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  Subjects -> AGRICULTURE (Total: 793 journals)
    - AGRICULTURAL ECONOMICS (70 journals)
    - AGRICULTURE (557 journals)
    - CROP PRODUCTION AND SOIL (92 journals)
    - DAIRYING AND DAIRY PRODUCTS (28 journals)
    - POULTRY AND LIVESTOCK (46 journals)

AGRICULTURE (557 journals)

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Journal Cover European Journal of Agronomy
  [SJR: 1.488]   [H-I: 75]   [11 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 1161-0301
   Published by Elsevier Homepage  [3043 journals]
  • Sowing date and maize grain quality for dry milling
    • Abstract: Publication date: January 2018
      Source:European Journal of Agronomy, Volume 92
      Author(s): Lucas J. Abdala, Brenda L. Gambin, Lucas Borrás
      Argentina is the single exporter of non-gmo hard endosperm maize to the European Union, and is internationally known for its grain hardness. This special hard endosperm maize supply chain follows strict regulations to ensure a high quality grain. Specific values for test weight, flotation index, grain vitreousness, and screen retention are demanded by the dry milling industry. Central temperate Argentinean production system is currently changing to later sowings, and there is limited information on the effect of contrasting sowing dates over specific grain quality attributes of interest for the industry. In this study we explored the effects of delaying maize sowing dates from September-October to December on maize dry milling grain quality in the central temperate area. Eighteen commercial genotypes differing in grain hardness were sown during two growing seasons and two sowing dates. Measured traits were grain yield, individual grain weight, dry milling quality (test weight, floaters, vitreousness, 8mm screen retention), and composition (oil, protein, starch). Grain yield varied significantly among genotypes (p<0.001), and semi-dents showed higher yields when compared to hard endosperm flints (13110 and 11463kgha−1, respectively). Early and late sown maize yielded 12737kgha−1 and 11003kgha−1, respectively. Significant genotype differences were observed for all grain quality and composition attributes. Delaying the sowing date from September-October to December had minimum effects on physical grain quality traits, only evident at some genotypes (significant sowing date x genotype interaction for most traits). Genotype to genotype differences in grain quality and composition were larger than variations between sowing dates. Grain hardness was strongly determined by the genotype, making genotype selection a critical management option for attaining high quality at any sowing date. It is evident that high dry milling quality can be obtained with adequate genotypes also at later sowings.

      PubDate: 2017-10-14T08:56:20Z
       
  • Yield differences get large with ascendant altitude between traditional
           paddy and water-saving ground cover rice production system
    • Abstract: Publication date: January 2018
      Source:European Journal of Agronomy, Volume 92
      Author(s): Lin Guo, Meiju Liu, Yanan Zhang, Yueyue Tao, Fan Zhang, Guoyuan Li, Klaus Dittert, Shan Lin
      In mountainous regions with high altitude, rice yield is mostly limited by low temperatures and insufficient irrigation facilities. The innovative ground cover rice production system (GCRPS) has a recognised potential to significantly increase rice grain yield where rice production is limited by water scarcity and low temperatures. We hypothesised that yield advantage of GCRPS over traditional Paddy might become larger at higher altitudes. We sampled 14 pairs of adjacent GCRPS and Paddy fields at altitudes of 900m and 23 pairs at 500m altitude with 3 replicates in central China. The study revealed that Badano et al. (2005) grain and straw yield were 40% and 35% greater in GCRPS compared to Paddy at 900m, while the difference was only 10% and 15% at 500m Bennie et al. (2006). Compared to Paddy, increase in productive tiller numbers, spikelets per square metre and percentage of filled grains were significantly larger in GCRPS at high than at low altitude Bennie et al. (2008). Soil temperature differences between GCRPS and Paddy were significantly higher at 900m than at 500m during the first month after transplanting. Our findings demonstrate that GCRPS has a good potential to increase rice yield in mountain regions with high altitudes where rice production is limited by low temperature and seasonal water shortage.
      Graphical abstract image

      PubDate: 2017-10-14T08:56:20Z
       
  • Trade-off between grain weight and grain number in wheat depends on GxE
           interaction: A case study of an elite CIMMYT panel (CIMCOG)
    • Abstract: Publication date: January 2018
      Source:European Journal of Agronomy, Volume 92
      Author(s): Alejandro Quintero, Gemma Molero, Matthew P. Reynolds, Daniel F. Calderini
      Identifying the functionally linked mechanisms of grain yield (GY) and its components —i.e. grain number (GN) and grain weight (GW) is necessary for boosting GY potential of wheat. The objectives of the current study were to: (i) analyze the trade-off between GW and GN in 27 elite wheat genotypes grown in two contrasting locations with different yield potential, (ii) assess its causes, and (iii) gain a better understanding of the physiology behind the trade-off between GW and GN. A set of 27 elite wheat genotypes was evaluated during three years in Ciudad Obregón, Mexico (CO), and two years in Valdivia, Chile (Val). GY was higher in Val than CO (783gm−2 and 665gm−2, respectively) and positively associated with above-ground biomass (BM) in both locations. In CO, 15,850 grains m−2 were recorded and 15,197 grains m−2 in Val, while thousand-grain weight (TGW) was higher (P<0.001) in Val than in CO by 23% (52.2 and 42.5g, respectively). Also, individual grain weight (IGW) of most categories was higher in Val than in CO. Remarkably, the relationships between GY and GN showed contrasting responses between locations despite the similar GN. A very low GY/GN relationship was found in CO, while a positive and linear relationship was plotted in Val. The virtual lack of association found in CO (11%) was due to a clear trade-off between TGW and GN, while the positive association in Val was the result of a very low trade-off between the two main yield components. Interestingly, the IGW of grains set in the G2 and G4 positions showed negative association with GN in CO across years as well as during each year, while in Val no association was found across years, though a very low association was found in each year. The source-sink treatments applied ten days after anthesis by halving the spikes showed that, G2 and G4 responded to the increased source by 7.7% and 16%, respectively in CO, while in Val the responses were 15% and 5.1% in Valy13 and 6.5% and 9.6% in Valy14, respectively. In conclusion, the lack of association between GY and GN found in CO was due to the trade-off between the two main yield components (GW and GN), which was mainly explained by higher average temperature and lower photothermal quotient during grain filling recorded in this location than in Val. These results highlight the need to employ different strategies aimed at increasing yield potential depending on the environment. The increase of grain number could be proposed for environments with favorable growing conditions as in Val. On the contrary, increasing GW would be the objective in environments with little chance of taking advantage of increased GN such as CO.

