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  Subjects -> AGRICULTURE (Total: 775 journals)
    - AGRICULTURAL ECONOMICS (68 journals)
    - AGRICULTURE (539 journals)
    - CROP PRODUCTION AND SOIL (94 journals)
    - DAIRYING AND DAIRY PRODUCTS (28 journals)
    - POULTRY AND LIVESTOCK (46 journals)

AGRICULTURE (539 journals)

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Journal Cover European Journal of Agronomy
  [SJR: 1.488]   [H-I: 75]   [10 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 1161-0301
   Published by Elsevier Homepage  [3042 journals]
  • Improved persistence of red clover (Trifolium pratense L.) increases the
           
    • Abstract: Publication date: September 2017
      Source:European Journal of Agronomy, Volume 89
      Author(s): A.H. Marshall, R.P. Collins, J. Vale, M. Lowe
      UK livestock agriculture can significantly reduce its protein imports by increasing the amount of forage based protein grown on-farm. Forage legumes such as red clover (Trifolium pratense L.) produce high dry matter yields of quality forage but currently available varieties lack persistence, particularly under grazing. To assess the impact of red clover persistence on protein yield, diploid red clover populations selected for improved persistence were compared with a range of commercially available varieties. All populations were grown over four harvest years in mixed swards with either perennial ryegrass (Lolium perenne L.) or perennial plus hybrid ryegrass (L. boucheanum Kunth). Red clover and total sward dry matter (DM) herbage yields were measured in Years 1–4, red clover plant survival in Years 3 and 4 and herbage protein (CP) yield and concentration in Years 2 and 4. In general, red clover DM yield in year 4 (3.4tha−1) was lower than in year 1 (13.9tha−1) but the red clover populations differed in the extent of this decline. Differences in the persistence of the red clover populations in terms of plant survival and yield were reflected in the contribution of red clover to the total sward yield in Year 4, which ranged from 61% for the highest yielding population, AberClaret, to 11% in the lowest yielding, Vivi. Increased red clover DM yield was reflected in a greater CP yield (protein weight per unit area), which ranged from 1.6tha−1 year−1 to 2.9tha−1 year−1 in Year 2 and from 1.1tha−1 year−1 to 1.9tha−1 year−1 in Year 4. CP concentration (protein weight per unit herbage weight) of all of the red clover populations was within a range considered suitable for ruminant production. The implication of these results for the future use of red clover in sustainable grassland systems is discussed.

      PubDate: 2017-06-22T09:17:34Z
       
  • Inside Front Cover - Editorial Board Page/Cover image legend if applicable
    • Abstract: Publication date: July 2017
      Source:European Journal of Agronomy, Volume 87


      PubDate: 2017-06-22T09:17:34Z
       
  • Early nitrogen deficiencies favor high yield, grain protein content and N
           use efficiency in wheat
    • Abstract: Publication date: September 2017
      Source:European Journal of Agronomy, Volume 89
      Author(s): Clémence Ravier, Jean-Marc Meynard, Jean-Pierre Cohan, Philippe Gate, Marie-Hélène Jeuffroy
      Nitrogen fertilization has been widely studied in wheat (Triticum aestivum L.), with a view to maximizing local yields and obtaining high grain protein contents. It has long been accepted that nitrogen nutrition must be non-limiting throughout the crop cycle for these targets to be reached. However, studies over the last 20 years have shown that some periods of N deficiency are detrimental, whereas others have no impact on grain yield. There is, therefore, still a need to define the precise N deficiency path that can be tolerated. Nitrogen nutrition index (NNI) is an appropriate indicator of N deficiency. Based on experiments with wheat crops showing various patterns of NNI dynamics from the start of stem elongation to flowering, we aimed to identify a minimum nitrogen nutrition path, including periods of N deficiency, defining the threshold above which there is no detrimental impact on wheat crop yield. We used experimental data from 18 site-year experiments, each including 1–14 cultivars and 2–8 fertilization strategies, with determinations of crop NNI at four growth stages (Z30, Z32, Z39 and Z60 on the Zadoks scale). Experimental treatments were assigned to two groups: those with and without yield loss due to N fertilization strategy, relative to the maximum yield in each trial. Using receiver operating characteristics curve analysis, we identified the NNI path best distinguishing between the two groups of treatments. We found that the lowest acceptable NNI value (i.e. the lowest value for which there was no yield loss), increased during the crop cycle. We characterized, for the cultivars studied, periods of N deficiency during vegetative growth that did not lead to a decrease in yield or grain protein content, and even some periods in which the deficiency improved nitrogen use efficiency. Finally, we concluded that references in NNI should be revised for more efficient N management and the threshold NNI path could be used to determine timing of N fertilizer application on the basis of real-time crop N status monitoring.

      PubDate: 2017-06-16T07:31:30Z
       
  • Inside Front Cover - Editorial Board Page/Cover image legend if applicable
    • Abstract: Publication date: August 2017
      Source:European Journal of Agronomy, Volume 88


      PubDate: 2017-06-12T14:36:38Z
       
  • Quantifying model-structure- and parameter-driven uncertainties in spring
           wheat phenology prediction with Bayesian analysis
    • Abstract: Publication date: August 2017
      Source:European Journal of Agronomy, Volume 88
      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: 2017-06-12T14:36:38Z
       
  • Spatial and temporal uncertainty of crop yield aggregations
    • Abstract: Publication date: August 2017
      Source:European Journal of Agronomy, Volume 88
      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: 2017-06-12T14:36:38Z
       
  • Multi-model simulation of soil temperature, soil water content and biomass
           in Euro-Mediterranean grasslands: Uncertainties and ensemble performance
    • Abstract: Publication date: August 2017
      Source:European Journal of Agronomy, Volume 88
      Author(s): R. Sándor, Z. Barcza, M. Acutis, L. Doro, D. Hidy, M. Köchy, J. Minet, E. Lellei-Kovács, S. Ma, A. Perego, S. Rolinski, F. Ruget, M. Sanna, G. Seddaiu, L. Wu, G. Bellocchi
      This study presents results from a major grassland model intercomparison exercise, and highlights the main challenges faced in the implementation of a multi-model ensemble prediction system in grasslands. Nine, independently developed simulation models linking climate, soil, vegetation and management to grassland biogeochemical cycles and production were compared in a simulation of soil water content (SWC) and soil temperature (ST) in the topsoil, and of biomass production. The results were assessed against SWC and ST data from five observational grassland sites representing a range of conditions – Grillenburg in Germany, Laqueuille in France with both extensive and intensive management, Monte Bondone in Italy and Oensingen in Switzerland – and against yield measurements from the same sites and other experimental grassland sites in Europe and Israel. We present a comparison of model estimates from individual models to the multi-model ensemble (represented by multi-model median: MMM). With calibration (seven out of nine models), the performances were acceptable for weekly-aggregated ST (R2 >0.7 with individual models and >0.8–0.9 with MMM), but less satisfactory with SWC (R2 <0.6 with individual models and <∼0.5 with MMM) and biomass (R2 <∼0.3 with both individual models and MMM). With individual models, maximum biases of about −5°C for ST, −0.3m3 m−3 for SWC and 360gDMm−2 for yield, as well as negative modelling efficiencies and some high relative root mean square errors indicate low model performance, especially for biomass. We also found substantial discrepancies across different models, indicating considerable uncertainties regarding the simulation of grassland processes. The multi-model approach allowed for improved performance, but further progress is strongly needed in the way models represent processes in managed grassland systems.

