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  Subjects -> AGRICULTURE (Total: 780 journals)
    - AGRICULTURAL ECONOMICS (80 journals)
    - AGRICULTURE (533 journals)
    - CROP PRODUCTION AND SOIL (93 journals)
    - DAIRYING AND DAIRY PRODUCTS (28 journals)
    - POULTRY AND LIVESTOCK (46 journals)

AGRICULTURE (533 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  [3041 journals]
  • Long-term P and K fertilisation strategies and balances affect soil
           availability indices, crop yield depression risk and N use
    • Abstract: Publication date: May 2017
      Source:European Journal of Agronomy, Volume 86
      Author(s): Frederik van der Bom, Jakob Magid, Lars Stoumann Jensen
      The last century has seen a large increase of fertiliser use, along with a subsequent rise of crop productivity. However, in many places its intensive use has become a burden to the environment, and legislation has been introduced to restrict nutrient applications. In combination with changing production scenarios as a result of climate change, this means an improved understanding is needed of how low nutrient availability and climatic stress factors affect yields and yield stability. We examined the long-term effects mineral and organic fertilisation on a nutrient-depleted field, and observed large annual variations: depending on the year, average spring barley yields under unfertilised management (U) were between 17–75% lower than the reference N½P½K½ (60–10–60kgha−1). Yields increased up to 174% under N1P1K1 (120–20–120kgha−1), while animal manure applications at an N availability level corresponding to N1 were between 79 and 137%. No temporal yield trends could be observed, but long-term changes of Olsen-P and exchangeable K were related to the nutrient balances (inputs-offtake) (r2 =0.60 and 0.59, respectively, P <0.001). Multiple linear regression analysis was used to examine the effects of the treatments in combination with annual weather variations. The results could be split into two outcomes, 1) a general relation between yields and temperatures for the periods of early spring (P< 0.01, multiple R2 =0.31) and summer (P< 0.001, multiple R2 =0.45), and 2) an interaction between temperature and nutrient applications during crop establishment, leading to a diverse response of relative yields (P< 0.001, multiple R2 =0.64), i.e. relative yield losses under the unfertilised treatment (U) were greater in years with lower spring temperatures, and, conversely, the increased nutrient availability in the fully mineral and organically fertilised treatments could partially alleviate the negative effects. After 13 years of repeated fertilisation, inputs were suspended for a single year and only N was applied to evaluate the residual effects. Yields were significantly affected by the different fertilisation histories (P< 0.001). Likewise, apparent nitrogen recovery tended to improve with previous inputs, but the observations were highly variable. Overall, the analyses agree with the notion that brief periods of stress at a critical stage may significantly affect yields, and confirmed that management of sufficient nutrient availability is critical for maintaining high and stable yields.
      Graphical abstract image

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

      PubDate: 2017-02-23T16:44:50Z
       
  • The effects of dairy cattle manure and mineral N fertilizer on irrigated
           maize and soil N and organic C
    • Abstract: Publication date: February 2017
      Source:European Journal of Agronomy, Volume 83
      Author(s): E. Martínez, F. Domingo, A. Roselló, J. Serra, J. Boixadera, J. Lloveras
      This work was aimed at providing a sustainable approach in the use of manure in irrigated maize crop under Mediterranean climatic conditions. To this end, the effect of continuous annual applications of dairy cattle manure, combined or not with mineral N fertilizer, on the following parameters was studied: grain yield, grain and plant N concentration, N uptake by plant, N use efficiency, and soil N and organic carbon. The experiment was conducted in a furrow-irrigated sandy soil under dry Mediterranean conditions during seven years. Three different rates of cattle manure (CM): 0, 30 and 60Mgha−1, were applied each year before sowing. These CM rates were combined with four mineral N rates (0, 100, 200 and 300kgNha−1) applied at sidedress. On average, the highest grain yields during the 7 years were obtained with the combination of CM at 30Mgha−1 and mineral fertilizer and with CM at 60Mgha−1 without mineral fertilizer. With CM at 30Mgha−1, mineral fertilizer increased yields during most of the growing seasons, meanwhile with CM at 60Mgha−1, there was not any significant effect of the joint application of mineral fertilizer on yields. Overall, best results were obtained exceeding maximum rates according to present legislation. The mean apparent nitrogen recovery (ANR) fraction during the 7 seasons was 29% for N exclusively applied as CM. Overall, increased N rates applied as CM resulted in decreased ANRs. However, ANR with CM at 30 and 60Mgha−1 increased during the first two seasons. This increased ANR ascribed to mineralization of residual organic N applied in previous seasons explained the increasing yields observed in the treatments along the study. The application of CM during 7 years increased the soil organic carbon in the first 30cm by 5.7 and 9.9Mgha−1 with CM at 30 and 60Mgha−1, respectively, when compared to the initial stock. Thus, manure-based fertilization could be an alternative to mineral fertilizer in order to achieve high maize yields while improving soil quality under dry Mediterranean conditions.

