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  Subjects -> AGRICULTURE (Total: 724 journals)
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Journal Cover   European Journal of Agronomy
  [SJR: 1.381]   [H-I: 60]   [8 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 1161-0301
   Published by Elsevier Homepage  [2807 journals]
  • Quantifying the impact of irrigation on groundwater reserve and crop
           production – A case study in the North China Plain
    • Abstract: Publication date: October 2015
      Source:European Journal of Agronomy, Volume 70
      Author(s): Hongyong Sun, Xiying Zhang, Enli Wang, Suying Chen, Liwei Shao
      The North China Plain (NCP) is one of the main grain production regions in China. However, the annual double cropping system of winter wheat and maize consumed a large amount of groundwater, has led to decline in groundwater table. For conservation of groundwater resource, deficit irrigation is promoted to reduce irrigation water use in recent years. This study combined process-based modeling and experimental data together to evaluate the effects of different irrigation strategies on crop production and groundwater table change for the past three decades in NCP. Data from a six year field trial (2006–2012) under four irrigation schedules and 28 year (1984–2012) field experiment under full irrigation was used to test the agricultural production systems simulator (APSIM) to simulate the responses of winter wheat and maize to different irrigation management. The results showed that APSIM model could well simulate the grain yield and water consumption of the double cropping system under the changing climate and management practices. Simulation results with four irrigation scenarios (critical stage irrigation (CI), minimum irrigation (MI), rainfed (RF) and full irrigation (FI)) from 1984 to 2012 showed that irrigation water use efficiency (IWUE) was highest under CI, although changing from FI would lead to reduction in average annual grain yield by 19.5%, 33.7%, and 58.8% under CI, MI and RF, respectively. Even the minimum irrigation strategy (MI—one irrigation for each crop) will result in continuous decline in the groundwater table, implying an inevitable future shift to alternative cropping systems like dryland wheat-maize system, single wheat or maize. Such change will likely result in lower crop productivity and increased inter-annual variability in crop yields, which will demand improved risk management strategies to minimize loss in bad year while maximize return in good years.


      PubDate: 2015-07-26T23:09:58Z
       
  • Regional differences of CO2 emissions performance in China’s
           agricultural sector: A Malmquist index approach
    • Abstract: Publication date: October 2015
      Source:European Journal of Agronomy, Volume 70
      Author(s): Boqiang Lin, Rilong Fei
      This study attempts to employ the Malmquist index approach to evaluate the energy-related CO2 emissions performance of China’s agricultural sector. The evaluation is based on the application of Data envelopment analysis (DEA) model, using the environmental production technology that allows for desirable outputs and undesirable outputs in the production process. The study covers the period 2003–2010 and thirty provincial regions. The values of the Malmquist index and their corresponding components (technical efficiency change and technological progress change) are derived from the distance function. Empirical results show that the average annual growth of the Malmquist index, accounting for the undesirable output CO2, is 6%, and the aggregated growth of the Malmquist index is approximately 48.5%. Additionally, the two components indices help to clarify the role played by technical efficiency change and technological progress change in the final performance. Moreover, in order to illustrate the differences in CO2 emissions performance of the different regions in China, we employ the Theil index methodology for decomposing the Malmquist index in per unit CO2 emissions and provide further analysis.


      PubDate: 2015-07-26T23:09:58Z
       
  • Effect of nitrogen management during the panicle stage in rice on the
           nitrogen utilization of rice and succeeding wheat crops
    • Abstract: Publication date: October 2015
      Source:European Journal of Agronomy, Volume 70
      Author(s): Huige Xu, Guorong Zhong, Jingjing Lin, Yanfeng Ding, Ganghua Li, Shaohua Wang, Zhenghui Liu, She Tang, Chengqiang Ding
      Background and aims The main objectives of this paper were to investigate the absorption and utilization of nitrogen applied at the panicle stage in rice for promoting and protecting spikelet and the effect of residual nitrogen on the utilization of nitrogen in the succeeding wheat crop in the rotation system. Methods A field experiment was combined with a mini-plot experiment with 15N labelled urea applied at the panicle stage in rice. The experiments included three nutrient management treatments: F, S1 and S2. 126kgNha−1, 120kgN ha−1, 72kgNha−1 labeled with 30 atom% excess 15N were applied in rice, respectively. Results (1) Compare to conventional fertilizer management (F), the optimized fertilizer management (S1&S2) reduced the amount of nitrogen applications, whereas the rice and wheat yield did not decrease, and nitrogen use efficiency was improved. (2) At rice harvest, 4.7–10.7% of the fertilizer 15N was found in the 0–20cm profile. The fertilizer 15N absorbed by the wheat during the period from jointing to heading accounted for 37.0%-51.1% of the total 15N absorbed. (3) The sum of the ratio of nitrogen absorption from the rice panicle fertilizer applied to the crops (rice and wheat) and ratio of soil residue nitrogen in the wheat field were ordered S2>S1>F. Conclusion The optimized fertilization management reduced the loss of the rice nitrogen in the rice–wheat rotation system through improved recycling of rice panicle nitrogen applied in the crop-soil system.


      PubDate: 2015-07-26T23:09:58Z
       
  • Conservation agriculture effects on soil organic carbon accumulation and
           crop productivity under a rice–wheat cropping system in the western
           Indo-Gangetic Plains
    • Abstract: Publication date: October 2015
      Source:European Journal of Agronomy, Volume 70
      Author(s): Ranjan Bhattacharyya, T.K. Das, S. Sudhishri, B. Dudwal, A.R. Sharma, A. Bhatia, Geeta Singh
      Retention of carbon (C) in arable soils has been considered as a potential mechanism to mitigate soil degradation and to sustain crop productivity. Hence, we appraised the 3-year effect of different conservation agriculture (CA) practices on grain yield, biomass productivity and soil organic C (SOC) accumulation rates under a tropical rice (Oryza sativa L.)-wheat (Triticum aestivum L.) and rice–wheat–green gram (mungbean in Hindi; Vigna radiata) cropping systems. Results indicate mean (of three years) rice grain yield under mungbean residue+direct seeded rice (DSR) followed by zero tilled wheat (ZTW) with rice residue (RR) retention and zero tilled relay summer mungbean (MBR+DSR-ZTW+RR-ZTMB) plots was similar to farmers’ practice [transplanted rice (TPR)- conventionally tilled wheat (CTW)], despite TPR-CTW plots had ∼18% higher rice yield than MBR+DSR-ZTW+RR-ZTMB plots in the first year. The MBR+DSR-ZTW+RR-ZTMB treated plots had about 15 and 10% higher mean wheat grain yield and mean system productivity (sum of grain yields of all crops) than TPR-CTW plots, respectively. The plots under DSR+brown manuring (BM)-ZTW+RR plots had comparable mean rice and wheat yields to MBR+DSR- ZTW+RR-ZTMB plots. Harvestable aboveground biomass productivity of MBR+DSR-ZTW+RR-ZTMB treated plots was ∼2.89Mgha−1 yr−1 higher than TPR-CTW. Total estimated C input (∼12.1MgCha−1 in three years) under MBR +DSR-ZTW+RR-ZTMB treated plots was ∼117 and 127% higher than DSR-ZTW and TPR-CTW treatments, respectively. All CA plots had significantly higher gain (over initial value) in total SOC than that in TPR-CTW and TPR-ZTW treatments in the 0–15cm layer and the gain in total SOC in the plots under MBR+DSR- ZTW+RR-ZTMB was significantly higher than all CA plots, despite having similar total SOC stocks. Again, plots under MBR+DSR-ZTW+RR-ZTMB had ∼24% larger labile C pools than that of TPR-CTW (3.1gkg−1) treated plots in the topsoil. Soil bulk density under MBR+DSR- ZTW+RR-ZTMB and DSR+BM-ZTW+RR treated plots significantly decreased in the 5–15cm layer compared to TPR-CTW plots. Thus, the MBR+DSR-ZTW+RR-ZTMB treatment (a novel CA practice), has considerable potential to retain C in surface soil, decrease soil compaction and increase system (rice–wheat–green gram) productivity and hence its adoption is recommended.


      PubDate: 2015-07-18T21:52:45Z
       
  • A trait-based approach to crop–weed interactions
    • Abstract: Publication date: October 2015
      Source:European Journal of Agronomy, Volume 70
      Author(s): Robin J. Pakeman , Ali J. Karley , Adrian C. Newton , Luna Morcillo , Rob W. Brooker , Christian Schöb
      Understanding the mechanisms of community assembly may provide evidence to improve crop management, and in particular how weeds impact on crop yields. Focussing on plant functional traits and their diversity, we analysed a crop–weed interaction study with different levels of weed species and barley cultivar diversity to assess how weed species and barley cultivars respond to competition. Pre-emption of light resources by the taller barley did not impact on the weeds, with both weeds and barley showing similar order of magnitude shifts in height, specific leaf area and leaf dry matter content in response to crop–weed competition. These shifts were to a more conservative growth pattern, and suggest in this study a greater importance of below- than above-ground interactions in driving trait responses. The mixture of barley cultivars shifted the weeds to a more conservative growth pattern compared to the cultivar monocultures. The results indicate that cultivar mixtures could result in less need for weed control in arable fields, and possibly that the development of complementary cultivar mixtures could reinforce this effect. This confirms the results of other studies which show that mixtures either improve yields or make yields less variable in response to weed competition.


      PubDate: 2015-07-14T19:52:26Z
       
  • Development of crop coefficient models of castor and maize crops
    • Abstract: Publication date: September 2015
      Source:European Journal of Agronomy, Volume 69
      Author(s): K. Chandrasekhar Reddy
      Castor and maize are the most commonly cultivated crops in the Rajendranagar region of Andhra Pradesh, India. The study aims to develop a crop coefficient (K c) models for these crops, using Lysimeter measured daily crop evapotranspiration (ETc) data and daily reference evapotranspiration (ET0) computed using FAO-56 Penman-Monteith (PM) method. K c values obtained using relationship K c =ETc/ET0, crop coefficient curves were derived as a function of days after sowing and polynomial model was fitted. The performances of the models were tested using performance indicators. The models performed well for both the crops. These models can, therefore, be used for estimating K c values of castor and maize crops for any day after sowing in the study region.


      PubDate: 2015-07-09T19:41:41Z
       
  • Use of sewage sludge in bioenergy production—A case study on the
           effects on sorghum biomass production
    • Abstract: Publication date: September 2015
      Source:European Journal of Agronomy, Volume 69
      Author(s): Barbara Kołodziej , Jacek Antonkiewicz , Magdalena Stachyra , Elżbieta J. Bielińska , Janusz Wiśniewski , Katarzyna Luchowska , Cezary Kwiatkowski
      The aim of the study was to determine the effect of different doses of municipal sewage sludge (0, 10, 20, 40, 60MgDMha−1) on sweet sorghum yields and quality as well as changes in physico-chemical and biological properties of the soil. In a three-year field experiment located on loamy clay on an area designated for a landfill site, three sorghum varieties (GK Csaba, Róna 1, Sucrosorgo 506) were tested in order to determine which one exploited the yielding potential of sewage sludge. It was found out that application of the highest doses of sewage sludge resulted in the highest yield of plants biomass. Among the tested cultivars of sorghum the most productive was Sucrosorgo 506, while the GK Csaba was characterized by the lowest productivity. What is more, the differences in yields of individual varieties were correlated with the level of sewage sludge fertilization. Sucrosorgo 506 generated the highest yields of biomass after the highest doses of sludge application, the best results for the GK Csaba variety were obtained after the application of 40MgDM sewage sludge per hectare, while Róna 1 gave the highest yields after applying the smallest doses of sludge. It was also observed that the content, uptake and index of bioaccumulation of macronutrients and heavy metals contained in the sludge increased along with the increasing dose of the applied biosolids, reaching the maximum at 60MgDMha−1. Sorghum biomass was characterized by favourable net and gross calorific values, which were the highest in objects with the lowest doses of sewage sludge. The highest energy value of biomass yield was obtained in the case of the Sucrosorgo 506 variety (on average 144GJMg−1 ha−1), about 32% lower energy value was found in Róna 1, while the energy value of GK Csaba biomass was by half lower in comparison to Sucrosorgo 506. Sorghum tissues bioaccumulated nitrogen and cadmium intensively, zinc, copper, and nickel—at a medium level, and potassium, phosphorous, magnesium, chromium and lead were slightly accumulated. Introduction of the higher doses of municipal sewage sludge significantly affected the physico-chemical properties and enzymatic activity of soil, decreasing its pH but increasing hydrolytic acidity, total nitrogen as well as the concentration of available macronutrients but at the same time the heavy metals content. Municipal sewage sludge contributed to an increase in the organic carbon concentration, which varied primarily due to the different doses of sewage sludge. Sewage sludge introduction also resulted in a marked increase in enzymatic activity compared to the control objects, wherein the activity of dehydrogenases, acid and alkaline phosphatase, protease as well as urease increased progressively with increasing doses of sludge.
      Graphical abstract image