      PubDate: 2017-06-12T14:36:38Z
       
  • Impact analysis of climate data aggregation at different spatial scales on
           simulated net primary productivity for croplands
    • Abstract: Publication date: August 2017
      Source:European Journal of Agronomy, Volume 88
      Author(s): Matthias Kuhnert, Jagadeesh Yeluripati, Pete Smith, Holger Hoffmann, Marcel van Oijen, Julie Constantin, Elsa Coucheney, Rene Dechow, Henrik Eckersten, Thomas Gaiser, Balász Grosz, Edwin Haas, Kurt-Christian Kersebaum, Ralf Kiese, Steffen Klatt, Elisabet Lewan, Claas Nendel, Helene Raynal, Carmen Sosa, Xenia Specka, Edmar Teixeira, Enli Wang, Lutz Weihermüller, Gang Zhao, Zhigan Zhao, Stephen Ogle, Frank Ewert
      For spatial crop and agro-systems modelling, there is often a discrepancy between the scale of measured driving data and the target resolution. Spatial data aggregation is often necessary, which can introduce additional uncertainty into the simulation results. Previous studies have shown that climate data aggregation has little effect on simulation of phenological stages, but effects on net primary production (NPP) might still be expected through changing the length of the growing season and the period of grain filling. This study investigates the impact of spatial climate data aggregation on NPP simulation results, applying eleven different models for the same study region (∼34,000km2), situated in Western Germany. To isolate effects of climate, soil data and management were assumed to be constant over the entire study area and over the entire study period of 29 years. Two crops, winter wheat and silage maize, were tested as monocultures. Compared to the impact of climate data aggregation on yield, the effect on NPP is in a similar range, but is slightly lower, with only small impacts on averages over the entire simulation period and study region. Maximum differences between the five scales in the range of 1–100km grid cells show changes of 0.4–7.8% and 0.0–4.8% for wheat and maize, respectively, whereas the simulated potential NPP averages of the models show a wide range (1.9–4.2gCm−2 d−1 and 2.7–6.1gCm−2 d−1 for wheat and maize, respectively). The impact of the spatial aggregation was also tested for shorter time periods, to see if impacts over shorter periods attenuate over longer periods. The results show larger impacts for single years (up to 9.4% for wheat and up to 13.6% for maize). An analysis of extreme weather conditions shows an aggregation effect in vulnerability up to 12.8% and 15.5% between the different resolutions for wheat and maize, respectively. Simulations of NPP averages over larger areas (e.g. regional scale) and longer time periods (several years) are relatively insensitive to climate data aggregation. However, the scale of climate data is more relevant for impacts on annual averages of NPP or if the period is strongly affected or dominated by drought stress. There should be an awareness of the greater uncertainty for the NPP values in these situations if data are not available at high resolution. On the other hand, the results suggest that there is no need to simulate at high resolution for long term regional NPP averages based on the simplified assumptions (soil and management constant in time and space) used in this study.

      PubDate: 2017-06-12T14:36:38Z
       
  • Accounting for both parameter and model structure uncertainty in crop
           model predictions of phenology: A case study on rice
    • Abstract: Publication date: August 2017
      Source:European Journal of Agronomy, Volume 88
      Author(s): Daniel Wallach, Sarath P. Nissanka, Asha S. Karunaratne, W.M.W. Weerakoon, Peter J. Thorburn, Kenneth J. Boote, James W. Jones
      We consider predictions of the impact of climate warming on rice development times in Sri Lanka. The major emphasis is on the uncertainty of the predictions, and in particular on the estimation of mean squared error of prediction. Three contributions to mean squared error are considered. The first is parameter uncertainty that results from model calibration. To take proper account of the complex data structure, generalized least squares is used to estimate the parameters and the variance-covariance matrix of the parameter estimators. The second contribution is model structure uncertainty, which we estimate using two different models. An ANOVA analysis is used to separate the contributions of parameter and model uncertainty to mean squared error. The third contribution is model error, which is estimated using hindcasts. Mean squared error of prediction of time from emergence to maturity, for baseline +2°C, is estimated as 108days2, with model error contributing 86days2, followed by model structure uncertainty which contributes 15days2 and parameter uncertainty which contributes 7days2. We also show how prediction uncertainty is reduced if prediction concerns development time averaged over years, or the difference in development time between baseline and warmer temperatures.

      PubDate: 2017-06-12T14:36:38Z
       
  • Improved evaluation of field experiments by accounting for inherent soil
           variability
    • Abstract: Publication date: September 2017
      Source:European Journal of Agronomy, Volume 89
      Author(s): K. Heil, U. Schmidhalter
      Well-controlled field experiments are used to test agronomic management practices and evaluate the performance of cultivars in highly managed plots at experimental stations, in breeding nurseries or on-farm. However, the performance of crops and therefore the interpretation of experiments is affected by the inherent soil variability. To avoid large residual errors, replicate measurements or optimized designs are usually helpful but seldom adequately consider the unknown soil variability. The use of spatial covariates, such as proximally sensed data, in the statistical modelling of the target variable may provide a better estimate of such experimental residual variations (errors). Therefore, the purpose of this study was to determine whether the apparent soil electrical conductivity, topographical parameters and location information (expressed as Gauß-Krüger coordinates) could be used for an enhanced spatial and temporal characterization of the long-term and annual wheat yields within a static, long-term nitrogen fertilizer experiment that included six different forms of nitrogen and three levels of nitrogen fertilizer. Furthermore, this investigation aimed to propose statistical strategies for analysing this background variation by testing ANOVA (Analysis of variance) and ANCOVA (Analysis of covariance). ANCOVA with soil ECa, location information and topographic parameters as covariates improved the accuracy of the yield estimates of the multi-annual means for all treatments. Without these independent variables in ANOVA, the coefficient of determination (R2) was smaller and the root mean square difference (RMSD) was larger than those of ANCOVA (fertilized plots ANOVA: R2 =0.19, RMSD=3.26 dt ha−1; ANCOVA: R2 =0.87, RMSD=1.29 dt ha−1). In addition to the factor level of fertilization and form of nitrogen fertilizer, ECa was the dominant covariate for the averaged long-term and annual yields. The ECa was measured with different sensors and configurations and represented a significant independent variable. Of the topographic relief parameters, the predictor plancurvature was the dominant independent variable. The inclusion of plot-wise, time-invariant soil and relief parameters significantly improved the discrimination of testing the treatment performance within the long-term field trial. A further application of this approach to other experimental sites and breeding nurseries would likely be highly rewarding.

      PubDate: 2017-06-06T19:02:08Z
       
  • Modelling phenological and agronomic adaptation options for narrow-leafed
           lupins in the southern grainbelt of Western Australia
    • Abstract: Publication date: Available online 1 June 2017
      Source:European Journal of Agronomy
      Author(s): Chao Chen, Andrew Fletcher, Roger Lawes, Jens Berger, Michael Robertson
      Australian modern narrow-leafed lupin (Lupinus angustifolius L.) cultivars tend to flower early and are vernalisation-unresponsive (VU). Cultivars have generally been selected for the warmer climates zones and sandy soils of the northern grain belt of Western Australia (NWA), where lupins are predominantly grown. In areas where climates are cooler and growing seasons are longer and wetter, such as the southern grain belt of Western Australia (SWA), it is probable that lupin would have a higher yield potential. Given that VU cultivars would have a longer vegetative phase (i.e. late flowering) we hypothesise that they may be more productive than those that are early flowering. Here we used a modelling approach to: 1) test the hypothesis that cool-climate SWA would have higher lupin yield than warm-climate NWA; 2) explore lupin phenological adaptation and yield potential in SWA over a range of proposed VU cultivars; and 3) further evaluate the combined effects of cultivar phenology, sowing time and seasonal type on lupin yields. Simulations from the Agricultural Production Systems Simulator (APSIM) showed that, on average, lupin yield in SWA was higher than that in NWA, with 23% greater yield for the early-flowering cultivar Mandelup. Proposed cultivars flowering 22days (late-flowering) and 15days (medium flowering) later than Mandelup would have their phenology better adapted in the high and medium rainfall zones of SWA, producing 16 and 7% more grain in the two rainfall zones, respectively. The proposed late-flowering cultivar sown before the end of April achieved higher yields for all seasons in the high rainfall zone and for above average and average rainfall seasons in the medium rainfall zone. In more water-limited situations early sowing was preferable with no obvious difference in yield among cultivars. Despite this, the early-flowering cultivar yielded more when sown in late April. The results indicate that lupin production would benefit from breeding VU varieties with a long vegetative phase for the SWA that should be sown in mid to late April.