      PubDate: 2017-02-23T16:44:50Z
       
  • Diversity of methodologies to experiment Integrated Pest Management in
           arable cropping systems: Analysis and reflections based on a European
           network
    • Abstract: Publication date: February 2017
      Source:European Journal of Agronomy, Volume 83
      Author(s): Martin Lechenet, Violaine Deytieux, Daniele Antichi, Jean-Noël Aubertot, Paolo Bàrberi, Michel Bertrand, Vincent Cellier, Raphaël Charles, Caroline Colnenne-David, Silke Dachbrodt-Saaydeh, Philippe Debaeke, Thierry Doré, Pascal Farcy, César Fernandez-Quintanilla, Gilles Grandeau, Cathy Hawes, Lionel Jouy, Eric Justes, Roman Kierzek, Per Kudsk, Jay Ram Lamichhane, Françoise Lescourret, Marco Mazzoncini, Bo Melander, Antoine Messéan, Anna-Camilla Moonen, Adrian C. Newton, Jean-Marie Nolot, Silvia Panozzo, Patrick Retaureau, Maurizio Sattin, Juergen Schwarz, Clotilde Toqué, Vasileios P. Vasileiadis, Nicolas Munier-Jolain
      Integrated Pest Management (IPM) aims to promote physical and biological regulation strategies that help farmers contain populations of pests (pathogens, animal pests and weeds) and to finally reduce the reliance on pesticides. It is based on the holistic combination of multiple management measures rather than on the sum of single methods, each of them having only small effects on pests reduction. Thus, to analyse the interactions between IPM measures and to evaluate the sustainability of their implementation, we require an approach considering the whole cropping system (CS), i.e. a functional entity whose complexity is more than the sum of its parts. A network of European experiments at the CS level was set up recently, and aimed at sharing data and expertise to enhance knowledge of IPM. Comparison of existing methodologies highlighted a diversity of CS designs and experimental layouts. We deduced that the concept of CS itself was viewed differently among scientists, and this affected experimental protocols. Other differences were related to the research context and objectives. Some experiments aimed to explore very innovative strategies and generated knowledge on both their effects on the agroecosystem and their ability to satisfy a set of performance targets, while others aimed to provide quickly adoptable solutions for local farmers in line with the current socio-economic constraints. In some research programmes, the experiment was part of the CS design process — and tested CS were regularly revised based on an continuous improvement loop — while in other cases CS were kept stable across years so as to enable the evaluation of their long-term cumulative effects. A critical aspect contributing to the diversity among CS experiments was the distinction between a factorial design of experimental CS and systemic approaches: factorial experiments allowed quantification of the effects of each IPM component regardless of the consistency between components defining the CS. In contrast, systemic approaches focused on the overall evaluation of CS designed with consideration of their consistency, hence maximising their ability to meet the objectives. Because CS experiments represent a huge investment in terms of economics and time, preliminary reflections of the relevance of the experimental strategy is of critical importance.

      PubDate: 2017-02-23T16:44:50Z
       
  • Soil compaction management and soybean yields with cover crops under
           no-till and occasional chiseling
    • Abstract: Publication date: April 2017
      Source:European Journal of Agronomy, Volume 85
      Author(s): Juliano C. Calonego, Juan P.A. Raphael, João P.G. Rigon, Leontino de Oliveira Neto, Ciro A. Rosolem
      The introduction of cover crops in agricultural systems under no-till is important in soil structuring and remediation. However, there is a lack of studies exploring the effects of cover crops compared with other soil compaction control tools, such as chiseling, in the long term, mainly under tropical climates. This study aimed to evaluate soil physical properties by cover crops and chiseling in a compacted soil, as well as its effects on soybean yields. The experiment was conducted in Botucatu, Brazil, under no-till. Three crops were grown per year. Soybean [Glycine max (L.) Merrill] was cropped as summer crop in rotation with triticale (X Triticosecale Wittmack) or sunflower [Helianthus annuus (L.)] as fall/winter crop. In spring, three different cover crops were grown, pearl millet [Pennisetum glaucum (L.) R. Brown], forage sorghum [Sorghum bicolor (L.) Moench] and sunn hemp [Crotalaria juncea (L.)], compared to a fallow treatment, which was chiseled in 2003, 2009 and 2013 only, always in October and down to 0.60m depth. The first chiseling increased soil macroporosity and soybean yields in the immediate cropping season (2003/2004). However, these benefits were short-lived and in two years the use of cover crops resulted in higher yields. In the long-term, cover crops improve soil structure, with equal or better results than those obtained by occasional chiseling, as an increase in soil macroporosity by sunn hemp up to 0.20m depth and a decrease in soil bulk density by sunn hemp and pearl millet in the 0.40–0.60m layer. Among the cover crops, sunn hemp is particularly interesting, because it increases macroporosity in clay soils otherwise with limited aeration and increases the soybean yield.

      PubDate: 2017-02-16T16:31:04Z
       
  • Climate impacts on palm oil yields in the Nigerian Niger Delta
    • Abstract: Publication date: April 2017
      Source:European Journal of Agronomy, Volume 85
      Author(s): Stanley U. Okoro, U. Schickhoff, J. Boehner, U.A. Schneider, N.I. Huth
      Palm oil production has increased in recent decades and is estimated to increase further globally. The optimal role of palm oil production, however, is controversial because of conflicts with other important land uses and ecosystem services. Local conditions and climate change affect resource competition and the desirability of palm oil production in the Niger Delta, Nigeria. The objectives of this study are to (1) establish a better understanding of the existing yield potentials of oil palm areas that could be used for integrated assessment models, (2) quantify for the first time uncertainties in yield potentials arising from the use of climate output data from different Global Circulation Models (GCM’s) with varied West African Monsoon (WAM) system representations forced to the same Regional Climate Models (RCM’s). We use the biophysical simulation model APSIM (Agricultural Production Systems Simulator) to simulate spatially variable impacts of climate change on oil palm yield over the Nigerian Niger Delta. Our results show that the impact of climate change on oil palm yield is considerable across our study region. The yield differences between the IPCC RCPs were small. The net impact of climate change on oil palm is positive and is dynamically inconsistent. There is no significant change in the simulated yield arising from the differences in the forcing’s data. We found the most effective strategy for oil palm yield optimization under climate change to be shifting of sowing dates and introduction of irrigation.

