carbon and nitrogen partitioning of winter oilseed rape differs under optimal and nitrogen (N) limited conditions. The quantitative description of these processes and their response to N deficiency is a prerequisite to develop process-oriented crop growth models capable to predict responses to a limited N supply. Dry matter (DM) partitioning, N dynamics and expansion of leaf, stem and pod area, as well as specific leaf area of oilseed rape were recorded during six seasons 2003/04–2005/06, and 2009/10, 2010/11 and 2012/13 within two series of field trials with varying N treatments at the experimental site Hohenschulen, northern Germany. DM partitioning is analysed using allometric relationships between leaf and stem DM as well as between stem and generative DM. The allometric relations between leaf and stem DM varied before and after beginning of stem elongation due to increasing DM allocation to stems during stem elongation. Allometric relations between DM fractions, however, were not affected by N treatment. N dilution curves, describing relations between N concentration and DM, differed between plant fractions, growth stages and N fertilization levels and indicated different response patterns under N limited conditions. This result is supported by relations between N amount and DM of leaves and stems, suggesting a sink priority for leaves under N deficiency. The approaches, describing green area expansion, dry matter partitioning and N distribution, can be used to improve dynamic crop growth models for oilseed rape.

      PubDate: 2016-10-25T00:19:59Z
       
  • Differences in the impacts of nighttime warming on crop growth of
           rice-based cropping systems under field conditions
    • Abstract: Publication date: Available online 20 October 2016
      Source:European Journal of Agronomy
      Author(s): Jin Chen, Changing Chen, Yunlu Tian, Xin Zhang, Wenjun Dong, Bin Zhang, Jun Zhang, Chengyan Zheng, Aixing Deng, Zhenwei Song, Chunrui Peng, Weijian Zhang
      Great attentions have been taken to the effects of climatic warming on crop production, however, fewer were known about the actual impacts of nighttime warming under different cropping systems. Therefore, a three-year field experiment with a passive nighttime warming (PNW) facility and a one-year field experiment with free air temperature increase (FATI) facility were conducted in major Chinese rice cropping systems. Four-year field observations from different rice cropping systems all showed that nighttime warming less than 1.0°C could shorten the length of crop pre-flowering phase period while prolonged the length of post-flowering phase period, resulting in insignificant reduction in the length of crop entire growth period. The temperature increase caused significant increments in grain yields by 16.2, 12.7 and 12.0% for late rice in the rice–rice cropping system, wheat in the rice-wheat cropping system and rice in the single rice cropping system, respectively. However, this warming declined grain yields significantly by 4.5 and 6.5% for early rice in the rice–rice cropping system and rice in the rice-wheat cropping system, respectively. Since warming-induced yield reduction was less than warming-induced increment in each cropping system, the annual yields was higher in the warmed plots than the non-warmed under all systems. Our findings can provide important references to cropping system adjustment for coping with global warming in China and other regions.

