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  Subjects -> AGRICULTURE (Total: 686 journals)
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    - AGRICULTURE (460 journals)
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Journal Cover European Journal of Agronomy
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   Hybrid Journal Hybrid journal (It can contain Open Access articles)
     ISSN (Print) 1161-0301
     Published by Elsevier Homepage  [2575 journals]   [SJR: 1.191]   [H-I: 53]
  • Heat stress in cereals: Mechanisms and modelling
    • Abstract: Publication date: Available online 13 December 2014
      Source:European Journal of Agronomy
      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: 2014-12-13T15:03:27Z
       
  • In field non-invasive sensing of the nitrogen status in hybrid
           bermudagrass (Cynodon dactylon × C. transvaalensis Burtt Davy) by a
           fluorescence-based method
    • Abstract: Publication date: February 2015
      Source:European Journal of Agronomy, Volume 63
      Author(s): Giovanni Agati , Lara Foschi , Nicola Grossi , Marco Volterrani
      The level of N fertilization and the content of leaf N in Cynodon dactylon × C. transvaalensis Burtt Davy cv. ‘Tifway 419’ bermudagrass were evaluated non-destructively with a fluorescence-based method. It was applied directly into the field by using the Multiplex portable fluorimeter during two consecutive seasons (2010 and 2011). In the 2010 experiment, the nitrogen balance index (NBI1) provided by the sensor was able to discriminate (at P <0.05) six different N levels applied, up to 250kgha−1, with a precision (root mean square error, RMSE) in the rate estimate of 3.29kgha−1. In 2011, the index was insensitive to the N treatment between 150kgha−1 and 250kgha−1 N rates, and its precision was 39.98kgha−1. Calibration of the sensor by using the destructive analysis of turf samplings showed a good linear regression between NBI1 and the leaf N content for both 2010 (R 2 =0.81) and 2011 (R 2 =0.93) experiments. This allowed mapping of the leaf N spatial distribution acquired by the sensor in the field with a prediction error of 0.21%. Averaging the overall estimates of leaf N content per N treatment provided an upper limit of 200kgha−1 for the required fertilization, corresponding to a critical level of leaf N of about 2.3%. Our results confirm the usefulness of the new fluorescence-based method and sensor for a precise management of fertilization in turfgrass.


      PubDate: 2014-12-13T15:03:27Z
       
  • 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: 2014-12-13T15:03:27Z
       
  • Significant decrease in yield under future climate conditions: Stability
           and production of 138 spring barley accessions
    • Abstract: Publication date: February 2015
      Source:European Journal of Agronomy, Volume 63
      Author(s): Cathrine Heinz Ingvordsen , Gunter Backes , Michael Foged Lyngkjær , Pirjo Peltonen-Sainio , Jens Due Jensen , Marja Jalli , Ahmed Jahoor , Morten Rasmussen , Teis Nørgaard Mikkelsen , Anders Stockmarr , Rikke Bagger Jørgensen
      The response in production parameters to projected future levels of temperature, atmospheric carbon dioxide ([CO2]), and ozone ([O3]) was investigated in 138 spring barley accessions. The comprehensive set of landraces, cultivars, and breeder-lines, were during their entire life cycle exposed to a two-factor treatment of combined elevated temperature (+5°C day/night) and [CO2] (700ppm), as well as single-factor treatments of elevated temperature (+5°C day/night), [CO2] (700ppm), and [O3] (100–150ppb). The control treatment was equivalent to present average South Scandinavian climate (temperature: 19/12°C (day/night), [CO2]: 385ppm). Overall grain yield was found to decrease 29% in the two-factor treatment with concurrent elevation of [CO2] and temperature, and this response could not be predicted from the results of treatments with elevated [CO2] and temperature as single factors, where grain yield increased 16% and decreased 56%, respectively. Elevated [O3] was found to decrease grain yield by 15%. Substantial variation in response to the applied climate treatments was found between the accessions. The results revealed landraces, cultivars, and breeder-lines with phenotypes applicable for breeding towards stable and high yield under future climate conditions. Further, we suggest identifying resources for breeding under multifactor climate conditions, as single-factor treatments did not accurately forecast the response, when factors were combined.


      PubDate: 2014-12-13T15:03:27Z
       
  • Net ecosystem carbon balance of an apple orchard
    • Abstract: Publication date: February 2015
      Source:European Journal of Agronomy, Volume 63
      Author(s): Damiano Zanotelli , Leonardo Montagnani , Giovanni Manca , Francesca Scandellari , Massimo Tagliavini
      Fruit tree ecosystems represent an important land use type in Southern Europe. Nevertheless, limited information and large uncertainty currently exist about their potential role as a sink of atmospheric CO2, which is measured through an index that accounts for all inputs and outputs of C, namely the net ecosystem carbon balance (NECB). In this paper, we studied the fluxes of C assimilation, the C release and the lateral C and their contribution to the NECB in an apple orchard at different time scales. Data of net ecosystem productivity (NEP) were recorded by eddy covariance and converted into ecosystem respiration and gross primary productivity (GPP). The net primary productivity (NPP) and the C partitioning among tree organs were also biometrically assessed. The study was carried out in the period 2009–2012 in a commercial apple orchard located in an intensive fruit production district of South Tyrol, Italy. We found a positive NEP from March to October and yearly NEP values of 403gCm−2. GPP (1346gCm−2 year−1 on average) was highest between May and September, when leaves intercepted the highest amount of PPFD. Tree growth accounted for more than 90% of the total new biomass produced in the orchard, the remaining part being represented by the herbaceous vegetation covering the orchard floor. Trees allocated to fruits approximately half of the yearly NPP, while they increased only to a limited extent their standing biomass. A significant fraction of NPP was also allocated to organs (leaves, pruned woody organs, etc.,) that feed the detritus cycle. The NECB was on average positive (69gCm−2) but showed high variation among years, and in the year when fruit yields was very high (74t fruits/ha), the NECB was even negative. NECB was accounted to a greater extent by the yearly increase of tree woody organs and to a minor extent by the C transfer to the soil from the decomposing litter. The most relevant agronomical suggestion of this study is that tree vegetative growth resulting into either increasing standing biomass and/or increasing tree litter should not be reduced if we aim at maintaining the CO2 sink capacity of the apple orchard.


      PubDate: 2014-12-13T15:03:27Z
       
  • On-farm evaluation of integrated weed management tools for maize
           production in three different agro-environments in Europe: Agronomic
           efficacy, herbicide use reduction, and economic sustainability
    • Abstract: Publication date: February 2015
      Source:European Journal of Agronomy, Volume 63
      Author(s): V.P. Vasileiadis , S. Otto , W. van Dijk , G. Urek , R. Leskovšek , A. Verschwele , L. Furlan , M. Sattin
      The development and implementation of integrated weed management (IWM) strategies that provide good weed control while reducing dependence on herbicides, and preferably without having side effects on the overall system economic performance, is still a challenge that has to be met. In 2011 and 2012, nine on-farm experiments (i.e., real field conditions on commercial farms, with natural weed flora) were conducted in three important European maize producing regions-countries, which represent the range of climatic and edaphic conditions in Europe, to evaluate the efficacy of different locally selected IWM tools for direct weed control in maize vs. the conventional approach (CON) followed by the farms. The IWM tools tested were: (1) early post-emergence herbicide band application combined with hoeing followed by a second hoeing in Southern Germany, (2) early post-emergence herbicide broadcast application when indicated by a predictive model of weed emergence after performing one scouting in the field to supply data for the model, followed by hoeing in Northern Italy, and (3) tine harrowing at 2–3rd leaf stage of maize and low dose of post-emergence herbicide in Slovenia. Results showed that the IWM tools tested in the different countries: (1) provided sufficient weed control without any significant differences in yields, (2) greatly reduced maize reliance on herbicides, and (3) IWM implementation was economically sustainable as no significant differences in gross margin were observed in any country compared to CON.


      PubDate: 2014-12-09T14:56:09Z
       
  • Changes in bread-making quality attributes of bread wheat varieties
           cultivated in Spain during the 20th century
    • Abstract: Publication date: February 2015
      Source:European Journal of Agronomy, Volume 63
      Author(s): Miguel Sanchez-Garcia , Fanny Álvaro , Ariadna Peremarti , Juan A. Martín-Sánchez , Conxita Royo
      Genetic gains in quality traits were assessed in grain samples from 4 field experiments involving 16 bread wheat varieties representative of those most widely cultivated in Spain during the 20th century. The allelic composition at three glutenin loci (Glu-A1, Glu-B1, and Glu-D1) was obtained by PCR-based DNA markers and published references. From 1930 to 2000 grain protein content decreased by −0.030%y−1, or in relative terms by −0.21%y−1, but the protein produced per hectare increased by 0.39%y−1. Alveographic tests revealed significant changes in dough rheological properties. Dough strength (W) and tenacity (P) increased at relative rates of 1.38%y−1 and 0.99%y−1, respectively, while dough extensibility (L) decreased by −0.46%y−1, resulting in an increase of 1.45%y−1in dough equilibrium (P/L). The rise in protein quality could be related to the replacement of the null allele by subunits 1 or 2* at Glu-A1 and the prevalence of subunits 7+8 and 5+10 at Glu-B1 and Glu-D1 loci, respectively, in the most recent varieties. Dough extensibility was affected by water input during the crop cycle, this relationship being partially explained by the presence of the 5+10 HMW glutenin subunit. Fermentation tolerance was improved in the most modern varieties. Collapse during fermentation was avoided only in doughs with a W ≥159 J ×10−4 and a P/L ≥0.56mm H2O mm−1, levels achieved by most of the modern varieties. The over-strong and unbalanced rheological properties of some modern varieties resulted in highly porous doughs, and no clear advances in dough maximum height during fermentation were attained.


      PubDate: 2014-12-09T14:56:09Z
       
  • Yield and energy balance of annual and perennial lignocellulosic crops for
           bio-refinery use: A 4-year field experiment in Belgium
    • Abstract: Publication date: February 2015
      Source:European Journal of Agronomy, Volume 63
      Author(s): Hilde Muylle , Steven Van Hulle , Alex De Vliegher , Joost Baert , Erik Van Bockstaele , Isabel Roldán-Ruiz
      In densely populated regions, such as, Belgium, value chains in the bio-economy can be organized on locally produced primary feedstock, allowing cutting down transport costs and reducing greenhouse gas emissions. The energy use efficiency of three major cropping systems under two fertilizer regimes was compared side by side in a 4-year field trial, with the farm-gate as system border. The annual crops maize, sorghum, and Italian ryegrass were compared with the grassland species perennial ryegrass, cocksfoot, timothy and tall fescue, and the lignocellulosic crops miscanthus, switchgrass, common reed, reed canary grass, and willow. Maize yielded as average a dry matter of 19.6tha−1 y−1 at medium fertilization level. The average dry matter yield of the other crops varied between 3tha−1 y−1 for common reed and 21.1tha−1 y−1 for Miscanthus × giganteus. However, the highest energy use efficiency was obtained for switchgrass and willow. The factors with the most important impact on the total energy input (EI) were fertilizer application, up to 79% for perennial ryegrass, and the preparation of starting material (e.g., up to 81% of the total EI is attributed to the production of miscanthus rhizomes). Targets for further improvement of the sustainability of the primary feedstock production are the development of resource efficient varieties, e.g., fertilizer use efficient maize varieties or seed-based miscanthus varieties, or the inclusion of energy efficient crops into the rotation system, such as energy beet instead of Italian ryegrass. This study provides interesting insight in the energy balances at the farm level for both the farmer and the industrial actors in the locally organized bio-refinery chains.