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

      PubDate: 2017-02-10T16:16:57Z
       
  • How accurately do maize crop models simulate the interactions of
           atmospheric CO2 concentration levels with limited water supply on water
           use and yield?
    • Abstract: Publication date: Available online 10 February 2017
      Source:European Journal of Agronomy
      Author(s): Jean-Louis Durand, Kenel Delusca, Ken Boote, Jon Lizaso, Remy Manderscheid, Hans Johachim Weigel, Alex C Ruane, Cynthia Rosenzweig, Jim Jones, Laj Ahuja, Saseendran Anapalli, Bruno Basso, Christian Baron, Patrick Bertuzzi, Christian Biernath, Delphine Deryng, Frank Ewert, Thomas Gaiser, Sebastian Gayler, Florian Heinlein, Kurt Christian Kersebaum, Soo-Hyung Kim, Christoph Müller, Claas Nendel, Albert Olioso, Eckart Priesack, Julian Ramirez Villegas, Dominique Ripoche, Reimund P. Rötter, Sabine I Seidel, Amit Srivastava, Fulu Tao, Dennis Timlin, Tracy Twine, Enli Wang, Heidi Webber, Zhigan Zhao
      This study assesses the ability of 21 crop models to capture the impact of elevated CO2 concentration ([CO2]) on maize yield and water use as measured in a 2-year Free Air Carbon dioxide Enrichment experiment conducted at the Thünen Institute in Braunschweig, Germany (Manderscheid et al., 2014). Data for ambient [CO2] and irrigated treatments were provided to the 21 models for calibrating plant traits, including weather, soil and management data as well as yield, grain number, above ground biomass, leaf area index, nitrogen concentration in biomass and grain, water use and soil water content. Models differed in their representation of carbon assimilation and evapotranspiration processes. The models reproduced the absence of yield response to elevated [CO2] under well-watered conditions, as well as the impact of water deficit at ambient [CO2], with 50% of models within a range of +/−1Mgha−1 around the mean. The bias of the median of the 21 models was less than 1Mgha−1. However under water deficit in one of the two years, the models captured only 30% of the exceptionally high [CO2] enhancement on yield observed. Furthermore the ensemble of models was unable to simulate the very low soil water content at anthesis and the increase of soil water and grain number brought about by the elevated [CO2] under dry conditions. Overall, we found models with explicit stomatal control on transpiration tended to perform better. Our results highlight the need for model improvement with respect to simulating transpirational water use and its impact on water status during the kernel-set phase.

      PubDate: 2017-02-10T16:16:57Z
       
  • On-farm rice yield and its association with biophysical factors in
           sub-Saharan Africa
    • Abstract: Publication date: April 2017
      Source:European Journal of Agronomy, Volume 85
      Author(s): Atsuko Tanaka, Jean-Martial Johnson, Kalimuthu Senthilkumar, Cyriaque Akakpo, Zacharie Segda, Louis P. Yameogo, Ibrahim Bassoro, Delphine Mapiemfu Lamare, Moundibaye D. Allarangaye, Henri Gbakatchetche, Belay A. Bayuh, Famara Jaiteh, Ralph K. Bam, Wilson Dogbe, Keita Sékou, Raymond Rabeson, Njato M. Rakotoarisoa, Nianankoro Kamissoko, Illiassou Maïga Mossi, Oladele S. Bakare, Fanny L. Mabone, Elie R. Gasore, Idriss Baggie, Geophrey J. Kajiru, Jerome Mghase, Komlan A. Ablede, David Nanfumba, Kazuki Saito
      Although increase in rice (Oryza spp.) production is a common objective for rice-producing countries in sub-Saharan Africa (SSA), basic information on yield and its variation at farm level is lacking. Field surveys were conducted in irrigated lowland (IL), rainfed lowland (RL), and rainfed upland (RU) rice production systems in 19 SSA countries in the 2012–2014 wet seasons. Mean yield varied widely across sites: 2.2–5.8t/ha, 1.1–5.2t/ha, and 1.0–2.5t/ha in IL, RL, and RU, respectively. Rice yield levels differed between the agro-ecological zones (AEZs) with the highest yield in the semi-arid zone in IL, and in the highlands zone for RL and RU. Cluster analysis identified four groups using mean yields, coefficient of variation, and skewness of yield distribution of 42 site–production system combinations. Grouping was related to production system, AEZ, and field water condition. A high-yielding group with 5.3t/ha mean yield and negative skewness had only four site–production system combinations. Other groups had mean yields from 1.6 to 3.5t/ha with positive skewness. In these groups, research and development priority for lifting rice yield could be given to low-yielding IL and RL sites with large yield gaps. Raising rice yield in the humid zone irrespective of the production systems and RU across AEZs remain major challenges. Further assessment of the impact of farmers’ agricultural practices on yield variation is warranted to identify potential interventions to realize further yield enhancement.

      PubDate: 2017-01-22T10:40:52Z
       
  • Effect of agronomic programmes with different susceptibility to
           deoxynivalenol risk on emerging contamination in winter wheat
    • Abstract: Publication date: April 2017
      Source:European Journal of Agronomy, Volume 85
      Author(s): Massimo Blandino, Valentina Scarpino, Michael Sulyok, Rudolf Krska, Amedeo Reyneri
      Deoxynivalenol (DON) is the most prevalent mycotoxin in small cereal crops throughout the world, and its occurrence is closely linked to the presence of Fusarium Head Blight (FHB) disease. In order to minimize the sanitary risk, wheat cropping systems are commonly designed to control DON contamination, as this represents the main target contaminant. However, several other mycotoxins and secondary metabolites produced by Fusarium and other fungal species have been detected in wheat. The objective of this study was to evaluate whether the application of agronomic programmes with different susceptibility to DON contamination could also affect the occurrence of emerging mycotoxins in wheat kernels. Field experiments have been conducted in North Italy, under naturally-infected conditions, over a period of 3 growing seasons, by comparing 4 field programmes, which were constituted by the combination of wheat cultivars (a durum wheat variety that is susceptible to DON contamination and a common moderately resistant one) and 2 fungicide applications at heading (untreated control compared to an azole application at heading). Grain samples have been analyzed by means of a dilute-and-shoot multi-mycotoxin LC–MS/MS method, and 43 fungal metabolites were detected. In addition to DON, the most abundant compounds were aurofusarin, culmorin and deoxynivalenol-3-glucoside, which were detected in all the growing seasons and agronomic strategies. Other trichothecenes and zearalenone derivatives were also found, but in clearly lower concentrations. Contamination by enniatins and moniliformin, produced by other Fusarium species e.g. Fusarium avenaceum, alternariol, alternariol methyl ether and tentoxin, produced by Alternaria species, has been observed for all the compared growing seasons. The presence of other mycotoxins and secondary metabolites was clearly affected by the climatic conditions: fumonisins, beauvaricin, bikaverin, fusaric acid and butenolid were detected in the warmer growing seasons, while chrysogine, infectopyrone, secalonic acid and ergot alkaloids (sum of 13 toxins) were only found in the more rainy and cool seasons. Equisetin, decalonectrin, toxin T-2 and HT-2 were only found in traces. The application of the field programmes clearly affected DON contamination in each growing season: a significant increase in this toxin has been observed moving from the lowest risk agronomic strategy to the highest one. The application of the most favourable DON control field programme (a moderately resistant variety combined with fungicide application at heading) reduced the content of this mycotoxin by 89%, compared to the worst programme (untreated susceptible variety). The application of the less risky agronomic strategy for DON contamination led to a significant reduction (>84%) of all the other mycotoxins produced by the DON producing fungal species. Moreover, although the considered agronomic factors (variety susceptibility and fungicide application) resulted in a control efficacy that varied in function of the environmental conditions and the type of mycotoxin, the results show a clear reduction trend, after the application of agronomic strategies that are able to minimize the DON content, for almost all the other Fusarium, Alternaria, Claviceps and Penicillium metabolites. The results summarized in this work, which have been obtained under different environmental and agronomical conditions, allow a first assessment to be made of the agronomic strategies that could be applied to control emerging mycotoxins in wheat.
      Graphical abstract image