      PubDate: 2016-10-25T00:19:59Z
       
  • Remotely assessing leaf N uptake in winter wheat based on canopy
           hyperspectral red-edge absorption
    • Abstract: Publication date: Available online 22 October 2016
      Source:European Journal of Agronomy
      Author(s): Bin-Bin Guo, Shuang-Li Qi, Ya-Rong Heng, Jian-Zhao Duan, Hai-Yan Zhang, Ya-Peng Wu, Wei Feng, Ying-Xin Xie, Yun-Ji Zhu
      Remote sensing is a rapid, non-destructive method for assessing crop nitrogen (N) status. In this research, we investigated the quantitative relationship between leaf N uptake and ground-based canopy hyperspectral reflectance in winter wheat (Triticum aestivum L.). We conducted field experiments over four years at different sites (Xinyang, Zhengzhou and Shangshui) in Henan, China using different N application rates, growth stages and wheat cultivars and developed a novel spectral index with improved predictive capacity for leaf N uptake estimation. Sixteen vegetation indices in the publications were examined for their reliability in monitoring leaf N uptake in winter wheat. Linear regression was integrated with optimized common indices DIDA and SDr/SDb to investigate the dynamic nature of leaf N uptake, which resulted in coefficients of determination (R2 ) of 0.816 and 0.807 and root mean square error (RMSE) of 1.707 and 1.767, respectively. Our novel area index, designated shifting red-edge absorption area (sREA), was constructed according to analysis of the red-edge characteristics and area-based algorithm with the formula: s R E A = 1 2 × ( R 680 + Δ λ − R 680 ) × Δ λ , Δ λ = 320 × D 725 + 140 × D 756 − 140 × D 680 7 × D 700 + 4 × D 725 . This index is highly correlated with leaf N uptake (highest R2 =0.831; lowest RMSE=1.556). On the whole, calculation of R2 and RMSE confirmed that sREA prediction models were better than optimized common indices for 16 out of 17 datasets across growing seasons, sites, N rates, cultivars and stages. Fitting independent data to the equations resulted in RE values of 19.6%, 18.8%, 17.6% and 16.2% between measured and estimated leaf N uptake values for RSI(D740, D522), SDr/SDb, DIDA and sREA, respectively, further confirming the superior test performance of sREA. These models can therefore be used to accurately predict leaf N uptake in winter wheat. The novel index sREA is superior for evaluating leaf N status on a regional scale in heterogeneous fields under variable climatic conditions.

      PubDate: 2016-10-25T00:19:59Z
       
  • Crop rotation effects on yield, technological quality and yield stability
           of sugar beet after 45 trial years
    • Abstract: Publication date: Available online 22 October 2016
      Source:European Journal of Agronomy
      Author(s): Philipp Götze, Jan Rücknagel, Monika Wensch-Dorendorf, Bernward Märländer, Olaf Christen
      Long-term field trials constitute an essential basis for research into the effects of agricultural management practices on yield and soil properties. The long-term field trial Etzdorf (Germany) was set up in 1970 and uses various crop rotations with sugar beets (Beta vulgaris L., SB) to investigate the influence of increasing cropping concentrations (20 %–100 %) and decreasing cropping intervals (0–4 years) on the yield and quality parameters of SB. However, evaluation of the yield stability of SB in diverse crop rotations has not been conducted in this context so far. For this reason, the yield for the last 13 years of the trial (2002 until 2014) was subjected to such an evaluation. Besides cropping interval and cropping concentration, the crop rotations investigated also differed in terms of the complementary crops cultivated (winter wheat, Triticum aestivum L.; alfalfa, Medicago ssp.; potato, Solanum tuberosum L. and grain maize, Zea mays L.). Both SB root yield and white sugar yield increased with an increasing cropping interval or decreasing cropping concentration of SB in the crop rotation. In addition, a positive effect on root yield and white sugar yield was seen when integrating alfalfa, while cultivating SB after SB displayed the lowest root yield and white sugar yield. Sugar content was lowest in SB monoculture. In order to assess stability of white sugar yield, the coefficient of variation and ecovalence were calculated, and a linear regression analysis of the individual crop rotations’ annual yield was performed for the annual average of all crop rotations. When considering these three parameters, the crop rotations with a cropping interval of at least 2 years displayed higher yield stability, with simultaneously higher white sugar yield, than the crop rotations with a cropping interval of 0 and 1year. By integrating alfalfa into the crop rotation, it was also possible to achieve above-average white sugar yield with high yield stability for a cropping interval of 1year.