      PubDate: 2014-12-06T14:48:06Z
       
  • Effects of free air CO2 enrichment on root growth of barley, sugar beet
           and wheat grown in a rotation under different nitrogen supply
    • Abstract: Publication date: February 2015
      Source:European Journal of Agronomy, Volume 63
      Author(s): Andreas Pacholski , Remigius Manderscheid , Hans-Joachim Weigel
      Elevated atmospheric CO2 concentrations [CO2] are known to change plant growth by stimulation of C3 photosynthesis and by reduction of transpiration of both C3 and C4 crops. In comparison to the information on above ground plant responses only limited knowledge exists on the response of root growth of arable crops to elevated [CO2] which is particularly true for temperate crop species under real field conditions. A free air CO2 enrichment (FACE) study (550ppm at daylight hours) was carried out in a crop rotation of winter barley, sugar beet and winter wheat repeated twice in the course of six years on a sandy loam soil at Braunschweig, Northern Germany. Winter barley and sugar beet were included for the first time in a FACE study. A possible interaction with restricted nitrogen (N) supply was studied by fertilizing the CO2 treatment plots with adequate and 50% of adequate N supply. Fine root samples were taken in the plough layer and below at 3–4 sampling dates during the vegetation period and root dry matter (excluding sugar beet storage root), shoot root ratio, root length density, specific root length and root tissue composition (CN ratio) were determined. Main effects of elevated [CO2] on the investigated variables were slightly significant. Significant CO2 effects were observed in interaction with the sampling date. In most cases elevated [CO2] increased root dry matter early in the vegetation period with a maximum growth stimulation of up to 54% as compared to ambient [CO2]. Concomitantly, root length densities were increased in both winter wheat and sugar beet. For winter barley also a significant decrease in root dry weight and significant increase of shoot root ratio was detected at final harvest while such an effect was not significant for sugar beet. Specific root length as an indicator of root morphology was mainly influenced by crop species. As a result, there was no consistent overall effect of elevated [CO2] on biomass partitioning in this study as changes in shoot root ratio only occurred at specific sampling dates indicating a similar stimulation of roots and above-ground biomass due to elevated [CO2]. Nitrogen supply did not alter the effect of elevated [CO2] on any of the root variables apart from CN ratios. A significant increase of root CN ratios in wheat and sugar beet was observed under elevated [CO2], but this effect was much smaller than the effect of N supply.


      PubDate: 2014-12-01T13:07:46Z
       
  • Genetic improvement of root growth increases maize yield via enhanced
           post-silking nitrogen uptake
    • Abstract: Publication date: February 2015
      Source:European Journal of Agronomy, Volume 63
      Author(s): Xiaohuan Mu , Fanjun Chen , Qiuping Wu , Qinwu Chen , Jingfeng Wang , Lixing Yuan , Guohua Mi
      Root breeding has been proposed as a key factor in the “second green revolution” for increasing crop yield and the efficient use of nutrient and water resources. However, few studies have demonstrated that the genetic improvement of root characteristics directly contributes to enhancing nutrient-use-efficiency in crops. In this study, we evaluated the contribution of root growth improvement to efficient nitrogen (N) acquisition and grain yield under two different N-levels in a 3-year field experiment. We used two near-isogenic maize testcrosses, T-213 (large-root) and T-Wu312 (small-root), derived from a backcross of a BC4F3 population from two parents (Ye478 and Wu312) with contrasting root size. We found that the root length density, root surface area, and dry weight at the silking stage were 9.6–19.5% higher in T-213 compared with the control T-Wu312. The root distribution pattern in the soil profile showed no significant differences between the two genotypes. The overall increase in root growth in T-213 enhanced post-silking N uptake, which increased grain yield by 17.3%. Correspondingly, soil nitrate concentrations in the >30cm soil layer were reduced in T-213 under the high N treatment. These positive effects occurred under both adequate and inadequate N-supply and different weather conditions. Our study provides a successful case that increasing root size via genetic manipulation contributes directly to efficient N-uptake and higher yield.


      PubDate: 2014-12-01T13:07:46Z
       
  • Determining the effects of land consolidation on the multifunctionlity of
           the cropland production system in China using a SPA-fuzzy assessment model
           
    • Abstract: Publication date: February 2015
      Source:European Journal of Agronomy, Volume 63
      Author(s): Beibei Guo , Xiaobin Jin , Xuhong Yang , Xu Guan , Yinan Lin , Yinkang Zhou
      The purpose of this study was to identify and measure the effect of land consolidation (LC) on the multifunctionality of cropland ecosystems. LC can serve agriculture multifunctionality, but it can also have a huge impact on the individual functions within the sector. We took 2006–2012 as study period, based on an analysis of county scale land consolidation projects (LCP) in the 31 provinces of China, this study found that the wide range of LC implementation has comprehensively influenced the multifunctionality of agriculture. LCP have significantly improved the production function of cropland, driven investment in agriculture, promoted development of the rural agricultural economy, maintained food security and stability in the rural area, and increased crop supply in most provinces. However, it also slightly impaired rural ecological benefits in some provinces. During the study period, land consolidation influenced the agricultural supply function in 14 provinces, covering 43.97% of the LC affected area and producing an increase of 1.25 million ha in cropland; In five provinces it influenced the production function over 31.18% of the LC area, changing the supply function outcome most and the ecological function least. Thus, the widespread implementation of LCP can result in significant impacts on the crop production system.


      PubDate: 2014-11-27T12:47:08Z
       
  • Response of primary production and biomass allocation to nitrogen and
           water supplementation along a grazing intensity gradient in semiarid
           grassland
    • Abstract: Publication date: February 2015
      Source:European Journal of Agronomy, Volume 63
      Author(s): Xiao Ying Gong , Nicole Fanselow , Klaus Dittert , Friedhelm Taube , Shan Lin
      Herbivory and resource availability interactively regulate plant growth, biomass allocation, and production. However, the compensatory growth of plants under grazing intensities and manipulated environmental conditions is not well understood. A 2-year experiment with water (unirrigated and irrigated) and nitrogen fertilizer (0 and 75kgNha−1 year−1) addition was conducted at sites with 4 grazing intensities (0–7 sheepha−1) in an annually rotational grazing system in Inner Mongolia. In this study, grazing had no significant effect on aboveground net primary production (ANPP) and net primary production (NPP). However, high grazing intensity strongly reduced the fraction of belowground net primary production to NPP. Water and nitrogen additions significantly increased ANPP by 39% and by 23%, respectively, but had no effect on belowground net primary production. ANPP showed lower response to nitrogen addition at high grazing intensity sites than at low grazing intensity sites. We found no evidence for grazing optimization on primary production of semiarid steppe, regardless of resource supplementations. Grazed plants minimized the reduction of ANPP by altering allocation priority and morphological traits. Our study highlights the “whole-plant” perspective when studying plant–herbivore interactions.


      PubDate: 2014-11-27T12:47:08Z
       
  • Integrative effects of soil tillage and straw management on crop yields
           and greenhouse gas emissions in a rice–wheat cropping system
    • Abstract: Publication date: February 2015
      Source:European Journal of Agronomy, Volume 63
      Author(s): Li Zhang , Jianchu Zheng , Liugen Chen , Mingxing Shen , Xin Zhang , Mingqian Zhang , Xinmin Bian , Jun Zhang , Weijian Zhang
      Significant efforts have been made to assess the impact of tillage regimes on crop yields and/or greenhouse gas (GHG) emissions across single crop growing season. However, few studies have quantified the impact across a whole rotation cycle in multiple cropping systems. Utilizing on a long-term tillage experiment with the rice–wheat rotation system in East China, we examined the GHG emissions under different tillage practices with or without crop straw incorporation. Results showed that compared to the no-straw control, straw incorporation increased wheat yield by 28.3% (P <0.05), irrespective of tillage practices, but had no significant effect on rice yield. Although straw incorporation did not significantly affect CH4 emissions during the wheat season and N2O emissions during the whole rice–wheat cycle, it significantly stimulated CH4 emissions by 98.8% (P <0.01) during the rice season. Also, there were no significant differences in CH4 and N2O emissions between tillage practices during the wheat season. Compared to plowing, rotary tillage increased CH4 emissions significantly by an average of 38.8% (P <0.01) but had no significant impacts on N2O emissions during the rice season. Across the rotation cycle, annual yield-scaled global warming potential of CH4 and N2O emissions under no-tillage plus rotary tillage was 26.8% (P <0.01) greater than that of rotary tillage plus plowing with or without straw incorporation. Significant interactions between soil tillage and straw management practices were found on annual GHG emissions, but not on crop yields. Together, these results indicate that plowing in the rice season plus rotary tillage in the wheat season may reduce GHG emissions while increasing crop yield in rice–wheat cropping areas.


      PubDate: 2014-11-27T12:47:08Z
       
  • Evaluating coffee yield gaps and important biotic, abiotic, and management
           factors limiting coffee production in Uganda
    • Abstract: Publication date: February 2015
      Source:European Journal of Agronomy, Volume 63
      Author(s): N. Wang , L. Jassogne , P.J.A. van Asten , D. Mukasa , I. Wanyama , G. Kagezi , K.E. Giller
      Coffee is Uganda’s biggest export commodity, produced mainly by an estimated one million smallholder farmers (<2.5ha). Arabica (Coffea arabica L.) and Robusta (Coffea canephora Pierre ex Froehn.) are the two coffee species grown. Robusta is dominantly cultivated at lower elevations (<1400m) such as in Central and Northern Uganda and Arabica is dominant at higher elevations (>1400m) such as Eastern, Southwest, and Northwest Uganda. Actual yields are far below (<30%) potential due to various biotic, abiotic, and management constraints. Yet, there is no quantitative information on site-specific production constraints and the yield gaps attributed to those constraints. In this study, yields and diverse production factors were monitored in 254 plots of five major coffee growing regions (i.e., Central, North, East, Southwest, and Northwest). Boundary line analysis was applied to evaluate the relative importance of the individual production factors in limiting coffee production and to quantify the associated yield gaps at regional level. The impacts of rainfall variation on coffee yield were evaluated separately by regression analysis. The results of boundary line analysis indicated that biotic constraints (coffee twig borer) and poor management practices (unproductive coffee trees and low coffee plant density) restricted Robusta production in the Central region; poor soil nutrient status (especially potassium) and lack of mulching were the causes of yield loss of Robusta grown in the Northern region. For Arabica, unfavorable soil properties (high soil pH and phosphorus concentration) and excessive number of shade trees were the most important constraints in the East; high soil magnesium concentration and poor mulching limited coffee yield in the Southwest; poor soil nutrient status (especially phosphorus and potassium) and low coffee plant density were the important yield limitations in the Northwest. Average explained yield gaps of individual coffee plot due to the most important production constraints were 45%, 52%, 57%, 49%, and 50% of attainable yield, respectively, in the Central, Northern, Eastern, Southwest, and Northwest regions. Considerably less annual precipitation was received in 2009/2010 coffee growing season compared with that in the previous three years (2006–2008). Seasonal rainfall shortage occurred in the Southwest was a significant limitation to Arabica production, while excessive rainfall across the whole growing season was associated with yield reduction in the Eastern and Northwest regions. We conclude that there was a large yield gap for both Robusta and Arabica coffee grown in Uganda. Boundary line analysis allows the evaluation of relative importance of individual production constraint directly in the plot. The important production constraints varied strongly depending on the regions, which calls for site-specific management implementations. Soil fertility can be improved by implementing integrated soil fertility management (ISFM) that makes use of nutrients from the soil, recycled crop residues, mulch and chemical fertilizers. Attentions should also be given to other management practices such as coffee plant density, unproductive coffee trees and shade trees etc.