      PubDate: 2017-01-22T10:40:52Z
       
  • Yield gaps in oil palm: A quantitative review of contributing factors
    • Abstract: Publication date: February 2017
      Source:European Journal of Agronomy, Volume 83
      Author(s): Lotte S. Woittiez, Mark T. van Wijk, Maja Slingerland, Meine van Noordwijk, Ken E. Giller
      Oil palm, currently the world’s main vegetable oil crop, is characterised by a large productivity and a long life span (≥25 years). Peak oil yields of 12tha−1 yr−1 have been achieved in small plantations, and maximum theoretical yields as calculated with simulation models are 18.5t oil ha−1 yr−1, yet average productivity worldwide has stagnated around 3t oil ha−1 yr−1. Considering the threat of expansion into valuable rainforests, it is important that the factors underlying these existing yield gaps are understood and, where feasible, addressed. In this review, we present an overview of the available data on yield-determining, yield-limiting, and yield-reducing factors in oil palm; the effects of these factors on yield, as measured in case studies or calculated using computer models; and the underlying plant-physiological mechanisms. We distinguish four production levels: the potential, water-limited, nutrient-limited, and the actual yield. The potential yield over a plantation lifetime is determined by incoming photosynthetically active radiation (PAR), temperature, atmospheric CO2 concentration and planting material, assuming optimum plantation establishment, planting density (120–150 palms per hectares), canopy management (30–60 leaves depending on palm age), pollination, and harvesting. Water-limited yields in environments with water deficits >400mmyear−1 can be less than one-third of the potential yield, depending on additional factors such as temperature, wind speed, soil texture, and soil depth. Nutrient-limited yields of less than 50% of the potential yield have been recorded when nitrogen or potassium were not applied. Actual yields are influenced by yield-reducing factors such as unsuitable ground vegetation, pests, and diseases, and may be close to zero in case of severe infestations. Smallholders face particular constraints such as the use of counterfeit seed and insufficient fertiliser application. Closing yield gaps in existing plantations could increase global production by 15–20Mt oil yr−1, which would limit the drive for further area expansion at a global scale. To increase yields in existing and future plantations in a sustainable way, all production factors mentioned need to be understood and addressed.

      PubDate: 2017-01-15T10:36:22Z
       
  • Genetic gains for physiological traits associated with yield in soft red
           winter wheat in the Eastern United States from 1919 to 2009
    • Abstract: Publication date: March 2017
      Source:European Journal of Agronomy, Volume 84
      Author(s): Maria Balota, A.J. Green, C.A. Griffey, R. Pitman, W. Thomason
      Wheat (Triticum aestivum L.) breeding strategies can benefit from periodic evaluation of genetic gains for physiological and morphological traits, and their contribution to yield progress over time in a particular environment. The objective of this research was to expand the recent work at Virginia Tech on genetic yield improvement in soft red winter (SRW) wheat and determine the magnitude of progress for several physiological traits in 50 SRW wheat cultivars released from 1919 to 2009. Physiological traits evaluated here were extensively reported in the literature to be relevant for future wheat breeding as they directly contributed to yield increase under optimum and suboptimal environmental conditions; these traits include canopy temperature depression (CTD), flag leaf width (W), flag leaf area (LA), flag leaf dry weight (DW), flag leaf specific area (SLA), SPAD (soil plant analysis development) chlorophyll reading, and grain 13C isotope discrimination (Δ). Replicated experiments were performed at Warsaw and Holland, VA, in 2009–2010 and 2010–2011 growing seasons. Results showed that three traits consistently changed in magnitude over time and, at the same time, were significantly (p<0.01) related to yield; they were LA, smaller leaf area-higher yields; DW, lighter leaves-higher yields; and Δ, higher Δ-higher yields. CTD decreased in magnitude and SLA, W, and SPAD chlorophyll reading did not significantly change over time. Our data suggest that further yield increase in the SRW wheat grown in eastern Unites States can be achieved through selection of cultivars with smaller leaves, and with high Δ.