      PubDate: 2017-10-14T08:56:20Z
       
  • Identifying crop rotation practice by the typification of crop sequence
           patterns for arable farming systems – A case study from Central Europe
    • Abstract: Publication date: January 2018
      Source:European Journal of Agronomy, Volume 92
      Author(s): Susanne Stein, Horst-Henning Steinmann
      During the last decades crop rotation practice in conventional farming systems was subjected to fundamental changes. This process was forced by agronomical innovations, market preferences and specialist food processing chains and resulted in the dominance of a few cash crops and short-term management plans. Classical crop rotation patterns became uncommon while short rotations and flexible sequence cropping characterize the standard crop rotation practice. The great variety and flexibility in cropping management as a reaction to economic demands and climatic challenges complicate the systematization of crop rotation practice and make historical systematization approaches less suitable. We present a generic typology approach for the analysis of crop rotation practice in a defined region based on administrative time series data. The typology forgoes the detection of fixed defined crop rotations but has its focus on crop sequence properties and a consideration of the main characteristics of crop rotation practice: i) the transition frequency of different crops and ii) the appropriate combination of crops with different physical properties (e.g. root system, nutritional needs) and growing seasons. The presented approach combines these characteristics and offers a diversity-related typology approach for the differentiation and localization of crop sequence patterns. The typology was successfully applied and examined with a data set of annual arable crop information available in the form of seven-year sequences for Lower Saxony in the north-western part of Germany. About 60% of the investigated area was cropped with the ten largest crop sequence types, which represent the full range of crop pattern diversity from continuous cropping to extreme diversified crop sequences. Maize played an ambivalent role as driver for simplified rotation practice in permanent cropping on the one hand and as element of diversified sequences on the other hand. It could be verified that the less diverse crop sequence types were more strongly related to explicit environmental and socio-economic factors than the widespread diverse sequence types.

      PubDate: 2017-10-14T08:56:20Z
       
  • Does intercropping enhance yield stability in arable crop production'
           A meta-analysis
    • Abstract: Publication date: November 2017
      Source:European Journal of Agronomy, Volume 91
      Author(s): Md. Raseduzzaman, Erik Steen Jensen
      The adverse effects of climate change are significantly decreasing yield levels and yield stability over time in current monocropping systems. Intercropping (IC), i.e. growing more than one species simultaneously in the same field, often increases resource use efficiency and agricultural productivity compared with growing the component crops solely and can enhance yield stability. This meta-analysis of published IC literature quantified and analysed yield stability in IC compared with the respective sole crops, focusing on the effect of intercrop components (e.g. cereal-grain legume, non-cereal-grain legume), experimental patterns (e.g. experiment over years, experiment over locations), IC design (e.g. additive and replacement) and climatic zone (e.g. tropical, subtropical, and temperate). In total, 33 articles were analysed. The coefficient of variation (%CV) of yields was used for assessing yield stability, with lower CV value indicating higher yield stability. The analysis showed that cereal-grain legume IC (CV=22.1) significantly increased yield stability compared with the respective grain legume sole crops (CV=31.7). Moreover, compared with the respective cereal and legume sole crops, IC in the cereal-grain legume systems gave higher yield stability than IC in the non-cereal-grain legume systems. Compared with the respective cereal (CV=25.3) and legume (CV=30.3) sole crops, IC (CV=19.1) in a replacement design had significantly (P<0.05) higher yield stability. Also intercropping in replacement design gave more stable yields than IC in an additive design. In tropical regions, cereal sole crops (CV=26.3) showed lower yield stability than IC (CV=17.7) and legume sole crops (CV=21.7). However, IC in all climatic zones showed higher yield stability than both sole crops. Moreover in our analysis, it was found that a higher yield level provided higher yield stability in crop production. Thus, increasing crop diversification through IC of cereals and grain legumes can enhance yield stability and food security, making an important contribution to eco-functional, ecological or sustainable intensification of global food production.

      PubDate: 2017-10-14T08:56:20Z
       
  • Predicting the slow decline of root lesion nematodes (Pratylenchus
           thornei) during host-free fallows to improve farm management decisions
    • Abstract: Publication date: November 2017
      Source:European Journal of Agronomy, Volume 91
      Author(s): J.P.M. Whish, J.P. Thompson, T.G Clewett, J. Wood, H.E. Rostad
      Pratylenchus thornei is a major pathogen of cereal and legume crops around the world, especially in the northern grains region of eastern Australia. The dominance of host species within the rotation has seen soil pathogen population densities increase. Long weed-free fallows combined with sorghum production (non host crop) to reduce population densities has been successful. However, little is known about the rate of population decline during the fallow or how long this non–host period should continue in order to reduce the population below an accepted damage threshold. The rate of decline from a range of initial starting populations (high, medium, low and very low) were monitored over a 30month weed free fallow. Fallows were initiated in November (late Spring) for three consecutive years. Nematode population densities and soil moisture were measured at eight depths down the soil profile to 1.5m and used to describe the rate of population decline over time in each soil layer. Dynamic populations of P. thornei existed within the upper layers (<0.6m) of the soil and these declined at a rate that could be described by the negative exponential model Y=ae−bt. The time taken for a population to decline was dependent on the initial population density at harvest of the previous host crop. Generally, between 300–600days of host-free fallow was required to reduce a moderately high initial population of 80 P. thornei/cm3 soil to the damage threshold of 2 P. thornei/cm3. The rate of decline varied between soil layers, particularly in the surface layer (0–0.15m), but remained constant from year to year for each layer. There was no interaction between year and soil layer. Knowing the expected rate of decline of a P. thornei population at the start of a fallow allows better management of the crop rotation to ensure populations do not continue to rise and thus reduce the yield potential of future crops.

      PubDate: 2017-10-14T08:56:20Z
       
  • Assessment of uncertainty and sensitivity analyses for ORYZA model under
           different ranges of parameter variation
    • Abstract: Publication date: November 2017
      Source:European Journal of Agronomy, Volume 91
      Author(s): Junwei Tan, Yuanlai Cui, Yufeng Luo
      We explore the effects of different ranges of parameter variation (RPV) on sensitivity and uncertainty analyses for ORYZA_V3 model. In this study, a latin hypercube sampling (LHS) technique is used to generate parameter sample sets, and a regression-based method is employed for the sensitivity analysis on 16 crop parameters. Then, a top-down concordance coefficient (TDCC) is calculated to assess the stability of parameter sensitivity rankings across diverse RPV. Furthermore, coefficients of variation (CV) and 90% confidence intervals (90CI) of daily model outputs are analyzed by considering uncertainty in observations. We find that the increasing RPV multiplies the CV of daily model outputs, whereas the RPV has no effect on the CV’s change rule over time. The 90CI of model outputs include most of the observations when the RPV is more than ±30% perturbation. The standardized regression coefficient (SRC) of some parameters are obviously minified when the RPV is ±5% or ±50% perturbation. The results highlights the importance of RPV selection in the sensitivity and uncertainty analysis of crop model, and ±30% perturbation was suggested when the RPV cannot be specifically obtained.