      PubDate: 2015-07-09T19:41:41Z
       
  • Soil nitrogen retention is increased by ditch-buried straw return in a
           rice-wheat rotation system
    • Abstract: Publication date: September 2015
      Source:European Journal of Agronomy, Volume 69
      Author(s): Haishui Yang , Bing Yang , Yajun Dai , Mingmin Xu , Roger T. Koide , Xiaohua Wang , Jian Liu , Xinmin Bian
      Ditch-buried straw return (DBSR) is a novel farming system that not only efficiently eliminates the need to burn straw, but also shows positive effects on soil carbon sequestration and crop yields. Implementation of DBSR, however, may penetrate the tillage pan, increasing the risk of N leaching losses. We therefore determined whether N retention could be increased by DBSR in order to reduce the risk of N loss to the environment. A four-year field experiment and a complementary greenhouse experiment were conducted to test the effects of DBSR on N retention in a rice-wheat rotation system. We found that DBSR altered the spatial distribution of fertilizer N. N content was significantly increased above but reduced below the straw layer in the field experiment. The greenhouse experiment further confirmed the N retention effects by the straw layer. In theory, a maximum of 9.09mg urea-N could be adsorbed by one gram dry wheat straw. Our results suggest that DBSR has the potential to increase N retention in the soil, thus increasing crop uptake and minimizing leaching N loss in the rice-wheat rotation system.


      PubDate: 2015-07-09T19:41:41Z
       
  • Life cycle assessment (LCA) of different fertilizer product types
    • Abstract: Publication date: September 2015
      Source:European Journal of Agronomy, Volume 69
      Author(s): K. Hasler , S. Bröring , S.W.F. Omta , H.-W. Olfs
      Appropriate use of fertilizer in crop production to limit the environmental impact is essential for sustainable agriculture. While much is known about the environmental impact of fertilizer production only a limited amount of data is available covering the whole fertilizer supply chain. Up to now no comparison was done on the environmental impact of different fertilizer types (i.e., complex fertilizer, bulk blend fertilizer and single nutrient fertilizer). A cradle-to-field life cycle assessment (LCA) for the fertilizer supply chain in Germany, from extraction of raw materials, via fertilizer production, transportation and storage until final application in the field was carried out. Two different complex fertilizers were compared with single nutrient fertilizers (containing only one nutrient) and bulk blend fertilizers (containing more than one nutrient as a dry mixture). The five most relevant impact categories (i.e., climate change, acidification, eutrophication, fossil fuel depletion and resource depletion) were selected to cover different environmental impacts. Additionally, a scenario analysis was carried out focusing on nitrous oxide (N2O) emissions, as new catalytic reduction techniques for the manufacturing of nitrogen (N) containing fertilizers are available that can lead to drastic reductions of N2O emissions. Production of fertilizers causes high values in the impact categories climate change, fossil fuel depletion and acidification, whereas resource depletion is dominant for production and transportation. For the impact category eutrophication, the application of fertilizer is the most important factor. For a fertilizer strategy with low phosphorus application rate, a bulk blend or single nutrient fertilizer with calcium ammonium nitrate is the most sustainable choice, while for a fertilizer strategy with a balanced nutrient formula, a bulk blend or single nutrient fertilizer with calcium ammonium nitrate or a standard complex fertilizer are sustainable options. Scenario calculations with reduced N2O emission during the production process reveals that this reduction technique is not relevant for urea based fertilizers leading to the conclusion that products containing urea need different emission reduction techniques to keep up with the environmental improvements of other nitrogen fertilizers. With an optimized fertilization strategy the environmental burden can be reduced up to 15%. As nitrogen application rates strongly affect the LCA results it is essential that the right amounts of N are used and that for N fertilizer production the best available technique should be installed. Furthermore, a careful consideration concerning the fertilizer product type should be part of every LCA of food and agricultural products, as this has a great impact on LCA results.


      PubDate: 2015-07-09T19:41:41Z
       
  • Photosynthetically active radiation determining yields for an intercrop of
           maize with cabbage
    • Abstract: Publication date: September 2015
      Source:European Journal of Agronomy, Volume 69
      Author(s): Qingsuo Wang , Dongbao Sun , Hong Hao , Xuejiao Zhao , Weiping Hao , Qiong Liu
      In order to explicate influential mechanism for yields of an intercrop of maize with cabbage, seven treatments for different intercropping rows of two crops were designed and conducted in the central Shanxi Province of China, and yield and PAR for each component crop of the intercropping treatments were measured. PAR of intercropped maize was higher than its monocropping while PAR of intercropped cabbage was lower than its monocropping. PAR highlighted a decline trend for intercropped maize and an increase trend for intercropped cabbage with increased rows of two crops in intercropping, respectively. Relationship between PAR and the number of intercropping rows of two crops was a negative linear function for intercropped maize and a positive logarithmic function for intercropped cabbage, respectively. Grain yield of intercropped maize declined and fresh yield of intercropped cabbage increased with intercropping rows of two crops, respectively. Relationship between yield and the number of intercropping rows of two crops was a logarithmic function, negative for intercropped maize and positive for intercropped cabbage, respectively. Generally, a positive linear function between yield and PAR in the intercropping system was developed for both intercropped maize and cabbage. M4‖C6 is recommended for an optimum combination of this intercropping system.


      PubDate: 2015-07-09T19:41:41Z
       
  • PRACT (Prototyping Rotation and Association with Cover crop and no Till)
           – a tool for designing conservation agriculture systems
    • Abstract: Publication date: September 2015
      Source:European Journal of Agronomy, Volume 69
      Author(s): K. Naudin , O. Husson , E. Scopel , S. Auzoux , S. Giner , K.E. Giller
      Moving to more agroecological cropping systems implies deep changes in the organization of cropping systems. We propose a method for formalizing the process of innovating cropping system prototype design using a tool called PRACT (Prototyping Rotation and Association with Cover crop and no Till) applied to a Malagasy case study. The input information for PRACT is comprised of: (i) crop and cover crop adaptation to biophysical conditions, (ii) agroecological functions of the cover crops, (iii) crop production, (iv) association possibilities between crop and cover crop, and (v) agroecological functions of the cropping system. All the information was derived from expert knowledge developed over more than 12 years of agronomic experiments in Madagascar. The final output from PRACT is a list of cropping systems, i.e., crop and cover crop associations and their sequences over three years. These cropping systems are characterized by their potential agroecological functions and crop production. The PRACT model selects a list of cropping systems taking into account the above information by using elaborate rules governing the intercropping and sequences between crops and cover crops. Examples of the outcomes of model simulations are provided for four different kinds of field. Taking into account the range of potential crops and cover crops, the number of cropping systems that was theoretically possible for the different field types ranged from 19,683 to 2.98× 1013. In a first step, PRACT reduced this number by a factor of up to 28 times to propose possible cropping systems. To do so, cropping systems are selected in terms of the biophysical requirements of plants, plant compatibility and agronomic rules. Not all of these systems are suitable for every farmer. Thus using PRACT output, a second cropping system selection step can be taken based on these cropping system characteristics, i.e., crop production and agroecological functions. By doing so the number of cropping systems selected can reach a reasonable value that can be handled by technicians and farmers. Possible uses and further development of the tool are discussed.


      PubDate: 2015-07-09T19:41:41Z
       
  • Analyzing the impact of the farming context and environmental factors on
           cropping systems: A regional case study in Burgundy
    • Abstract: Publication date: May 2015
      Source:European Journal of Agronomy, Volume 66
      Author(s): N. Aouadi , J.N. Aubertot , J. Caneill , N. Munier-Jolain
      Developing cropping systems able to improve overall sustainability requires socio-economic drivers, farm features, environmental conditions and local constraints to be taken into account. The aim of this study was to analyze the relationship between the farming context and the cropping system (CS) and to identify the components of a production situation (PS) that drive the CS characteristics. Surveys on cropping practices in 2006 in the Burgundy region were analyzed using multivariate analysis including hierarchical clustering. Thirteen groups of CS were identified and their crop sequence and level of pesticide and fertilizer use were described. A multivariate analysis was used to study the diversity in PS according to their climate, soil, and farm features. Classification and the regression tree method (CART) identified the PS variables which were most influential on CS, and defined six groups of PS that minimized intra-group CS variability. However, this variability remained high, suggesting that differences in farmer’s objectives and knowledge also contributed to differentiate cropping systems in the region studied.


      PubDate: 2015-07-09T19:41:41Z
       
  • Light interception, leaf nitrogen and yield prediction in almonds: A case
           study
    • Abstract: Publication date: May 2015
      Source:European Journal of Agronomy, Volume 66
      Author(s): Jose L. Zarate-Valdez , Saiful Muhammad , Sebastian Saa , Bruce D. Lampinen , Patrick H. Brown
      Crop yield prediction is important for the optimization of irrigation water, fertilizers, and other inputs and resources on the farm. In perennial crops, yield prediction is influenced by multiple factors regulated within the tree such as carry over effects from previous years, source-sink interactions and resource allocation and remobilization, but the bases for those regulation mechanisms are not well understood. This study reports the analysis of intensive sampling of light interception, leaf and nut nutrient concentration and yield of 768 almond trees subjected to fertilization and irrigation treatments within a mid-age commercial orchard. Nitrogen fertilization had a significant effect on individual tree fPAR, LAI, leaf nitrogen content and nut yield. While light interception and leaf area index (LAI) were poor predictors of kernel yield (R 2 =0.16–0.36 for light interception and 0.21–0.40 for LAI), leaf nitrogen pool (LNP) was able to predict 71–76% of the tree yield variability observed in two and three years. Near harvest, the LNP was highly correlated with fruit nitrogen pool (FNP) (R 2 =0.87). The results indicate that tree yield and nitrogen demand can be predicted based on leaf nitrogen content.


      PubDate: 2015-07-09T19:41:41Z
       
  • Modeling nitrous oxide emissions from organic and conventional
           cereal-based cropping systems under different management, soil and climate
           factors
    • Abstract: Publication date: May 2015
      Source:European Journal of Agronomy, Volume 66
      Author(s): Jordi Doltra , Jørgen E. Olesen , Dolores Báez , Aránzazu Louro , Ngonidzashe Chirinda
      Mitigation of greenhouse gas emissions from agriculture should be assessed across cropping systems and agroclimatic regions. In this study, we investigate the ability of the FASSET model to analyze differences in the magnitude of N2O emissions due to soil, climate and management factors in cereal-based cropping systems. Forage maize was grown in a conventional dairy system at Mabegondo (NW Spain) and wheat and barley in organic and conventional crop rotations at Foulum (NW Denmark). These two European sites represent agricultural areas with high and low to moderate emission levels, respectively. Field trials included plots with and without catch crops that were fertilized with either mineral N fertilizer, cattle slurry, pig slurry or digested manure. Non-fertilized treatments were also included. Measurements of N2O fluxes during the growing cycle of all the crops at both sites were performed with the static chamber method with more frequent measurements post-fertilization and biweekly measurements when high fluxes were not expected. All cropping systems were simulated with the FASSET version 2.5 simulation model. Cumulative soil seasonal N2O emissions were about ten-fold higher at Mabegondo than at Foulum when averaged across systems and treatments (8.99 and 0.71kgN2O-Nha−1, respectively). The average simulated cumulative soil N2O emissions were 9.03 and 1.71kgN2O-Nha−1 at Mabegondo and at Foulum, respectively. Fertilization, catch crops and cropping systems had lower influence on the seasonal soil N2O fluxes than the environmental factors. Overall, in its current version FASSET reproduced the effects of the different factors investigated on the cumulative seasonal soil N2O emissions but temporally it overestimated emissions from nitrification and denitrification on particular days when soil operations, ploughing or fertilization, took place. The errors associated with simulated daily soil N2O fluxes increased with the magnitude of the emissions. For resolving causes of differences in simulated and measured fluxes more intensive and temporally detailed measurements of N2O fluxes and soil C and N dynamics would be needed.