      PubDate: 2017-01-07T10:30:16Z
       
  • Forage production, quality and water-use-efficiency of four warm-season
           annual crops at three sowing times in the Loess Plateau region of China
    • Abstract: Publication date: March 2017
      Source:European Journal of Agronomy, Volume 84
      Author(s): Zhixin Zhang, Jeremy P.M. Whish, Lindsay W. Bell, Zhibiao Nan
      Increasing demand for livestock products is driving development of livestock systems worldwide. That requires improved and new forage production options. The Loess Plateau region in central-northern China is an important area for livestock production, as it supports11% and 19% of the country’s cattle and sheep, respectively (China statistical yearbook 2014). The rain-fed semi-arid environment of the Loess Plateau means that maximizing the water-use-efficiency (WUE) of forage production is vital to guarantee enough fodder supply the livestock demand. A three-year field experiment in north-west Loess Plateau compared forage production, water use and water-use-efficiency as well as crude protein (CP) content of forage maize, Sudan grass, foxtail millet and Japanese millet sown at three sowing dates according to the opening rain during 2011–2013. On average, forage maize produced the highest biomass (12.1tha−1) and had the highest WUE (43.4kg DM ha−1 mm−1). This was followed by Sudan grass (7.8tha−1; 26.5kg DM ha−1 mm−1), Japanese millet (6.7tha−1; 26.2kg DM ha−1 mm−1) and foxtail millet (6.7tha−1; 24.6kg DM ha−1 mm−1). Optimizing sowing date played an important role in maximizing forage production and WUE of all tested forages. Compared to the earliest sowing date, a delay of two weeks reduced forage production by 17% in maize, 35% in foxtail millet, and 16% in Japanese millet. A delay of four to six weeks reduced biomass yield by 58% in maize, 57% in foxtail millet, and 56% in Japanese millet. Late sowing also greatly reduced WUE of forage maize and foxtail millet by 33% and 42%, respectively, when compared to early sowing. The middle sowing date maximized forage production and WUE of Sudan grass in two of the three growing seasons, which was 20% and 38% higher than the early and late sowing, respectively. Late sowing in all forages reduced crop water use by 42–57mm compared to the early sowing. Among four test crops, CP of Sudan grass (7.9%) and forage maize (7.7%) was higher than foxtail millet (6.8%) and Japanese millet (6.7%). Compared with early sowing, CPf in late sowing significantly increased in Sudan grass and decreased in Japanese millet, in contrast, no evident sowing date effect was found in forage maize and foxtail millet. This study showed that all four warm-season annual grasses had high forage production potential, forage maize was the most reliable and efficient option. Forage maize and the millets could easily be integrated into existing cropping systems and provide opportunities as both grain and forage-producing crop to provide added flexibility for farmers.

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

      PubDate: 2017-01-07T10:30:16Z
       
  • Root decomposition at high and low N supply throughout a crop rotation
    • Abstract: Publication date: March 2017
      Source:European Journal of Agronomy, Volume 84
      Author(s): J.M. Herrera, L. Büchi, G. Rubio, C. Torres-Guerrero, M. Wendling, P. Stamp, D. Pellet
      Soil nitrogen (N) dynamics can be modified by cover crops in rotations with cereals. Although, roots are a major source of N, little is known about the dynamics of root decomposition of cash and cover crops. The objective of this study was to assess the effects that cover crop species have on i) the decomposition of spring wheat roots during the growth of cover crops, and ii) the decomposition of cover crop roots during the growing season of spring wheat. The experiment aimed also at comparing three non-winter hardy cover crops of varying shoot C/N ratios under low and high N input levels of 6 and 12gNm−2 y−1, respectively. The experiment included spring wheat (Triticum aestivum L.) as the main crop and non-winter hardy cover crops (yellow mustard (Sinapis alba L.), phacelia (Phacelia tanacetifolia Benth), and sunflower (Helianthus annuus L.) as well as bare soil fallow treatment. Minirhizotrons were used to non-destructively assess the spatial and temporal patterns of root growth and decomposition from 0.10 to 1.00m. Simultaneously, we grew all crops in soil columns to measure destructively C and N content in the roots. We concluded that wheat root decomposition was not affected by cover crop species. In contrast, during the growing season of wheat root decomposition of yellow mustard was on average twice as high for phacelia and sunflower as a consequence of a higher production of roots with a significantly higher C/N ratio compared to the other cover crops.

      PubDate: 2017-01-07T10:30:16Z
       
  • Plasticity of seed weight compensates reductions in seed number of oilseed
           rape in response to shading at flowering
    • Abstract: Publication date: March 2017
      Source:European Journal of Agronomy, Volume 84
      Author(s): Marcelo H. Labra, Paul C. Struik, Jochem B. Evers, Daniel F. Calderini
      Understanding the response of the number of seeds and seed weight to the availability of assimilates is crucial for designing breeding strategies aimed to increase seed and oil yield in oilseed rape. This study aims to answer the questions: i) do seed number and seed weight in oilseed rape differ in their plasticity in response to the availability of assimilates at flowering? and ii) how sensitive are oil and protein concentrations to the availability of assimilates during flowering? A spring oilseed rape hybrid was sown in two field experiments and the treatments were combinations of i) two plant densities and ii) shading or no shading between the beginning and end of flowering. Seed yield was not affected by plant density or by shading. Lower plant density was compensated by an increase in seed number per plant, without effects on single-seed weight. However, the negative effect of shading during flowering on seed number per area was fully compensated by an increase in single-seed weight by 47–61%. The plasticity of single-seed weight observed in the present study of oilseed rape has never been reported for annual seed crops. Shading at flowering increased both the seed filling rate and the duration of the seed filling period at all positions in the canopy. We also observed that the reduction of the source-sink ratio at flowering increasing seed weight does not necessarily modify oil or protein concentrations. Thus, single-seed weight could be targeted to increase seed yield in oilseed rape without compromising oil content.
      Graphical abstract image

      PubDate: 2017-01-07T10:30:16Z
       
  • Intercropping wheat and maize increases total radiation interception and
           wheat RUE but lowers maize RUE
    • Abstract: Publication date: March 2017
      Source:European Journal of Agronomy, Volume 84
      Author(s): Fang Gou, Martin K. van Ittersum, Elisabeth Simon, Peter A. Leffelaar, Peter E.L. van der Putten, Lizhen Zhang, Wopke van der Werf
      Row configuration has a large influence on the intensity of species interactions in intercrops. Row configuration affects how many crop rows interact with the same species and how many rows interact with the other species, shaping the expression of plasticity, resource capture, and growth. This study aims to determine how row configuration influences radiation interception and productivity in wheat-maize intercropping under western European growing conditions. Field experiments with different row configurations were carried out in 2013 and 2014 in the Netherlands. We compared seven treatments, comprising sole crops of wheat and maize (SW and SM), a replacement intercrop (6:2WM), skip-row designs (6:0WM, 0:2WM) and add-row designs (6:3WM, 8:2WM). We determined leaf area and biomass dynamics over time, and developed a simple geometry-based model to estimate light capture in these different row configurations. The model was tested with light measurements in the field. Crop radiation use efficiency (RUE) was estimated by linear regression of above-ground biomass on the calculated cumulative intercepted light (photosynthetically active radiation – PAR). This study showed that: 1) wheat-maize intercropping had significantly higher PAR interception than sole wheat in 2013 and 2014, and sole maize in 2013, but not in 2014; 2) intercropping significantly increased RUE of wheat, whereas it significantly decreased RUE of maize; 3) both light interception and light use efficiency changed with planting configuration. Thus we showed that the row configuration of the intercrop affected light interception as well as light use efficiency by modulating the strength of competitive and compensatory interactions within and between crop species.