      PubDate: 2017-10-14T08:56:20Z
       
  • Effect of biogas digestate, animal manure and mineral fertilizer
           application on nitrogen flows in biogas feedstock production
    • Abstract: Publication date: November 2017
      Source:European Journal of Agronomy, Volume 91
      Author(s): Antje Herrmann, Henning Kage, Friedhelm Taube, Klaus Sieling
      The expansion of biogas feedstock cultivation may affect a number of ecosystem processes and ecosystem services, and temporal and spatial dimensions of its environmental impact are subject to a critical debate. However, there are hardly any comprehensive studies available on the impact of biogas feedstock production on the different components of nitrogen (N) balance. The objectives of the current study were (i) to investigate the short-term effects of crop substrate cultivation on the N flows in terms of a N balance and its components (N fertilization, N deposition, N leaching, NH3 emission, N2O emission, N recovery in harvested product) for different cropping systems, N fertilizer types and a wide range of N rate, and (ii) to quantify the N footprint of feedstock production in terms of potential N loss per unit of methane produced. In 2007/08 and 2008/09, two field experiments were conducted at two sites in Northern Germany differing in soil quality, where continuous maize (R1), maize–whole crop wheat followed by Italian ryegrass as a double crop (R2), and maize–grain wheat followed by mustard as a catch crop (R3) were grown on Site 1 (sandy loam), and R1 and a perennial ryegrass ley (R4) at Site 2 (sandy soil rich in organic matter). Crops were supplied with varying amounts of N (0–360kgNha−1, ryegrass: 0–480kgNha−1) supplied as biogas digestate, cattle slurry, pig slurry or calcium-ammonium nitrate (CAN). Mineral-N fertilization of maize-based rotations resulted in negative N balances at N input for maximum yield (Nopt), with R2 having slightly less negative balances than R1 and R3. In contrast, N balances were close to zero for cattle slurry or digestate treatments. Thus, trade-offs between substrate feedstock production and changes of soil organic matter stocks have to be taken into consideration when evaluating biogas production systems. Nitrogen losses were generally dominated by N leaching, whereas for the organically fertilized perennial ryegrass ley the ammonia emission accounted for the largest proportion. Nitrogen balance of the ryegrass ley at Nopt was close to zero (CAN) or highly positive (cattle slurry, digestate). Nitrogen footprint (NFP) was applied as an eco-efficiency measure of N-loss potential (difference of N input and N recovery) related to the unit methane produced. NFP ranged between −11 and +6kgN per 1000m3 methane at Nopt for maize-based rotations, without a significant impact of cropping system or N fertilizer type. However, for perennial ryegrass ley, NFP increased up to 65kgN per 1000m3. The loose relation between NFP and observed N losses suggests only limited suitability for NFP.

      PubDate: 2017-10-14T08:56:20Z
       
  • Cultivar placement affects pollination efficiency and fruit production in
           European pear (Pyrus communis) orchards
    • Abstract: Publication date: November 2017
      Source:European Journal of Agronomy, Volume 91
      Author(s): Muriel Quinet, Anne-Laure Jacquemart.
      European pear (Pyrus communis) requires insect pollination among compatible cultivars for fruit production. However, most commercial orchards have a limited number of cultivars arranged in monotypic blocks or rows. This can result in insufficient inter-cultivar pollination. We hypothesise that limitations in pollen transfer among cultivars could be explained by both insect behaviour and orchard design. We compared insect activity and pollination efficiency in two European pear cultivars, in orchards with different designs: (i) cultivars alternated in the same row or (ii) cultivars in separate rows. To assess limitations in pollen transfer, we also compared hand pollination with compatible pollen versus open pollination by insects. Insect visitors mainly foraged on neighbouring trees within a row, with few movements across rows (1%). Honey bees (Apis mellifera) and bumble bees (Bombus terrestris) visited significantly more flowers per tree (8.5 vs. 3) and more trees (2.1 vs. 1.3) than solitary bees (Andrena spp.) and hoverflies. Insect visitors deposited large amounts of pollen (∼500 pollen grains) on flower stigmas regardless of the insect type. Cultivar placement affected inter-cultivar pollination; less incompatibility signs were observed when cultivars alternated in the same row (5%) than when cultivars were in separate rows (38%). We observed limitations in pollen transfer as open pollination resulted in significant reduced fruit set, compared with hand pollination, in ‘Conférence’ (21% vs. 30.7%) and ‘Doyenné du Comice’ (7.2% vs. 16.8%). The foraging behaviour of the insects limited thus inter-cultivar pollen transfer in the orchards with cultivars in separate rows. Cultivars used for pollination (pollinizers) should be planted in the same rows as the main cultivar to increase inter-cultivar pollination.

      PubDate: 2017-10-14T08:56:20Z
       
  • Inside Front Cover - Editorial Board Page
    • Abstract: Publication date: October 2017
      Source:European Journal of Agronomy, Volume 90


      PubDate: 2017-09-20T06:53:03Z
       
  • Effects of best management practices on dry matter production and fruit
           production efficiency of oil palm
    • Abstract: Publication date: October 2017
      Source:European Journal of Agronomy, Volume 90
      Author(s): H.H. Tao, C. Donough, M.P. Hoffmann, Y.L. Lim, S. Hendra, Rahmadsyah, G. Abdurrohim, K. Indrasuara, A. Lubis, T. Dolong, T. Oberthür
      Enhancing dry matter production with higher partitioning to fruit bunches is important for sustainable intensification of oil palm. A series of best management practices including site-specific nutrient management, canopy management, and harvesting has been developed for oil palm plantations. However, the effects of these practices on dry matter production and partitioning, and how the effects vary with climatic and soil conditions of plantation sites, remain largely unknown. We established a four-year field trial including 30 paired commercial blocks across Sumatra and Kalimantan, Indonesia. The paired treatments included site-specific best management practices, and standard estate practices as the control. The annual production of aboveground dry matter was 30.0±0.5tha−1 yr−1 (mean±se) under best management practices, higher than 28.8±0.5tha−1 yr−1 under standard estate practices. The bunch index, an indicator of the fruit production efficiency, increased by 12% under best management practices compared to standard estate practices. Partitioning of dry matter to the fronds decreased by 8% under best management practices, compared to standard estate practices. The positive effect of best management practices on the annual production of total aboveground dry matter was stronger in the plantation site with higher annual rainfall. These results are useful for optimizing management practices to improve sustainable intensification of oil palm.