      PubDate: 2015-07-09T19:41:41Z
       
  • Bread wheat genetic variation for grain’s protein, iron and zinc
           concentrations as uptake by their genetic ability
    • Abstract: Publication date: July 2015
      Source:European Journal of Agronomy, Volume 67
      Author(s): Reza Amiri , Sohbat Bahraminejad , Shahryar Sasani , Saeid Jalali-Honarmand , Rosa Fakhri
      Genetic diversity among 80 irrigated bread wheat genotypes was studied for their grain’s protein, iron and zinc concentrations as well as agronomic traits. The trend of these traits over the 70 years of cultivar releasing was demonstrated. The experiment was conducted as a RCBD with three replicates under normal and terminal drought stress conditions in Kermanshah, Iran during 2011–2012 cropping season. The results of combined ANOVA revealed high significant genotypic differences for all traits, except grain iron and zinc yield. Terminal drought stress reduced all studied traits except grain iron concentration which it increased by 14.10%. The maximum effect of drought stress was on grain zinc yield, grain yield and thousand grain weight as much as 26.65, 23.48 and 18% reduction, respectively. In both conditions, there were negative correlations among grain yield and grain iron, zinc and protein concentrations. Moreover, it was found that grain yield was increased with a small improvement during 70 years while protein, iron and zinc concentrations were decreased over the years. A wide range of genetic diversity in micronutrients uptake, particularly iron and zinc within studied wheat genotypes was identified which suggesting that selection for improved micronutrients efficiency is possible. What was concluded from this study is breeders’ attention to enhancing grain production caused to neglect the quality of wheat production specially protein, iron and zinc concentrations during the last 70 years.


      PubDate: 2015-07-09T19:41:41Z
       
  • The effects of short-term waterlogging on the lint yield and yield
           components of cotton with respect to boll position
    • Abstract: Publication date: July 2015
      Source:European Journal of Agronomy, Volume 67
      Author(s): Jie Kuai , Zhiguo Zhou , Youhua Wang , Yali Meng , Binglin Chen , Wenqing Zhao
      The objectives of this study were to determine the influence of waterlogging on the lint yield and yield components, biomass accumulation and distribution in the cotton boll with respect to boll position. Cottons were subjected to waterlogging 66 days after the seedlings were transplanted into ponds created by maintaining 1–2cm of water on the soil surface for 0, 3, 6, 9 or 12d. The ponds were then drained to allow recovery. The tap root and main stem biomass were significantly reduced and the plant biomass decreased resulting from decreased biomass in fruiting branch 1–8 (FB1–8) after waterlogging. The vegetative and reproductive biomass of FB9–16 increased by altered fruiting dynamics resulted from previous waterlogging, and the highest biomass was measured in 6 days of waterlogging (WL6). Waterlogging of 3, 6, 9 and 12d resulted in a 16.0%, 24.1%, 39.5% and 50.2% reduction in lint yield, due to decreased boll number. Altered fruiting dynamics after waterlogging increased the contribution of bolls at position 3 on FB9–16 to the total yield due to an increase in boll number. The proportion of the boll wall and the seed biomass increased, while the proportion of the fiber biomass and the fiber/seed ratio decreased progressively with waterlogging duration. Insufficient assimilates were preferred compensation in boll number to boll biomass. These findings demonstrate that the bolls at various positions differed in their response to waterlogging and that even short periods (3d) of waterlogging can have considerable long-term effects on the growth of cotton.


      PubDate: 2015-07-09T19:41:41Z
       
  • Propensity for seed-mediated gene flow from potato crops and potential
           consequences for the coexistence of GM and non-GM potato systems
    • Abstract: Publication date: July 2015
      Source:European Journal of Agronomy, Volume 67
      Author(s): S. Phelan , T. Fitzgerald , J. Grant , S. Byrne , C. Meade , E. Mullins
      Potato is a critical crop to European growers, both economically and agronomically as a break crop in the standard cereal rotation. As studies investigating the agronomic performance and environmental impact of disease resistant, GM potatoes come to an end across several sites in Europe, past discussions on achieving the effective coexistence of GM and equivalent non-GM crops have too often focussed on the purported risk of excessive pollen-mediated gene flow. Dependent on the crop in question, the impact of seed loss pre- and/or post-harvest presents a greater challenge to securing efficient coexistence practises. To examine this issue for potato, a total of 51 fields that had been commercially cultivated with potatoes were surveyed in two separate cohorts for post-harvest tuber loss and/or volunteer emergence. Across 17 fields studied, the average post-harvest tuber loss was recorded at 141,758±911 tubers ha−1, with volunteer establishment in the following crop ranging from 400±59ha−1 to 55,698±47ha−1. In parallel, by surveying a separate cohort of 34 commercial fields an average of 30,789±2658 volunteer ha−1 was recorded in the subsequent cereal crop, with a repeat survey made after an additional year indicating an 87.2% reduction in this mean number of volunteers across the 34 fields (P <0.001). Of the additional variables studied only location (P <0.001), herbicide application (P =0.037) and potato variety used (P =0.045) significantly influenced volunteer proliferation. Volunteer fecundity was confirmed with upto 3 tubers produced per 1st generation volunteer, with tuber yield from the 2nd generation volunteers reduced significantly (P <0.001). Assessments of the tuber lots from these 2nd generation volunteers confirmed their ability to sprout post-dormancy, therefore, indicating the potential for 3rd generation volunteers to emerge. Combined, the datasets confirm the potential for significant seed-mediated gene flow from commercial potato systems; indicating that the regulated 0.9% coexistence threshold would in all probability be compromised if GM potatoes were grown in rotations of 1:4 years or less, in the absence of a comprehensive tuber loss and/or volunteer management system.


      PubDate: 2015-07-09T19:41:41Z
       
  • Productivity and resource use in intensified cropping systems in the
           Rolling Pampa, Argentina
    • Abstract: Publication date: July 2015
      Source:European Journal of Agronomy, Volume 67
      Author(s): J.F. Andrade , S.L. Poggio , M. Ermácora , E.H. Satorre
      Increasing cropland productivity is critical to meet future global demand of food, fibers and biofuels. Recent innovations in grain crop management are aimed at designing more ecologically complex cropping systems by growing doublecrop sequences comprising a great variety of crop species. The objectives of this study were to compare (i) the pattern of resource use and the productivity in cool-season crops and their influence on the following warm-season second crops, and (ii) the overall resource capture, resource use efficiency, and productivity of various single and double cropping systems. Hence, three field experiments under rainfed conditions and computer-simulated experiments were conducted in contrasting sites in the Rolling Pampa. Seven cropping systems were evaluated, which included five double crop sequences (rapeseed/soybean, wheat/soybean, barley/soybean, field pea/soybean, and field pea/maize) and maize and soybean as single crops. Cool-season crops differed in resource use, which therefore affected differently the following second crop. The highest and the lowest yields with double cropped soybean were produced after field pea and wheat, respectively. Soybean single crop was the least productive treatment because of low resource capture and moderate resource use efficiency. Double cropping systems including soybean as second crop outperformed soybean single crop productivity due to larger resource use. Comparatively, maize single crop used fewer resources but with higher efficiency than the cropping systems including soybean, which led to higher yields when water was not limiting. Field pea/maize double crop was the most productive system, since field pea allowed for long resource use periods, while maintaining similar resource use efficiency as maize single crops. Field experiment results were confirmed by crop yield simulations based on 39 years of environmental data from the same sites. Wheat/soybean double crops expanded and contributed to raise productivity in the Pampas with available farming technologies. However, novel crop type combinations appeared as feasible ways for improving resource use balance in the growing season among the component crops. This may raise the total annual productivity or, at least, increase the grain yield of soybean, the more profitable component at present. These findings have important implications regarding the ecological intensification of commodity grain cropping systems, which can be implemented by proactive farmers in the short-term in various regions of the world.


      PubDate: 2015-07-09T19:41:41Z
       
  • Increased utilization of lengthening growing season and warming
           temperatures by adjusting sowing dates and cultivar selection for spring
           maize in Northeast China
    • Abstract: Publication date: July 2015
      Source:European Journal of Agronomy, Volume 67
      Author(s): Jin Zhao , Xiaoguang Yang , Shuwei Dai , Shuo Lv , Jing Wang
      Global warming has lengthened the theoretical growing season of spring maize in Northeast China (NEC), and the temperatures during the growing season have increased. In practise, crop producers adjust sowing dates and alternate crop cultivars to take advantage of the lengthening growing season and increasing temperatures. In this study, we used crop data and daily weather data for 1981–2007 at five locations in NEC to quantify the utilization of the lengthening growing season and increasing temperatures by adjusting sowing dates and cultivar selection for spring maize production. If these two positive factors are not fully utilized, then it is important to know the potential impacts of these climatic trends on spring maize grain yields. The results show that in NEC, both the actual and theoretical growing seasons are lengthening, i.e., the sowing dates have been advanced and the maturity dates have been delayed. The actual sowing dates are 1–8days later and the actual maturity dates are 6–22days earlier than the theoretical perspective. Advancing sowing dates and changing cultivars led to 0–5days and 6–26days extension of the growing season. For the potential thermal time (TT), adjusting the sowing dates decreased the unutilized TT before sowing, while the cultivar selection increased the utilized TT and decreased the unutilized TT after maturity. On average, the unutilized heating resource before sowing is less than that after the maturity date (0.3–1.9% vs. 2.1–7.8%). During 1981–2007, for per day extension of the growing season, the spring maize grain yield increased by 75.2kgha−1. The spring maize grain yields have increased by 7.1–57.2% when both early sowing and changing cultivars during 1981–2007. In particular, adjusting the sowing dates increased the grain yield by 1.1–7.3%, which was far less than the increase effect (6.5–43.7%) from switching to late maturing cultivars. Therefore, selecting late maturing cultivars is an important technique to improve maize grain yields in NEC under the global warming context. Nevertheless, if the currently unutilized TT were fully explored, the local spring maize grain yield would have increased by 12.0–38.4%.


      PubDate: 2015-07-09T19:41:41Z
       
  • Strategies to optimize nitrogen efficiency when fertilizing with pig
           slurries in dryland agricultural systems
    • Abstract: Publication date: July 2015
      Source:European Journal of Agronomy, Volume 67
      Author(s): A.D. Bosch-Serra , C. Ortiz , M.R. Yagüe , J. Boixadera
      In dryland agricultural systems, pig slurry (PS) is usually applied to cereal crops only at sowing, and slurries accumulate for the rest of the year in pits. In this context, a four-year experiment was established in order to evaluate the feasibility of PS applications at the barley or wheat tillering stage. The main treatments were PS either applied at sowing (25Mgha−1) or not, but they alternated after a two-year period. Both were annually combined with eight side-dressing treatments at cereal tillering: mineral N as NH4NO3 (M; 60 or 120kgNha−1 yr−1), PS from fattening pigs (PSf; 17, 30, 54 Mgha−1 yr−1), PS from sows (PSs; 25, 45, 81 Mgha−1 yr−1) and a treatment without N. The combined fertilization treatments were 18 plus a control (no N applied). In the context of crop rotation, the biennial alternation of PS applied at sowing allowed the control of soil nitrate increments, while PS side-dressing improved N recovery compared with a unique application at sowing. The highest yields (>3.6 Mgha−1 yr−1) were obtained with an annual average (4-yr) N rate close to 173kg Nha−1 (±40kg Nha−1). The best overall strategies corresponded to PSs side-dressings of 50–90kg Nha−1. These PSs rates also recorded the highest values on the five calculated N-efficiency indexes, which were higher than or similar to results from M side-dressings or those recorded in the literature. These similarities (M vs. PSs) were also shown by the reduction of unaccounted-for N inside the overall N balance. Thus, split PS application during the crop cycle is a sound fertilization option in dryland systems.