      PubDate: 2017-01-07T10:30:16Z
       
  • Effects of integrated agronomic practices management on root growth and
           development of summer maize
    • Abstract: Publication date: March 2017
      Source:European Journal of Agronomy, Volume 84
      Author(s): Zheng Liu, Kunlun Zhu, Shuting Dong, Peng Liu, Bin Zhao, Jiwang Zhang
      Root growth and development of summer maize (Zea mays L.) is an important process in determining grain yield. In comparison to the information on above ground plant responses only limited knowledge exists on the response of root growth and development to integrated agronomic practices management (defined as a comprehensive management framework consisted of tillage method, plant density, seeding and harvest date, and fertilizer application) under field conditions. Two experiments, integrated agronomic practices management (IAPM) and nitrogen rate testing (NAT) were used to determine the effects on summer maize root system in the course of five years in North China. IAPM consisted of four treatments (CK: local conventional cultivation practices, Opt-1: an optimized combination of cropping system and fertilizer treatment, HY: treatment based on high-yield studies, and Opt-2: a further optimized combination of cropping system and fertilizer treatment). NAT had four treatments of nitrogen rate (0, 129.0, 184.5, and 300.0kgNha−1).Individual/population root dry weight, individual/population absorption area, surface, volume, and length density of root and grain yield were measured. Roots were sampled per plot at six-leaf stage (V6), tasseling stage (VT), milk stage (R3) and physiological maturity stage (R6). The results from IAPM revealed that Opt-2 significantly increased dry weight, volume, superficial area, and length density of root across the 0–30cm soil layer of whole growth period. Root active absorption area of Opt-2 exhibited a significant increase in the 0–30cm soil layer of whole growth period except V6. In compare with root/shoot ratio of CK, this of Opt-2 increased by 14.5% at VT and 16.3% at R6. Results from NAT revealed that N with a range from 0 to 184.5kgNha−1 played a positive role in root growth and development. Dry weight, absorbing area of root, and the root/shoot ratio increased as N rate rise within certain limits and then decreased significantly. Dry weight, the proportion of deeply distributed, absorption area, length density of root, and root/shoot ratio increased due to appropriate population, reasonable fertilizer management, and suitable harvest date, which provided sufficient nutrients and moisture to aboveground parts for growth, development, and high grain yield of summer maize.

      PubDate: 2017-01-07T10:30:16Z
       
  • Multi-model uncertainty analysis in predicting grain N for crop rotations
           in Europe
    • Abstract: Publication date: March 2017
      Source:European Journal of Agronomy, Volume 84
      Author(s): Xiaogang Yin, Kurt Christian Kersebaum, Chris Kollas, Sanmohan Baby, Nicolas Beaudoin, Kiril Manevski, Taru Palosuo, Claas Nendel, Lianhai Wu, Munir Hoffmann, Holger Hoffmann, Behzad Sharif, Cecilia M. Armas-Herrera, Marco Bindi, Monia Charfeddine, Tobias Conradt, Julie Constantin, Frank Ewert, Roberto Ferrise, Thomas Gaiser, Iñaki Garcia de Cortazar-Atauri, Luisa Giglio, Petr Hlavinka, Marcos Lana, Marie Launay, Gaëtan Louarn, Remy Manderscheid, Bruno Mary, Wilfried Mirschel, Marco Moriondo, Isik Öztürk, Andreas Pacholski, Dominique Ripoche-Wachter, Reimund P. Rötter, Françoise Ruget, Mirek Trnka, Domenico Ventrella, Hans-Joachim Weigel, Jørgen E. Olesen
      Realistic estimation of grain nitrogen (N; N in grain yield) is crucial for assessing N management in crop rotations, but there is little information on the performance of commonly used crop models for simulating grain N. Therefore, the objectives of the study were to (1) test if continuous simulation (multi-year) performs better than single year simulation, (2) assess if calibration improves model performance at different calibration levels, and (3) investigate if a multi-model ensemble can substantially reduce uncertainty in reproducing grain N. For this purpose, 12 models were applied simulating different treatments (catch crops, CO2 concentrations, irrigation, N application, residues and tillage) in four multi-year rotation experiments in Europe to assess modelling accuracy. Seven grain and seed crops in four rotation systems in Europe were included in the study, namely winter wheat, winter barley, spring barley, spring oat, winter rye, pea and winter oilseed rape. Our results indicate that the higher level of calibration significantly increased the quality of the simulation for grain N. In addition, models performed better in predicting grain N of winter wheat, winter barley and spring barley compared to spring oat, winter rye, pea and winter oilseed rape. For each crop, the use of the ensemble mean significantly reduced the mean absolute percentage error (MAPE) between simulations and observations to less than 15%, thus a multi–model ensemble can more precisely predict grain N than a random single model. Models correctly simulated the effects of enhanced N input on grain N of winter wheat and winter barley, whereas effects of tillage and irrigation were less well estimated. However, the use of continuous simulation did not improve the simulations as compared to single year simulation based on the multi-year performance, which suggests needs for further model improvements of crop rotation effects.