      PubDate: 2017-09-20T06:53:03Z
       
  • Old tall durum wheat cultivars are suited for dual-purpose utilization
    • Abstract: Publication date: October 2017
      Source:European Journal of Agronomy, Volume 90
      Author(s): Francesco Giunta, Giovanni Pruneddu, Francesco Cadeddu, Rosella Motzo
      The lateness, tallness and high vigour of old tall durum wheat cultivars could be advantageous for dual-purpose use and their high propensity for lodging should be reduced by grazing. A 3-year field trial was performed in Sardinia, Italy, in a typical Mediterranean environment. Crops of the durum wheat cultivar Senatore Cappelli were sown in October, and grazing was simulated by clipping half of the plots at the terminal spikelet stage of development. The forage biomass derived from clipping varied greatly between seasons (from 0.8 to 3.3tha−1 dry matter) in response to the notable inter-seasonal variability in weather conditions. Cultivar Senatore Cappelli showed good recovery following clipping, with the ability to attain almost complete radiation interception well before anthesis. The high number of leaves that emerged after clipping might have contributed to this good recovery. Nevertheless, clipping reduced the dry matter produced by anthesis (16tha−1 in clipped compared to 21tha−1 in unclipped crops) as well as the final dry matter (DMMAT) (19tha−1 in clipped compared to 23tha−1 in unclipped crops), although these differences disappeared when the clipped biomass was included. The lower lodging observed at anthesis in the clipped (21%) compared with unclipped crops (63%) likely reduced the difference between treatments. The lower DMMAT of clipped treatments was reflected in a lower grain yield (GY) (3.4tha−1 vs 4.2tha−1 in the unclipped treatment). Clipping did not affect the amount of nitrogen present in the biomass, nitrogen uptake efficiency or radiation use efficiency. GY reduction after clipping was mediated by the reduction in spikes m−2 and kernels m−2 (KNO). Spike fertility was not affected by clipping, because the same amount of radiation was available for each spike (about 1MJ). The period with reduced ground cover after clipping was reflected in an increased evaporation and reduced transpiration, which did not alter the total water used and increased the transpiration efficiency in terms of DMMAT. Old tall durum wheat cultivars manifested good suitability for dual-purpose use in environments with low attainable yields because their low grain yield potential contributed to reducing the negative effects of clipping on GY. Their high straw yield and kernel protein percentage represented an advantage with respect to semi-dwarf cultivars.

      PubDate: 2017-09-02T09:58:07Z
       
  • Biological nitrogen fixation in three long-term organic and conventional
           arable crop rotation experiments in Denmark
    • Abstract: Publication date: October 2017
      Source:European Journal of Agronomy, Volume 90
      Author(s): Arjun Pandey, Fucui Li, Margrethe Askegaard, Jørgen E. Olesen
      Biological nitrogen (N) fixation (BNF) by legumes in organic cropping systems has been perceived as a strategy to substitute N import from conventional sources. However, the N contribution by legumes varies considerably depending on legumes species, as well as local soil and climatic conditions. There is a lack of knowledge on whether the N contribution of legumes estimated using short-term experiments reflects the long-term effects in organic systems varying in fertility building measures. There is also limited information on how fertilizer management practices in organic crop rotations affect BNF of legumes. Therefore, this study aimed to estimate BNF in long-term experiments with a range of organic and conventional arable crop rotations at three sites in Denmark varying in climate and soils (coarse sand, loamy sand and sandy loam) and to identify possible causes of differences in the amount of BNF. The experiment included 4-year crop rotations with three treatment factors in a factorial design: (i) rotations, i.e. organic with a year of grass-clover (OGC), organic with a year of grain legumes (OGL), and conventional with a year of grain legumes (CGL), (ii) with (+CC) and without (−CC) cover crops, and (iii) with (+M) and without (−M) animal manure in OGC and OGL, and with (+F) mineral fertilizer in CGL. Cover crops consisted of a mixture of perennial ryegrass and clover (at the sites with coarse sand and sandy loam soils) or winter rye, fodder radish and vetch (at the site with loamy sand soil) in OGC and OGL, and only perennial ryegrass in CGL at all sites. The BNF was measured using the N difference method. The proportion of N derived from the atmosphere (%Ndfa) in aboveground biomass of clover grown for an entire year in a mixture with perennial ryegrass and harvested three times during the growing season in OGC was close to 100% at all three sites. The Ndfa of grain legumes in both OGL and CGL rotations ranged between 61% and 95% depending on location with mostly no significant difference in Ndfa between treatments. Cover crops had more than 92% Ndfa at all sites. The total BNF per rotation cycle was higher in OGC than in OGL and CGL, mostly irrespective of manure/fertilizer or cover crop treatments. There was no significant difference in total BNF between OGL and CGL rotations, but large differences were observed between sites. The lowest cumulated BNF by all the legume species over the 4-year rotation cycle was obtained at the location with sandy loam soil, i.e. 224–244, 96–128, and 144–156kgNha−1 in OGC, OGL and CGL, respectively, whereas it was higher at the locations with coarse sand and loamy sand soil, i.e. 320–376, 168–264, and 200–220kgNha−1 in OGC, OGL and CGL, respectively. The study shows that legumes in organic crop rotations can maintain N2 fixation without being significantly affected by long-term fertilizer regimes or fertility building measures.

      PubDate: 2017-09-02T09:58:07Z
       
  • Can conservation tillage mitigate climate change impacts in Mediterranean
           cereal systems' A soil organic carbon assessment using long term
           experiments
    • Abstract: Publication date: October 2017
      Source:European Journal of Agronomy, Volume 90
      Author(s): Ileana Iocola, Simona Bassu, Roberta Farina, Daniele Antichi, Bruno Basso, Marco Bindi, Anna Dalla Marta, Francesco Danuso, Luca Doro, Roberto Ferrise, Luisa Giglio, Fabrizio Ginaldi, Marco Mazzoncini, Laura Mula, Roberto Orsini, Giuseppe Corti, Massimiliano Pasqui, Giovanna Seddaiu, Rodica Tomozeiu, Domenico Ventrella, Giulia Villani, Pier Paolo Roggero
      Simulation models, informed and validated with datasets from long term experiments (LTEs), are considered useful tools to explore the effects of different management strategies on soil organic carbon (SOC) dynamics and evaluate suitable mitigative options for climate change. But, while there are several studies which assessed a better prediction of crop yields using an ensemble of models, no studies are currently available on the evaluation of a model ensemble on SOC stocks. In this study we assessed the advantages of using an ensemble of crop models (APSIM-NWheat, DSSAT, EPIC, SALUS), calibrated and validated with datasets from LTEs, to estimate SOC dynamics. Then we used the mean of the model ensemble to assess the impacts of climate change on SOC stocks under conventional (CT) and conservation tillage practices (NT: No Till; RT: Reduced Tillage). The assessment was completed for two long-term experiment sites (Agugliano – AN and Pisa – PI2 sites) in Italy under rainfed conditions. A durum wheat (Triticum turgidum subsp. durum (Desf.) Husn.) – maize (Zea mays L.) rotation system was evaluated under two different climate scenarios over the periods 1971–2000 (CP: Present Climate) and 2021–2050 (CF: Future Climate), generated by setting up a statistical model based on canonical correlation analysis. Our study showed a decrease of SOC stocks in both sites and tillage systems over CF when compared with CP. At the AN site, CT lost −7.3% and NT −7.9% of SOC stock (0–40cm) under CF. At the PI2 site, CT lost −4.4% and RT −5.3% of SOC stocks (0–40cm). Even if conservation tillage systems were more impacted under future scenarios, they were still able to store more SOC than CT, so that these practices can be considered viable options to mitigate climate change. Furthermore, at the AN site, under CF, NT demonstrated an annual increase of 0.4%, the target value suggested by the 4 per thousand initiative launched at the 21st meeting of the Conference of the Parties in Paris. However, RT at the PI2 needs to be coupled with other management strategies, as the introduction of cover crops, to achieve such target.