      PubDate: 2014-11-23T12:26:35Z
       
  • Relating soil microbial properties to yields of no-till canola on the
           Canadian prairies
    • Abstract: Publication date: Available online 11 November 2014
      Source:European Journal of Agronomy
      Author(s): Newton Z. Lupwayi , K. Neil Harker , John T. O’Donovan , T. Kelly Turkington , Robert E. Blackshaw , Linda M. Hall , Christian J. Willenborg , Yantai Gan , Guy P. Lafond , William E. May , Cynthia A. Grant
      Soil microorganisms mediate many important biological processes for sustainable agriculture. However, correlations between soil microbial properties and crop productivity cannot always be demonstrated. We collected soil microbial data from a canola (Brassica napus L.) study that was conducted at seven sites on the Canadian prairies about agricultural practices focused on increasing canola yields. The treatments consisted of two canola seeding rates (75 or 150seedsm−2), two nitrogen rates (1× and 1.5× soil test recommendation) and three nitrogen form–fungicide (prothioconazole) combinations (uncoated urea, no fungicide; uncoated urea+fungicide; and 50% polymer-coated urea+fungicide) in a 2×2×3 factorial arrangement. Microbial biomass C (MBC), β-glucosidase enzyme activity and functional bacterial diversity (based on C substrate utilization patterns) were determined in canola rhizosphere and in bulk soil and related to canola yields. The effects of seeding rate, nitrogen (N) rate and N form on soil microbial biomass, enzyme activity or bacterial functional diversity were usually not statistically significant. In the few cases where significance occurred, doubling the seeding rate from 75 to 150seedsm−2 usually increased these microbial properties in canola rhizosphere or bulk soil. Increasing N rate to 1.5× the recommended rate had mostly positive effects in canola rhizosphere and negative effects in bulk soil. The effects of N form (including addition of fungicide) were inconsistent. Soil MBC and β-glucosidase enzyme activity correlated positively with canola grain yield at the five sites where yields were <4000kgha−1 (r =0.51** to 0.76**), but no or weak negative correlations were observed at the two sites with yields >4000kgha−1. The functional diversity of soil bacteria was not or was weakly negatively correlated with grain yields. Some of these relationships appeared to be influenced by canola root maggot damage because root damage was usually negatively correlated with the soil microbial characteristics, but the correlations were too weak to be relevant. These results suggest underground feedback interactions between crops and soil microbes, i.e., crop/soil management practices that enhance crop growth also enhance soil microbial communities and their activities, and vice versa.


      PubDate: 2014-11-11T11:22:08Z
       
  • Comparative advantages of conservation agriculture based rice–wheat
           rotation systems under water and salt dynamics typical for the irrigated
           arid drylands in Central Asia
    • Abstract: Publication date: January 2015
      Source:European Journal of Agronomy, Volume 62
      Author(s): K.P. Devkota , J.P.A. Lamers , A.M. Manschadi , M. Devkota , A.J. McDonald , P.L.G. Vlek
      In Central Asia, the increasing water shortage and labor scarcity, high cost of production, increasing secondary soil salinization, and land abandonment are compelling farmers to change to water saving irrigation and conservation agriculture (CA) technologies. Such CA practices aim at maximizing profits while making a better use of soil and water resources lowering labor demands, farm power and production costs. The CA experiments with rice–wheat systems combined two establishment methods (beds and flats) with three residue levels (all zero tillage) and with alternate wet and dry (AWD) irrigation followed by surface seeded wheat (SSW); and conventional tillage (dry tillage) and continuously flooded rice (water seeded rice, WSR) followed by SSW. These were evaluated for 2 years (2008–2010) by using several financial indicators such as gross margins (GMs) estimates and benefit/cost ratio (BCR) while accounting for the soil water balance and soil salinity dynamics. The GM and BCR were higher under WSR–SSW than under treatments of dry seeded rice (DSR)–SSW. Both were higher under residue removal compared to residue retainments in DSR-SSW. Surface seeded wheat, which involved minor production costs, yielded >6tha−1 in both years in all treatments. Furthermore, >80% of the total irrigation water was applied to rice. Yet, >90% from WSR–SSW and ∼67% from DSR–SSW were lost through seepage and percolation. Dry seeded rice in bed (DSRB)–SSW saved 15% more irrigation water compared to dry seeded rice in flat (DSRF)–SSW and 67% compared to WSR–SSW. Soil salinity decreased with rice cultivation. After 2 years, WSR–SSW had the lowest while residue-removed DSRB–SSW had the highest salinity level at all soil depths. Groundwater salinity under deep groundwater tables was higher under treatments of DSR–SSW than under WSR–SSW. However, under shallow groundwater tables, groundwater salinity was higher under WSR–SSW than under DSR–SSW. Under the conditions that irrigation water is subsidized or even free of charge, conventional WSR–SSW into the standing rice field (20 days before rice harvest) is the most profitable option. However, under water scarce conditions, the CA based rice–wheat system could be a suitable alternative to cope with water scarcity and secondary soil salinization. Before this crop production system can be advocated and promoted, it needs to be flanked by adequate water pricing policies.


      PubDate: 2014-11-06T10:49:15Z
       
  • Differential physiological and biochemical responses to drought in
           grapevines subjected to partial root drying and deficit irrigation
    • Abstract: Publication date: January 2015
      Source:European Journal of Agronomy, Volume 62
      Author(s): Alexandros Beis , Angelos Patakas
      The effects of two different irrigation methodologies, partial root drying (PRD) and deficit irrigation (DI), on grapevines (Vitis vinifera L., cv. Mavrodafni) physiological and biochemical parameters were studied using split-rooted potted plants. Five irrigation treatments were applied: fully irrigated (FI) at both parts of the rootzone to soil capacity; deficit irrigated (DI50 and DI25) receiving 50% and 25% irrigation water of FI plants, respectively, to the entire rootzone and partial root drying (PRD50 and PRD25) receiving 50% and 25% irrigation water of FI plants, respectively, which was successively applied to one and the other part of the rootzone. Compared with DI50, PRD50 plants exhibited higher stomatal conductance and photosynthetic rate maintaining more favorable plant water status throughout the experimental period. On the contrary, no significant differences in physiological parameters between PRD25 and DI25 plants were observed, suggesting that irrigation amount could influence different irrigation methodologies effects on plant's performance. Leaf abscisic acid (ABA) concentration at the end of the drought period was significantly higher in DI compared to PRD plants while the opposite trend was evident concerning cytokinins (Cks) concentration. Irrespective the irrigation amount applied, stomatal conductance (g s ) in DI plants exhibited the strongest correlation with leaf abscisic acid (ABA) concentration among the treatments but this relationship was significantly weakened when g s was regressed against ABA/CKs ratio. PRD plant's stomatal conductance was also strongly correlated with leaf abscisic acid (ABA) concentration but this relationship was markedly improved when ABA/CKs ratio was used. These results imply a more pronounced role of CKs in mediating stomatal responses in PRD plants. In contrast in DI grapevines ABA concentration seemed to dominate stomatal responses to drought.


      PubDate: 2014-10-29T10:12:02Z
       
  • Impact of a woody biochar on properties of a sandy loam soil and spring
           barley during a two-year field experiment
    • Abstract: Publication date: January 2015
      Source:European Journal of Agronomy, Volume 62
      Author(s): Victoria Nelissen , Greet Ruysschaert , Delphine Manka’Abusi , Tommy D’Hose , Kristof De Beuf , Bashar Al-Barri , Wim Cornelis , Pascal Boeckx
      Biochar is often proposed to increase soil quality and crop yield, while sequestering carbon. Despite the growing number of studies in temperate regions, the claimed positive effects are still unsure for northwestern European soils. Moreover, there is a need to upscale results from lab and pot studies in these soil types to field experiments. The objectives of this study were therefore to investigate the effect of biochar application to a temperate agricultural soil on soil chemical, physical and biological properties, and on crop growth and nutrient uptake under field circumstances. A field trial, located in Merelbeke (Belgium), was established in October 2011 and monitored until August 2013. The biochar applied was produced from a mixture of hard- and softwood at 480°C. The biochar dose was 0 (control) or 20tha−1 (on dry weight basis). Over two years, biochar addition to soil did not affect soil chemical properties, except for organic carbon content and C:N ratios. Effects on bulk density, porosity and soil water retention curves were non-consistent over time, possibly due to interaction with tillage operations. Biochar increased soil water content in 2012, although mostly not significantly. However, in 2013, when soil water content was overall lower compared to 2012, it was not affected by biochar addition. Soil temperature, as measured at a soil depth interval of 8–20cm, was not changed by biochar addition. Furthermore, biochar addition to soil did only slightly influence soil microbiological community structure during the first year after biochar application, as only certain bacterial biomarker PLFAs were significantly affected by biochar addition, but no fungal biomarker PLFAs. Hence, it was not surprising that biochar addition did not affect crop yield, N or P uptake during the first two years after biochar application.


      PubDate: 2014-10-18T08:50:40Z
       
  • Effects of nitrogen application rate on grain yield and grain nitrogen
           concentration in two maize hybrids with contrasting nitrogen
           remobilization efficiency
    • Abstract: Publication date: January 2015
      Source:European Journal of Agronomy, Volume 62
      Author(s): Yanling Chen , Changxin Xiao , Dali Wu , Tingting Xia , Qinwu Chen , Fanjun Chen , Lixing Yuan , Guohua Mi
      A target in crop production is to simultaneously increase grain yield (GY) and grain nitrogen concentration (GNC). In maize, nitrogen (N) and genotype are two major factors affecting GY and GNC. Both N remobilization from vegetative tissues and post-silking N uptake contribute to grain N, but their relative contributions are genotype specific, and are affected by the N application rate. It is unclear whether the responses of GY and GNC to N application differ between genotypes with different post-silking N uptake and vegetative N remobilization characteristics. We investigated the effect of N application rate on post-silking N uptake, vegetative N remobilization, GY, and GNC of two high-yielding maize hybrids, ZD958 and XY335, which have contrasting N remobilization characteristics. We tested five N application rates (0, 60, 120, 180, 240kgNha−1) in a 4-year field study (from 2010 to 2013). There was a significant year×N×genotype interaction in the amount of vegetative N remobilization and N remobilization efficiency (NRE), and residual stalk N concentration at maturity. Compared with the low-NRE cultivar ZD958, XY335 showed the same GY but higher GNC because it had higher vegetative N remobilization, NRE but lower residual stalk N concentration under the favorable weather condition in 2010. The response of GNC to increasing N levels was the same between XY335 and ZD958 and was not affected by year conditions. The N level required to obtain the highest GY was the same in the two hybrids (156±13kgha−1and 159±19kgha−1), but that required to obtain the highest GNC was greater in XY335 (216±30kgha−1) than in ZD958 (195±23kgha−1). From these results, we conclude that precise N fertilizer management as well as the selection of high-yielding hybrids with high NRE can increase GNC without negatively affecting GY or leading to surplus N storage in vegetative organs.