      PubDate: 2017-01-07T10:30:16Z
       
  • Determination of sufficiency values of canopy reflectance vegetation
           indices for maximum growth and yield of cucumber
    • Abstract: Publication date: March 2017
      Source:European Journal of Agronomy, Volume 84
      Author(s): Francisco M. Padilla, M. Teresa Peña-Fleitas, Marisa Gallardo, Rodney B. Thompson
      Large nitrogen (N) fertilizer applications are a feature of intensive vegetable production systems, and optimal N management is required to maximize N use efficiency and minimize N losses. Vegetation indices (VIs) of canopy reflectance, measured with proximal sensors, are generally strongly related to crop N status. For practical application, sufficiency values that distinguish between N deficiency and sufficiency are required. In this work, sufficiency values of VIs for maximum crop growth and for yield were determined for two cucumber crops grown in contrasting seasons (Autumn and Spring). Canopy reflectance was measured with a Crop Circle ACS-470 sensor. Sufficiency values for maximum growth were based on the relationships of VIs with the Nitrogen Nutrition Index (NNI), i.e. the ratio between actual and critical crop N contents. Sufficiency values for maximum yield were based on linear-plateau relationships of yield with VIs. Strong relationships were obtained between all VIs and both NNI and yield for most of the weekly measurements during both crops. For NNI, best-fit relationships were linear, quadratic, power or exponential, and had coefficients of determination (R2) of 0.61–0.98. For yield, most linear-plateau relationships between yield and VIs had R2 values of 0.47–0.89. VIs based on reflectance in green and red edge had slightly better relationships with NNI and yield than VIs in the red, with the Green Normalized Difference Vegetation Index (GNDVI) and the Green Ratio Vegetation Index (GRVI) being the most sensitive and consistent indices for estimating both crop NNI and yield. Relationships between VIs and NNI and yield for all weekly measurements of each crop, and for the two crops combined, were also analyzed to provide unique sufficiency values for maximum growth and yield that applied to the entire crop cycle of each crop and of both crops considered together. Overall, there were slight differences between sufficiency values for maximum growth and for maximum yield and the unique sufficiency values were generally intermediate to the weekly sufficiency values. This study demonstrated the potential for using VIs for monitoring crop N nutrition and yield in cucumber. The calculated sufficiency values of VIs may facilitate the use of proximal optical sensors in farming practice for optimal N management through periodic monitoring for deviation from sufficiency values.

      PubDate: 2016-12-27T14:16:17Z
       
  • Water relations and use-efficiency, plant survival and productivity of
           nine alfalfa (Medicago sativa L.) cultivars in dryland Mediterranean
           conditions
    • Abstract: Publication date: March 2017
      Source:European Journal of Agronomy, Volume 84
      Author(s): Alejandro del Pozo, Carlos Ovalle, Soledad Espinoza, Viviana Barahona, Macarena Gerding, Alan Humphries
      The potential for alfalfa to be a valuable rainfed pasture option that can be used to increase livestock and crop production in central-south Chile is demonstrated for the first time. The persistence, productivity and water use efficiency of alfalfa (Medicago sativa) cultivars was evaluated at four sites in dryland Mediterranean environments of Chile between 2012 and 2015. Nine alfalfa cultivars were evaluated for plant persistence, winter growth, forage yield, shoot water potential (Ψ), stomatal conductance (gs), and carbon (δ13C) and oxygen (δ18O) compositions. The percentage of plant survival after four years varied between 69 and 97% of the established plants. Alfalfa forage yield was >9tha−1yr−1 at Yungay (Andes foothills) in year two, and at Cauquenes (interior dryland site) in years three and four. The highest forage yield was obtained in cultivars SARDI Ten and Aquarius and the lowest in WL326HQ. In 2015, the forage yield during late spring and early summer (November 2015–January 2016) ranged from 3170 to 3570kgha−1 (average of the nine cultivars), which represented between 29% and 38% of the total production. The response of gs to Ψ was different among cultivars but all cultivars exhibited a strong decline when Ψ was <−1.0 MP. Shoot water potential evaluated in October–November was negatively correlated with δ13C and δ18O in shoot biomass. The apparent water use efficiency (kg DM/ha/mm of rainfall) across the nine cultivars was highest in Cauquenes in the three years evaluated (>16kgmm−1). It is concluded that alfalfa is a high yielding forage that can extend the growing season into early summer and autumn in dryland Mediterranean environments.

      PubDate: 2016-12-27T14:16:17Z
       
  • Quantifying the impact of crop protection practices on pesticide use in
           wine-growing systems
    • Abstract: Publication date: March 2017
      Source:European Journal of Agronomy, Volume 84
      Author(s): Florine Mailly, Laure Hossard, Jean-Marc Barbier, Marie Thiollet-Scholtus, Christian Gary
      Reducing pesticide use is a major challenge in agriculture, and farmers are encouraged to develop integrated practices. The aim of this study was to describe, analyse and assess the current contribution of various options to pest, disease and weed management on the reduction of fungicides, herbicides and insecticides by quantifying both their use and their effect on pesticide use intensity, within the context of different wine-growing regions. We conducted a statistical analysis of pesticide use and crop management over two seasons (2006 and 2010) for 11 French wine-growing regions (10,000 data). We used the Treatment Frequency Index (TFI) indicator to characterise the intensity of pesticide use. We analysed three crop management options: timing of first fungicide spray, type of soil cover cropping, and type of weed control. For each management option, we compared alternative or low-input practices to normal chemical-based practices, e.g., mechanical weed control (alternative option) vs. herbicide (normal chemical option). To strengthen the results, two quantitative variables completed the analysis: fungicide mean sprayed dose in the field and number of fungicides sprayed in the field. Results showed that each alternative or low input practice had an impact on TFI, but that this impact differed between wine-growing regions and between the management options under consideration. Regarding fungicides, our results showed that late timing of first fungicide spray (compared to regional reference) contributed to a reduction up to 50% of the part of the TFI due to fungicides, as compared to fields sprayed at median or early timing. Regarding herbicides, results of low-input/alternative practices were more homogeneous in terms of their relative impact on TFI reduction. The differences in use and impact of crop protection practices were more important between regions than between the two studied years. Our results may help policy makers to target methods for decreasing pesticide use, based on particularities of wine-growing regions and locally realistic practices.