      PubDate: 2017-09-02T09:58:07Z
       
  • Mid-season prediction of grain yield and protein content of spring barley
           cultivars using high-throughput spectral sensing
    • Abstract: Publication date: October 2017
      Source:European Journal of Agronomy, Volume 90
      Author(s): Gero Barmeier, Katharina Hofer, Urs Schmidhalter
      The ability to forecast grain yields and protein contents of spring barley is of particular interest for the malting and brewing industry, as well as for plant breeding. However, methods for early prediction of grain yield and protein content should ideally be timesaving, non-destructive and inexpensive. In this 3-year study using the mobile phenotyping platform PhenoTrac 4, proximally sensed reflectance data of 34 cultivars were used to develop vegetation indices and to calibrate PLSR models, followed by subsequent validation in independent field trials. A comparison among PLSR, the NDVI and REIP indices and an optimized vegetation index indicated that PLSR and REIP (R2 =0.71-0.95) gave superior predictions of grain yield. Furthermore, it was possible to distinguish the performance of different cultivars. In contrast, protein content could not be predicted reliably. As an alternative, a PLSR model of leaf N uptake at anthesis was tested to predict grain protein content. Satisfactory correlations were obtained with R2 =0.61, but protein content was considerably overestimated. The results show that tractor-based proximal sensing is a high-throughput, non-destructive and precise method to predict the grain yield of spring barley and could be a suitable tool to deliver information for the brewing industry and plant breeders.

      PubDate: 2017-09-02T09:58:07Z
       
  • Agronomic effects of bovine manure: A review of long-term European field
           experiments
    • Abstract: Publication date: October 2017
      Source:European Journal of Agronomy, Volume 90
      Author(s): Laura Zavattaro, Luca Bechini, Carlo Grignani, Frits K. van Evert, Janine Mallast, Heide Spiegel, Taru Sandén, Alicja Pecio, Juan Vicente Giráldez Cervera, Gema Guzmán, Karl Vanderlinden, Tommy D’Hose, Greet Ruysschaert, Hein F.M. ten Berge
      To evaluate the agronomic value of animal manure, we quantified the effects of pedo-climatic, crop and management factors on crop productivity, N use efficiency, and soil organic matter, described with simple indicators that compare manures with mineral fertilizers. We selected 80 European long-term field experiments that used bovine farmyard manure or bovine liquid slurry, alone (FYM and SLU) or combined with mineral fertilizers (FYMm and SLUm), and compared them to mineral fertilizer only reference treatments. We collected 5570 measurements from 107 papers. FYM produced slightly lower crop yields (−9.5%) when used alone and higher (+11.3%) yields when used in combination with N fertilizer (FYMm), compared to those obtained using mineral fertilizers only. Conditions promoting manure-N mineralization (lighter soil texture, warmer temperature, longer growing season, and shallower incorporation depth) significantly increased the effect of FYM/FYMm on crop yield and yield N. The production efficiency of FYM (yield:N applied ratio) was slightly lower than that of mineral fertilizers (-1.6%). The apparent N recoveries of FYM and FYMm were 59.3% and 78.7%, respectively, of mineral fertilizers. Manured soils had significantly higher C (+32.9% on average for FYM and FYMm) and N (+21.5%) concentrations. Compared to mineral fertilizers, yield was reduced by 9.1% with SLU, but not with SLUm. Influencing factors were similar to those of FYM/FYMm. Efficiency indicators indicated SLU (but not SLUm) was less effective than mineral fertilizers. Slurry significantly increased SOC (on average for SLU and SLUm by +17.4%) and soil N (+15.7%) concentrations. In conclusion, compared to mineral N fertilizers, bovine farmyard manure and slurry were slightly less effective on the crop, but determined marked increases to SOC and soil N, and thus, to long-term soil fertility maintenance.
      Graphical abstract image

      PubDate: 2017-09-02T09:58:07Z
       
  • In-season assessment of grain protein and amylose content in rice using
           critical nitrogen dilution curve
    • Abstract: Publication date: October 2017
      Source:European Journal of Agronomy, Volume 90
      Author(s): Syed Tahir Ata-Ul-Karim, Yan Zhu, Qiang Cao, Muhammad Ishaq Asif Rehmani, Weixing Cao, Liang Tang
      Effective nitrogen (N) management strategies ensure optimal N status in rice (Oryza sativa L.) plants for improving crop growth and grain quality with optimal N use efficiency. In-season plant N status affects rice grain quality. The critical N (Nc) dilution curves have been applied for predicting in-season nitrogen requirement (NR) and grain yield in rice, however, its application for estimating rice grain quality at harvest is yet to be tested. This research was endeavored to establish the quantitative relationships of protein content (PC) and amylose content (AC) with nitrogen nutrition index (NNI), accumulated nitrogen deficit (AND), and NR at various growth stages during vegetative growth period of rice and to validate these relationships in Japonica and Indica rice ecotypes. Five multi-locational field trials with five rice cultivars and varied N application rates were carried out in eastern China. The quantitative relationships of PC and AC with NNI, AND, and NR at various growth stages in both rice ecotypes were highly significant (for Japonica and Indica, R2 >0.88 and 0.85 for PC, R2 >0.85 and 0.81 for AC, respectively). The strongest relations were observed for both rice ecotypes at later vegetative growth stages and periods. The validation of the developed quantitative relationships with the independent dataset revealed a solid model performance, especially during later vegetative growth period (R2 >0.90, root mean square error <18%) and confirmed their robustness as reliable predictors for assessing in-season grain quality in rice. The projected results can be used for estimating in-season grain quality and precision N management for rice.

      PubDate: 2017-09-02T09:58:07Z
       
  • Modelling wheat yield change under CO2 increase, heat and water stress in
           relation to plant available water capacity in eastern Australia
    • Abstract: Publication date: October 2017
      Source:European Journal of Agronomy, Volume 90
      Author(s): Bin Wang, De Li Liu, Senthold Asseng, Ian Macadam, Qiang Yu
      Increasing heat and water stress are important threats to wheat growth in rain-fed conditions. Using climate scenario-based projections from the Coupled Model Intercomparison Project phase 5 (CMIP5), we analysed changes in the probability of heat stress around wheat flowering and relative yield loss due to water stress at six locations in eastern Australia. As a consequence of warmer average temperatures, wheat flowering occurred earlier, but the probability of heat stress around flowering still increased by about 3.8%–6.2%. Simulated potential yield across six sites increased on average by about 2.5% regardless of the emission scenario. However, simulated water-limited yield tended to decline at wet and cool locations under future climate while increased at warm and dry locations. Soils with higher plant available water capacity (PAWC) showed a lower response of water-limited yield to rainfall changes except at very dry sites, which means soils with high PAWC were less affected by rainfall changes compared with soils with low PAWC. Our results also indicated that a drought stress index decreased with increasing PAWC and then stagnated at high PAWC. Under high emission scenario RCP8.5, drought stress was expected to decline or stay about the same due to elevated CO2 compensation effect. Therefore, to maintain or increase yield potential in response to the projected climate change, increasing cultivar tolerance to heat stress and improving crop management to reduce impacts of water stress on lower plant available water holding soils should be a priority for the genetic improvement of wheat in eastern Australia.