      PubDate: 2017-06-06T19:02:08Z
       
  • Zinc biofortification of wheat through preceding crop residue
           incorporation into the soil
    • Abstract: Publication date: Available online 29 May 2017
      Source:European Journal of Agronomy
      Author(s): Amir Hossein Khoshgoftarmanesh, Mojtaba Norouzi, Majid Afyuni, Rainer Schulin
      We conducted a two-year field experiment to investigate the potential benefit of preceding crop residue incorporation into the soil as a strategy to enhance the density of bioavailable grain zinc (Zn) in a subsequent wheat (Triticum aestivum L.) crop. Sunflower (Heilianthus annuus L. cv. Allstar), sorghum (Sorghum bicolor L. cv. Speed Feed), clover (Trifolium pratense L.) and safflower (Carthamus tinctorius L. cv. Koseh-e-Isfahan) were grown as preceding crop (precrop) on a Zn-deficient calcareous soil in central Iran, followed by a culture of two wheat cultivars i.e., Kavir and Back Cross Rushan. The harvested aboveground plant matter was air-dried, crushed into pieces of 0.5–2cm size, mixed, and after taking a sample for analysis, incorporated manually into the upper 15cm of the soil of one half of the same plot from which it had been harvested, while the other half received no residues. The aboveground residues of precrops were incorporated into soil or removed. A treatment with no preceding crop (fallow) and no residue incorporation, but with the same management otherwise, was implemented as control treatment. For both wheat cultivars studied, higher grain yield was obtained after clover (between 14 and 25.6%) and sunflower (between 11.3 and 19.5%) than that after safflower, sorghum and the fallow. All precrop treatments significantly increased the accumulation of grain Zn and N and decreased the phytic-acid-to-Zn (PA:Zn) molar ratio (by 5–41% in Kavir and by 11–48% in Back Cross), most effectively the clover treatment. The treatment effects on grain Zn were closely correlated with soil pH and dissolved soil organic carbon (DOC). The results show that the cultivation of appropriate precrops, especially legumes, can be an effective strategy to biofortify wheat grains with Zn without compromising yields.

      PubDate: 2017-06-01T18:54:49Z
       
  • Modelling productivity and resource use efficiency for grassland
           ecosystems in the UK
    • Abstract: Publication date: Available online 24 May 2017
      Source:European Journal of Agronomy
      Author(s): Aiming Qi, Philip J. Murray, Goetz M. Richter
      Estimating spatially resolved grassland productivity is essential for benchmarking the total UK productive potential to assess food, feed and fuel trade-offs in the context of whole systems analyses. Our objectives were to adapt and evaluate a well-known process-based model (PBM) and estimate productivity of improved (permanent, temporary) and semi-natural grassland systems using meta-models (MM) trained by extensive PBM scenario simulations. Observed dry matter (DM) yields in multi-site nitrogen (N) response (0, 150 and 300kgNha−1) experiments were well emulated describing the average productivity of rough grazing, permanent and temporary grassland (3.1, 7.4 and 9.8tDMha−1, respectively). Cross-validated with independent and long-term data (Park Grass Experiment), the PBM explained more variation when considering all systems combined (81%) than across all improved grasslands (61%) but little for rough grazing (26%). The PBM-trained MMs explained 48, 72 and 70% of the simulated yield variation in the grasslands of increasing management intensity, and 43 and 75% of observed variation in the combined improved and all three grassland systems, respectively. Considering the assessment of ecosystem services, like drainage and water productivity, PBM scenario simulations are essential. Compared to improved grassland rough grazing will result in 40% more groundwater recharge due to its lower simulated water use and water productivity (12 versus 25 and 43kgha−1 mm−1 for permanent and temporary grassland, respectively).

      PubDate: 2017-05-28T03:54:02Z
       
  • Yield, growth and grain nitrogen response to elevated CO2 in six lentil
           (Lens culinaris) cultivars grown under Free Air CO2 Enrichment (FACE) in a
           semi-arid environment
    • Abstract: Publication date: July 2017
      Source:European Journal of Agronomy, Volume 87
      Author(s): M. Bourgault, J. Brand, S. Tausz-Posch, R.D. Armstrong, G.L. O’Leary, G.J. Fitzgerald, M. Tausz
      Atmospheric CO2 concentrations ([CO2]) are predicted to increase from current levels of about 400ppm to reach 550ppm by 2050. The direct benefits of elevated [CO2] (e[CO2]) to plant growth appear to be greater under low rainfall conditions, but there are few field (Free Air CO2 Enrichment or FACE) experimental set-ups that directly address semi-arid conditions. The objectives of this study were to investigate the following research questions: 1) What are the effects of e[CO2] on the growth and grain yield of lentil (Lens culinaris) grown under semi-arid conditions under FACE? 2) Does e[CO2] decrease grain nitrogen in lentil? and 3) Is there genotypic variability in the response to e[CO2] in lentil cultivars? Elevated [CO2] increased yields by approximately 0.5tha−1 (relative increase ranging from 18 to 138%) by increasing both biomass accumulation (by 32%) and the harvest index (by up to 60%). However, the relative response of grain yield to e[CO2] was not consistently greater under dry conditions and might depend on water availability post-flowering. Grain nitrogen concentration was significantly reduced by e[CO2] under the conditions of this experiment. No differences were found between the cultivars selected in the response to elevated [CO2] for grain yield or any other parameters observed despite well expressed genotypic variability in many traits of interest. Biomass accumulation from flowering to maturity was considerably increased by elevated [CO2] (a 50% increase) which suggests that the indeterminate growth habit of lentils provides vegetative sinks in addition to reproductive sinks during the grain-filling period.

      PubDate: 2017-05-22T18:45:30Z
       
  • A methodology for multi-objective cropping system design based on
           simulations. Application to weed management
    • Abstract: Publication date: July 2017
      Source:European Journal of Agronomy, Volume 87
      Author(s): Nathalie Colbach, Floriane Colas, Olivia Pointurier, Wilfried Queyrel, Jean Villerd
      Weeds are harmful for crop production but important for biodiversity. In order to design cropping systems that reconcile crop production and biodiversity, we need tools and methods to help farmers to deal with this issue. Here, we developed a novel method for multi-objective cropping system design aimed at scientists and technical institutes, combining a cropping system database, decision trees, the “virtual field” model FlorSys and indicators translating simulated weed floras into scores in terms of weed harmfulness (e.g. crop yield loss, weed-borne parasite risk, field infestation), weed-mediated biodiversity (e.g. food offer for bees) and herbicide use intensity. 255 existing cropping systems were simulated with FlorSys, individual indicator values were aggregated into a multi-performance score, and decision trees were built to identify combinations of management practices and probabilities for reaching performance goals. These trees are used to identify the characteristics of existing cropping systems that must be changed to achieve the chosen performance goals, depending on the user's risk strategy. Alternative systems are built and simulated with FlorSys to evaluate their multi-criteria performance. The method was applied to an existing oilseed rape/wheat/barley rotation with yearly mouldboard ploughing from Burgundy which was improved to reconcile weed harmfulness control, reduced herbicide use and biodiversity promotion, based on a risk-minimizing strategy. The best alternative replaced a herbicide entering plants via shoot tips (during emergence) and roots after barley sowing by a spring herbicide entering via leaves, introduced crop residue shredding before cereals and rolled the soil at sowing, which reduced the risk of unacceptable performance from 90% to 40%. When attempting to reconcile harmfulness control and reduced herbicide use, the best alternative changed the rotation to oilseed rape/wheat/spring pea/wheat, replaced one herbicide in oilseed rape by mechanical weeding, delayed tillage before rape and applied the PRE herbicide before oilseed rape closer to sowing. This option reduced the risk of unacceptable performance to 30%. None of the initial or alternative cropping systems succeeded in optimal performance, indicating that more diverse cropping systems with innovative management techniques and innovative combinations of techniques are needed to build the decision trees. This approach can be used in workshops with extension services and farmers in order to design cropping systems. Compared to expert-based design, it has the advantage to go beyond well-known options (e.g. plough before risky crops) to identify unconventional options, with a particular focus on interactions between cultural techniques.