      PubDate: 2014-10-18T08:50:40Z
       
  • Effect of temperature and precipitation on nitrate leaching from organic
           cereal cropping systems in Denmark
    • Abstract: Publication date: January 2015
      Source:European Journal of Agronomy, Volume 62
      Author(s): Mohamed Jabloun , Kirsten Schelde , Fulu Tao , Jørgen E. Olesen
      The effect of variation in seasonal temperature and precipitation on soil water nitrate (NO3 N) concentration and leaching from winter and spring cereals cropping systems was investigated over three consecutive four-year crop rotation cycles from 1997 to 2008 in an organic farming crop rotation experiment in Denmark. Three experimental sites, varying in climate and soil type from coarse sand to sandy loam, were investigated. The experiment included experimental treatments with different rotations, manure rate and cover crop, and soil nitrate concentrations was monitored using suction cups. The effects of climate, soil and management were examined in a linear mixed model, and only parameters with significant effect (P <0.05) were included in the final model. The model explained 61% and 47% of the variation in the square root transform of flow-weighted annual NO3 N concentration for winter and spring cereals, respectively, and 68% and 77% of the variation in the square root transform of annual NO3 N leaching for winter and spring cereals, respectively. Nitrate concentration and leaching were shown to be site specific and driven by climatic factors and crop management. There were significant effects on annual N concentration and NO3 N leaching of location, rotation, previous crop and crop cover during autumn and winter. The relative effects of temperature and precipitation differed between seasons and cropping systems. A sensitivity analysis revealed that the predicted N concentration and leaching increased with increases in temperature and precipitation.


      PubDate: 2014-10-12T12:11:37Z
       
  • Strategic double cropping on Vertisols: A viable rainfed cropping option
           in the Indian SAT to increase productivity and reduce risk
    • Abstract: Publication date: January 2015
      Source:European Journal of Agronomy, Volume 62
      Author(s): V. Nageswara Rao , H. Meinke , P.Q. Craufurd , D. Parsons , M.J. Kropff , Niels P.R. Anten , S.P. Wani , T.J. Rego
      Our study suggests the possibility for transformational change in the productivity and risk profile of some of India's rainfed cropping systems. In the semi-arid regions of Southern India, farmers traditionally crop sorghum or chickpea on Vertisols during the post-rainy season, keeping the fields fallow during the rainy season. This practice avoids land management problems, but limits the potential for crop intensification to increase systems productivity. A long-term (15 year) experiment at ICRISAT demonstrated that cropping during the rainy season is technically feasible, and that grain productivity of double cropped sorghum+chickpea (SCP–SCP) and mung bean+sorghum (MS–MS) sequential systems were higher than their conventional counterparts with rainy season fallow, i.e. fallow+post-rainy sorghum (FS–FS) and fallow+post-rainy chickpea (FS–FCP). Without N application, mean grain yield of post-rainy sorghum in the MS–MS system was significantly greater (2520kgha−1 per two-year rotation) than in the FS–FS system (1940kgha−1 per two-year rotation), with the added benefit of the mung bean grain yield (1000kgha−1 per two-year rotation) from the MS–MS system. In the SCP–SCP system the additional grain yield of rainy sorghum (3400kgha−1 per two-year rotation) ensured that the total productivity of this system was greater than all other systems. Double cropping MS–MS and SCP–SCP sequential systems had significantly higher crop N uptake compared to traditional fallow systems at all rates of applied nitrogen (N). The intensified MS–MS and SCP–SCP sequential systems without any N fertilizer applied recorded a much higher median gross profit of Rs. 20,600 (US $ 375) and Rs. 15,930 (US $ 290) ha−1 yr−1, respectively, compared to Rs. 1560 (US $ 28) ha−1 yr−1) with the FS–FS system. Applying 120kg of Nha−1 considerably increased the profitability of all systems, lifting median gross profits of the sorghum+chickpea system over Rs. 60,000 (US $ 1091) ha−1 yr−1 and the conventional system to Rs. 20,570 (US $ 374) ha−1 yr−1. The gross profit margin analysis showed that nitrogen is a key input for improving productivity, particularly for the double cropping systems. However, traditional systems are unviable and risky without N application in the variable climates of the semi-arid tropics. Together, our results show that on Vertisols in semi-arid India, double cropping systems increase systems’ productivity, and are financially more profitability and less risky than traditional fallow post-rainy systems while further benefits can be achieved through fertilizer application.


      PubDate: 2014-10-09T11:53:18Z
       
  • Assessing nitrate leaching in cropping systems based on integrated weed
           management using the STICS soil–crop model
    • Abstract: Publication date: January 2015
      Source:European Journal of Agronomy, Volume 62
      Author(s): C. Bécel , N.M. Munier-Jolain , B. Nicolardot
      Agriculture in Europe and other parts of the world is currently under strong pressure to reduce its reliance on pesticides. Regarding arable crops, strategies based on integrated weed management (IWM) combine several agronomic practices aimed at reducing herbicide use, but these strategies can generate negative collateral effects, such as increased nitrate leaching. An evaluation of nitrate leaching in a long-term experiment set up in 2000 was performed for five tested cropping systems: four IWM-based systems and one reference system. After the validation of the predictive performance of the STICS soil–crop model, nitrate leaching was simulated for the five cropping systems tested over the 12 years of the experiment and over 12 years of implementing alternative scenarios (i.e. the introduction of early sowing for winter cereals, ceasing deep tillage and the introduction of a mustard catch crop). The results showed that the total amount of nitrate leaching varied between cropping systems and was lowest in the cropping system using no herbicide and that with no tillage, two systems combining several agronomic practices. Alternative scenarios based on both early sowing of winter crops and the introduction of catch crops can reduce the total amount of nitrate leached by 25 to 43% over the 12 years of simulations, although early sowing can, in some cases, increase nitrate leaching. This study contributes to the multi-criteria evaluation of innovative cropping systems.


      PubDate: 2014-10-04T11:04:18Z
       
  • Effect of depth of fertilizer banded-placement on growth, nutrient uptake
           and yield of oilseed rape (Brassica napus L.)
    • Abstract: Publication date: January 2015
      Source:European Journal of Agronomy, Volume 62
      Author(s): Wei Su , Bo Liu , Xiaowei Liu , Xiaokun Li , Tao Ren , Rihuan Cong , Jianwei Lu
      A better understanding of crop growth and nutrient uptake responses to the depth of fertilizer banded-placement in the soil is needed if growth and nutrient uptake responses are to be maximized. A two-year field study covering two rape seasons (2010–2011 and 2011–2012) was conducted to examine the effect of banded-placement of N–P–K fertilizer at various depths on growth, nutrient uptake and yield of oilseed rape (Brassica napus L.). The results showed that fertilization at 10cm and 15cm soil depth produced greater taproot length and dry weight than fertilization at 0cm and 5cm. 0 cm and 5cm deep fertilization significantly increased the lateral root distribution at 0–5cm soil depth, while 10cm and 15cm deep fertilization induced more lateral root proliferation at 5–15cm soil depth. At 36 days after sowing (DAS), 5cm deep fertilization produced better aboveground growth and nutrient uptake than 10cm and 15cm deep fertilization. However, reversed results were observed after 36 DAS. 10 cm and 15cm deep fertilization produced more rapeseed than 0cm and 5cm deep fertilization, moreover, the yield difference was more significant in drought season (2010–2011) than in relatively normal season (2011–2012). In summary, these results preliminarily suggest that both 10cm and 15cm are relatively proper fertilizer placement depth when the practice of banding fertilizer is used in oilseed rape production. But from the viewpoint of diminishing the production cost, 10cm deep fertilization should be recommended in actual farming. Because 15cm deep fertilization may require higher mechanical power input, and thus resulting in higher cost of production.


      PubDate: 2014-10-04T11:04:18Z
       
  • Using indicators to assess the environmental impacts of wine growing
           activity: The INDIGO® method
    • Abstract: Publication date: January 2015
      Source:European Journal of Agronomy, Volume 62
      Author(s): Marie Thiollet-Scholtus , Christian Bockstaller
      Environmental assessment methods are needed by agronomists working on the enhancement of cropping systems to meet the demand for more sustainable farming practices. A growing number of operational methods based on a set of indicators have been designed, more for arable crops and livestock than for perennial crops like viticulture. Among them, the INDIGO® method, originally developed for arable crops, offers a compromise between feasibility and predictive quality. Here we present a modified and expanded version of INDIGO® for viticulture. The development of new indicators specific to viticulture and the adaptation of existing ones followed a five step approach: (i) preliminary definition of the objectives and identification of the end-users, (ii) construction of the indicator, (iii) selection of a reference value, (iv) sensitivity analysis and (v) validation. Stakeholders from professional institutions and winegrower organizations were closely associated with step (i) to define the framework and step (ii) to supply technical databases. We designed INDIGO® indicators with all available scientific and expert knowledge which was aggregated into expert systems associating fuzzy subsets or, when possible, quantitative equations. Four indicators; pesticides, nitrogen, energy and soil organic matter, were directly adapted from the initial INDIGO® method, whereas soil cover and frost protection management were new indicators. Potentialities of their use are highlighted by examples of implementation on different scales and for various purposes.
      Graphical abstract image

      PubDate: 2014-10-04T11:04:18Z
       
  • Validity of the pineapple crop model SIMPIÑA across the climatic
           gradient in Réunion Island
    • Abstract: Publication date: January 2015
      Source:European Journal of Agronomy, Volume 62
      Author(s): Elodie Dorey , Patrick Fournier , Mathieu Lechaudel , Philippe Tixier
      Models used for designing cropping systems and for responding to cropping problems caused by climate variations must generate accurate predictions. Here, we describe the SIMPIÑA model, which simulates the development and growth of the ‘Queen Victoria’ pineapple cultivar and which accounts for stress resulting from nitrogen and water deficiencies. We present the calibration and the validation of SIMPIÑA with 15 independent data sets derived from experiments carried out on Réunion Island and covering wide ranges of climatic conditions and management practices. Comparison of simulations with data sets shows that the predictive accuracy of SIMPIÑA is very good, with relative RMSE values ranging from 0.06 to 0.19 for plant fresh biomass; such precision is sufficient for informing management decisions. Interestingly, there was no bias between observed and simulated values. A process-removal approach allowed us to determine how stress processes resulting from water or nitrogen deficiency influence the predictive capacity of the model across a broad range of climatic conditions. There was no clear trend for the effect of climate on model error in comparisons of the model with stress processes removed. When stress processes were partially removed from the model, fruit biomass error was particularly high when the effect of stress was removed from the radiation conversion efficiency and from biomass remobilization. Given its ability to correctly predict crop dynamics under contrasting conditions, SIMPIÑA appears to include the essential processes at the correct level of complexity.