      PubDate: 2017-09-02T09:58:07Z
       
  • Designing cotton ideotypes for the future: Reducing risk of crop failure
           for low input rainfed conditions in Northern Cameroon
    • Abstract: Publication date: October 2017
      Source:European Journal of Agronomy, Volume 90
      Author(s): Romain Loison, Alain Audebert, Philippe Debaeke, Gerrit Hoogenboom, Louise Leroux, Palaï Oumarou, Edward Gérardeaux
      Climate change is threatening the ability to grow cotton (Gossypium hirsutum L.) under low input rainfed production areas in Sub-Saharan Africa. In Northern Cameroon, yield has been declining due to unsuitable cropping practices such as sub-optimal planting dates, along with an absence in genetic gain. The aim of this study was to use a cropping system model (DSSAT CSM-CROPGRO-Cotton) to identify the best cultivars (ideotypes) for Northern Cameroon that are adapted to low input rainfed productions systems for 2050 under RCP4.5 and RCP8.5. Calibration and evaluation of the CSM-CROPGRO-Cotton were performed with field observations for two cultivars (Allen Commun and L484). For RCP4.5 and RCP8.5, 50 replications for 2050 were generated based on an ensemble of 17 Global Circulating Models. In total, 3125 virtual cultivars representing existing genetic variability for phenology, morphology and photosynthesis were simulated. Thereafter, they were evaluated for performance under the projected future climate based on potential yield and the resilience of yield to sub-optimal planting date. The widely cultivated cultivar L484 will be unsuitable under projected future climate, due to boll opening during the middle of the rainy season (median: 10/09 under RCP4.5 and 12/09 under RCP8.5). None of the ideotypes tested could optimize both yield and resilience (Pearson correlation <−0.82). However, compared to the current cultivar L484, two virtual ideotypes were identified: (a) “Ideo_sub” had a wide planting window, especially in the 10 worst replications of 2050, up to +5days in RCP8.5; (b) “Ideo_Pot” had a high potential yield trait with low resilience to sub-optimal planting date, in the 10 worst replications of 2050, +530kgha−1 in RCP4.5 and +591kgha−1 in RCP8.5. Both ideotypes had an earlier anthesis date, a longer reproductive duration, and increase in the maximum photosynthetic rate. Therefore, breeding programs should consider these traits suggested by this system analysis using a crop simulation model for the identification of suitable cultivars under the projected future climate.
      Graphical abstract image

      PubDate: 2017-09-02T09:58:07Z
       
  • Inside Front Cover - Editorial Board Page
    • Abstract: Publication date: September 2017
      Source:European Journal of Agronomy, Volume 89


      PubDate: 2017-09-02T09:58:07Z
       
  • Diverse dynamics in agroecological transitions on fruit tree farms
    • Abstract: Publication date: October 2017
      Source:European Journal of Agronomy, Volume 90
      Author(s): Marie Dupré, Thierry Michels, Pierre-Yves Le Gal
      Agroecological transition refers to the adoption by farmers of practices based on on-farm biological processes rather than imported or non-renewable inputs. Drawing from a comprehensive survey of 31 diversified farms cultivating citrus on Réunion Island (Indian Ocean, France), this study aims to understand the diverse dynamics in farmers’ agroecological transitions and to identify the factors and processes driving farmers’ choices. The analysis considers both the current protection, fertilization and weed control practices implemented by farmers in their orchards and the trajectories of change they have followed over the last thirty years. Orchard management was categorized according to the kind of inputs mobilized (i.e., “synthetic inputs”, “alternative off-farm inputs” and “alternative on-farm inputs”). Diverse managements were observed, targeting security, autonomy, ecology or simplicity. The six types of practice trajectories identified illustrate the diverse and incremental nature of agroecological transition. Drawing from these results, drivers of alternative practice adoption and lock-in effects in synthetic input reliance were characterized. Internal drivers, depending directly on the farmer and his/her farm, included the characteristics of the orchard and its environment, the labor force, and the farmer’s environmental concerns. External drivers included local citrus markets, public legislation, access to extension services, the organization of input supply and the social environment. The combination of these internal and external drivers at the farm level makes each farm relatively unique. However, three factors determine the main differences in practices: the marketing channel used, the farmer’s environmental objectives, and the farmer’s economic behavior, which is linked to the weight of the crop activity in farm revenue. Understanding farmers’ points of view and decisions regarding agroecological transition deserves the attention of scientists, agricultural advisors and policy makers when designing innovative cropping systems, new support methodologies and incentives to respond effectively to farmers’ objectives and contexts of action.

      PubDate: 2017-08-03T09:20:07Z
       
  • Understanding effects of multiple farm management practices on barley
           performance
    • Abstract: Publication date: October 2017
      Source:European Journal of Agronomy, Volume 90
      Author(s): Libère Nkurunziza, Iman Raj Chongtham, Christine A. Watson, Håkan Marstorp, Ingrid Öborn, Göran Bergkvist, Jan Bengtsson
      Because of the complexity of farming systems, the combined effects of farm management practices on nitrogen availability, nitrogen uptake by the crop and crop performance are not well understood. To evaluate the effects of the temporal and spatial variability of management practices, we used data from seventeen farms and projections to latent structures analysis (PLS) to examine the contribution of 11 farm characteristics and 18 field management practices on barley performance during the period 2009–2012. Farm types were mixed (crop-livestock) and arable and were categorized as old organic, young organic or conventional farms. The barley performance indicators included nitrogen concentrations in biomass (in grain and whole biomass) and dry matter at two growing stages. Fourteen out of 29 farm characteristics and field management practices analysed best explained the variation of the barley performance indicators, at the level of 56%, while model cross-validation revealed a goodness of prediction of 31%. Greater crop diversification on farm, e.g., a high proportion of rotational leys and pasture, which was mostly observed among old organic farms, positively affected grain nitrogen concentration. The highest average grain nitrogen concentration was found in old organic farms (2.3% vs. 1.7 and 1.4% for conventional and young organic farms, respectively). The total nitrogen translocated in grain was highest among conventional farms (80kgha−1 vs. 33 and 39kgha−1 for young and old organic farms, respectively). The use of mineral fertilizers and pesticides increased biomass leading to significant differences in average grain yield which became more than double for conventional farms (477±24gm−2) compared to organic farms (223±37 and 196±32gm−2 for young and old organic farms, respectively). In addition to the importance of weed control, management of crop residues and the organic fertilizer application methods in the current and three previous years, were identified as important factors affecting the barley performance indicators that need closer investigation. With the PLS approach, we were able to highlight the management practices most relevant to barley performance in different farm types. The use of mineral fertilizers and pesticides on conventional farms was related to high cereal crop biomass. Organic management practices in old organic farms increased barley N concentration but there is a need for improved management practices to increase biomass production and grain yield. Weed control, inclusion of more leys in rotation and organic fertilizer application techniques are some of the examples of management practices to be improved for higher N concentrations and biomass yields on organic farms.