      PubDate: 2015-07-09T19:41:41Z
       
  • A simulation model for predicting canopy structure and light distribution
           in wheat
    • Abstract: Publication date: July 2015
      Source:European Journal of Agronomy, Volume 67
      Author(s): Wenyu Zhang , Liang Tang , Xue Yang , Leilei Liu , Weixing Cao , Yan Zhu
      Quantitative simulation of architectural structure and light distribution within a crop canopy is important for photosynthesis estimation and virtual construction. This study was undertaken to simulate the leaf curve, canopy structure and light distribution in winter wheat (Triticum aestivum L.). The field experiments with different plant types and sowing densities were carried out, and the time-course changes in canopy structure and light distribution were measured in winter wheat. The leaf curvature in wheat canopy increased with increasing sowing density and the leaf curve could be simulated with a quadratic function and its varied forms. The maximal value of leaf curvature was considered as a cultivar parameter reflecting the genetic characteristics, and the plant number per unit area was used to quantify the effects of sowing density on leaf curvature. Based on the simulated canopy structure, the leaf angle distribution function (f(θL )), extinction coefficient (K(θ)) and leaf area index (LAI) of the canopy were directly calculated by dividing leaf inclination angle into tiny units and accumulating the corresponding leaf areas. Then, the vertical distribution of photosynthetic photon flux density (PPFD) in a canopy could be simulated by using the Beer’s law. The models were validated with the independent dataset from the field experiment of different wheat cultivars. The average relative root mean square error (RRMSE) between the estimated and observed values were 17.44% for layered LAI and 19.35% for PPFD. These results indicated that the present model could effectively predict the growth dynamics of structure and of light distribution within wheat canopies, which would be useful for structural visualization or photosynthesis simulation.


      PubDate: 2015-07-09T19:41:41Z
       
  • Physiological differences in yield related traits between flint and dent
           Argentinean commercial maize genotypes
    • Abstract: Publication date: August 2015
      Source:European Journal of Agronomy, Volume 68
      Author(s): Santiago Tamagno , Ignacio A. Greco , Helbert Almeida , Lucas Borrás
      Argentina is the worldwide single maize (Zea mays L.) exporter of non-GMO flint maize, also called plata maize. This grain is known for high dry-milling yields, the production of large endosperm grits and specific cooking functional properties. But, this special maize has lower yields at farmer fields when compared to regular dent germplasm, and studies describing the physiological characteristics behind this are scarce. Our objective was to understand differences in yield determination mechanisms between flint and dent commercial germplasm for the temperate area. We characterized 31 genotypes (24 dent and 7 flint) growing at five different environments for describing their yield differences, and also described specific physiological traits to unravel the mechanisms behind these yield differences. Grain yield, KNP, KW, plant growth rate and biomass partitioning around flowering, kernel set efficiency per unit of accumulated ear biomass at flowering and assimilate availability per kernel during flowering all showed significant kernel type (flints vs. dents) effects (p <0.05). And significant genotype differences within each kernel type were evident for all traits (p <0.01). Flint kernel type showed lower yields (ca. 80% of dents) due to reduced KNP and KW. This lower KNP in flints was mostly related to a lower plant growth rate around flowering, although they also showed a reduced biomass partitioning to the ear during this period. Flint genotypes, however, showed higher kernel set efficiency per unit of accumulated ear biomass when compared to dents (p <0.01). Lower KW in flints was related to a reduced assimilate availability per kernel around flowering (p <0.01), both kernel types showed similar assimilate availability per kernel during grain filling (p >0.05). This indicated flint and dent kernel types had the same amount of assimilates to fulfill their early established potential KW. Our results emphasize the importance of the flowering period for understanding yield differences between flints and dents, and biomass accumulation rate during this period was identified as a key trait for increasing flint yields.


      PubDate: 2015-07-09T19:41:41Z
       
  • Selecting crop models for decision making in wheat insurance
    • Abstract: Publication date: August 2015
      Source:European Journal of Agronomy, Volume 68
      Author(s): A. Castañeda-Vera , P.A. Leffelaar , J. Álvaro-Fuentes , C. Cantero-Martínez , M.I. Mínguez
      In crop insurance, the accuracy with which the insurer quantifies the actual risk is highly dependent on the availability on actual yield data. Crop models might be valuable tools to generate data on expected yields for risk assessment when no historical records are available. However, selecting a crop model for a specific objective, location and implementation scale is a difficult task. A look inside the different crop and soil modules to understand how outputs are obtained might facilitate model choice. The objectives of this paper were (i) to assess the usefulness of crop models to be used within a crop insurance analysis and design and (ii) to select the most suitable crop model for drought risk assessment in semi-arid regions in Spain. For that purpose first, a pre-selection of crop models simulating wheat yield under rainfed growing conditions at the field scale was made, and second, four selected models (Aquacrop, CERES-Wheat, CropSyst and WOFOST) were compared in terms of modelling approaches, process descriptions and model outputs. Outputs of the four models for the simulation of winter wheat growth are comparable when water is not limiting, but differences are larger when simulating yields under rainfed conditions. These differences in rainfed yields are mainly related to the dissimilar simulated soil water availability and the assumed linkages with dry matter formation. We concluded that for the simulation of winter wheat growth at field scale in such semi-arid conditions, CERES-Wheat and CropSyst are preferred. WOFOST is a satisfactory compromise between data availability and complexity when detail data on soil is limited. Aquacrop integrates physiological processes in some representative parameters, thus diminishing the number of input parameters, what is seen as an advantage when observed data is scarce. However, the high sensitivity of this model to low water availability limits its use in the region considered. Contrary to the use of ensembles of crop models, we endorse that efforts be concentrated on selecting or rebuilding a model that includes approaches that better describe the agronomic conditions of the regions in which they will be applied. The use of such complex methodologies as crop models is associated with numerous sources of uncertainty, although these models are the best tools available to get insight in these complex agronomic systems.


      PubDate: 2015-07-09T19:41:41Z
       
  • Seed yield prediction of sesame using artificial neural network
    • Abstract: Publication date: August 2015
      Source:European Journal of Agronomy, Volume 68
      Author(s): Samad Emamgholizadeh , M. Parsaeian , Mehdi Baradaran
      The prediction of seed yield is one of the most important breeding objectives in agricultural research. So, in this study, two methods namely artificial neural network (ANN) and multiple regression model (MLR) were employed to estimate the seed yield of sesame (SYS) from readily measurable plant characters (e.g., flowering time of 100% (days), the plant height (cm), the capsule number per plant, the 1000-seed weight (g) and the seed number per capsule). The ANN and MLR were tested using field data. Results showed that the ANN predicts the SYS accurately with a root-mean-square-error (RMSE) of 0.339t/ha and a determination coefficient (R 2) of 0.901. Also, it was found that the ANN model performed better than the MLR model with a RMSE of 0.346t/ha, and R 2 of 0.779. Finally, sensitivity analysis was conducted to determine the most and the least influential characters affecting SYS. It was found that the capsule number per plant and the flowering time of 100% had the most and least significant effects on SYS, respectively.


      PubDate: 2015-07-09T19:41:41Z
       
  • Sowing date affected shoot and root biomass accumulation of lucerne during
           establishment and subsequent regrowth season
    • Abstract: Publication date: August 2015
      Source:European Journal of Agronomy, Volume 68
      Author(s): Richard E. Sim , Derrick J. Moot , Hamish E. Brown , Edmar I. Teixeira
      The pattern of perennial dry matter (DM) was manipulated over two seasons to determine if the establishment of lucerne (Medicago sativa L.) is regulated by the demand for assimilate by perennial organs, (taproot plus crown) or crop ontogeny. Crops of ‘Stamina 5’ lucerne were established from spring to late summer at two sites which differed by 230mm to 2.3m soil depth in plant available water content (PAWC) at Lincoln University, New Zealand. The establishment phase was characterised from sowing until crops reached a maximum accumulation of perennial biomass of ∼5tDMha−1. Demand for biomass offered insight into the variability in fractional partitioning of DM to the perennial organs (P root) during establishment. This showed that P root was 0.48 until a perennial biomass of 2.9±0.28tDMha−1. Lucerne continued to partition DM to the perennial organs until a maximum biomass of ∼5tDMha−1, but at a decreasing rate shown by a linear decline in P root in response to increasing perennial biomass. This meant P root was independent of crop ontogeny, but most likely still under the control of environmental influences, and the establishment phase extended into the second season for crops which had not attained a perennial biomass >3tDMha−1. These crops continued to prioritise the allocation of DM to the perennial organs which explained the 20–25% decrease in shoot yield in the second season when sowing was delayed. This study quantified the establishment phase of lucerne to perennial biomass demand as independent of crop ontogeny. It showed establishment was regulated by biomass demand of these perennial organs. The spring sown crops on the High PAWC soils completed this phase at the earliest in 4 months. In contrast, autumn sown crops on the Low PAWC soils took nearly 9 months to complete this phase. These results indicate different management strategies may be required to establish lucerne rather than solely using first flowering as a sign that the establishment phase is complete. Results can be incorporated into the current partitioning framework to improve the simulation modelling of lucerne.


      PubDate: 2015-07-09T19:41:41Z
       
  • A simple approach to predict growth stages in winter wheat (Triticum
           aestivum L.) combining prediction of a crop model and marker based
           prediction of the deviation to a reference cultivar: A case study in
           France
    • Abstract: Publication date: August 2015
      Source:European Journal of Agronomy, Volume 68
      Author(s): Matthieu Bogard , Jean-Baptiste Pierre , Bertrand Huguenin-Bizot , Delphine Hourcade , Etienne Paux , Xavier Le Bris , David Gouache
      Predicting wheat growth stages using ecophysiological models is of particular interest as it allows anticipating important agricultural managements. Numerous ecophysiological models exist but they need cultivar-specific parameterization, which is often costly and time consuming. The work presented here proposes a simple approach to predict wheat growth stages using the allelic composition of wheat cultivars. It relies on using the prediction of a modified version of the ARCWHEAT model for a well parameterized reference cultivar (Soissons) and the marker-based predicted deviation in days to the reference cultivar. First, the deviations to the reference cultivar Soissons for the beginning of stem elongation (δZ30) and heading date (δZ55) were calculated for a large panel of cultivars. Analysis of variance showed prominent genetic effects for δZ30 and δZ55 and possible genotype×environment interactions (G × E) for δZ30. Genotypic means δZ30 and δZ55 were used in association genetics revealing 90 and 83 genetic markers associated to these traits, respectively. Multiple linear regression models predicting δZ30 using 11 genetic markers (R 2 =76%) or δZ55 using 17 markers (R 2 =85%) were obtained by a stepwise procedure. Marker PPD-D1 had the largest impact in both models. Finally, marker-based deviations added to the prediction for the reference cultivar Soissons allowed predicting Z30 or Z55 for a large independent validation dataset. The root mean square error of prediction for Z30 and Z55 using the approach proposed in this paper (6.8 and 4.7 days, respectively) was comparable to the one obtained using the conventional approach with cultivar-specific parameters values (6.5 and 4.1, respectively). The models proposed in this paper appeared sufficient in order to predict growth stages of cultivars which cannot be parameterized such as new cultivars coming out on the market. Moreover, genetic markers involved in the multiple linear regression models predicting δZ30 and δZ55 may provide interesting candidates to unravel new genes determining earliness in winter wheat.


      PubDate: 2015-07-09T19:41:41Z
       
  • Winter wheat cultivars and nitrogen (N) fertilization—Effects on
           root growth, N uptake efficiency and N use efficiency
    • Abstract: Publication date: August 2015
      Source:European Journal of Agronomy, Volume 68
      Author(s): Irene Skovby Rasmussen , Dorte Bodin Dresbøll , Kristian Thorup-Kristensen
      One way to reduce nitrate leaching losses from agricultural land is to increase crop nitrogen uptake efficiency (NUpE). In this aspect, root growth is an essential parameter, as more and deeper roots may improve the uptake from deeper soil layers and reduce nitrate leaching. This study examined the root growth, soil N depletion and yields of modern, commercial winter wheat (Triticum aestivum L.) cultivars in a two-year field experiment conducted on sandy loam soils. The effects of N fertilization on root growth and inorganic soil N utilization were quantified. In order to obtain data from the entire winter wheat rooting zone, the measurements were conducted to 2.3m soil depth. Root growth was studied by means of minirhizotrons. Parallel to the belowground measurements, the effects on aboveground biomass and N uptake were measured. In the two experimental years the average maximum root depths were 1.1 and 1.5m, respectively, and the average root depth penetration rates were 0.7 and 1.0mm°C day−1, respectively. N fertilization affected root density, which increased at least up to an application of 150kg N ha−1. The effect on root density was mostly seen in soil layers below 0.5m. N fertilization did not appear to affect root depth. There were root growth differences among the cultivars, though not strongly pronounced. The cultivar Hereford showed tendencies to higher root densities and deeper root growth, and this trend was correlated with a tendency to increased subsoil N depletion. Also, Hereford showed higher N use efficiency (NUE) compared to the other cultivars, as it produced more grain per N supply. Under the existing experimental conditions, a spring application up to 150kg N ha−1 did not increase the amount of nitrate left in the soil at harvest. In contrast, by an increase of N fertilization from 150 to 250kg N ha−1, on average 36 % of the extra 100kg N ha−1 was left in the soil. With a further increase from 250 to 350kg N ha−1, up to 90% of the extra N was left in the soil. The soil N increase at high N fertilization was most profound in the upper soil layer but also significant in the subsoil.