      PubDate: 2014-10-04T11:04:18Z
       
  • Coupling a sugarcane crop model with the remotely sensed time series of
           fIPAR to optimise the yield estimation
    • Abstract: Publication date: November 2014
      Source:European Journal of Agronomy, Volume 61
      Author(s): Julien Morel , Agnès Bégué , Pierre Todoroff , Jean-François Martiné , Valentine Lebourgeois , Michel Petit
      The objective of this study was to assess the efficiency of the assimilation of the fraction of intercepted photosynthetically active radiation (fIPAR) data derived from Satellite Pour l’Observation de la Terre SPOT images into the MOSICAS sugarcane crop growth model for estimating the yield at field scale on Reunion Island. Over 3 years, time series of SPOT satellite imagery were used to estimate the daily evolution of NDVI for 60 plots located on two climatically contrasted farms. Ground measurements of the fIPAR were performed on 5 reference fields and used to calibrate a relationship with the corresponding NDVI values. Forced and not forced simulations were run and compared with respect to their ability to predict the final observed yield. Forcing MOSICAS with fIPAR values derived from SPOT images improved the accuracy of the model for the yield estimation (RMSE=12.2 against 14.8tha−1) closer to the 1:1 line. However, underestimations of the yield by the forced model suggest that some of the model parameters were not optimal. The maximal radiation use efficiency parameter (RUE m ) was optimised for each field, and an analysis of variance showed the significant effect of the ratoon number of the field, of its cultivar and of the farm where it is planted. Accordingly, the RUE m was recalibrated for each cultivar for the number of ratoons and farms. New RUE m values ranged from 3.09 to 3.77gMJ−1, and new computations were run using the optimised values of RUE m . The results indicate that recalibrating the maximal radiation use efficiency according to the number of ratoons improved the yield estimation accuracy by as much as 10.5tha−1 RMSE. This study highlights the potential of time series of satellite images to enhance the estimation of the yield by a forced ecophysiological model and to obtain better knowledge about the ecophysiological processes that are involved in crop dynamics with the recalibration method.


      PubDate: 2014-09-23T08:30:52Z
       
  • Genetic gain in yield and changes associated with physiological traits in
           Brazilian wheat during the 20th century
    • Abstract: Publication date: November 2014
      Source:European Journal of Agronomy, Volume 61
      Author(s): Eduardo Beche , Giovani Benin , Cristiano Lemes da Silva , Lucas Berger Munaro , José Abramo Marchese
      The objective of this study was to characterize physiologically wheat cultivars released in different decades and identify selection criteria for the continued genetic progress in Brazil. Ten cultivars released from 1940 up to 2009 were tested during 2010 and 2011 crop seasons. The following traits were evaluated: grain yield (GY), thousand-kernel weight (TKW), grain number per m−2 (GN), plant height (PH), harvest index (HI), above-ground biomass (BIO), relative Chlorophyll content and leaf gas exchanges. The increase in grain yield was 29kgha−1 yr−1 a genetic gain of 0.92%, annually. Grain yield improvement was largely associated with HI (0.94**), number of grainsm−2 (0.93**), BIO (0.88**) and reduced PH (−0.93**). The post-anthesis Chlorophyll content, stomatal conductance and pre/post-anthesis photosynthetic rate were positively correlated with GY. Genetic gains of Brazilian wheat are mainly related to the increases of HI, GN, and BIO. These improvements were achieved by reducing PH and raising gas exchanges and chlorophyll content.


      PubDate: 2014-09-18T07:58:46Z
       
  • ‘Fingerprints’ of four crop models as affected by soil input
           data aggregation
    • Abstract: Publication date: November 2014
      Source:European Journal of Agronomy, Volume 61
      Author(s): Carlos Angulo , Thomas Gaiser , Reimund Paul Rötter , Christen Duus Børgesen , Petr Hlavinka , Mirek Trnka , Frank Ewert
      The spatial variability of soil properties is an important driver of yield variability at both field and regional scale. Thus, when using crop growth simulation models, the choice of spatial resolution of soil input data might be key in order to accurately reproduce observed yield variability. In this study we used four crop models (SIMPLACE<LINTUL-SLIM>, DSSAT-CSM, EPIC and DAISY) differing in the detail of modeling above-ground biomass and yield as well as of modeling soil water dynamics, water uptake and drought effects on plants to simulate winter wheat in two (agro-climatologically and geo-morphologically) contrasting regions of the federal state of North-Rhine-Westphalia (Germany) for the period from 1995 to 2008. Three spatial resolutions of soil input data were taken into consideration, corresponding to the following map scales: 1:50000, 1:300000 and 1:1000000. The four crop models were run for water-limited production conditions and model results were evaluated in the form of frequency distributions, depicted by bean-plots. In both regions, soil data aggregation had very small influence on the shape and range of frequency distributions of simulated yield and simulated total growing season evapotranspiration for all models. Further analysis revealed that the small influence of spatial resolution of soil input data might be related to: (a) the high precipitation amount in the region which partly masked differences in soil characteristics for water holding capacity, (b) the loss of variability in hydraulic soil properties due to the methods applied to calculate water retention properties of the used soil profiles, and (c) the method of soil data aggregation. No characteristic “fingerprint” between sites, years and resolutions could be found for any of the models. Our results support earlier recommendation to evaluate model results on the basis of frequency distributions since these offer quick and better insight into the distribution of simulation results as compared to summary statistics only. Finally, our results support conclusions from other studies about the usefulness of considering a multi-model approach to quantify the uncertainty in simulated yields introduced by the crop growth simulation approach when exploring the effects of scaling for regional yield impact assessments.


      PubDate: 2014-09-08T05:58:06Z
       
  • No-tillage permanent bed planting and controlled traffic in a maize-cotton
           irrigated system under Mediterranean conditions: Effects on soil
           compaction, crop performance and carbon sequestration
    • Abstract: Publication date: November 2014
      Source:European Journal of Agronomy, Volume 61
      Author(s): Patricio Cid , Inmaculada Carmona , José Manuel Murillo , Helena Gómez-Macpherson
      Under irrigated Mediterranean conditions, no-tillage permanent bed planting (PB) is a promising agriculture system for improving soil protection and for soil carbon sequestration. However, soil compaction may increase with time up to levels that reduce crop yield. The aim of this study was to evaluate the mid-term effects of PB on soil compaction, root growth, crop yield and carbon sequestration compared with conventionally tilled bed planting (CB) and with a variant of PB that had partial subsoiling (DPB) in a Typic Xerofluvents soil (Soil Survey Staff, 2010) in southern Spain. Traffic was controlled during the whole study and beds, and furrows with (F+T) and without traffic (F−T), were spatially distinguished during measurements. Comparisons were made during a crop sequence of maize (Zea mays L.)—cotton (Gossypium hirsutum L.)—maize, corresponding to years 4–6 since trial establishment. After six years, soil compaction was higher in PB than in CB, particularly under the bed (44 and 27% higher in top 0.3- and 0.6-m soil layers, respectively). Around this time, maize root density at early grain filling was 17% lower in PB than in CB in the top 0.6-m layer. In DPB, the subsoiling operation was not effective in increasing root density. Nevertheless, root density appeared to maintain above-ground growth and yield in both PB and DPB compared to CB. Furthermore, at the end of the study, more soil organic carbon was stocked in PB than in CB and the difference increased significantly with a depth down to 0.5m (5.7Mgha−1 increment for the top 0.5-m soil layer). Residues tended to accumulate on furrows, and this resulted in spatial and temporal differences in superficial soil organic carbon concentration (SOC) in the permanent planting systems. In PB, SOC in the top 0.05-m layer increased with time faster in furrows than on beds, and reached higher stable values (1.67 vs. 1.09% values, respectively). In CB, tillage homogenized the soil and reduced SOC in the top 0.05-m layer (average stable value of 0.96% on average for beds and furrows).


      PubDate: 2014-09-08T05:58:06Z
       
  • Phenological development of East African highland banana involves
           trade-offs between physiological age and chronological age
    • Abstract: Publication date: October 2014
      Source:European Journal of Agronomy, Volume 60
      Author(s): Godfrey Taulya , Piet J.A. van Asten , Peter A. Leffelaar , Ken E. Giller
      The phenology of East African highland banana (Musa acuminata AAA-EA, hereafter referred to as ‘highland banana’) is poorly understood. We tested three hypotheses: (1) the physiological age at flowering is independent of site effects, (2) there is no difference in threshold size at flowering between sites with different growth potential, and (3) morphological and physiological components of highland banana relative growth rate (RGR) contribute equally to mitigate growth reduction in response to limiting supply of water, K or N. The physiological age of highland banana plants from field trials at Kawanda (central Uganda) and Ntungamo (south-western Uganda) was computed from daily temperature records. Growth analysis was conducted using RGR, net assimilation rate (NAR), specific leaf area (SLA) and leaf mass ratio (LMR) estimated from allometry. Growth response coefficients were used for quantifying the relative contribution of NAR, SLA and LMR to RGR. Physiological age at flowering was delayed by 739°Cd at Kawanda compared with that at Ntungamo whose chronological age at flowering was in turn 51d older. At both sites a threshold total dry mass of 1.5kg per plant was required for flowering. Faster absolute growth rate and NAR fostered by wet conditions, K input and cooler temperatures enabled plants at Ntungamo to attain the threshold total dry mass sooner than those at Kawanda, hence the phenotypic plasticity in age at flowering. Net assimilation rate contributed at least 90% to RGR increase due to wet conditions at both sites. The contribution of NAR to RGR increase in response to K at Kawanda reduced to 38% while that for SLA increased to 49%. Net assimilation rate contributes more to highland banana RGR modulation than SLA except when warmer conditions reduce NAR. Differences in crop growth rate cause phenotypic plasticity in highland banana rate of phenological development.


      PubDate: 2014-09-03T05:25:18Z
       
  • Emergence and performance of volunteer oilseed rape (Brassica napus) in
           different crops
    • Abstract: Publication date: October 2014
      Source:European Journal of Agronomy, Volume 60
      Author(s): Ernst Albrecht Weber , Sabine Gruber , Wilhelm Claupein
      Volunteer oilseed rape (OSR, Brassica napus L.) causes various agronomic problems in crop rotations and can contribute to gene dispersal by pollen and by seed admixture. A 4-year field experiment (2008–2011) was set up in south-west Germany to investigate the performance of volunteers derived from two OSR cultivars with different levels of seed dormancy. Volunteers of a high-dormancy (HD) and a low-dormancy (LD) OSR cultivar were deliberately generated by spreading 10,000seedsm−2 on a field in August 2008 and 2009. Four different crops were grown on that area in the first year following the seed rain: winter wheat (Triticum aestivum L.), winter turnip rape (Brassica rapa L.), spring barley (Hordeum vulgare L.) and field pea (Pisum sativum L.). In the second year, maize (Zea mays L.) was sown uniformly across all plots. Numbers of OSR seedlings emerging in early autumn shortly after seed rain were not connected with the size of the soil seed bank in early spring of the following year. The seeds of the HD-cultivar formed a much greater soil seed bank (up to 14% of the initially spread seed number) compared with the LD-cultivar (up to 1.3%) in the soil layer of 0 to 30cm in early spring 2009 and 2010). Across all crops, considerably more volunteers of the HD-cultivar than of the LD-cultivar were present at several survey dates in the first year following seed rain. The highest number of volunteers originated from the HD-cultivar with up to 11volunteersm−2 in winter turnip rape compared with a maximum of 0.48plantsm−2 in the other crops. Cultivar-specific differences in volunteer density were observed as well in maize two years after OSR seed rain. Flowering and seed setting volunteers were only present in 2010 and the flowering time was crucially overlapping with that of sown winter OSR. The reproductive ability (seedsproducedm−2) of the LD-volunteers was five times lower in winter turnip rape than of the HD-volunteer; a similar trend was observed for the OSR volunteers in the other host crops. Strategies to definitely reduce unwanted effects of OSR volunteers, such as gene flow, should include the use of LD-cultivars with a low potential to form a soil seed bank, particularly if selective herbicides are not available, for instance in broad-leaved crops, or if the volunteers are herbicide-tolerant.