      PubDate: 2017-08-03T09:20:07Z
       
  • Climate change effects on leaf rust of wheat: Implementing a coupled
           crop-disease model in a French regional application
    • Abstract: Publication date: October 2017
      Source:European Journal of Agronomy, Volume 90
      Author(s): Julie Caubel, Marie Launay, Dominique Ripoche, David Gouache, Samuel Buis, Frédéric Huard, Laurent Huber, François Brun, Marie Odile Bancal
      Leaf rust is responsible for significant wheat yield losses. Its occurrence and severity have increased in recent years, partly because of warmer climate. It is therefore critical to understand and anticipate the effects of climate change on leaf rust. Direct climate effects and indirect effects via host plants that provide a biophysical environment for disease development were both considered. The coupled STICS-MILA model simulates both crop and pathogen dynamics in a mechanistic way and their interaction is managed by two sub-models: one calculating the microclimate within the canopy and the other converting numbers of spores and lesions to affected surfaces. In this study, STICS-MILA was first calibrated and evaluated using leaf rust severity observed at various sites in France for multiple years. STICS-MILA was then run on three contrasting French sites under 2.6, 4.5 and 8.5 RCP future climate scenarios. Results focused firstly on changes in disease earliness and intensity, secondly on disease dynamics, particularly the synchronism between plant and disease developments, and finally on elementary epidemic processes. The calibration and evaluation of STICS-MILA revealed a high sensitivity to the initial amount of primary inoculum (a forcing variable in STICS-MILA) and thus the need to properly simulate the summering and overwintering pathogen survival. The simulations in the context of future climate showed a significant change in host-pathogen synchronism: in the far future, according to RCP 4.5 and 8.5 scenarios, disease onset is expected to occur not only with an advance of around one month but also at an earlier developmental stage of wheat crops. This positive effect results from rising temperatures, nevertheless partly counter-balanced during spring by lower wetness frequency. The crop growth accelerates during juvenile stages, providing a greater support for disease development. The resulting microclimate shortens latency periods and increases infection and sporulation efficiencies, thus causing more infectious cycles. An increase of final disease severity is thus forecasted with climate change.

      PubDate: 2017-08-03T09:20:07Z
       
  • Dynamics of oil and tocopherol accumulation in sunflower grains and its
           impact on final oil quality
    • Abstract: Publication date: September 2017
      Source:European Journal of Agronomy, Volume 89
      Author(s): R. González Belo, S. Nolasco, C. Mateo, N. Izquierdo
      Tocopherols are one of the most important bioactive compounds in vegetable oils. It is known that these antioxidants present a dilution like relationship with oil weight per grain but the mechanism underlying this relationship are unknown. The aim of this work was to analyze the dynamics of tocopherol accumulation in sunflower grains, its relationship with oil accumulation and its effects on final oil quality in genotypes with different fatty acid composition. Three field experiments were conducted with genotypes with different potential fatty acid composition (a traditional, a high oleic and a high stearic−high oleic) and treatments with different source (intercepted solar radiation) or sink (grains) during grain filling to obtain varied grain filling conditions and grains with different oil concentration and oil unsaturation. Intercepted solar radiation modified oil per grain but did not affect tocopherol per grain. The rate of accumulation explained 79% and 74% of the oil and tocopherol per grain variation, respectively. When intercepted solar radiation increased, the duration of the period of oil and tocopherols accumulation increased, being the first the most responsive. These differences in the duration of accumulation periods are reflected in a larger relative increase in oil than tocopherols per grain and thus a dilution of the latter in the oil. These differences in the dynamics of oil and tocopherol accumulation are common to genotypes with different level of unsaturation. These results help to understand the mechanism associated with the dilution curve of oil tocopherol concentration reported in the literature.

      PubDate: 2017-08-03T09:20:07Z
       
  • Modelling fertiliser significance in three major crops
    • Abstract: Publication date: October 2017
      Source:European Journal of Agronomy, Volume 90
      Author(s): Ben Parkes, Benjamin Sultan, Philippe Ciais, Xuhui Wang
      We present work using two long-term climate datasets to show that nitrogen fertiliser is an important aspect of yield projection for three major crops. The ability of linear models using climate variables as predictors to accurately project the yield of maize, rice and wheat over multi-decadal scales is improved with the addition of fertiliser as an input. Highly productive nations including Argentina, India, Poland and South Africa show significant improvement in yield simulations and show that fertiliser use should not be discounted when estimating yield variability. The use of nitrogen fertiliser in the generalised linear models improves yield forecast by 18% using the Princeton climate dataset and 23% using the WFDEI climate dataset. This work therefore supports the use of additional predictors than climate for improving the ability of statistical models to reconstruct yield variability.

      PubDate: 2017-07-24T09:09:46Z
       
  • Productivity of organic and conventional arable cropping systems in
           long-term experiments in Denmark
    • Abstract: Publication date: October 2017
      Source:European Journal of Agronomy, Volume 90
      Author(s): Ambreen Shah, Margrethe Askegaard, Ilse A. Rasmussen, Eva Maria Cordoba Jimenez, Jørgen E. Olesen
      A field experiment comparing different arable crop rotations was conducted in Denmark during 1997–2008 on three sites varying in climatic conditions and soil types, i.e. coarse sand (Jyndevand), loamy sand (Foulum), and sandy loam (Flakkebjerg). The crop rotations followed organic farm management, and from 2005 also conventional management was included for comparison. Three experimental factors were included in the experiment in a factorial design: 1) crop rotation (organic crop rotations varying in use of whole-year green manure (O1 and O2 with a whole-year green manure, and O4 without), and a conventional system without green manure (C4)), 2) catch crop (with and without), and 3) manure (with and without). The experiment consisted of three consecutive cycles using four-course rotations with all crops present every year, i.e. 1997–2000 (1st cycle), 2001–2004 (2nd cycle), and 2005–2008 (3rd cycle). In the 3rd cycle at all locations C4 was compared with two organic rotations, i.e. O2 and O4. The O2 rotation in the third cycle included spring barley, grass-clover, potato, and winter wheat, whereas C4 and O4 included spring barley, faba bean, potato, and winter wheat. For the O2 rotation with green manure there was a tendency for increased DM yield over time at all sites, whereas little response was seen in N yield. In the O4 rotation DM and N yields tended to increase at Foulum over time, but there was little change at Flakkebjerg. The DM yield gap between organic and conventional systems in the 3rd cycle varied between sites with 34–66% at Jyndevad, 21–44% at Foulum, and 32–52% at Flakkebjerg. The inclusion of grass-clover resulted in lower cumulated yield over the rotation than the treatment without grass-clover. The use of manure reduced the DM yield gap between conventional and organic systems on an average by 15 and 21%-points in systems with and without grass-clover, respectively, and the use of catch crops reduced the yield gap by 3 and 5%-points in the respective systems. Across all crops the agronomic efficiency of N in manure (yield benefit for each kg of mineral N applied) was greater in O4 compared with O2 for all crops.