      PubDate: 2016-10-25T00:19:59Z
       
  • Linking process-based potato models with light reflectance data: Does
           model complexity enhance yield prediction accuracy?
    • Abstract: Publication date: Available online 23 October 2016
      Source:European Journal of Agronomy
      Author(s): R. Quiroz, H. Loayza, C. Barreda, C. Gavilán, A. Posadas, D.A. Ramírez
      Data acquisition for parameterization is one of the most important limitations for the use of potato crop growth models. Non-destructive techniques such as remote sensing for gathering required data could circumvent this limitation. Our goal was to analyze the effects of incorporating ground-based spectral canopy reflectance data into two light interception models with different complexity. A dynamic- hourly scale- canopy photosynthesis model (DCPM), based on a non-rectangular hyperbola applied to sunlit and shaded leaf layers and considering carbon losses by respiration, was implemented (complex model). Parameters included the light extinction coefficient, the proportion of light transmitted by leaves, the fraction of incident diffuse photosynthetically active radiation and leaf area index. On the other hand, a simple crop growth model (CGM) based on daily scale of light interception, light use efficiency (LUE) and harvest index was parameterized using either canopy cover (CGMCC) or the weighted difference vegetation index (CGMWDVI). A spectroradiometer, a chlorophyll meter and a multispectral camera were used to derive the required parameters. CGMWDVI improved yield prediction compared to CGMCC. Both CGMWDVI and DCPM showed high degree of accuracy in the yield prediction. Since large LUE variations were detected depending on the diffuse component of radiation, the improvement of simple CGM using remotely sensed data is contingent on an appropriate LUE estimation. Our study suggests that the incorporation of remotely sensed data in models with different temporal resolution and level of complexity improves yield prediction in potato.
      Graphical abstract image

      PubDate: 2016-10-25T00:19:59Z
       
  • Intercropping leek (Allium porrum L.) with dyer’s woad (Isatis tinctoria
           L.) increases rooted zone and agro-ecosystem retention of nitrogen
    • Abstract: Publication date: Available online 15 October 2016
      Source:European Journal of Agronomy
      Author(s): Yue Xie, Hanne Lakkenborg Kristensen
      Nitrate leaching can be high in organic vegetable production. Late-harvested crops like leek limit the use of autumn catch crops. The aim of this study was to investigate the growing of a combination of a deep-rooted catch crop and a shallow-rooted vegetable to reduce the risk of nitrate leaching. We compared a leek sole crop (S) with two intercropped systems of leek and early-sown dyer’s woad (five weeks after leek planting) (IE) or late-sown dyer’s woad (eight weeks after leek planting) (IL) in two seasons: 2012 and 2013. To reveal root and resource competition, leek with dyer’s woad rows left empty (Semp), and early and late-sown dyer’s woad with leek rows left empty (DEemp, DLemp) were included. Yield, dry above-ground biomass, aboveground N accumulation and soil inorganic N (Ninorg) were measured as well as root growth by use of minirhizotrons to 2.3m soil depth. Results showed that the marketable yield of leek in IE and IL systems was comparable with the yield in the S system when calculated per length of leek row. The Relative Competition Index (RCI) revealed that interspecific competition facilitated the growth of leek but hampered that of dyer’s woad. The rooted zone increased from 0.5m in the S system to more than 2m depth in those of the intercropped systems. Dyer’s woad ceased growing above ground but kept growing below ground after crop harvest and extended roots under the leek root system in 2012. Intercropping increased the root intensity of late-sown dyer’s woad after leek harvest in the 0.75–1.75m soil layer compared to dyer’s woad growing alone (DLemp), while the root depth was not affected. The intercropped system with early-sown dyer’s woad reduced soil Ninorg by 52kgha−1 relative to the sole-cropped system, and dyer’s woad accumulated 48kgNha−1 in aboveground biomass at harvest in 2013. Late-sown dyer’s woad had fewer roots, left higher soil Ninorg and had lower aboveground N accumulation than early-sown dyer’s woad until the following spring. Therefore, early-sown dyer’s woad is applicable in an organic intercropped system with high yields of leek to decrease the risk of nitrate leaching.