      PubDate: 2014-09-03T05:25:18Z
       
  • Response of giant reed (Arundo donax L.) to nitrogen fertilization and
           soil water availability in semi-arid Mediterranean environment
    • Abstract: Publication date: October 2014
      Source:European Journal of Agronomy, Volume 60
      Author(s): Salvatore Luciano Cosentino , Danilo Scordia , Emanuele Sanzone , Giorgio Testa , Venera Copani
      The aim of the present work was to evaluate the effect of soil water availability and nitrogen fertilization on yield, water use efficiency and agronomic nitrogen use efficiency of giant reed (Arundo donax L.) over four-year field experiment. After the year of establishment, three levels for each factor were studied in the following three years: I0 (irrigation only during the year of establishment), I1 (50% ETm restitution) and I2 (100% ETm restitution); N0 (0kgNha−1), N1 (60kgNha−1) and N2 (120kgNha−1). Irrigation and nitrogen effects resulted significant for stem height and leaf area index (LAI) before senescence, while no differences were observed for stem density and LAI at harvest. Aboveground biomass dry matter (DM) yield increased following the year of establishment in all irrigation and N fertilization treatments. It was always the highest in I2N2 (18.3, 28.8 and 28.9tDMha−1 at second, third and fourth year growing season, respectively). The lowest values were observed in I0N0 (11.0, 13.4 and 12.9tDMha−1, respectively). Water use efficiency (WUE) was significantly higher in the most stressed irrigation treatment (I0), decreasing in the intermediate (I1) and further in the highest irrigation treatment (I2). N fertilization lead to greater values of WUE in all irrigation treatment. The effect of N fertilization on agronomic nitrogen use efficiency (NUE) was significant only at the first and second growing season. Giant reed was able to uptake water at 160–180cm soil depth when irrigation was applied, while up to 140–160cm under water stress condition. Giant reed appeared to be particularly suited to semi-arid Mediterranean environments, showing high yields even in absence of agro-input supply.


      PubDate: 2014-09-03T05:25:18Z
       
  • Estimation of past and recent carbon input by crops into agricultural
           soils of southeast Germany
    • Abstract: Publication date: November 2014
      Source:European Journal of Agronomy, Volume 61
      Author(s): Martin Wiesmeier , Rico Hübner , Rene Dechow , Harald Maier , Peter Spörlein , Uwe Geuß , Edzard Hangen , Arthur Reischl , Bernd Schilling , Margit von Lützow , Ingrid Kögel-Knabner
      In agricultural soils, the formation of soil organic matter largely depends on the carbon (C) input by crop residues and rhizodeposition, which is thus of decisive importance for the management and prediction of soil organic carbon (SOC) stocks in cropland and grassland. However, there is a remarkable lack of reliable, crop-specific C input data. We used a plant C allocation approach to estimate the C input of major crops and grassland into agricultural soils of Bavaria in southeast Germany. Historic and recent plant C allocation coefficients were estimated and C inputs were calculated for a 60-year period (1951–2010) using long-term agricultural statistics. The spatial distribution of C inputs within Bavaria was derived from county-specific statistical data. The results revealed increases of the C input by 107–139% for cereals, 173–188% for root, forage and leguminous crops and 34% for grassland in the last 60 years. This increase was related to linear yield increases until 1995 despite significant changes of plant C allocation. However, from 1995 onwards, crop yields and related C inputs stagnated, which allowed a robust estimation of recent crop-specific C input values. A total C input of 3.8–6.7tha−1 yr−1 was estimated for cereals, 5.2–6.3tha−1 yr−1 for root, forage and leguminous crops and 2.4tha−1 yr−1 for grassland. These amounts were partly higher compared to estimations in the literature. A generally high spatial variability of C inputs was detected within Bavaria with differences of up to 40% between adjacent counties. The results of this study could be used to optimize the C input of crop rotations and thus promote the formation of soil organic matter and C sequestration in agricultural soils on the basis of a soil carbon model. Moreover, recent estimations of C inputs could be used to model the future development of agricultural SOC stocks. A further stagnation of crop yields and the related C input under an ongoing temperature increase bears the risk of a future decrease of SOC stocks in cropland soils of Bavaria.


      PubDate: 2014-09-03T05:25:18Z
       
  • Durum wheat quality prediction in Mediterranean environments: From local
           to regional scale
    • Abstract: Publication date: November 2014
      Source:European Journal of Agronomy, Volume 61
      Author(s): P. Toscano , B. Gioli , L. Genesio , F.P. Vaccari , F. Miglietta , A. Zaldei , A. Crisci , E. Ferrari , F. Bertuzzi , P. La Cava , C. Ronchi , M. Silvestri , A. Peressotti , J.R. Porter
      Durum wheat is one of the most important agricultural crops in the Mediterranean area. In addition to yield, grain quality is very important in wheat markets because of the demand for high-quality end products such as pasta, couscous and bulgur wheat. Grain quality is directly affected by several agronomic and environmental factors. Our objective is to determine the general principles underlying how, in Mediterranean environments, grain protein content (GPC) is affected by these factors and provide a system model with high predictive ability. We initially evaluated the capability of the Delphi system to simulate GPC in the major Italian supply basins (Basilicata, Capitanata, Marche, Tuscany) for 9 years (1999–2007) a month ahead of harvesting and we then analyzed relations between Delphi system errors and selected environmental variables during flowering and grain filling stages. The results were evaluated on the basis of regression with observed GPC, while errors were calculated performing a linear correlation analysis with environmental variables. The model showed a high capability to reproduce the inter-annual variability, with important year to year differences, with better performance in the southern study areas (Basilicata and Capitanata). In this study the highest overestimation occurred in conjunction with the year (2004) characterized by the lowest quality in terms of GPC, lowest average temperature in May and highest yield production for the whole study period.


      PubDate: 2014-09-03T05:25:18Z
       
  • Interference between red kidneybean (Phaseolus vulgaris L.) cultivars and
           redroot pigweed (Amaranthus retroflexus L.)
    • Abstract: Publication date: October 2014
      Source:European Journal of Agronomy, Volume 60
      Author(s): Rouhollah Amini , Hassan Alizadeh , Alireza Yousefi
      Field experiments were conducted in 2006 and 2007 to evaluate the competitive ability of bush type red kidneybean (RKB) (Phaseolus vulgaris L.) cultivars against redroot pigweed (Amaranthus retroflexus L.). Three cultivars of RKB (Akhtar, Sayyad and D81083) and five A. retroflexus densities (0, 4, 8, 16 and 32plantsm−2) were established in a factorial arrangement. A. retroflexus had a greater plant height and growth rate (GR) but a lower leaf area index (LAI) than RKB cultivars in almost all treatments. Higher densities of A. retroflexus increased LAI and GR but decreased yield of RKB cultivars. The cv. Sayyad and D81083 had the greatest and lowest LAI and GR, respectively, in competition with A. retroflexus. The maximum intercepted photosynthetically active radiation (PAR) at noon by A. retroflexus was 90.4 and 66.0% in competition with cv. D81083 and Sayyad, respectively. The seed yield and pod number per plant of RKB cultivars decreased severely with increasing A. retroflexus density. A. retroflexus seed numberm−2 was the highest and lowest in competition with cv. D81083 and Sayyad, respectively. The competitive ability of RKB cultivars was compared using parameters estimated through two-parameter yield loss-relative leaf area model. The relative ranking of the RKB cultivars examined for their competitiveness, supported by modeling results, was Sayyad>Akhtar>D81083.


      PubDate: 2014-08-17T04:34:45Z
       
  • Energy crops: Prospects in the context of sustainable agriculture
    • Abstract: Publication date: October 2014
      Source:European Journal of Agronomy, Volume 60
      Author(s): Luis López-Bellido , Jacques Wery , Rafael J. López-Bellido
      The objectives of this review are to analyse the potential of bioenergy crops development in European agriculture and to identify research objectives based on transformation technologies. Bioenergy is the chemical energy stored in organic material, which can be directly converted into useful energy sources by biological, mechanical or thermochemical processes. The substitution of food crops with energy crops and the demand for agricultural raw materials for liquid biofuel production will affect agriculture over the next decade and possibly beyond. It is expected that both second-generation biofuel production technology and energy crops used will be more efficient than first-generation. Nonetheless, there are still technical limitations for crop growth and fuel production from second-generation technology. In general, many of the crops that could supply the raw materials for second-generation biofuels are largely undomesticated and are in the first stages of development and management. The development of specific crops dedicated to energy has been proposed as a strategy to produce energy without affecting food security and the environment. The research seeks to develop enzymatic systems for the cost-efficient decomposition of cellulose into its molecular sugar components, which can then be fermented to produce ethanol. This biorefinery of crops into multiple products, including energy, chemical products and materials, will augment the overall value of the biomass. Clearly, multidisciplinary research is necessary to address sustainable biofuel production.


      PubDate: 2014-07-30T02:30:41Z
       
  • Agricultural sciences in transition from 1800 to 2020: Exploring knowledge
           and creating impact
    • Abstract: Publication date: September 2014
      Source:European Journal of Agronomy, Volume 59
      Author(s): Huub Spiertz
      Transitions in agricultural sciences are brought about by incorporating new findings and insights emerging from biological, chemical and biophysical sciences, by more advanced ways of experimentation and last but not least by quantitative methods and models for data analyses and processing. Major breakthroughs occurred from 1800 onwards when new insights on photosynthesis and mineral nutrition were incorporated in the theory on the growth of crops. It took almost half a century before the humus theory was replaced by a more sound theory on mineral nutrition. The publication by Darwin on domestication in 1868 and the rediscovery of Mendel's laws in 1900 gave a boost to genetics underlying classical plant and animal breeding, which was mainly based on crossing and selection. A major accomplishment of the evolutionary synthesis was the compatibility of Mendelian inheritance with Darwinian natural selection. The discovery of the DNA-structure in the mid-fifties of the 20th century on modern plant breeding showed already impact within some decades. To assess the wide diversity of plant traits for the performance of plants in yield and quality of the produce advanced phenotyping method under controlled conditions has become popular. Genome-wide selection for environments with multiple stresses, however, does require phenotyping in situ. Since 1800 the transition from observations on the plant, field and farm towards dedicated experimentation took place. During the 19th and 20th century the methods for experimentation and data analyses were strongly improved. It took until the mid-20th century before the importance of experiments under controlled conditions was recognized. Studies of plant processes under controlled conditions provided the building blocks for mechanistic modelling of crop growth and production. A systems approach combining knowledge at different scales and incorporating cutting-edge findings from the basic sciences into applied sciences will become important for making a great leap forward in developing agricultural science with impact. Transitions in agricultural research will continue to depend on progress made in the related basic sciences and the capacity for agricultural research and innovation. Therefore, an adequate public funding is required to maintain or even accelerate progress in sciences. This requires the support of the public at large. Public–private partnerships will be needed to bridge the gap between science and innovation.