      PubDate: 2017-05-22T18:45:30Z
       
  • Uncertainty from model structure is larger than that from model parameters
           in simulating rice phenology in China
    • Abstract: Publication date: July 2017
      Source:European Journal of Agronomy, Volume 87
      Author(s): Shuai Zhang, Fulu Tao, Zhao Zhang
      Rice models have been widely used in simulating and predicting rice phenology in contrasting climate zones, however the uncertainties from model structure (different equations or models) and/or model parameters were rarely investigated. Here, five rice phenological models/modules (i.e., CERES-Rice, ORYZA2000, RCM, Beta Model and SIMRIW) were applied to simulate rice phenology at 23 experimental stations from 1992 to 2009 in two major rice cultivation regions of China: the northeastern China and the southwestern China. To investigate the uncertainties from model biophysical parameters, each model was run with randomly perturbed 50 sets of parameters. The results showed that the median of ensemble simulations were better than the simulation by most models. Models couldn’t simulate well in some specific years despite of parameters optimization, suggesting model structure limit model performance in some cases. The models adopting accumulative thermal time function (e.g., CERES-Rice and ORYZA2000) had better performance in the southwestern China, in contrast, those adopting exponential function (e.g., Beta model and RCM model) had better performance in the northeastern China. In northeastern China, the contribution of model structure and model parameters to model total variance was, respectively, about 55.90% and 44.10% in simulating heading date, and about 75.43% and 24.57% in simulating maturity date. In the southwestern China, the contribution of model structure and model parameters to model total variance was, respectively, about 79.97% and 27.03% in simulating heading date, about 92.15% and 7.85% in simulating maturity date. Uncertainty from model structure was the most relevant source. The results highlight that the temperature response functions of rice development rate under extreme climate conditions should be improved based on environment-controlled experimental data.

      PubDate: 2017-05-12T18:10:59Z
       
  • Differences in gluten protein composition between old and modern durum
           wheat genotypes in relation to 20th century breeding in Italy
    • Abstract: Publication date: July 2017
      Source:European Journal of Agronomy, Volume 87
      Author(s): Michele A. De Santis, Marcella M. Giuliani, Luigia Giuzio, Pasquale De Vita, Alison Lovegrove, Peter R. Shewry, Zina Flagella
      The impact of breeding on grain yields of wheat varieties released during the 20th century has been extensively studied, whereas less information is available on the changes in gluten quality associated with effects on the amount and composition of glutenins and gliadins. In order to explore the effects of breeding during the 20th century on gluten quality of durum wheat for processing and health we have compared a set of old and modern Italian genotypes grown under Mediterranean conditions. The better technological performance observed for the modern varieties was found to be due not only to the introgression of superior alleles of high (HMW-GS) and low molecular weight (LMW-GS) glutenin subunits encoded at Glu-B1 and Glu-B3 loci, but also to differential expression of specific storage proteins. In particular, the higher gluten index observed in modern genotypes was correlated with an increased glutenin/gliadin ratio and the expression of B-type LMW-GS which was, on average, two times higher in the modern than in the old group of durum wheat genotypes. By contrast, no significant differences were found between old and modern durum wheat genotypes in relation to the expression of α-type and γ-type gliadins which are major fractions that trigger coeliac disease (CD) in susceptible individuals. Furthermore, a drastic decrease was observed in the expression of ω-type gliadins in the modern genotypes, mainly ω-5 gliadin (also known as Tri a 19) which is a major allergen in wheat dependent exercise induced anaphylaxis (WDEIA). Immunological and 2DE SDS-PAGE analyses indicated that these differences could be related either to a general down-regulation or to differences in numbers of isoforms. Lower rainfall during grain filling period was related to overall higher expression of HMW-GS and ω-gliadins. In conclusion, breeding activity carried out in Italy during the 20th century appears to have improved durum wheat gluten quality, both in relation to technological performance and allergenic potential.
      Graphical abstract image

      PubDate: 2017-05-02T09:29:55Z
       
  • Inside Front Cover - Editorial Board Page/Cover image legend if applicable
    • Abstract: Publication date: May 2017
      Source:European Journal of Agronomy, Volume 86


      PubDate: 2017-05-02T09:29:55Z
       
  • Functional identity has a stronger effect than diversity on mycorrhizal
           symbiosis and productivity of field grown organic tomato
    • Abstract: Publication date: May 2017
      Source:European Journal of Agronomy, Volume 86
      Author(s): Ezekiel Mugendi Njeru, Gionata Bocci, Luciano Avio, Cristiana Sbrana, Alessandra Turrini, Manuela Giovannetti, Paolo Bàrberi
      Beneficial soil biota, and in particular, arbuscular mycorrhizal fungi (AMF) are increasingly being recognized as key elements of organic and low-input agriculture where agrobiodiversity is central to enhanced crop production. However, the role of AMF in diversified organic systems, especially in field crops, is still poorly understood. A 3-year field experiment was carried out in Central Italy to investigate whether organic cropping systems that promote species and genetic diversity are more prone to mycorrhizal symbiosis increasing tomato growth, production and yield quality. Three tomato cultivars with varying genetic diversity were grown following four cover treatments: Indian mustard (Brassica juncea L. Czern.), hairy vetch (Vicia villosa Roth), a commercial mixture of seven cover crop species (Mix 7) and no-till fallow. Plants were either inoculated or not in nursery, with the two AMF isolates Funneliformis mosseae (IMA1) and Rhizoglomus intraradices (IMA6) used alone or mixed in a 1:1 volume ratio. On average, Mix 7 produced higher shoot dry matter (5.0tha−1) than V. villosa (3.5tha−1) or B. juncea (2.5tha−1). Pre-transplant inoculation increased tomato root colonization at flowering and harvest compared to the non inoculated plants (31.8 vs 23.6%) and cv. Rio Grande was on average the best colonized. The mean fresh weight of marketable fruits was 18.4, 28.0 and 28.6tha−1 for cvs. Rio Grande, Roma and Perfect Peel, respectively. Cover crops inconsistently affected tomato marketable fruit production in year 1, while in years 2 and 3, Vicia villosa and Mix 7 showed the best effect respectively. In year 3, among the pre-inoculated plants those treated with isolate IMA6 showed a higher production of marketable fruit number m−2 (56.7) than those inoculated either with IMA1 (51.5) or the mixed inocula (52.1). Most fruit quality parameters were affected by tomato genotype. This study shows that while increased agrobiodiversity is important to increase agroecosystem resilience, AMF, crop and cover crop functional identity may be more important than diversity per se to promote mycorrhizal symbiosis and productivity of field grown organic tomato.