      PubDate: 2015-07-09T19:41:41Z
       
  • Which cropping systems to reconcile weed-related biodiversity and crop
           production in arable crops? An approach with simulation-based
           indicators
    • Abstract: Publication date: August 2015
      Source:European Journal of Agronomy, Volume 68
      Author(s): Delphine Mézière , Nathalie Colbach , Fabrice Dessaint , Sylvie Granger
      Weed management must both control weed harmfulness for crop production and promote weed contribution to biodiversity as an essential component of biodiversity in agricultural landscapes. The objective of the present paper was to evaluate a large range of existing cropping systems to determine management rules for reconciling weed-related biodiversity and weed harmfulness, comparing 26 contrasting cropping systems identified via farm surveys in two contrasting French regions, Burgundy and Poitou-Charentes. These systems were simulated, using the weed dynamics model FlorSys which predicts weed flora dynamics over the years, depending on cropping system and pedoclimate. The simulated flora was translated into five weed harmfulness indicators (crop yield loss, harvest contamination, harvesting difficulty, field infestation, additional crop disease due to weeds) and five weed-related biodiversity indicators (weed species richness and equitability, weed-based trophic offer for birds, insects and pollinators). Cropping system performance was assessed with a Principal Component Analysis (PCA) on the 10 weed-impact indicators, followed by a hierarchical clustering analysis. Five contrasting profiles in terms of weed harmfulness and contribution to biodiversity were identified, combining different levels of weed harmfulness and biodiversity. To identify management strategies (i.e., combinations of cultural practices) for reaching these different performance profiles, tree-based regression and classification models (CART) were constructed to explain performance profiles as a function of cropping system descriptors and pedoclimatic variables. Ten management strategies were identified for reaching the five performance profiles. The most interesting performance profile, which minimized all harmfulness indicators (except harvest contamination and harvesting difficulty) and maximized all biodiversity indicators (except species richness), was reached by a single strategy type, consisting of low or no-till systems. Systems with cover crops and little or no mechanical weeding also reconciled most production and biodiversity goals. Multiple management pathways for reaching a given goal present the advantage of letting farmers choose the strategy most compatible with the objectives and constraints of their farm. The present results were obtained with annual weed species only, and taking into account the management of perennial weeds will probably modify the strategies. The same method was also applied to identify strategies for reconciling crop production, biodiversity and reduced herbicide use, though none of the investigated cropping systems was able to reconcile all three objectives, indicating that novel cropping systems must be designed specifically for this objective.


      PubDate: 2015-07-09T19:41:41Z
       
  • More rice with less water – evaluation of yield and resource use
           efficiency in ground cover rice production system with transplanting
    • Abstract: Publication date: August 2015
      Source:European Journal of Agronomy, Volume 68
      Author(s): Yueyue Tao , Yanan Zhang , Xinxin Jin , Gustavo Saiz , Ruying Jing , Lin Guo , Meiju Liu , Jianchu Shi , Qiang Zuo , Hongbin Tao , Klaus Butterbach-Bahl , Klaus Dittert , Shan Lin
      Adoption of the innovative water-saving ground cover rice production system (GCRPS) based on transplanting of rice seedlings under high soil moisture conditions, resulted in an overall increase in grain yield compared to previous reports on GCRPS employing direct seeding. However, there is a lack of quantitative information on water and nitrogen use efficiency as affected by water and nitrogen management in GCRPS-transplanting. To close this knowledge gap, we conducted a two-year field experiment with traditional paddy rice (Paddy) and GCRPS-transplanting under two soil moisture conditions (GCRPSsat and GCRPS80%), combined with 3 nitrogen fertilizer management regimes (0, 150kg urea-N/ha as basal fertilizer for Paddy and GCRPS, 150kg urea-N/ha in 3 splits for Paddy or 75kg urea-N/ha plus 75kg N/ha as chicken manure for GCRPS). Grain yield, water and nitrogen use efficiency, stable isotope 13C of plant shoots and yield components were evaluated. The study showed: (1) compared to Paddy, both GCRPSsat and GCRPS80% produced significantly more grain yield, while no significant difference in grain yield was found between both GCRPS treatments. (2) Irrigation water use efficiency was increased by 140% in GCRPSsat and >500% in GCRPS80%, while total water use efficiency was improved by 52–96% as compared to Paddy. (3) δ 13C of plant shoots was significantly higher in GCRPS than in Paddy, and showed significant positive correlations with total and irrigation water use efficiencies. (4) Compared to Paddy, agronomic N use efficiency was significantly higher in both forms of GCRPS. However, N recovery rates were only significantly higher in GCRPS than in Paddy when all urea nitrogen was applied as basal fertilizer before transplanting. With improved fertilizer N management, i.e., split N application in Paddy or combined application of urea and chicken manure in GCRPS, there were no significant differences. Overall, this quantitative evaluation of water use efficiency highlights that the use of GCRPS involving transplanting of seedlings has a great potential to reduce irrigation water input, increase grain yield and resource use efficiency.
      Graphical abstract image

      PubDate: 2015-07-09T19:41:41Z
       
  • Meta-modelling of the impacts of regional cropping system scenarios for
           phoma stem canker control
    • Abstract: Publication date: August 2015
      Source:European Journal of Agronomy, Volume 68
      Author(s): L. Hossard , V. Souchere , E. Pelzer , X. Pinochet , M.H. Jeuffroy
      In agricultural landscapes, pest and disease control mainly rely on cropping system characteristics and location. We have combined a participatory approach and a spatially-explicit model, to design and assess cropping system scenarios for future contextual changes in the small region of Picardie, France. Phoma stem canker of winter oilseed rape (WOSR), a widespread disease responsible for major economic losses, was used as a case study to investigate the effects of modifying cropping systems, at a regional scale, on disease controlling and on the sustainability of a newly introduced specific resistance gene (RlmX). Meta-models were fitted to assess the effects of cropping practices and weather conditions included in scenarios on three complementary model outputs: size of the pathogen population, yield loss, and fraction of the virulent population on RlmX-cultivars. We ran three replicates of each cropping practice scenario, varying the location of WOSR and associated cropping characteristics within the region. Outputs differed slightly between replicates, but there were no significant differences between replicates (alpha=0.001) for each output. The size of the pathogen population was well explained by winter oilseed rape acreages, cultivar landscape composition and tillage, and the yield loss was explained by weather conditions and cultivars. The fraction of the virulent population on RlmX-cultivars was explained primarily by cultivar landscape composition. These differences in explanatory variables for the different outputs highlighted their complementarity. Cropping practices and weather impacts on the three variables remained consistent among the explored possible future contexts. Highlighting the most efficient cropping practices to be applied in the event of different future changes could help local decision-makers to design cropping practices in the face of contextual change.


      PubDate: 2015-07-09T19:41:41Z
       
  • Large-scale assessment of optimal emergence and destruction dates for
           cover crops to reduce nitrate leaching in temperate conditions using the
           STICS soil–crop model
    • Abstract: Publication date: September 2015
      Source:European Journal of Agronomy, Volume 69
      Author(s): Julie Constantin , Christine Le Bas , Eric Justes
      Cover crops can be an efficient agricultural practice to reduce nitrate leaching during the fallow period and decrease nitrate pollution of aquifers. For maximum reduction of nitrate leaching, cover-crop management must be adapted to the pedoclimatic context. We used the soil–crop model STICS to assess optimal emergence dates in summer and destruction dates in autumn and winter for three species of cover crops (mustard, ryegrass and vetch) at a large scale in France. We first calibrated and validated STICS’s predictions of soil and crop dynamics under a wide range of conditions, including bare soil and cover crops. Since predictions were sufficiently accurate, we then predicted the impact of several emergence and destruction dates of cover crops on nitrate leaching in 24 contrasting climatic sites over 20 years. These sites represented a wide range of conditions found in France and much of Europe. Using generalized linear model (GLM), we extrapolated to the vulnerable nitrate zones in France the optimal dates predicted for the 24 sites. We defined optimal emergence date as the date allowing the higher nitrate leaching decrease in drained water and optimal destruction dates as those for which a high reduction of nitrate leaching was predicted and that also avoided negative effects on the subsequent main crop and water resources. STICS accurately predicted mineral N and water dynamics from both calibration and validation datasets, despite lower accuracy for vetch simulations. Over the 20-year simulations, optimal dates varied, depending mainly on site, cover crop and year. Optimal emergence dates for cover crops were earlier for vetch (late July) than for ryegrass (early August) and mustard (late August) and earlier in the north (cold and rainy) than in the south of France (warm and dry). Optimal destruction dates, as defined in this paper, were frequently between October and December. Mean optimal dates by site and species were strongly correlated with climatic characteristics of the 24 sites tested, which enabled us to extrapolate them to a larger scale and identify areas with similar optimal emergence and destruction dates according to cover-crop species. Later optimal emergence dates occurred in southeastern France in late August and September, while the earliest dates occurred in late July and early August in the north and east of France. The extrapolated optimal destruction dates occurred in autumn (October–December), with later destruction dates located in zones with higher temperature in the western coastal zones of the Atlantic Ocean and in southeastern France.


      PubDate: 2015-07-09T19:41:41Z
       
  • Six-year transition from conventional to organic farming: effects on crop
           production and soil quality
    • Abstract: Publication date: September 2015
      Source:European Journal of Agronomy, Volume 69
      Author(s): Dario Sacco , Barbara Moretti , Stefano Monaco , Carlo Grignani
      Organic farming has become increasingly important in recent decades as the consumer has grown its focus on the food and environmental benefits of the technique. However, when compared to conventional farming systems, organic farm system are known to yield less. Presented in this paper are the results from two organic cropping systems following six years of organic management. Fertilisation management differentiated the two systems; one was fertilised with green manure and commercial organic fertilisers, while the other was fertilised with dairy manure. A conventional cropping system, managed with mineral fertiliser as typical in the southern Piemonte region (Italy), served as the bussiness as usual crop management. The first hypothesis tested related to crop yield variation during the initial phase of organic management; we expected a sharp reduction in the early phase, then minor reductions later on. The second hypothesis tested related to soil fertility variation; we expected enhanced soil fertility under organic management. Overall, the organic system produced less, relative to the conventional system in interaction with year effect. Yield reduction seemed related to the lower soil nutrient availability of organic fertilisers that provided nutrients consequent to mineralisation. Therefore, summer crops are well-suited to manure-fertilised organic farms as mineralisation happens at higher temperatures, as opposed to winter wheat, which is largely reduced in such systems. Commercial organic fertilisers can, however, limit this effect through their high nutrient availability in the winter and early spring Also shown was that soil quality, defined as a general decrease in soil organic carbon (SOC) over time in the three analysed arable systems, can be mitigated by manure additions. Green manuring can maintain SOC and increase total N in soil, only if introduced for a sufficient number of years during crop rotation. Finally, soil fertility and Potential Mineralisable N in the different systems demonstrated that organic systems managed with commercial organic nitrogen fertilisers and green manure do not improve soil quality, compared to systems managed with mineral fertilisers.


      PubDate: 2015-07-09T19:41:41Z
       
  • Factors influencing adoption of cover crops for weed management in
           Machakos and Makueni counties of Kenya
    • Abstract: Publication date: September 2015
      Source:European Journal of Agronomy, Volume 69
      Author(s): H.W. Mwangi , A.W. Kihurani , J.M. Wesonga , E.S. Ariga , F. Kanampiu
      Despite the many advantages of growing cover crops most farmers have not adopted them in their cropping systems. The objective of this study was to examine adoption and sociological factors associated with adoption of cover crops in Kalama (Machakos county) and Kee (Makueni county), Kenya. A semi-structured questionnaire was administered to 80 randomly selected participants to obtain sociological information including gender, age category, education levels, and adoption of cover crops. Two binary logistic regression models were used to determine the factors affecting cover crops adoption by respondents. Results showed that 80% of the respondents had adopted cover crop technologies at Kalama compared to 57.5% at Kee. Results indicated that gender had a significant (P <0.05) effect on adoption. Men were less likely to adopt. Age category had mixed effects on cover crop adoption. At Kalama age category had a significant (P< 0.05) effect on cover crops adoption however age effect was not significant at Kee. Education indicated mixed effects on cover crop adoption suggesting other factors not covered in the study were at play. Views from farmers with experience in growing cover crops revealed that, knowledge and skills, demonstration of gains and related cost had a significant (P< 0.05) effect on cover crop adoption. Majority of farmers, adopters or non-adopters used seeds from market. Non-adopters in Kee (37.5%) used relief seed suggesting other factors were required to give the threshold required to influence adoption. This implies research is needed to identify factors with likelihood to reach threshold for adoption under different farming systems. The study recommends capacity building to develop cover crop knowledge and skills, demonstrate gains and related costs to improve men and women’s likelihood to adopt. In addition, the study recommends research to shed light on other factors likely to influence adoption.