      PubDate: 2014-07-25T01:01:29Z
       
  • Elytrigia repens population dynamics under different management schemes in
           organic cropping systems on coarse sand
    • Abstract: Publication date: August 2014
      Source:European Journal of Agronomy, Volume 58
      Author(s): Ilse A. Rasmussen , Bo Melander , Margrethe Askegaard , Kristian Kristensen , Jørgen E. Olesen
      Elytrigia repens is a rhizomatous perennial weed prevalent in organic cropping systems in Scandinavia. This study analysed the population dynamics of E. repens in a long-term crop rotation experiment on coarse sand in Denmark in order to gain insights into the factors influencing its population changes, especially those important for outbreaks of E. repens infestations. Data were obtained from three cycles of four-year crop rotations with various cash crops and annual grass–clover subjected to four treatment combinations: with and without animal manure and with and without catch crops. E. repens was controlled by different tillage and mowing strategies between and within crops. Pulses and spring cereals caused the highest population increases, especially when preceded by grass–clover. Potatoes grown in ridges and winter rye suppressed the E. repens population, but tillage between crops was necessary to decrease the population. Manuring generally reduced E. repens growth by 28%. Thus there are crops that need particular attention when designing crop sequences, provision of sufficient nutrients is important to strengthen crop suppression of weeds, and mechanical interventions are needed to manage E. repens satisfactorily.


      PubDate: 2014-07-25T01:01:29Z
       
  • MIMYCS.Moisture, a process-based model of moisture content in developing
           maize kernels
    • Abstract: Publication date: September 2014
      Source:European Journal of Agronomy, Volume 59
      Author(s): Andrea Maiorano , Davide Fanchini , Marcello Donatelli
      Moisture content influences harvest timing and the consequent drying process and drying costs, and the development of spoilage fungi during pre- and post-harvest phases. Maize kernel development in the field can be partitioned into three phases: i) lag phase, ii) grain filling and maturation drying, and iii) post-maturity dry-down. A model simulating maize kernel moisture content during maturation can help either monitoring or foreseen maize kernel humidity during the harvest period. Also, it would be useful in simulation studies via crop models to estimate the infield feasibility of harvest but also the interaction with diseases responsible for mycotoxin production, against weather scenarios. A process-based model was developed, called MIMYCS.Moisture. When the hybrids were analyzed all together, MIMYCS.Moisture showed a good general predictive capability with an average error in moisture estimation of ±3.28% moisture (considering the root mean square error – RMSE). The model efficiency (EF) was positive (0.85) and the model was able to explain the 89.7% of variation. When the two sub-models were analyzed separately, the RMSE remained approximately at the same level of the general model, while the other indicators changed revealing the different characteristics of the two models. The developmental moisture sub-model has a slight tendency to overestimate, while the dry-down sub-model tended to underestimate final moisture content. However, when the model was analyzed separately for each hybrid, both calibration and validation results suggested that more data are needed to improve the model likely with respect to kernel characteristics of hybrids. Finally, the equilibrium moisture content equation used, taken from industrial drying models, might not be adequate for simulating the field conditions where temperature is well below the one in dryers and environmental air humidity may vary considerably across sites and harvest periods.


      PubDate: 2014-07-25T01:01:29Z
       
  • Evaluation of WARM for different establishment techniques in Jiangsu
           (China)
    • Abstract: Publication date: September 2014
      Source:European Journal of Agronomy, Volume 59
      Author(s): Valentina Pagani , Caterina Francone , ZhiMing Wang , Lin Qiu , Simone Bregaglio , Marco Acutis , Roberto Confalonieri
      WARM is a model for rice simulation accounting for key biotic and a-biotic factors affecting quantitative and qualitative (e.g., amylose content, chalkiness) aspects of production. Although the model is used in different international contexts for yield forecasts (e.g., the EC monitoring and forecasting system) and climate change studies, it was never explicitly evaluated for transplanting, the most widespread rice establishment method especially in tropical and sub-tropical Asia. In this study, WARM was tested for its ability to reproduce nursery growth and transplanting shock, using data on direct sown and transplanted (both manual and mechanical) rice collected in 24 dedicated field experiments performed at eight sites in Jiangsu in 2011, 2012 and 2013. The agreement between measured and simulated aboveground biomass data was satisfactory for both direct sowing and transplanting: average R 2 of the linear regression between observed and simulated values was 0.97 for mechanical transplanting and direct sowing, and 0.99 for manual transplanting. RRMSE values ranged from 5.26% to 30.89%, with Nash and Sutcliffe modelling efficiency always higher than 0.78; no notable differences in the performance achieved for calibration and validation datasets were observed. The new transplanting algorithm – derived by extending the Oryza2000 one – allowed WARM to reproduce rice growth and development for direct sown and transplanted datasets (i) with comparable accuracy and (ii) using the same values for the parameters describing morphological and physiological plant traits. This demonstrates the reliability of the proposed transplanting simulation approach and the suitability of the WARM model for simulating rice biomass production even for production contexts where rice is mainly transplanted.


      PubDate: 2014-07-25T01:01:29Z
       
  • Use of soil and vegetation spectroradiometry to investigate crop water use
           efficiency of a drip irrigated tomato
    • Abstract: Publication date: September 2014
      Source:European Journal of Agronomy, Volume 59
      Author(s): S. Marino , M. Aria , B. Basso , A.P. Leone , A. Alvino
      An agronomic research was conducted in Tuscany (Central Italy) to evaluate the effects of an advanced irrigation system on the water use efficiency (WUE) of a tomato crop and to investigate the ability of soil and vegetation spectroradiometry to detect and map WUE. Irrigation was applied following an innovative approach based on CropSense system. Soil water content was monitored at four soil depths (10, 20, 30 and 50cm) by a probe. Rainfall during the crop cycle reached 162mm and irrigation water applied with a drip system amounted to 207mm, distributed with 16 irrigation events. Tomato yield varied from 7.10 to 14.4kgm−2, with a WUE ranging from 19.1 to 38.9kgm−3. The irrigation system allowed a high yield levels and a low depth of water applied, as compared to seasonal ET crop estimated with Hargraves’ formula and with the literature data on irrigated tomato. Measurements were carried out on geo-referenced points to gather information on crop (crop yield, eighteen Vegetation indices, leaf area index) and on soil (spectroradiometric and traditional analysis). Eight VIs, out of nineteen ones analyzed, showed a significant relationship with georeferenced yield data; PVI maps seemed able to return the best response, before harvesting, to improve the knowledge of the area of cultivation and irrigation system. CropSense irrigation system reduced seasonal irrigation volumes. Some vegetation indexes were significantly correlated to tomato yield and well identify, a posteriori, crop area with low WUE; spectroradiometry can be a valuable tool to improve irrigated tomato field management.


      PubDate: 2014-07-25T01:01:29Z
       
  • Evaluation of pixel- and object-based approaches for mapping wild oat
           (Avena sterilis) weed patches in wheat fields using QuickBird imagery for
           site-specific management
    • Abstract: Publication date: September 2014
      Source:European Journal of Agronomy, Volume 59
      Author(s): Isabel Luisa Castillejo-González , José Manuel Peña-Barragán , Montserrat Jurado-Expósito , Francisco Javier Mesas-Carrascosa , Francisca López-Granados
      This paper compares of pixel- and object-based techniques for mapping wild oat weed patches in wheat fields using multi-spectral QuickBird satellite imagery for site-specific weed management. The research was conducted at two levels: (1) at the field level, on 11 and 15 individual infested wheat fields in 2006 and 2008, respectively, and (2) on a broader level, by analysing the entire 2006 and 2008 images. To evaluate the wild oat patches mapping at the field level, both pixel- and object-based image analyses were tested with six classification algorithms: Parallelepipeds (P), Mahalanobis Distance (MD), Maximum Likelihood (ML), Spectral Angle Mapper (SAM), Support Vector Machine (SVM) and Decision Tree (DT). The results showed that weed patches could be accurately detected with both analyses obtaining global accuracies between 80% and 99% for most of the fields. The MD and SVM classifiers were the most accurate for both the pixel- and object-based images from 2006 and 2008, respectively. In the broad-scale analysis, all of the wheat fields were identified in the imagery using a multiresolution hierarchical segmentation based on two scales. The first segmentation scale was classified using the MD and ML algorithms to discriminate wheat fields from other land uses. Accuracies greater than 85% were obtained for MD and 88% for ML for both imagery. A hierarchical analysis was then performed with the second segmentation scale, increasing the accuracies to 93% and 91% for 2006 and 2008 imagery, respectively. Finally, based on the most accurate results obtained in the field-level study, pixel-based classifications using the MD, ML and SVM algorithms were applied to the wheat fields identified. The results of these broad-level analyses showed that wild oat patches were accurately discriminated in all the wheat fields present in the entire images with accuracies greater than 91% for all the classifiers tested.


      PubDate: 2014-07-25T01:01:29Z
       
  • Global warming over 1960–2009 did increase heat stress and reduce
           cold stress in the major rice-planting areas across China
    • Abstract: Publication date: September 2014
      Source:European Journal of Agronomy, Volume 59
      Author(s): Zhao Zhang , Pin Wang , Yi Chen , Xiao Song , Xing Wei , Peijun Shi
      Increasing extreme temperature events have raised concerns regarding the risk of rice production to extreme temperature stress (ETS). However, across China what places were exposed to higher ETS during rice-growing period and how ETS has changed over the past five decades, remain unclear. Here, we first compared two indexes for characterizing ETS on rice crop, including Duration-based ETS index (DETS) and Growing Degree Days (GDD). Then, based on the better-performing index and an improved dataset of rice phenological records, we comprehensively assessed the spatio-temporal patterns of ETS at county scale in the major rice-planting areas across China during 1960–2009. The results showed that GDD had an advantage over DETS in characterizing ETS, due to fully consideration of both the specific intensity and duration of extreme temperature events. Based on GDD, we found that ETS on rice crops had significantly changed in both space and time over the last five decades. Spatially, single rice in Northeast China (Region I) and late rice in southern China (Region IV) saw high exposure to cold stress, especially during the heading-flowering stage. The hot spots of heat stress were found for single rice in the Yangtze River basin (Region III) (2.25°C) during the booting stage, and for early rice in Region IV (4.42°C) during the heading-flowering stage. During 1960–2009, global warming did increase heat stress (0.04 and 0.12°Cyear−1 for the stages of booting and heading-flowering, respectively) and reduce cold stress (−0.03 and −0.21°Cyear−1 for the stages of booting and heading-flowering, respectively) in the major rice-planting areas across China. Some particular areas, such as Yunan Province (P4) with increasing cold stress and Zhejiang Province (P13) with increasing heat stress, should be priorities for adaptations to cope with the rising risk of ETS under climate warming.