      PubDate: 2017-05-02T09:29:55Z
       
  • A RVI/LAI-reference curve to detect N stress and guide N fertigation using
           combined information from spectral reflectance and leaf area measurements
           in potato
    • Abstract: Publication date: July 2017
      Source:European Journal of Agronomy, Volume 87
      Author(s): Zhenjiang Zhou, Finn Plauborg, Anton G. Thomsen, Mathias Neumann Andersen
      More user-friendly methods are needed to detect crop N status/stress and guide the timing of in-season N application. In the current study, a reference curve method of detecting N stress was proposed to remedy practical problems of methods that require leaf sampling or maintaining a N sufficient strip in the field. The reference curve method was derived from the integrated information of ratio vegetation index (RVI) and leaf area index (LAI), which were obtained from field experimental potato crops. Different N treatments received 42kgNha−1 at planting and, subsequently, the rest of N was applied during the season. The total N ranged from 0 to180kgNha−1. RVI and LAI from the economically optimum 180kgNha−1 treatments were used to derive the reference curve. RVI and LAI from 180kgNha−1 treatment had a high (R2 =0.97) correlation and were best fitted with a 2nd order polynomial function, which was independent of season. The treatments where N fertigation was stopped before reaching 180kgNha−1 started to deviate from the 95% confidence interval of the reference curve about 10days after N-fertigation was stopped. This corresponded to 10–20kgha−1 difference in total plant N uptake between reference and the N deprived treatments, implying that a deviation from the reference curve occurred for small N deficits. Besides, running crop simulation model to alert for impendent N stress closely corresponded to the reference curve and was recommended as a second management tool. Therefore two tools are hereby made available to guide supplementary N-fertilization. These will be helpful in regional potato production for diagnosis of N status, and allow discrimination between situations of sub-optimal and optimal N supply.

      PubDate: 2017-04-18T09:05:41Z
       
  • Radiation use efficiency, chemical composition, and methane yield of
           biogas crops under rainfed and irrigated conditions
    • Abstract: Publication date: July 2017
      Source:European Journal of Agronomy, Volume 87
      Author(s): Burkhard Schoo, Henning Kage, Siegfried Schittenhelm
      For biomethane production, the cup plant (Silphium perfoliatum L.) is considered a promising alternative substrate to silage maize (Zea mays L.) due to its high biomass potential and associated ecological and environmental benefits. It has also been suggested to grow cup plant on less productive soils because of its presumed drought tolerance, but robust information on the impact of water shortage on biomass growth and substrate quality of cup plant is rare. Therefore, this study assesses the effects of soil water availability on the chemical composition and specific methane yield (SMY) of cup plant. Furthermore above-ground dry matter yield (DMY) was analysed as a function of intercepted photosynthetic active radiation (PAR) and radiation use efficiency (RUE). Data were collected in a two-year field experiment under rainfed and irrigated conditions with cup plant, maize, and lucerne-grass (Medicago sativa L., Festuca pratensis Huds., Phleum pratense L.). The cup plant revealed a slight decrease of −6% in the SMY in response to water shortage (less than 50% of plant available water capacity). The average SMY of cup plant [306l (kg volatile solids (VS))−1] was lower than that of maize [362l (kg VS)−1] and lucerne-grass [334l (kg VS)−1]. The mean drought-related reduction of the methane hectare yield (MHY) was significantly greater for cup plant (−40%) than for maize (−17%) and lucerne-grass (−13%). The DMY reduction in rainfed cup plant was mainly attributed to a more severe decrease in RUE (−29%) than for maize (−16%) and lucerne-grass (−12%). Under water stress, the mean cup plant RUE (1.3gMJ−1) was significantly lower than that of maize (2.9gMJ−1) and lucerne-grass (1.4gMJ−1). Compared to RUE, the reduced PAR interception was less meaningful for DMY in rainfed crops. Hence, the cup plant is not suitable for growing on drought prone lands due to its high water demand required to produce reasonably high MHYs.

      PubDate: 2017-04-18T09:05:41Z
       
  • White clover living mulch reduces the need for phosphorus fertilizer
           application to corn
    • Abstract: Publication date: May 2017
      Source:European Journal of Agronomy, Volume 86
      Author(s): Shin Deguchi, Sunao Uozumi, Eiko Touno, Hiroshi Uchino, Makoto Kaneko, Keitaro Tawaraya
      White clover living mulch (LM) increases the uptake of phosphorus (P) and the yield of the main crop by promoting the colonization of arbuscular mycorrhiza (AM). However, the extent to which the P fertilizer application rate can be reduced by using LM is not yet known. This study aimed to address this question. Two field experiments were conducted from 2008 to 2009 (Experiment 1) and from 2009 to 2010 (Experiment 2) at the fields where the available P of soil fluctuated near the lower limit of the optimum P level (43.6mgkg−1: Truog method). Experiment 1 had a randomized block design, and Experiment 2 had a split-plot design with a factorial arrangement of two cropping systems (LM and no LM) with three P application treatments (0kgha−1, 43.6kgha−1, and 87.3kgha−1). LM increased P concentrations in the early stages of growth and the yield of corn. This can be attributed to the increased AM colonization rate in the early stages of growth. The yield and total digestible nutrient yield of corn in LM with no P application was comparable to the maximum yield in no LM with or without P application. Therefore, LM could make unnecessary P fertilization in soils where P fertilization is required for silage corn.

      PubDate: 2017-04-18T09:05:41Z
       
  • Cytokinins: A key player in determining differences in patterns of canopy
           senescence in Stay-Green and Fast Dry-Down sunflower (Helianthus annuus
           L.) hybrids
    • Abstract: Publication date: May 2017
      Source:European Journal of Agronomy, Volume 86
      Author(s): Mariano A. Mangieri, Antonio J. Hall, Gustavo G. Striker, Claudio A. Chimenti
      Leaf senescence during grain filling can reduce crop yield. We studied, under field conditions and during grain-filling, the association between leaf cytokinin levels and the onset of leaf senescence in sunflower hybrids of contrasting canopy senescence patterns (Paraiso75, stay-green [SG] and Paraiso65, fast dry down [FDD]). At crop level, dynamics of live root length density (LRLD) and green leaf area index (GLAI) were followed, while at leaf level dynamics of total chlorophyll content, trans-Zeatin content, net photosynthesis and PSII quantum yield, were followed in leaf positions 17, 20, 22 and 24. Responses of these leaf variables to exogenous cytokinin applications to leaves at position 17 were also followed. SG exhibited greater (p<0.05) LRLD and GLAI values at anthesis. In both hybrids, LRLD began to fall before GLAI. All variables decreased earlier (p<0.05) in FDD. Initial leaf levels of trans-Zeatin were three times higher (p<0.05) in SG. Exogenous cytokinin applications maintained leaf-level variables. These are the first results showing associations between LRLD dynamics with the dynamics of leaf cytokinin levels and changes in indicators of leaf functionality. Also, this is the first study in which estimates are made of cytokinin thresholds below which leaf senescence begins in two hybrids of contrasting canopy senescence patterns. These advances in the understanding, at both crop and leaf levels, of the controls and consequences of SG during grain filling, a trait known to improve crop water uptake under drought and increase biomass accumulation during grain filling, provide support for breeding efforts aimed at profiting from this trait to increase crop yields.