      PubDate: 2015-07-09T19:41:41Z
       
  • Simulating dry matter yield of two cropping systems with the simulation
           model HERMES to evaluate impact of future climate change
    • Abstract: Publication date: October 2015
      Source:European Journal of Agronomy, Volume 70
      Author(s): Rüdiger Graß , Burga Thies , Kurt-Christian Kersebaum , Michael Wachendorf
      Regionalized model calculations showed increased rainfall and temperatures in winter and less precipitation and higher temperatures in summer due to climate change effects in the future for numerous countries in the northern hemisphere. Furthermore, model simulations predicted enhanced weather variability with an increased risk of yield losses and reduced yield stability. Recently, double cropping systems (DCS) were suggested as an environmental friendly and productive adaptation strategy with increased yield stability. This paper reviews the potential benefit of four DCS (rye (Secale cereale L.) as first crop and maize (Zea mays L.), sunflower (Helianthus annuus L.), sorghum (Sorghum sudanense L.× Sorghum bicolor L.) and sudan grass (S. sudanense L.) as second crops) in comparison with four conventional sole cropping systems (SCS) (maize, sunflower, sorghum and sudan grass) with regard to dry matter (DM) yield and soil water under conditions of climate change. We used the agro-ecosystem model HERMES for simulating these variables until the year 2100. The investigated crops sunflower, sorghum and sudan grass were parameterised first for HERMES achieving a satisfying performance. Results showed always higher DM yields per year of DCS compared with SCS. This was mainly caused by yield increases of the first crop winter rye harvested at the stage of milk ripeness. As a winter hardy crop, rye will benefit from increased precipitation and higher temperatures during winter months as well as from extended growth periods with an earlier onset in spring and an increase of growing days. Furthermore, rye is able to use the increased winter humidity for its spring growth in an efficient way. By contrast, model simulations showed that summer crops will be affected by reduced precipitation and higher temperatures during summer month for periods from 2050 onwards with the consequence of reduced yields. This yield reduction was found for all summer crops both in conventional sole crop and in DCS. Preponed harvesting of first crop winter rye as a consequence of earlier onset of growth period in spring under prospective climatic conditions lead to yield decrease, which could not be equalised by preponed sowing of second crops and extension of their growth period. Hence, total annual yield of both crops together decreased. The modification of sowing and harvesting dates as an adaptation strategy requires further research with the use of more holistic simulation models. To summarize, DCS may provide a promising adaptation strategy to effects of climate change with a substantial stabilisation of crop yields.


      PubDate: 2015-07-09T19:41:41Z
       
  • Impact of conservation agriculture practices on energy use efficiency and
           global warming potential in rainfed pigeonpea–castor systems
    • Abstract: Publication date: May 2015
      Source:European Journal of Agronomy, Volume 66
      Author(s): G. Pratibha , I. Srinivas , K.V. Rao , B.M.K. Raju , C.R. Thyagaraj , G.R. Korwar , B. Venkateswarlu , Arun K. Shanker , Deepak K. Choudhary , K.Srinivas Rao , Ch. Srinivasarao
      Identification of agricultural practices which maximize crop productivity, energy use efficiency (EUE) and minimize greenhouse gas (GHG) emissions is essential. There is dearth of information in rainfed agriculture in general and conservation agriculture in particular, hence a study was conducted to assess the EUE and GHG emissions of different tillage practices like conventional tillage (CT), reduced tillage (RT) and zero tillage (ZT) and residue levels (harvesting heights resulting in 0, 10 and 30cm anchored residue) in pigeonpea–castor systems under semi-arid rainfed regions of India. CT recorded 30 and 31% higher energy inputs than ZT in pigeonpea and castor, respectively. The fuel consumption in ZT was 58 and 81% lower than CT in pigeonpea and castor, respectively. This lower fuel consumption in ZT reduced the GHG emissions by 21 and 23% in pigeonpea and castor, respectively, in comparison with CT. EUE and energy productivity were maximum in ZT with 10cm anchored residue. Further, castor grown on pigeonpea residue recorded 10 and 20% higher energy inputs and GHG emissions over pigeonpea grown on castor residues. Our results indicate that, reduction in one tillage operation with residue have a minimal impact on the crop yields but have a substantial environmental benefits.


      PubDate: 2015-07-09T19:41:41Z
       
  • Surface liming and nitrogen fertilization for crop grain production under
           no-till management in Brazil
    • Abstract: Publication date: May 2015
      Source:European Journal of Agronomy, Volume 66
      Author(s): E.F. Caires , A. Haliski , A.R. Bini , D.A. Scharr
      Supplying a large amount of NO3 − in the subsurface can be a strategy to combat subsoil acidity under no-till systems. However, soil acidification caused by ammoniacal fertilizers can increase both aluminum toxicity and lime requirement. A field experiment was performed in the period from 2004 to 2012 in Parana State, Brazil, on a loamy, kaolinitic, thermic Typic Hapludox to evaluate the effects of surface liming and ammoniacal fertilization on soil chemical attributes and yields of crops in rotation under continuous no-till. The region has a mesothermal, humid subtropical climate, with mild summer, frequent frosts during the winter, and no defined dry season. The average altitude is 970m and the annual precipitation is about 1550mm. The treatments consisted of annual applications of NH4NO3 at 0, 60, 120, and 180kgNha−1 to subplots within plots with surface-applied lime previously at 0, 4, 8, and 12Mgha−1, calculated to raise the base saturation in the topsoil (0–20cm) to 40, 65, and 90%. Lime was broadcast on the soil surface in May 2004. The nitrogen rates were applied during the period from 2004 to 2011 in top dressing at tillering of winter crops [black oat (Avena strigosa Schreb.) or wheat (Triticum aestivum L.)], before growing corn (Zea mays L.), soybean (Glycine max L. Merr.) or bean (Phaseolus vulgaris L.) during the summer (2004–2012). Surface-applied lime under no-till was effective in alleviating soil acidity from the soil surface to a 20cm depth. The soil pH increased in the layers below the soil surface to 20cm depth during a 6 years period following surface lime application. Ammoniacal fertilization had an acidifying effect and did not change the effectiveness of surface applied lime to alleviate subsoil acidity. Soil organic matter content was higher in the upper few centimeters under no-till and remained unchanged over time after surface liming and ammoniacal fertilization. Increasing the rate and frequency of ammoniacal fertilizer application increased crop response to surface liming, but did not change the lime requirement to achieve higher crop grain yields. The lime rate estimated by the soil base saturation method at 70% in the 0–20cm depth was appropriate for surface liming recommendation, even when substantial amounts of ammoniacal fertilizer were applied in a no-till system. The results suggest that nitrogen fertilizer use for winter crops could be dramatically reduced in areas under a continuous no-till system, particularly where lime has been applied.


      PubDate: 2015-07-09T19:41:41Z
       
  • Analyzing inter-factor substitution and technical progress in the Chinese
           agricultural sector
    • Abstract: Publication date: May 2015
      Source:European Journal of Agronomy, Volume 66
      Author(s): Boqiang Lin , Rilong Fei
      In this paper, we employ a trans-log production function model for China’s agricultural sector, with capital, labor and energy as input factors. The output elasticity, substitution elasticity and relative difference in technical progress among the factors are analyzed. The results show that during the period 1980–2012 the growth of the agricultural economy in China benefited from the combined effects of factors accumulation and technical progress. Among the factors, the output elasticity of labor is the largest, followed by capital and energy. Capital, labor and energy are substitutes for one another, but the elasticity of substitution between capital and energy is the highest, with a value of 1.1. In the meantime, the relative difference in technical progress among these factors is insignificant and there is a convergence trend over time. We suggest increasing technological innovation in order to improve the contribution of technology progress as well as allocating more capital into the agricultural sector in order to alleviate the shortage of energy supply and the current problem of “hollow” in the rural labor force. This is of great significance to reducing energy consumption and improving the total factor productivity in the China’s agricultural sector.


      PubDate: 2015-07-09T19:41:41Z
       
  • Do soil organic carbon levels affect potential yields and nitrogen use
           efficiency? An analysis of winter wheat and spring barley field trials
           
    • Abstract: Publication date: May 2015
      Source:European Journal of Agronomy, Volume 66
      Author(s): Myles Oelofse , Bo Markussen , Leif Knudsen , Kirsten Schelde , Jørgen E. Olesen , Lars Stoumann Jensen , Sander Bruun
      Soil organic carbon (SOC) is broadly recognised as an important parameter affecting soil quality, and can therefore contribute to improving a number of soil properties that influence crop yield. Previous research generally indicates that soil organic carbon has positive effects on crop yields, but in many studies it is difficult to separate the effect of nutrients from the effect of SOC in itself. The aim of this study was to analyze whether the SOC content, in itself, has a significant effect on potential yields of commonly grown cereals across a wider range of soil types in Denmark. The study draws on historical data sets from the Danish national field trials consisting of 560 winter wheat (Triticum aestivum L.) trials and 309 spring barley (Hordeum vulgare L.) trials conducted over the past 20 and 17 years, respectively. We hypothesised that for these two crops, the potential grain yield, the yield with no fertiliser N application and the N use efficiency would be positively affected by SOC level. A statistical model was developed to explore relationships between SOC and potential yield, yields at zero N application and N use efficiency (NUE). The model included a variety of variables and aimed to elucidate the sole effect of SOC by controlling for potential confounding variables. No significant effect of SOC on potential winter wheat was found, whilst for spring barley, only for the course sandy loam soil type was a borderline significantly positive effect of SOC on potential yields found. The relationship between unfertilized plot yields and SOC was positive for winter wheat, although not significant, whilst for spring barley a significant positive effect of SOC was found only for the coarse sandy soil type, and a borderline significant positive effect of SOC was found for the coarse sandy loam soil type. A significant negative relationship was found between SOC and NUE for both winter wheat and spring barley. Based on the large dataset analyzed, we cautiously challenge the importance of SOC in contributing to crop productivity in contexts with similar soils and climate, and we speculate that in situations where nutrient limitation does not occur, SOC levels above 1% may be sufficient to sustain yields. In light of the findings presented in this study, further work should be conducted which can further elucidate the effect of SOC on yields.


      PubDate: 2015-07-09T19:41:41Z
       
  • Nitrogen management is the key for low-emission wheat production in
           Australia: A life cycle perspective
    • Abstract: Publication date: May 2015
      Source:European Journal of Agronomy, Volume 66
      Author(s): Weijin Wang , Ram C. Dalal
      Farm management affects the global greenhouse gas (GHG) budget by changing not only soil organic carbon (SOC) stocks and nitrous oxide (N2O) emissions but also other pre-farm, on-farm and off-site emissions. The life cycle assessment (LCA) approach has been widely adopted to assess the “carbon footprint” of agricultural products, but rarely used as a tool to identify effective mitigation strategies. In this study, the global warming impacts of no-till (NT) vs. conventional till (CT), stubble retention (SR) vs. stubble burning (SB), and N fertilization (NF) vs. no N fertilization (N0) in an Australian wheat cropping system were assessed using in situ measurements of N2O fluxes over three years, SOC changes over forty years and including other supply chain GHG sources and sinks. The results demonstrated the importance of full GHG accounting compared to considering SOC changes or N2O emissions alone for assessing the global warming impacts of different management practices, and highlighted the significance of accurately accounting for SOC changes and N2O emissions in LCAs. The GHG footprints of wheat production were on averaged 475kg carbon dioxide equivalent (CO2-e) ha−1 (or 186kg CO2-e t−1 grain) higher under NF than N0. Where fertilizer N was applied (70kgNha−1), the life cycle emissions were 200kg CO2-e ha−1 (or 87t−1 grain) lower under NT than CT and 364kg CO2-e ha−1 (or 155t−1 grain) lower under SR than SB. Classification of the emission sources/sinks and re-calculation of published data indicated that under the common practices of SR combined with NT, N-related GHG emissions contributed 60–95% of the life cycle emissions in the predominantly rain-fed wheat production systems in Australia. Therefore, future mitigation efforts should aim to improve N use efficiency, explore non-synthetic N sources, and most importantly avoid excessive N fertilizer use whilst practising NT and SR.