      PubDate: 2014-07-25T01:01:29Z
       
  • Assessment of insurance coverage and claims in rainfall related risks in
           processing tomato in Western Spain
    • Abstract: Publication date: September 2014
      Source:European Journal of Agronomy, Volume 59
      Author(s): A. Castañeda-Vera , L. Barrios , A. Garrido , I. Mínguez
      An extension of guarantees related to rainfall-related risks in the insurance of processing tomato crops has been accompanied with a large increase in claims in Western Spain, suggesting that damages may have been underestimated in previous years. A database was built by linking agricultural insurance records, meteorological data from local weather stations, and topographic data. The risk of rainfall-related damages in processing tomato in the Extremenian Guadiana river basin (W Spain) was studied using a logistic model. Risks during the growth of the crop and at harvesting were modelled separately. First, the risk related to rainfall was modelled as a function of meteorological, terrain and management variables. The resulting models were used to identify the variables responsible for rainfall-related damages, with a view to assess the potential impact of extending insurance coverage, and to develop an index to express the suitability of the cropping system for insurance. The analyses reveal that damages at different stages of crop development correspond to different hazards. The geographic dependence of the risk influences the scale at which the model might have validity, which together with the year dependency, the possibility of implementing index based insurances is questioned.


      PubDate: 2014-07-25T01:01:29Z
       
  • Carbon assimilation, leaf area dynamics, and grain yield in contemporary
           earlier- and later-senescing maize hybrids
    • Abstract: Publication date: September 2014
      Source:European Journal of Agronomy, Volume 59
      Author(s): Horacio A. Acciaresi , Eduardo A. Tambussi , Mariana Antonietta , María S. Zuluaga , Fernando H. Andrade , Juan J. Guiamét
      Maize breeding during the past 50 years has been associated with a delay of leaf senescence, but it is not clear whether this trait is likewise associated with higher grain yield in modern hybrids. Post-silking growth, leaf area dynamics, photosynthetic parameters and yield were compared in modern maize hybrids differing in canopy senescence rate. In the first two experiments, four hybrids were grown in the field at Balcarce, Argentina (37°45′ S, 58°18 W). In spite of differences in chlorophyll retention and photosynthesis of the ear leaf, post-silking growth and grain yield were very similar in all four hybrids while kernel N concentration was lower in the later-senescing hybrids. In a third experiment, a later-senescing (NK870) and an earlier-senescing (DK682) hybrid were grown to analyze the potential photosynthetic contribution of delayed leaf senescence. Leaf area and chlorophyll content were larger in NK870, especially at the lower canopy level (0.75m above the ground). However, hybrids did not differ for canopy light interception. Because photosynthetic photon flux density below 1m above the ground was less than 10% of incident radiation and photosynthesis quantum yield did not change during senescence, the potential photosynthetic output of lower leaves below 1m was very low. Lower leaves of NK870 had N concentrations higher than those needed to sustain photosynthesis at the light conditions below 1m. Therefore, we show that delayed senescence does not necessarily improve post-silking C accumulation because: (i) canopy light interception is not reduced by senescence except at very late stages of grain filling; (ii) contrasting hybrids show more pronounced senescence differences at canopy levels receiving less than 10% of incident radiation; (iii) delayed senescing hybrids present lower kernel N concentrations while extra N is retained in leaves exposed to a light limiting micro-environment. Delayed senescence at lower canopy levels may be unproductive, at least under non-stressing conditions.


      PubDate: 2014-07-25T01:01:29Z
       
  • Assessment of irrigation scenarios to improve performances of Lingot bean
           (Phaseolus vulgaris) in southwest France
    • Abstract: Publication date: September 2014
      Source:European Journal of Agronomy, Volume 59
      Author(s): H. Marrou , T.R. Sinclair , R. Metral
      In the context of climate change, producing the same amount of food with less water has become a challenge all over the world. This is also true for the Lingot bean production in the area of Castelnaudary of southwest France where market competition with imported bean has made it crucial to achieve high yields to maintain production in the area. The use of an appropriate and robust crop model can help to identify crop management solutions to face such issues. We used SSM-legumes, a crop model generic to legume species, as well as field observations recorded over five years on eight farms of the Castelnaudary area to assess the effect of different irrigation scenarios on bean yield and water consumption. First, it was demonstrated that the SSM-legumes model is robust in simulating the development and growth of Lingot bean in non-stressed or moderately stressed conditions of this region regarding water and nutrient availability. Then, the use of the model to compare irrigation scenarios provided guidance on how to improve irrigation management for Lingot bean production. These results showed that farmers could achieve slightly higher yields with less water by basing irrigation decisions on the water content of the soil.


      PubDate: 2014-07-25T01:01:29Z
       
  • Application of pig slurry—First year and residual effects on yield
           and N balance
    • Abstract: Publication date: September 2014
      Source:European Journal of Agronomy, Volume 59
      Author(s): Klaus Sieling , Kang Ni , Henning Kage
      Crops generally utilize nitrogen (N) from slurries less efficiently than from mineral fertilizers. In order to compare the effects of slurry and mineral N application on yield and residual fertilization effects, a long-term field trial was established in autumn 1994, where pig slurry was applied to oilseed rape (OSR), winter wheat and winter barley at the same application dates as mineral N fertilizer. N amounts ranged from 0 to 240kg total Nha−1. The same treatment regimes were applied to the same plots in each year. Starting in 2010 (2011), wheat (barley) received no N fertilization in order to allow for testing residual fertilizer effects. Every year seed yield and N offtake by the seeds were determined. Accounting only for ammonia N of pig slurry, similar seed yields in OSR and slightly higher grain yields in wheat and barley compared to mineral N fertilizer were achieved. This indicates that mineralization of organically bounded slurry N compensated gaseous ammonia losses. In plots without N fertilization, OSR showed no yield trends during the experimental period, whereas wheat (barley) yield started to decrease after 10 (13) years without N fertilization. In the highly fertilized treatments, no significant trend in seed yield or N amount required for maximum yield could be detected. In the subsequent unfertilized wheat crop, accumulated slurry effects increased grain yield more than those of mineral N fertilizer. Barley grown in the second year without N supply remained unaffected by the previous slurry N application.


      PubDate: 2014-07-25T01:01:29Z
       
  • Low yield gap of winter wheat in the North China Plain
    • Abstract: Publication date: September 2014
      Source:European Journal of Agronomy, Volume 59
      Author(s): Kenan Li , Xiaoguang Yang , Zhijuan Liu , Tianyi Zhang , Shuo Lu , Yuan Liu
      The yield gap (YG) between the potential yields (Yp) and the average on-farm yields (Ya) is an indicator of the potential improvement for crop production. Understanding how large the current gap is and how this gap has changed over the past few decades is essential for increasing wheat production to meet increased food demand in China. This paper describes a study conducted using an APSIM-Wheat model and farm-level crop yield to analyze the spatio-temporal distribution of the yield gap of winter wheat from 1981 to 2010 in the North China Plain. Nine varieties were calibrated and evaluated based on the data from 16 agro-meteorological experimental sites and then potential yields were estimated considering cultivar replacement. In addition, a trend pattern analysis of on-farm yields for the period 1981–2010 was conducted. Results revealed an estimated yield gap across the entire North China Plain region of 1140–6810kgha−1, with a weight average of 3630kgha−1 in 1981–2010. Expressed as a relative yield (yield gap % of potential yields), the range was 15–80%, and the weight average was 45%. Despite the negative effects of increasing temperature and decreasing radiation, the potential yields significantly increased by 45kgha−1 per year due to cultivar improvement. On-farm yields increased even more notably because of new cultivar selection, increased fertilizer application and other management improvements, but were stagnating in 32.3% of wheat areas, located mainly in Hebei province, Shandong province, Beijing and Tianjin. The improvement of on-farm yields have substantially contributed to yield gap spatio-temporal variation. As a result, the yield gap decreased from 4200kgha−1 (56%) in 1981–1990 to 3000kgha−1 (35%) in 2001–2010 at a rate of −69kgha−1 per year. However, yields stagnation will expand to the northern Henan province without cultivar potential productivity improving, where yield gap was close to or less than 20% of the potential yields and proved difficult to reduce. To further improve the total production of winter wheat in the coming decades, efforts should be paid to break the potential ceiling and reduce the yield gap by breeding higher yield variety and introduction of new agricultural technology.


      PubDate: 2014-07-25T01:01:29Z
       
  • Agronomic performance of an IR64 introgression line with large leaves
           derived from New Plant Type rice in aerobic culture
    • Abstract: Publication date: August 2014
      Source:European Journal of Agronomy, Volume 58
      Author(s): Midori Okami , Yoichiro Kato , Nobuya Kobayashi , Junko Yamagishi
      Aerobic culture is a promising water-saving technology in irrigated rice ecosystems, but the vulnerability of plants to fluctuations in soil moisture constrains leaf expansion and yield. The objective of this study was to examine whether an aboveground architecture with large leaves and reduced tillering is associated with vigorous leaf growth in aerobic rice culture. In a series of field experiments, we evaluated the agronomic performance of an IR64 introgression line, YTH323 (IR84640-11-27-1-9-3-2-4-2-2-2-B), with fewer tillers and larger leaves than IR64, derived from New Plant Type rice, under various water and nitrogen conditions. In flooded culture, YTH323 yielded the same as IR64 and 38% more than IR65564-44-51 (a New Plant Type rice) (9.0 vs. 6.6tha−1). In aerobic culture, in contrast, it yielded 81% more than IR64 in slightly dry soils (5.1 vs. 2.8tha−1). YTH323 had a higher leaf area index than IR64 and IR65564-44-51 under slightly dry soil conditions and under a range of nitrogen conditions. The higher and more stable yield of YTH323 in aerobic culture was attributable to greater early vigor, high specific leaf area, a high ratio of leaf weight to total biomass, and larger leaves, along with the characteristics of high-yield cultivars such as high responsiveness to fertilizers and good grain filling. We conclude that genetic modification of the aboveground architecture of IR64, a typical tropical lowland rice cultivar, to reduce tiller and leaf number improves adaptation to aerobic culture.


      PubDate: 2014-04-28T17:21:07Z
       
  • Changes in the morphological traits of maize genotypes in China between
           the 1950s and 2000s
    • Abstract: Publication date: August 2014
      Source:European Journal of Agronomy, Volume 58
      Author(s): D.L. Ma , R.Z. Xie , X.K. Niu , S.K. Li , H.L. Long , Y.E. Liu
      Maize (Zea mays L.) morphological traits influence light attenuation within the canopy, and, ultimately, yield. The objectives of this 3-year field study were to: (i) examine the morphological characteristics of specific genotypes using varieties of maize that were widely used in Chinese agriculture from the 1950s to the 2000s; (ii) assess the canopies and yields of maize populations in relation to changes in their morphological characteristics. There were significant decrease on the ear ratio, center of gravity height and leaf angle with improved genotypes regardless of plant density. However, the ear leaves and adjacent leaves appeared to be longer in improved maize varieties. The mean leaf orientation value (LOV) and individual LOVs increased considerably during the time series of the genotypes, but more obvious changes in LOV occurred in the uppermost leaves. The average leaf area (LA) per plant and LA on the ears increased significantly from the 1950s to the 2000s. At the optimum density, current hybrid's canopy architecture was more compact, having short plant height and more upright leaf. The SDLA above or under ear significantly increased with improving genotypes, mainly due to new hybrids allowing the use of more individuals per area and thus increasing leaf area index (LAI). At the highest plant density, new hybrids had the rates of light transmittance (0.04–0.05), low attenuation coefficient (K =0.47) and gained the highest yield. Leaf angle and LOV were highly correlated with TPAR/IPAR on ear, K, grain yield. Consequently, yield improvement in maize was probably a result of increased plant density tolerance through dependence on changes in leaf orientation characteristics.


      PubDate: 2014-04-28T17:21:07Z
       
 
 
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