      PubDate: 2017-04-10T21:57:41Z
       
  • Changes of starch composition by postflowering environmental conditions in
           kernels of maize hybrids with different endosperm hardness
    • Abstract: Publication date: May 2017
      Source:European Journal of Agronomy, Volume 86
      Author(s): R.D. Martínez, A.G. Cirilo, A. Cerrudo, F.H. Andrade, L. Reinoso, O.R. Valentinuz, C.N. Balbi, N.G Izquierdo
      Starch composition of maize grains is of great importance when used in animal feed and many processing industries. Maize production involves hybrids with different kernel composition and hardness, sown at areas that range from subtropical to temperate cold climates. Therefore, it is relevant to understand how the environment influences starch composition. The objective of this work was to analyze the effect of location and sowing date on starch composition of maize grains. Field experiments were carried out at five locations across the argentinean maize-production area during two growing seasons. At each location, two sowing dates and three hybrids differing in endosperm hardness (i.e. semi-dent, a semi-flint and flint) were evaluated. Late sowing dates reduced amylose percentage and amylose/starch ratio. This last variable increased as latitude decreased. Minimum temperature during effective grain filling period explained those latitude and sowing date effects. This finding would be helpful to estimate starch composition of maize kernels to be expected in order to satisfy specific end uses.

      PubDate: 2017-04-10T21:57:41Z
       
  • Tree-crop interactions in maize-eucalypt woodlot systems in southern
           Rwanda
    • Abstract: Publication date: May 2017
      Source:European Journal of Agronomy, Volume 86
      Author(s): C.P. Mugunga, K.E. Giller, G.M.J. Mohren
      We studied the interaction between Eucalyptus saligna woodlots and maize crop in southern Rwanda. Three sites were selected and in each, a eucalypt woodlot with mature trees and a suitable adjoining crop field of 12.75m×30m was selected. This was split into two plots of 6m×12m and further subdivided into nine sub-plots running parallel to the tree-crop interface. Maize was grown in both 6m×12m plots and one of these received fertiliser. Soil moisture, nutrients and solar radiation were significantly reduced near the woodlots, diminishing grain yield by 80% in the 10.5m crop-field strip next to the woodlot. This reduction however affects only 10.5% of the maize crop field, leaving 89.5% unaffected. Spreading the loss to a hectare crop field, leads to an actual yield loss of 0.21tha−1, equivalent to 8.4%. Expressing yield loss in tree-crop systems usually presented as a percentage of yield recorded near the trees to that obtained in open areas may be misleading. Actual yields should be reported with corresponding crop field areas affected. Variation in grain yield coincided with those for soil moisture, soil N and K; all increasing from the woodlot-maize interface up to 10.5m and remaining similar to the values in open areas thereafter. Solar radiation continued to increase with distance up to 18m from the woodlot-maize interface. Harvest index in unfertilised maize exceeded that in the fertilised treatment reflecting the crop’s strategy to allocate resources to grain production under unfavourable conditions. Fertilisation increased maize yield from 1.3–2.6tha−1 but the trend in the woodlot effects on maize remained unaltered.

      PubDate: 2017-04-10T21:57:41Z
       
  • Crop yield and energy use in organic and conventional farming: A case
           study in north-east Italy
    • Abstract: Publication date: May 2017
      Source:European Journal of Agronomy, Volume 86
      Author(s): Nicola Dal Ferro, Giuseppe Zanin, Maurizio Borin
      The role played by organic farming as an alternative system to conventional farming is widely questioned, since conflicting results on crop yields sometimes greatly affect system efficiency. As a result, prolonged monitoring studies on organic (OF) and conventional farming (CF) systems are still required, especially in real-life farm conditions, in which the entire production process is quantified. In this context, this study reports crop yields (winter wheat, maize, soybean) and energy efficiency, over a 13-year monitoring period, on a farm in north-east Italy in which two sectors are farmed following OF and CF practices. Results showed that organic yields were always lower than conventional ones, averaging 69%, although their range varied greatly over the years (from 45% to 90%) and depended on crop type. Several management constraints had effects on the lower yields, especially reduced available nutrients and cropping season, but also the timings and types of tillage operations. By contrast, OF practices usually had positive effects on the environment, due to reduced energy input mainly fertilisation (−33.4%MJha−1 y−1) and the generally higher productivity of invested energy (EOut EIn −1 =4.53 in OF and 4.28 in CF); energy use differences per product unit were mainly equal. Other factors, such as local climate and soil variability, may have influenced system performance, but as the two experimental sites were located at a distance of 3.5km from each other, the data reported here are still valuable, in that they represent the results of 13years of monitoring, during which farm management played a major role. This case study, although conducted in two separate sites, did not highlight the best overall solution at farm level, it does indicate that the agricultural systems applied would be better suited for different situations and targets (e.g., productive, energetic, ecologic).

      PubDate: 2017-03-27T19:13:49Z
       
  • Accumulation, partitioning, and bioavailability of micronutrients in
           summer maize as affected by phosphorus supply
    • Abstract: Publication date: May 2017
      Source:European Journal of Agronomy, Volume 86
      Author(s): Wei Zhang, Dun-Yi Liu, Chao Li, Xin-Ping Chen, Chun-Qin Zou
      Decreased micronutrient concentration in cereal grains caused by excessive application of phosphorus (P) fertilizer may contribute to reduce their nutritional quality. To help correct this problem in maize grain, a 3-year field experiment was conducted to determine how P application rate affects micronutrient partitioning in maize shoots and other plant organs and micronutrient bioavailability in grain. Phosphorus application significantly decreased shoot zinc (Zn) and copper (Cu) concentrations at all growth stages but had no effects on shoot iron (Fe) and manganese (Mn) concentrations. As the P application rate increased, shoot Zn and Cu contents decreased, and shoot Fe and Mn contents increased. The ratios of pre-anthesis to post-anthesis mineral contents were not affected by P application rate except Zn. P application increased the percentage of Zn that was allocated to grain and decreased the percentage that was allocated to other tissues, but had no effects on the allocation of other micronutrients among tissues. The bioavailability of Zn, Cu, Fe, and Mn in grain decreased as P application rate increased. Overall, taking account of grain yield and nutrients concentration, P fertilizer rates should range from 12.5 to 25.0kg P ha−1 under the local condition. It can be concluded that not only grain yields, but also nutritional quality, should be considered in assessing optimal P rates in maize.

      PubDate: 2017-03-27T19:13:49Z
       
  • Reduced inter-row distance improves yield and competition against weeds in
           a semi-dwarf durum wheat variety
    • Abstract: Publication date: April 2017
      Source:European Journal of Agronomy, Volume 85
      Author(s): Pasquale De Vita, Salvatore Antonio Colecchia, Ivano Pecorella, Sergio Saia
      Weed and nutrient management in cropping systems of semi-arid areas is a major constraint to cereal yield. Where the use of herbicides is banned or discouraged, the competitive ability of a crop is crucial to reduce weed growth and diffusion. Genotypic differences in the competitive abilities of crops are an important trait to reduce weeds, especially for plant height. However, there is contrasting information about the interactions of other management practices and genotypic traits on wheat yield and competitive ability against weeds and weed growth. The present study investigated yield and quality of durum wheat (Triticum durum Desf.) and weed growth and composition for two wheat cultivars with contrasting competitive abilities against weeds. Wheat was grown under three spatial arrangements (5-cm, 15-cm, 25-cm inter-row distance) and three sowing densities, and broadleaf weeds were either removed or not. The sowing rate did not affect the yield of these wheat cultivars or the weed growth. Reduced inter-row distance dramatically reduced weed biomass for both wheat cultivars, and increased wheat yield and nitrogen uptake in the low-competitive, high-yielding, semi-dwarf cv. ‘PR22D89’, when both weed free and with weeds. These results have direct implications for weed and nutrient management in low-input and organic cropping systems.