      PubDate: 2017-07-24T09:09:46Z
       
  • Cassava yield loss in farmer fields was mainly caused by low soil
           fertility and suboptimal management practices in two provinces of the
           Democratic Republic of Congo
    • Abstract: Publication date: September 2017
      Source:European Journal of Agronomy, Volume 89
      Author(s): K. Kintché, S. Hauser, N.M. Mahungu, A. Ndonda, S. Lukombo, N. Nhamo, V.N.E. Uzokwe, M. Yomeni, J. Ngamitshara, B. Ekoko, M. Mbala, C. Akem, P. Pypers, K.P. Matungulu, A. Kehbila, B. Vanlauwe
      A better understanding of the factors that contribute to low cassava yields in farmers’ fields is required to guide the formulation of cassava intensification programs. Using a boundary line approach, we analysed the contribution of soil fertility, pest and disease infestation and farmers’ cultivation practices to the cassava yield gap in Kongo Central (KC) and Tshopo (TSH) provinces of the Democratic Republic of Congo. Data were obtained by monitoring 42 and 37 farmer-managed cassava fields during two cropping cycles in KC and one cropping cycle in TSH, respectively. Each field was visited three times over the cassava growing period for the observations. Logistic model was fitted against the observed maximum cassava root yields and used to calculate the achievable yield per field and for individual factor. At field level, the factor that led to the lowest achievable yield (Yup(i)1) was considered as the dominant yield constraint. Cassava yield loss per field was expressed as the increase in the maximal root yield observed per province (Yatt- attainable yield) compared to Yup(i)1. Yatt was 21 and 24tha−1 in TSH and KC, respectively. With the cassava varieties that farmers are growing in the study areas, pests and diseases played a sparse role in the yield losses. Cassava mosaic was the only visible disease we observed and it was the dominant yield constraint in 3% and 12% of the fields in KC and TSH, respectively. The frequent yield constraints were suboptimal field management and low soil fertility. Cultivation practices and soil parameters led to Yup(i)1 in 47% and 50% of the fields in KC, and in 47% and 41% of those in TSH, respectively. Individual soil parameters were the yield constraint in few fields, suggesting that large-scale programs in terms of lime application or recommendation of the blanket fertilisers would result in sparse efficacy. In KC, yield losses caused by low soil fertility averaged 6.2tha−1 and were higher than those caused by suboptimal field management (5.5tha−1); almost nil for cassava mosaic disease (CMD). In TSH, yield losses caused by low soil fertility (4.5tha−1) were lower than those caused by suboptimal field management (6.5tha−1) and CMD (6.1tha−1). Irrespective of the constraint type, yield loss per field was up to 48% and 64% of the Yatt in KC and TSH, respectively. Scenario analysis indicated that the yield losses would remain at about two third of these levels while the dominant constraint was only overcome. We concluded that integrated and site-specific management practices are needed to close the cassava yield gap and maximize the efficacy of cassava intensification programs.

      PubDate: 2017-07-11T23:44:15Z
       
  • Does long-term plastic film mulching really decrease sequestration of
           organic carbon in soil in the Loess Plateau'
    • Abstract: Publication date: September 2017
      Source:European Journal of Agronomy, Volume 89
      Author(s): Feng Zhang, Wenjuan Zhang, Ming Li, Yongshun Yang, Feng-Min Li
      Plastic film mulching (PM) is used extensively in China to increase the productivity of food crops, especially in the arid and semi-arid regions, although a recent concern is whether the practice decreases soil organic carbon (SOC). A process-based biogeochemical model applied in the Loess Plateau, where PM is widespread, examined the status of SOC over 30 years of maize cultivation with PM. The model explained 96% of the observed variance in SOC. The root mean square error was 0.39gkg−1, the mean absolute error was 0.32gkg−1, and the bias value from the SOC simulation was −0.006gkg−1. The model’s projections showed that PM has no significant impact on the overall average content of SOC across the entire study area compared to the fields without mulching, or control (CK), assuming that 5% of the crop residue was ploughed back into soil. However, based on individual simulation points in the 0–50cm soil profile after 30 years of PM, 59.29% of the points, mainly on the western parts of the Loess Plateau, showed significantly higher SOC than that in CK, 8.30% showed significantly lower, and 32.41%, mainly on the south-eastern part of the Plateau, showed no significant difference between sites with PM and without it. Mulching increased the biomass, rhizodeposition, and the speed of turnover of SOC significantly, compared to the corresponding values in CK. High biomass in PM led to more carbon (C) being retained in soil and lowered the depletion of SOC. Ploughing the crop residues back into soil increased SOC, the greater the percentage of residue thus returned to soil, the higher the SOC. For a given residue return percentage, PM could increase more SOC than the CK. At 15%, which is the current average residue return ratio in the Loess Plateau, SOC levels remained stable or even increased in 77% of the study area if it adopted PM; in CK, the corresponding figure was only 63%. In regions such as the Loess Plateau where biomass is in great demand as a fuel or animal feed, PM provides greater biomass, which also means that more of it is available to be returned to soil—PM thus promotes the sequestration of SOC.

      PubDate: 2017-07-02T23:08:03Z
       
  • Within-field variations in sugar beet yield and quality and their
           correlation with environmental variables in the East of England
    • Abstract: Publication date: September 2017
      Source:European Journal of Agronomy, Volume 89
      Author(s): Salar A. Mahmood, Alistair J. Murdoch
      Spatial variability of sugar beet yield and quality within fields and their correlation with environmental variables was investigated in order to explore the potential for more precise agronomy. In three uniformly-managed, commercial sugar beet fields in the east of England spatial variation in the commercial value of the sugar yield ranged from £232 to £3320 per hectare. This variation was not random; there were high and low yielding patches in each field. Sugar beet root yield was positively correlated with the spatial distribution of crop plant population, soil organic matter and soil moisture, but negatively with weed density and canopy temperature. Correlations of sugar beet yield with soil type, elevation and soil available phosphate, potassium and magnesium were, however, inconsistent between the three fields and over two seasons. With respect to sugar beet quality, spatial variation in the amino acid and potassium concentrations in the sugar beet roots was associated with soil type and elevation, whereas sugar percentage varied randomly in two of the fields. Interventions and research that could help to optimize yield on a spatially-variable basis are discussed.
      Graphical abstract image

      PubDate: 2017-07-02T23:08:03Z
       
  • 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
       
  • 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
       
  • 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
       
  • 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
       
 
 
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