      PubDate: 2016-10-16T23:15:31Z
       
  • Yield variation of double-rice in response to climate change in Southern
           China
    • Authors: Sheng-Li Liu; Chao Pu; Yong-Xiang Ren; Xiu-Ling Zhao; Xin Zhao; Fu Chen; Xiao-Ping Xiao; Hai-Lin Zhang
      Abstract: Publication date: Available online 4 October 2016
      Source:European Journal of Agronomy
      Author(s): Sheng-Li Liu, Chao Pu, Yong-Xiang Ren, Xiu-Ling Zhao, Xin Zhao, Fu Chen, Xiao-Ping Xiao, Hai-Lin Zhang
      Food security is a major concern in China due to increasing nutritional demands, limited resources, and a changing and uncertain climate. Rice (Oryza sativa L.) plays an important role in food security, whilst its yield is greatly influenced by climate change. Thus, it is critical to quantify changes in rice yield, determine the potential climatic conditions affecting yield variation, and identify strategies to counter the effects of climate change. Historical double-rice yields and climatic variables were analyzed in the major double-rice region of Southern China. Yield varied nonlinearly in most provinces, fluctuated more for late-rice, and exhibited stagnation in 1980–2012. During the growth stages, the mean temperature (Tmean) increased significantly at 75.1% of the stations examined (P <0.05), while high inter-annual variation in precipitation (Prec) and radiation (Rad) decreased for 64.2% and 62.2% of stations. The joint effects of the three climatic variables increased yields of early- and late- rice by 0.51% and 2.83%, respectively. Climatic variation accounted for 40.04% and 29.72% of yield variability for early- and late-rice, respectively. Thus, double-rice production in Southern China is strongly affected by inter-annual climatic variation, requiring resilient farming practices to adapt to climate change and consequently enhance food security.

      PubDate: 2016-10-12T12:36:48Z
      DOI: 10.1016/j.eja.2016.09.014
       
  • Effects of shade, altitude and management on multiple ecosystem services
           in coffee agroecosystems
    • Authors: Rolando Cerda; Clémentine Allinne; Christian Gary; Philippe Tixier; Celia A. Harvey; Louise Krolczyk; Charlie Mathiot; Eugénie Clément; Jean-Noel Aubertot; Jacques Avelino
      Abstract: Publication date: Available online 6 October 2016
      Source:European Journal of Agronomy
      Author(s): Rolando Cerda, Clémentine Allinne, Christian Gary, Philippe Tixier, Celia A. Harvey, Louise Krolczyk, Charlie Mathiot, Eugénie Clément, Jean-Noel Aubertot, Jacques Avelino
      Agroforestry systems provide diverse ecosystem services that contribute to farmer livelihoods and the conservation of natural resources. Despite these known benefits, there is still limited understanding on how shade trees affect the provision of multiple ecosystem services at the same time and the potential trade-offs or synergies among them. To fill this knowledge gap, we quantified four major ecosystem services (regulation of pests and diseases; provisioning of agroforestry products; maintenance of soil fertility; and carbon sequestration) in 69 coffee agroecosystems belonging to smallholder farmers under a range of altitudes (as representative of environmental conditions) and management conditions, in the region of Turrialba, Costa Rica. We first analyzed the individual effects of altitude, types of shade and management intensity and their interactions on the provision of ecosystem services. In order to identify potential trade-offs and synergies, we then analyzed bivariate relationships between different ecosystem services, and between individual ecosystem services and plant biodiversity. We also explored which types of shade provided better levels of ecosystem services. The effectiveness of different types of shade in providing ecosystem services depended on their interactions with altitude and coffee management, with different ecosystem services responding differently to these factors. No trade-offs were found among the different ecosystem services studied or between ecosystem services and biodiversity, suggesting that it is possible to increase the provision of multiple ecosystem services at the same time. Overall, both low and highly diversified coffee agroforestry systems had better ability to provide ecosystem services than coffee monocultures in full sun. Based on our findings, we suggest that coffee agroforestry systems should be designed with diversified, productive shade canopies and managed with a medium intensity of cropping practices, with the aim of ensuring the continued provision of multiple ecosystem services.