      PubDate: 2017-03-27T19:13:49Z
       
  • Long-term P and K fertilisation strategies and balances affect soil
           availability indices, crop yield depression risk and N use
    • Abstract: Publication date: May 2017
      Source:European Journal of Agronomy, Volume 86
      Author(s): Frederik van der Bom, Jakob Magid, Lars Stoumann Jensen
      The last century has seen a large increase of fertiliser use, along with a subsequent rise of crop productivity. However, in many places its intensive use has become a burden to the environment, and legislation has been introduced to restrict nutrient applications. In combination with changing production scenarios as a result of climate change, this means an improved understanding is needed of how low nutrient availability and climatic stress factors affect yields and yield stability. We examined the long-term effects mineral and organic fertilisation on a nutrient-depleted field, and observed large annual variations: depending on the year, average spring barley yields under unfertilised management (U) were between 17–75% lower than the reference N½P½K½ (60–10–60kgha−1). Yields increased up to 174% under N1P1K1 (120–20–120kgha−1), while animal manure applications at an N availability level corresponding to N1 were between 79 and 137%. No temporal yield trends could be observed, but long-term changes of Olsen-P and exchangeable K were related to the nutrient balances (inputs-offtake) (r2 =0.60 and 0.59, respectively, P <0.001). Multiple linear regression analysis was used to examine the effects of the treatments in combination with annual weather variations. The results could be split into two outcomes, 1) a general relation between yields and temperatures for the periods of early spring (P< 0.01, multiple R2 =0.31) and summer (P< 0.001, multiple R2 =0.45), and 2) an interaction between temperature and nutrient applications during crop establishment, leading to a diverse response of relative yields (P< 0.001, multiple R2 =0.64), i.e. relative yield losses under the unfertilised treatment (U) were greater in years with lower spring temperatures, and, conversely, the increased nutrient availability in the fully mineral and organically fertilised treatments could partially alleviate the negative effects. After 13 years of repeated fertilisation, inputs were suspended for a single year and only N was applied to evaluate the residual effects. Yields were significantly affected by the different fertilisation histories (P< 0.001). Likewise, apparent nitrogen recovery tended to improve with previous inputs, but the observations were highly variable. Overall, the analyses agree with the notion that brief periods of stress at a critical stage may significantly affect yields, and confirmed that management of sufficient nutrient availability is critical for maintaining high and stable yields.
      Graphical abstract image

      PubDate: 2017-03-08T17:40:10Z
       
  • Crop residue incorporation can mitigate negative climate change impacts on
           crop yield and improve water use efficiency in a semiarid environment
    • Abstract: Publication date: April 2017
      Source:European Journal of Agronomy, Volume 85
      Author(s): De Li Liu, Ketema Tilahun Zeleke, Bin Wang, Ian Macadam, Fiona Scott, Robert John Martin
      Mitigation of the deleterious impacts of climate change on agriculture is a crucial strategy for securing food resources to meet the future demand of the world with a steadily increasing population. We used a pre-validated Agricultural Production Systems sIMulator (APSIM) to explore the implementation of crop residue incorporation (RI) to mitigate the impacts of climate change on water use and crop yield for four winter crops at six sites in eastern Australia. Various residue management practices were simulated under current climate data and statistically downscaled climate data from 28 GCM simulations of RCP4.5 and RCP8.5 for the period 1900–2100. The results showed that increasing future temperature shortened crop growth duration ranged from 7.4±0.9days °C−1 for barley to 3.9±1.9days °C−1 for canola. Under projected increases in the CO2 concentration and associated climate change, the overall average crop yield for 2021–2100 in eastern Australia without RI could change by −28±5% for wheat, −22±6% for barley, −6±6% for canola and +7±17% for chickpea relative to 1951–2000 yields. With RI, crop yields could be changed by +16±14% for wheat, 11±12% for barley and 7±8% for canola and +9±17% for chickpea. Further analysis showed that greater crop transpiration was the major advantage of RI. WUE in wheat and barley also increased significantly under RI due to reduced soil evaporation and surface runoff. This effect increased under future climate changes, but the effectiveness of RI varied by location. In general, the positive effects of RI on water balance and crop yield were higher at dry sites than at wet sites. Therefore, RI can be an effective adaptation option for mitigating the impacts of climate change on winter crops by improving WUE, but is more effective in narrow-leaf cropping systems in hot and dry environments.

      PubDate: 2017-02-23T16:44:50Z
       
  • Climate impacts on palm oil yields in the Nigerian Niger Delta
    • Abstract: Publication date: April 2017
      Source:European Journal of Agronomy, Volume 85
      Author(s): Stanley U. Okoro, U. Schickhoff, J. Boehner, U.A. Schneider, N.I. Huth
      Palm oil production has increased in recent decades and is estimated to increase further globally. The optimal role of palm oil production, however, is controversial because of conflicts with other important land uses and ecosystem services. Local conditions and climate change affect resource competition and the desirability of palm oil production in the Niger Delta, Nigeria. The objectives of this study are to (1) establish a better understanding of the existing yield potentials of oil palm areas that could be used for integrated assessment models, (2) quantify for the first time uncertainties in yield potentials arising from the use of climate output data from different Global Circulation Models (GCM’s) with varied West African Monsoon (WAM) system representations forced to the same Regional Climate Models (RCM’s). We use the biophysical simulation model APSIM (Agricultural Production Systems Simulator) to simulate spatially variable impacts of climate change on oil palm yield over the Nigerian Niger Delta. Our results show that the impact of climate change on oil palm yield is considerable across our study region. The yield differences between the IPCC RCPs were small. The net impact of climate change on oil palm is positive and is dynamically inconsistent. There is no significant change in the simulated yield arising from the differences in the forcing’s data. We found the most effective strategy for oil palm yield optimization under climate change to be shifting of sowing dates and introduction of irrigation.

      PubDate: 2017-02-16T16:31:04Z
       
  • Effects of elevated CO2 on rice grain yield and yield components: Is
           non-flooded plastic film mulching better than traditional flooding?
    • Abstract: Publication date: April 2017
      Source:European Journal of Agronomy, Volume 85
      Author(s): Yuting Li, Shu Kee Lam, Xue Han, Yongxiang Feng, Erda Lin, Yingchun Li, Xingyu Hao
      The atmospheric carbon dioxide (CO2) concentration has been increasing rapidly since the Industrial Revolution. The responses to elevated CO2 of rice (Oryza sativa L.) growth and yield have been widely reported, but the majority of these studies investigated rice grown under traditional flooding at two contrasting CO2 levels. The effects of a range of CO2 concentrations (CO2 gradient) on the yield and its components of rice grown under non-flooded vs. flooded conditions remain unclear. Using a CO2 Gradient Tunnel (CGT), we investigated the effects of elevated CO2 (450, 500, 550 and 600μmolmol−1) on rice yield and yield components under two cultivation practices, viz. traditional flooding (TF) and non-flooded plastic film mulching (PM). Elevated CO2 increased rice yield by 25% under the TF treatment at 450–500μmolmol−1, but had no effect or decreased the rice yield under the PM treatment. The number of panicles per square meter was decreased by 4–26% under progressive elevation of CO2 concentration, regardless of cultivation practice. Elevated CO2 increased the spikelet number per panicle and filled spikelet percentage under the TF treatment, but had no effect on these parameters under the PM treatment. Specifically, elevated CO2 decreased the number of degenerated spikelets on secondary rachis branches of rice grown under the TF treatment by 75%, but increased that of filled spikelets by 43%. This was the major reason for the CO2-induced increase in rice yield under the TF treatment. The 1000-grain weight and Harvest Index (HI) under the two cultivation practices was increased only when CO2 concentration was elevated to 550–600μmolmol−1. The CO2 ×cultivation interaction was detected for grain yield. When CO2 concentration was increased to 600μmolmol−1, the rice yield of the PM treatment was 2% higher than the TF treatment. This study demonstrated that improved management practices are needed to maximize the benefits of non-flooded plastic film mulching cultivation in a CO2-rich world. Our results provide major implications for water management of rice production systems and global food security under future higher CO2, and potentially drier, environments.