      PubDate: 2015-07-09T19:41:41Z
       
  • Associations between drought resistance, regrowth and quality in a
           perennial C4 grass
    • Abstract: Publication date: April 2015
      Source:European Journal of Agronomy, Volume 65
      Author(s): Yi Zhou , Christopher J Lambrides , Shu Fukai
      Climate change has brought a sharp and renewed focus on plant breeding programs to develop cultivars with improved performance in dry environments. The pleiotropic effects of selection for drought resistance are not well understood in perennial C4 grasses. The objective of this study was to determine the commercial production characteristics including sod strength and post-harvest regrowth of bermudagrass ecotypes selected for drought resistance. These attributes were studied in a set of bermudagrasses (Cynodon dactylon), a species used extensively around the world for forage and turfgrass. Three field experiments using 12 genotypes contrasting for drought resistance were evaluated, on bermudagrass turf production facilities, for quality and regrowth after the canopy (sod) was mechanically removed. Among the genotypes tested, there was large genotypic variation for rhizome dry matter (RhDM) (0.01–0.81kgm−2), aboveground dry matter (ADM) (0.59–0.17kgm−2) and root dry matter (RDM) (0.04–0.12kgm−2). Regrowth of the canopy was positively correlated to RhDM (r=0.79∼0.80) and negatively correlated to ADM (r=−0.69∼−0.74) but there was no association with RDM. Biomass partitioning determined at the time of the second harvest revealed that genotypes with more rapid regrowth had larger proportional DM distributed to rhizome (63.5% vs 7.1%) than to aboveground (27.2% vs 86.5%) and root (8.5% vs 8.1%). Our previous research with these genotypes showed a strong correlation between drought resistance and RhDM prior to the drought period. Consequently, an analysis of the relationship between drought resistance measured previously and post-harvest regrowth in the experiments described here revealed a strong positive correlation (r>0.64). Genotypic variation for sod strength, an important turf quality attribute, was large ranging from 1281kgm−2 to 5671kgm−2. However, sod strength was neither correlated to drought resistance, nor the traits measured from harvested sod such as stolon diameter, internode length, number of branches and single stolon strength, nor to dry matter distribution. These results may reflect the existence of a range of different mechanisms for sod strength present in the material tested. Nevertheless, there were genotypes e.g., MED1 that combined the favorable traits of drought resistance, faster regrowth rate and higher sod strength and could be used as an important genetic resource for future breeding. MED1 was one of several highly rhizomatous genotypes in the study that originated from the Mediterranean climatic zone of Australia.


      PubDate: 2015-07-09T19:41:41Z
       
  • Climatic risk assessment to improve nitrogen fertilisation
           recommendations: A strategic crop model-based approach
    • Abstract: Publication date: April 2015
      Source:European Journal of Agronomy, Volume 65
      Author(s): B. Dumont , B. Basso , B. Bodson , J.-P. Destain , M.-F. Destain
      Within the context of nitrogen (N) management, since 1950, with the rapid intensification of agriculture, farmers have often applied much larger fertiliser quantities than what was required to reach the yield potential. However, to prevent pollution of surface and groundwater induced by nitrates, The European Community launched The European Nitrates Directive 91/6/76/EEC. In 2002, in Wallonia (Belgium), the Nitrates Directive has been transposed under the Sustainable Nitrogen Management in Agriculture Program (PGDA), with the aim of maintaining productivity and revenue for the country’s farmers, while reducing the environmental impact of excessive N application. A feasible approach for addressing climatic uncertainty lies in the use of crop models such as the one commonly known as STICS (simulateur multidisciplinaire pour les cultures standard). These models allow the impact on crops of the interaction between cropping systems and climatic records to be assessed. Comprehensive historical climatic records are rare, however, and therefore the yield distribution values obtained using such an approach can be discontinuous. In order to obtain better and more detailed yield distribution information, the use of a high number of stochastically generated climate time series was proposed, relying on the LARS-Weather Generator. The study focused on the interactions between varying N practices and climatic conditions. Historically and currently, Belgian farmers apply 180kgNha−1, split into three equal fractions applied at the tillering, stem elongation and flag-leaf stages. This study analysed the effectiveness of this treatment in detail, comparing it to similar practices where only the N rates applied at the flag-leaf stage were modified. Three types of farmer decision-making were analysed. The first related to the choice of N strategy for maximising yield, the second to obtaining the highest net revenue, and the third to reduce the environmental impact of potential N leaching, which carries the likelihood of taxation if inappropriate N rates are applied. The results showed reduced discontinuity in the yield distribution values thus obtained. In general, the modulation of N levels to accord with current farmer practices showed considerable asymmetry. In other words, these practices maximised the probability of achieving yields that were at least superior to the mean of the distribution values, thus reducing risk for the farmers. The practice based on applying the highest amounts (60–60–100kgNha−1) produced the best yield distribution results. When simple economical criteria were computed, the 60–60–80kgNha−1 protocol was found to be optimal for 80–90% of the time. There were no statistical differences, however, between this practice and Belgian farmers’ current practice. When the taxation linked to a high level of potentially leachable N remaining in the soil after harvest was considered, this methodology clearly showed that, in 3 years out of 4, 30kgNha−1 could systematically be saved in comparison with the usual practice.


      PubDate: 2015-07-09T19:41:41Z
       
  • Cotton yield and fiber quality affected by row spacing and shading at
           different growth stages
    • Abstract: Publication date: April 2015
      Source:European Journal of Agronomy, Volume 65
      Author(s): Fábio R. Echer , Ciro A. Rosolem
      Carbohydrate production and reproductive structure development in cotton (Gossypium hirsutum) depends on light availability, a determinant of cotton yield. Light availability is decreased by cloud cover or self-shading when cotton plants are grown in dense populations. The objective of this study was to evaluate the effects of shading during cotton growth and its interactions with plant row spacings on yield and fiber quality. Three independent experiments were conducted as follows: in Paranapanema (23°39′S; 48°58′W), cotton was planted in November in row spacings of 0.45, 0.75 and 0.96m; in Primavera do Leste (15°33′S; 54°11′W), planting was in January with at row spacings of 0.45 and 0.76m; and in Chapadão do Céu (18°38′S; 52°40′W), cotton was planted in February in rows spaced at 0.45 and 0.90 m. Plants were exposed to shading during the phenological stages B1 (floral bud), F1 (early flowering), PF (peak flowering) and 3OB (fruit maturity). In addition, there was one treatment without shade. There were no interactions of crop spacing with shading. Increasing plant population and shading both decreased net photosynthetic rate. The number of bolls m−2 increased with higher plant populations only when planting was delayed, and were not affected by shading. When cotton was planted in November and January, higher yields were obtained at 0.75/0.76m, but when planting was delayed to February, 0.45m resulted in higher yields with no effect on fiber quality. Shading for eight or ten days decreases boll weight and yields, but do not affect fiber quality. Cotton yield is the most decreased when shading occurs during flowering. These results may be used to build management strategies to minimize shading effects by adjusting cotton sowing time and plant density, by selecting cultivars with increased shade tolerance and by choosing an adequate irrigation period to improve yield.


      PubDate: 2015-07-09T19:41:41Z
       
  • “Productivity, quality and sustainability of winter wheat under
           long-term conventional and organic management in Switzerland”
    • Abstract: Publication date: April 2015
      Source:European Journal of Agronomy, Volume 65
      Author(s): Jochen Mayer , Lucie Gunst , Paul Mäder , Marie-Françoise Samson , Marina Carcea , Valentina Narducci , Ingrid K. Thomsen , David Dubois
      Long-term sustainability and high resource use efficiency are major goals for high quality baking wheat production throughout the world. Present strategies are low input systems such as organic agriculture or improved conventional systems (integrated). The fertilisation level and strategy, crop protection as well as preceding crop effects may modulate system performance with respect to wheat grain yield, quality and environmental performance of the systems. Our aim was to evaluate data of winter wheat (Triticum aestivum L.) performance from the DOK long-term systems experiment in Switzerland comparing two mixed organic (biodynamic and bioorganic: BIODYN and BIOORG) and a mixed conventional cropping system (CONFYM) using mineral fertilisers and farmyard manure at two fertilisation intensities (level 1: 50% of standard fertilisation, level 2: standard fertilisation) since 1978. A conventional system was fertilised exclusively minerally at level 2 (CONMIN) and a control remained unfertilised (NOFERT). We compared crop yields, baking quality parameters, the nitrogen use efficiency and the effect of maize and potatoes as preceding crops obtained between 2003 and 2010 along with long-term soil sustainability parameters. The mean grain yields across both fertiliser levels of the organic cropping systems (BIODYN and BIOORG) were 64% of CONFYM, whereas crude protein contents were 79% of CONFYM at fertilisation level 2 and achieved 90% at level 1. The main driving factor of lower yields was a reduction of the numbers of ears per m2 and the thousand kernel weight. The apparent nitrogen use efficiency decreased with increasing N fertilisation. Doubling the organic fertilisation in the organic systems only slightly improved wheat grain yields but was not able to improve grain baking quality, due to low mineral N additions via slurry and farmyard manure. In contrast the effects of the preceding crop potatoes in comparison with preceding silage maize outperformed the organic fertilisation effects, resulting in 33% higher yields and 11% higher crude protein contents. The yield components recorded in the case of preceding potatoes demonstrated a more synchronised nutrient supply throughout the wheat development. Over all low input systems and both fertilisation levels in the conventional mixed farm system at half standard fertilisation (level 1) performed best with distinctly higher grain yields and crude protein contents than in the organic systems with standard fertilisation. However, all systems, organic and conventional, with the low or zero organic fertiliser inputs performed poorly considering the long-term soil quality parameters, indicating a degradation of soil quality. The DOK long-term experiment allows an integrated view on the performance of baking wheat production and long-term sustainability. The results emphasise the importance of a sufficient supply of soils with organic fertilisers as well as the need to improve the availability of organic nitrogen and synchrony between nutrient supply and demand in organic baking wheat production, beside the selection of a suitable preceding crop.


      PubDate: 2015-07-09T19:41:41Z
       
  • Designing eco-efficient crop rotations using life cycle assessment of crop
           combinations
    • Abstract: Publication date: April 2015
      Source:European Journal of Agronomy, Volume 65
      Author(s): Thomas Nemecek , Frank Hayer , Emmanuel Bonnin , Benoît Carrouée , Anne Schneider , Christophe Vivier
      Intensive arable crop production has major impacts on the environment and solutions for their reduction are needed. Diversification of crop rotations together with improved nitrogen management is an option for more eco-efficient cropping systems. The potentials for reducing the environmental impacts cropping systems were investigated by means of life cycle assessment (LCA) in three regions in France (Beauce, Burgundy and Moselle). The crop management data were compiled by the Chambers of Agriculture in the three regions based on field survey data (2002–2009 in Burgundy and Moselle and 2004–2008 in Beauce) and completed by experts. The LCA calculations were carried out by the SALCA-crop tool, using the ecoinvent and SALCA inventory databases and SALCA emission models. The LCAs were calculated for crop combinations, which were an efficient way to analyse a large number of crop rotations. A crop combination is defined as the inventory of a given crop, with a defined preceding crop and eventually including a catch crop. Nitrogen management revealed to be a key driver for the environmental impacts. It dominated the non-renewable energy demand, the global warming potential, the ozone formation potential, the acidification potential, and the eutrophication potential. Strong correlations between N fertilisation and these environmental impacts were found. The introduction of pea allowed to reduce the total eutrophication over the whole crop rotation. The mitigation of environmental impacts was not only possible per hectare, but also per € gross margin II. The eco-efficiency can thus be improved by reducing the level of N fertilisation. A reduction of N fertilisation could be achieved also by a reduction of the fertiliser doses to the non-legume crops, in addition to the introduction of legumes. Both ways proved to be effective and the combination of both was the most promising. However, trade-off between environmental and economic goals was identified. Diversification of cereal intensive crop rotations proved to be generally favourable from an environmental point of view. Catch crops had favourable effects on nutrient leaching a slightly favourable effects on biodiversity and soil quality. The ecotoxicity potentials were dominated by a few active ingredients only; the diversification did not lead to generally reduced ecotoxicity potentials. Diverse crop rotations with reduced N input are a promising way to reduce the environmental impacts of intensive arable crop rotations.