      PubDate: 2016-10-12T12:36:48Z
      DOI: 10.1016/j.eja.2016.09.019
       
  • Quantifying model-structure- and parameter-driven uncertainties in spring
           wheat phenology prediction with Bayesian analysis
    • Authors: Phillip D. Alderman; Bryan Stanfill
      Abstract: Publication date: Available online 6 October 2016
      Source:European Journal of Agronomy
      Author(s): Phillip D. Alderman, Bryan Stanfill
      Recent international efforts have brought renewed emphasis on the comparison of different agricultural systems models. Thus far, analysis of model-ensemble simulated results has not clearly differentiated between ensemble prediction uncertainties due to model structural differences per se and those due to parameter value uncertainties. Additionally, despite increasing use of Bayesian parameter estimation approaches with field-scale crop models, inadequate attention has been given to the full posterior distributions for estimated parameters. The objectives of this study were to quantify the impact of parameter value uncertainty on prediction uncertainty for modeling spring wheat phenology using Bayesian analysis and to assess the relative contributions of model-structure-driven and parameter-value-driven uncertainty to overall prediction uncertainty. This study used a random walk Metropolis algorithm to estimate parameters for 30 spring wheat genotypes using nine phenology models based on multi-location trial data for days to heading and days to maturity. Across all cases, parameter-driven uncertainty accounted for between 19 and 52% of predictive uncertainty, while model-structure-driven uncertainty accounted for between 12 and 64%. This study demonstrated the importance of quantifying both model-structure- and parameter-value-driven uncertainty when assessing overall prediction uncertainty in modeling spring wheat phenology. More generally, Bayesian parameter estimation provided a useful framework for quantifying and analyzing sources of prediction uncertainty.

      PubDate: 2016-10-12T12:36:48Z
      DOI: 10.1016/j.eja.2016.09.016
       
  • Biotic and abiotic factors impacting establishment and growth of relay
           intercropped forage legumes
    • Authors: Sylvain Vrignon-Brenas; Florian Celette Piquet-Pissaloux Christophe David
      Abstract: Publication date: Available online 4 October 2016
      Source:European Journal of Agronomy
      Author(s): Sylvain Vrignon-Brenas, Florian Celette, Agnès Piquet-Pissaloux, Christophe David
      In organic agriculture, weeds and nitrogen deficiency are the main factors that limit crop production. The use of relay-intercropped forage legumes may be a way of providing ecological services such as weed control, increasing N availability in the cropping system thanks to N fixation, reducing N leaching and supplying nitrogen to the following crop. However, these ecological services vary considerably depending on the forage legume biomass. The aim of this study was to identify factors that affect forage legume establishment and growth to help farmers adjust the management of the cover crop. Sixteen field experiments were conducted over a period of five years. In each experiment, winter wheat was grown as sole crop or intercropped with one of two species of forage legumes; Trifolium repens L. or Trifolium pratense L. After the intercropping stage, the cover crop was maintained until the end of winter and then destroyed by plowing before maize was sown. Climatic conditions, and the accumulation of legume and weed biomass were monitored from when the legume was sown to destruction of the cover crop. Our results showed that a minimum threshold of about 500kgha−1 biomass in the aboveground parts of the cover crop was needed at the end of intercropping to obtain the minimum biomass of 2000kgha−1 in September necessary to guarantee ecological services. To obtain sufficient legume biomass at the end of intercropping period, a thermal time greater than 1900°Cd and more rainfall than 300mm are required for legume growth. Moreover, a legume density of at least of 300 plants per square meter at the wheat flowering stage was a good indicator of legume biomass at the end of the intercropping period. Rainfall was a limiting factor of legume growth between the end of the intercropping period and September. Legume density at wheat flowering and climatic conditions during the intercropping period thus appear to be good indicators to predict to capacity of cover crop to produce sufficient biomass in September. These indicators can be used by farmers as a management tool for the cover crop.

      PubDate: 2016-10-04T13:38:58Z
       
 
 
JournalTOCs
School of Mathematical and Computer Sciences
Heriot-Watt University
Edinburgh, EH14 4AS, UK
Email: journaltocs@hw.ac.uk
Tel: +00 44 (0)131 4513762
Fax: +00 44 (0)131 4513327
 
Home (Search)
Subjects A-Z
Publishers A-Z
Customise
APIs
Your IP address: 50.16.52.237
 
About JournalTOCs
API
Help
News (blog, publications)
JournalTOCs on Twitter   JournalTOCs on Facebook

JournalTOCs © 2009-2016