      PubDate: 2017-02-10T16:16:57Z
       
  • Effect of agronomic programmes with different susceptibility to
           deoxynivalenol risk on emerging contamination in winter wheat
    • Abstract: Publication date: April 2017
      Source:European Journal of Agronomy, Volume 85
      Author(s): Massimo Blandino, Valentina Scarpino, Michael Sulyok, Rudolf Krska, Amedeo Reyneri
      Deoxynivalenol (DON) is the most prevalent mycotoxin in small cereal crops throughout the world, and its occurrence is closely linked to the presence of Fusarium Head Blight (FHB) disease. In order to minimize the sanitary risk, wheat cropping systems are commonly designed to control DON contamination, as this represents the main target contaminant. However, several other mycotoxins and secondary metabolites produced by Fusarium and other fungal species have been detected in wheat. The objective of this study was to evaluate whether the application of agronomic programmes with different susceptibility to DON contamination could also affect the occurrence of emerging mycotoxins in wheat kernels. Field experiments have been conducted in North Italy, under naturally-infected conditions, over a period of 3 growing seasons, by comparing 4 field programmes, which were constituted by the combination of wheat cultivars (a durum wheat variety that is susceptible to DON contamination and a common moderately resistant one) and 2 fungicide applications at heading (untreated control compared to an azole application at heading). Grain samples have been analyzed by means of a dilute-and-shoot multi-mycotoxin LC–MS/MS method, and 43 fungal metabolites were detected. In addition to DON, the most abundant compounds were aurofusarin, culmorin and deoxynivalenol-3-glucoside, which were detected in all the growing seasons and agronomic strategies. Other trichothecenes and zearalenone derivatives were also found, but in clearly lower concentrations. Contamination by enniatins and moniliformin, produced by other Fusarium species e.g. Fusarium avenaceum, alternariol, alternariol methyl ether and tentoxin, produced by Alternaria species, has been observed for all the compared growing seasons. The presence of other mycotoxins and secondary metabolites was clearly affected by the climatic conditions: fumonisins, beauvaricin, bikaverin, fusaric acid and butenolid were detected in the warmer growing seasons, while chrysogine, infectopyrone, secalonic acid and ergot alkaloids (sum of 13 toxins) were only found in the more rainy and cool seasons. Equisetin, decalonectrin, toxin T-2 and HT-2 were only found in traces. The application of the field programmes clearly affected DON contamination in each growing season: a significant increase in this toxin has been observed moving from the lowest risk agronomic strategy to the highest one. The application of the most favourable DON control field programme (a moderately resistant variety combined with fungicide application at heading) reduced the content of this mycotoxin by 89%, compared to the worst programme (untreated susceptible variety). The application of the less risky agronomic strategy for DON contamination led to a significant reduction (>84%) of all the other mycotoxins produced by the DON producing fungal species. Moreover, although the considered agronomic factors (variety susceptibility and fungicide application) resulted in a control efficacy that varied in function of the environmental conditions and the type of mycotoxin, the results show a clear reduction trend, after the application of agronomic strategies that are able to minimize the DON content, for almost all the other Fusarium, Alternaria, Claviceps and Penicillium metabolites. The results summarized in this work, which have been obtained under different environmental and agronomical conditions, allow a first assessment to be made of the agronomic strategies that could be applied to control emerging mycotoxins in wheat.
      Graphical abstract image

      PubDate: 2017-01-22T10:40:52Z
       
  • Genetic gains for physiological traits associated with yield in soft red
           winter wheat in the Eastern United States from 1919 to 2009
    • Abstract: Publication date: March 2017
      Source:European Journal of Agronomy, Volume 84
      Author(s): Maria Balota, A.J. Green, C.A. Griffey, R. Pitman, W. Thomason
      Wheat (Triticum aestivum L.) breeding strategies can benefit from periodic evaluation of genetic gains for physiological and morphological traits, and their contribution to yield progress over time in a particular environment. The objective of this research was to expand the recent work at Virginia Tech on genetic yield improvement in soft red winter (SRW) wheat and determine the magnitude of progress for several physiological traits in 50 SRW wheat cultivars released from 1919 to 2009. Physiological traits evaluated here were extensively reported in the literature to be relevant for future wheat breeding as they directly contributed to yield increase under optimum and suboptimal environmental conditions; these traits include canopy temperature depression (CTD), flag leaf width (W), flag leaf area (LA), flag leaf dry weight (DW), flag leaf specific area (SLA), SPAD (soil plant analysis development) chlorophyll reading, and grain 13C isotope discrimination (Δ). Replicated experiments were performed at Warsaw and Holland, VA, in 2009–2010 and 2010–2011 growing seasons. Results showed that three traits consistently changed in magnitude over time and, at the same time, were significantly (p<0.01) related to yield; they were LA, smaller leaf area-higher yields; DW, lighter leaves-higher yields; and Δ, higher Δ-higher yields. CTD decreased in magnitude and SLA, W, and SPAD chlorophyll reading did not significantly change over time. Our data suggest that further yield increase in the SRW wheat grown in eastern Unites States can be achieved through selection of cultivars with smaller leaves, and with high Δ.

      PubDate: 2017-01-07T10:30:16Z
       
  • Conservation Agriculture practices reduce the global warming potential of
           rainfed low N input semi-arid agriculture
    • Abstract: Publication date: March 2017
      Source:European Journal of Agronomy, Volume 84
      Author(s): Angela Tellez-Rio, Antonio Vallejo, Sonia García-Marco, Diana Martin-Lammerding, Jose Luis Tenorio, Robert Martin Rees, Guillermo Guardia
      Conservation tillage and crop rotations improve soil quality. However, the impact of these practices on greenhouse gas (GHG) emissions and crop yields is not well defined, particularly in dry climates. A rainfed 2-year field-experiment was conducted to evaluate the effect of three long-term (17–18 years) tillage systems (Conventional Tillage (CT), Minimum Tillage (MT) and No Tillage (NT)) and two cropping systems (rotational wheat (Triticum aestivum L.) preceded by fallow, and wheat in monoculture), on nitrous oxide (N2O) and methane (CH4) emissions, during two field campaigns. Soil mineral N, water-filled pore space, dissolved organic carbon (C) and grain yield were measured and yield-scaled N2O emissions, N surplus and Global Warming Potentials (GWP) were calculated. No tillage only decreased cumulative N2O losses (compared to MT/CT) during campaign 1 (the driest campaign with least fertilizer N input), while tillage did not affect CH4 oxidation. The GWP demonstrated that the enhancement of C stocks under NT caused this tillage management to decrease overall CO2 equivalent emissions. Monoculture increased N2O fluxes during campaign 2 (normal year and conventional N input) and decreased CH4 uptake, as opposed to rotational wheat. Conversely, wheat in monoculture tended to increase soil organic C stocks and therefore resulted in a lower GWP, but differences were not statistically significant. Grain yields were strongly influenced by climatic variability. The NT and CT treatments yielded most during the dry and the normal campaign, and the yield-scaled N2O emissions followed the same tendency. Minimum tillage was not an adequate tillage management considering the GWP and the yield-scaled N2O emissions (which were 39% lower in NT with respect to MT). Regarding the crop effect, wheat in rotation resulted in a 32% increase in grain yield and 31% mitigation of yield-scaled N2O emissions. Low cumulative N2O fluxes (<250gN2O-Nha−1 campaign−1) highlighted the relevance of soil organic C and CO2 emissions from inputs and operations in rainfed semi-arid cropping systems. This study suggests that NT and crop rotation can be recommended as good agricultural practices in order to establish an optimal balance between GHGs fluxes, GWP, yield-scaled N2O emissions and N surpluses.

      PubDate: 2017-01-07T10:30:16Z
       
 
 
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