      PubDate: 2015-07-09T19:41:41Z
       
  • Seasonal changes in nutrient content and concentrations in a mature
           deciduous tree species: Studies in almond (Prunus dulcis (Mill.) D. A.
           Webb)
    • Abstract: Publication date: April 2015
      Source:European Journal of Agronomy, Volume 65
      Author(s): Saiful Muhammad , Blake L. Sanden , Bruce D. Lampinen , Sebastian Saa , Muhammad I. Siddiqui , David R. Smart , Andres Olivos , Kenneth A. Shackel , Theodore DeJong , Patrick H. Brown
      Knowledge of the pattern of nutrient uptake and loss and the within-tree allocation of nutrients in trees is critical to the understanding of ecosystem nutrient fluxes and to the management of applied nutrients in agricultural ecosystems. Fluxes of nutrients in whole trees and determination of total annual uptake, nutrient allocation within organs and loss in annual organs were obtained in a mature commercial almond (Prunus dulcis) orchard managed with non-limiting irrigation under varied nitrogen (N) and potassium (K) fertilization regimes from 2008 through 2012. Whole tree nutrient dynamics were derived from multiple in-season measurements of nutrients in leaves and fruits and biomass in all years. Whole tree nutrient budgets in perennial tree parts were derived from whole tree excavations and tree coring in 2011 and 2012 when the orchard had reached >85% full canopy closure. The annual N increment in perennial tree organs was 21kg, 41kg, 44kg and 45kgha−1 for the four N application rates of 140kg, 224kg, 309kg and 392kgha−1 N, respectively. In this orchard maximum agronomic productivity (yield plus increment in tree size) was recorded with an N application rate of 309kgha−1. Under optimal N application the annual increment in P, K, Ca and Mg was 8kg, 38kg, 3.5kg and 2.8kgha−1. Total N in leaves in midsummer in 2012 (a low yield year) was 37kg, 43kg, 54kg and 58kgha−1 for the four N application rates. In contrast, total N in leaves at mid-summer in 2011 (high yield year) was 21kg, 28kg, 35kg and 39kgha−1 for the four N application rates. In years 2009 through 2011 nitrogen in fruit at harvest represented 90% of whole tree N fluxes. In trees provided just adequate N to achieve maximal yield (309kgha−1 in this experiment in years 2009–11), N, P, K, S, Ca and Mg export in fruit was 212kg–366kgha−1, 26kg–45kgha−1, 265kg–389kgha−1, 7.9kg–14.4kgha−1, 24.7kg–29.6kgha−1 and 15.9kg–22.6kgha−1, respectively. The majority of whole tree macro and micronutrient uptake occurred between anthesis and kernel fill with 35–50% of total N uptake occurring before 40 days after full bloom (DAFB) and 80–90% of the total N being accumulated by 112 DAFB coinciding with kernel filling. Over 70% of the total P and 65–80% of the total K was accumulated in fruits by mid-season. Ninety percent of total S, 80–90% of total Ca and 70–85% of total Mg accumulated in fruit by 112 DAFB. The findings from the study can be used for in-season fertilizer management according to plant demand based on expected yield.


      PubDate: 2015-07-09T19:41:41Z
       
  • Impact of data resolution on heat and drought stress simulated for winter
           wheat in Germany
    • Abstract: Publication date: April 2015
      Source:European Journal of Agronomy, Volume 65
      Author(s): E. Eyshi Rezaei , S. Siebert , F. Ewert
      Heat and drought stress can reduce crop yields considerably which is increasingly assessed with crop models for larger areas. Applying these models originally developed for the field scale at large spatial extent typically implies the use of input data with coarse resolution. Little is known about the effect of data resolution on the simulated impact of extreme events like heat and drought on crops. Hence, in this study the effect of input and output data aggregation on simulated heat and drought stress and their impact on yield of winter wheat is systematically analyzed. The crop model SIMPLACE was applied for the period 1980–2011 across Germany at a resolution of 1km×1km. Weather and soil input data and model output data were then aggregated to 10km×10km, 25km×25km, 50km×50km and 100km×100km resolution to analyze the aggregation effect on heat and drought stress and crop yield. We found that aggregation of model input and output data barely influenced the mean and median of heat and drought stress reduction factors and crop yields simulated across Germany. However, data aggregation resulted in less spatial variability of model results and a reduced severity of simulated stress events, particularly for regions with high heterogeneity in weather and soil conditions. Comparisons of simulations at coarse resolution with those at high resolution showed distinct patterns of positive and negative deviations which compensated each other so that aggregation effects for large regions were small for mean or median yields. Therefore, modelling at a resolution of 100km×100km was sufficient to determine mean wheat yield as affected by heat and drought stress for Germany. Further research is required to clarify whether the results can be generalized across crop models differing in structure and detail. Attention should also be given to better understand the effect of data resolution on interactions between heat and drought impacts.


      PubDate: 2015-07-09T19:41:41Z
       
  • Evaluation of monocropped and intercropped grain legumes for cover
           cropping in no-tillage and reduced tillage organic agriculture
    • Abstract: Publication date: April 2015
      Source:European Journal of Agronomy, Volume 65
      Author(s): Lars Rühlemann , Knut Schmidtke
      Intensive tillage by means of mouldboard ploughing can be highly effective for weed control in organic farming, but it also carries an elevated risk for rapid humus decomposition and soil erosion. To develop organic systems that are less dependent on tillage, a two-year study at Reinhardtsgrimma and Köllitsch, Germany was conducted to determine whether certain legume cover crops could be equally successfully grown in a no-till compared with a reduced tillage system. The summer annual legumes faba bean (Vicia faba L.), normal leafed field pea (Pisum sativum L.), narrow-leafed lupin (Lupinus angustifolius L.), grass pea (Lathyrus sativus L.), and common vetch (Vicia sativa L.) were examined with and without sunflower (Helianthus annuus L.) as a companion crop for biomass and nitrogen accumulation, symbiotic nitrogen fixation (N2 fixation) and weed suppression. Total cover crop biomass, shoot N accumulation and N2 fixation differed with year, location, tillage system and species due to variations in weather, inorganic soil N resources and weed competition. Biomass production reached up to 1.65 and 2.19Mgha−1 (both intercropped field peas), and N2 fixation up to 53.7 and 60.5kgha−1 (both common vetches) in the no-till and reduced tillage system, respectively. In the no-till system consistently low sunflower performance compared with the legumes prevented significant intercropping effects. Under central European conditions no-till cover cropping appears to be practicable if weed density is low at seeding. The interactions between year, location, tillage system and species demonstrate the difficulties in cover crop species selection for organic conservation tillage systems.


      PubDate: 2015-07-09T19:41:41Z
       
  • Heat stress in cereals: Mechanisms and modelling
    • Abstract: Publication date: March 2015
      Source:European Journal of Agronomy, Volume 64
      Author(s): Ehsan Eyshi Rezaei , Heidi Webber , Thomas Gaiser , Jesse Naab , Frank Ewert
      Increased climate variability and higher mean temperatures are expected across many world regions, both of which will contribute to more frequent extreme high temperatures events. Empirical evidence increasingly shows that short episodes of high temperature experienced around flowering can have large negative impacts on cereal grain yields, a phenomenon increasingly referred to as heat stress. Crop models are currently the best tools available to investigate how crops will grow under future climatic conditions, though the need to include heat stress effects has been recognized only relatively recently. We reviewed literature on both how key crop physiological processes and the observed yields under production conditions are impacted by high temperatures occurring particularly in the flowering and grain filling phases for wheat, maize and rice. This state of the art in crop response to heat stress was then contrasted with generic approaches to simulate the impacts of high temperatures in crop growth models. We found that the observed impacts of heat stress on crop yield are the end result of the integration of many processes, not all of which will be affected by a “high temperature” regime. This complexity confirms an important role for crop models in systematizing the effects of high temperatures on many processes under a range of environments and realizations of crop phenology. Four generic approaches to simulate high temperature impacts on yield were identified: (1) empirical reduction of final yield, (2) empirical reduction in daily increment in harvest index, (3) empirical reduction in grain number, and (4) semi-deterministic models of sink and source limitation. Consideration of canopy temperature is suggested as a promising approach to concurrently account for heat and drought stress, which are likely to occur simultaneously. Improving crop models’ response to high temperature impacts on cereal yields will require experimental data representative of field production and should be designed to connect what is already known about physiological responses and observed yield impacts.


      PubDate: 2015-07-09T19:41:41Z
       
  • The use of 13C and 15N based isotopic techniques for assessing soil C and
           N changes under conservation agriculture
    • Abstract: Publication date: March 2015
      Source:European Journal of Agronomy, Volume 64
      Author(s): Kenza Ismaili , Mohammed Ismaili , Jamal Ibijbijen
      A four years experiment was conducted to investigate the effect of tillage and addition of crop residues in wheat–faba bean rotation. The soil was fertilized with a total of 150kgnitrogen (N)ha−1 enriched with 9.96 percent nitrogen-15 (15N) atom excess, in four applications. The first crop was corn, a C4 plant cropped under till (T) and no-till (NT) conditions. Percent N derived from fertilizer (Ndff) by corn was 37.12–48.62. The leaves had the lowest delta carbon-13 (δ 13C) values of −12.7 and the seeds the highest (−11.8). Soil δ 13C was affected by addition of C4 plant residues. Soil under residue and till treatment (RT) had the highest percent 15N values. Residues and no-till (RNT) had the lower percent 15N values. At the end of the corn crop soil percent 15N was 0.211, 0.26, and 0.253 in the three soil depths. Residues and tillage increased significantly the Ndff of wheat: from 6.43 to 6.46kgNha−1 for no residues no-till (NRNT) and no-residues and till (NRT) and from 11.1 to 13kgNha−1 in RNT and RT treatments. In wheat nitrogen derived from residues (Ndfr) was 4.68 and 1.53kgNha−1 in grain and residues, respectively. Residues and tillage affected significantly soil C, N, 15N, and δ 13C from seeding to two months after and have no effect at harvest. The interaction was always significant. After four years the 15N fertilizer contributed only with 1.5–2.85kgNha−1 in NRNT and NRT, respectively, and 3.3–5.63kgNha−1 in RNT and RT, respectively. Cumulated N recovered during the three growing seasons following corn was 8.59–11.07kgNha−1 for NRNT and NRT; 20.24–15.6kgNha−1 for RT and RNT, respectively. Residues increased N mineralization by 50 percent and the quantity of 15N available to plants increased with tillage.


      PubDate: 2015-07-09T19:41:41Z
       
  • Breeding effects on the cultivar×environment interaction of durum
           wheat yield
    • Abstract: Publication date: August 2015
      Source:European Journal of Agronomy, Volume 68
      Author(s): Joan Subira , Fanny Álvaro , Luis F. García del Moral , Conxita Royo
      Understanding the effect of past durum wheat breeding activities on the cultivar×environment (C×E) interaction of yield and yield components may guide future breeding strategies. A historical series of 24 cultivars released in Italy and Spain during the 20th century was grown in 13 environments with average yields ranging between 1425 and 6670kgha−1. The most important environmental factors affecting the C×E interaction for yield were reference evapotranspiration before anthesis and water input during grain filling. The response of cultivars to environmental variables in terms of yield and yield components was associated to the allelic composition for the Rht-B1 locus. Improved semi-dwarf cultivars (carrying the Rht-B1b allele) had the best yield performance in environments with high water input after anthesis, while tall cultivars (carrying allele Rht-B1a) were better adapted to environments with high evapotranspirative demand before anthesis and low water input after it. The introduction of the Rht-B1b allele improved the capacity of the crop to respond to water availability during grain filling by increasing the number of grains spike−1 and grain weight. Yield increases due to breeding caused a loss of stability from the static viewpoint, but not from a dynamic approach based on the superiority measure (Pi ). Some semi-dwarf cultivars maintained the levels of yield stability characteristic of the old tall ones. Our results suggest that durum breeding in the 20th century enhanced the response of the crop to environmental improvements.


      PubDate: 2015-05-18T11:02:54Z
       
 
 
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