      PubDate: 2016-12-27T14:16:17Z
       
  • Effects of walnut trees on biological nitrogen fixation and yield of
           intercropped alfalfa in a Mediterranean agroforestry system
    • Abstract: Publication date: March 2017
      Source:European Journal of Agronomy, Volume 84
      Author(s): Aurélie Querné, Patricia Battie-laclau, Lydie Dufour, Jacques Wery, Christian Dupraz
      While intercropping annual non nitrogen-fixing crops with deciduous hardwood species is now well documented, there is a need to investigate if nitrogen-fixing intercrops may succeed in agroforestry systems. Intercropping with trees usually leads to a decline in crop yield, and could in addition possibly reduce the biological N fixation (BNF) over time due to the competition for resources. In a Mediterranean experimental site, 17 year-old hybrid walnut trees (Juglans nigra x Juglans regia L.) planted in East-West oriented lines were intercropped with alfalfa (Medicago sativa L.) to assess the impact of competition for light and water on alfalfa yield and BNF. Alfalfa yield and shoot δ15N values (a proxy for the proportion of N derived from the air, %Ndfa) were measured during one year at different distances from the tree row in two directions (north and south). Alfalfa yield was reduced close to the tree row (−28% and −22% on the northern and southern sides respectively), but less than the reduction of irradiation (−59% and −33% respectively). Shading improved by 35% the apparent light use efficiency (LUE: aboveground biomass produced per unit of global radiation) of alfalfa, indicating that alfalfa was shade tolerant at this Mediterranean site. Alfalfa shoot δ15N values were lower close to the tree rows than at mid inter-row: BNF was stimulated close to the trees. Compensative and facilitative mechanisms between trees and alfalfa plants led to a rise in LUE and%Ndfa in shaded areas. These results contradict the frequent assumption that N fixation is reduced in the shade of trees. Appropriate tree canopy management may help maintain light competition between trees and alfalfa to a level that still enhance complementary, which would further improve the sustainability of the use of alfalfa as an intercrop in Mediterranean regions.

      PubDate: 2016-12-27T14:16:17Z
       
  • Vineyard row orientation and grape ripeness level effects on vegetative
           and reproductive growth characteristics of Vitis vinifera L. cv.
           Shiraz/101-14 Mgt
    • Abstract: Publication date: March 2017
      Source:European Journal of Agronomy, Volume 84
      Author(s): J.J. Hunter, C.G. Volschenk, M. Booyse
      Effects of vineyard row orientation (NS, EW, NE-SW, NW-SE) and harvesting dates/grape ripeness levels (23°B, 25°B and 27°B) on vegetative and reproductive growth characteristics of vertically trellised, shoot positioned Vitis vinifera L. cv. Shiraz, grafted onto rootstock 101–14Mgt, were investigated for seven consecutive seasons on a flat site of approximately 3ha with uniform clayey loam soil at the experiment farm of ARC Infruitec-Nietvoorbij in the Breede River Valley, Robertson, South Africa. Primary and secondary shoot characteristics showed minor differences between row orientations and canopy sides. Primary shoot lengths and primary leaf area:secondary leaf area ratios averaged 110–120cm and 0.80–0.90, respectively. Secondary leaf area of primary shoots on S and SW sides tended to be lower. The SW canopy side displayed generally lower values for most characteristics. Higher cane mass was obtained for NS and EW orientations. Bud fertility, berry set and general morphology of bunches were largely unaffected by row orientation. Bunch and berry mass and volume progressively decreased during ripening for all row orientation treatments. The EW row orientation resulted in consistently higher berry mass and volume. Leaf area (10–12cm2)/g fresh mass values showed equal balance for differently orientated vines, aligned with generally acknowledged criteria. Average yields of three ripeness levels over row orientations and seasons were 19.2, 17.4 and 15.9tons/ha. Overall total yield losses from ripeness level 1–2 and 2–3 averaged 9.5% and 8.6%, respectively, with an overall total yield loss from ripeness level 1–3 of 17.3%. This is mainly attributed to a decrease in berry mass; rachis mass showed high stability. The NS orientated vines had highest yields over seasons and at all ripeness levels; it also displayed most stable yields over the years of study and may be considered the most ideal row orientation for yield within the terroir of study. Yields of the other row orientations varied according to season/ripeness level: at ripeness level 1, NE-SW was followed by NW-SE and EW; at ripeness level 2, NW-SE was followed by EW and NE-SW; and at ripeness level 3; EW was followed by NW-SE and NE-SW. The NW-SE row orientation was stable at an average level and EW and NE-SW orientations were variable. Overall average yields (over ripeness levels) of NS, EW, NE-SW and NW-SE orientations were 18.2, 17.1, 17.1 and 17.4ton/ha, respectively. Despite minor differences in vegetative characteristics, yield:cane mass ratios indicated that growth balances were affected by row orientation. These trends are of great significance in considerations of an optimal ripeness level for a specific product objective and are very important aspects of sustainability. Results showed significant trends that can globally be used as guidelines for row orientation choices, even when multiple (straight or curved) row orientations per vineyard are used and when vineyards are established in more complex terrains/terroirs. The study provided the first comprehensive and much needed scientific evidence on the role of row orientation in vegetative and reproductive growth of the grapevine and as viticulture practice.

      PubDate: 2016-12-27T14:16:17Z
       
  • Hyper-spectral estimation of wheat biomass after alleviating of soil
           effects on spectra by non-negative matrix factorization
    • Abstract: Publication date: March 2017
      Source:European Journal of Agronomy, Volume 84
      Author(s): Yanli Li, Ya Liu, Shiwen Wu, Changkun Wang, Aiai Xu, Xianzhang Pan
      Hyper-spectral technology has been proven to be an effective method for the fast and non-destructive monitoring of crop biomass. However, the biomass estimation accuracy of this method is limited due to the effects of background factors, such as soils and water. In this study, a spectral separation method, non-negative matrix factorization (NMF), was proposed to alleviate the effects of soil on spectra. With the application of the NMF method, pure vegetation spectra were extracted from the field-observed spectra of wheat canopy, which were collected in four growing seasons from the tillering to the booting stages of wheat. Then, prediction models of wheat biomass (WB) were established and validated using the extracted spectra with the partial least squares regression (PLSR) method. The results showed that the NMF method could effectively separate the vegetation spectra from the mixed canopy spectra. Based on the extracted vegetation spectra, the WB prediction accuracy could be greatly improved with an increase of 31.7% for the R 2 p and an increase of 46.6% for the ratio of performance to deviation (RPD) as compared to the original spectra, indicating that the NMF method could significantly improve the performance of the WB prediction model. This method has potential application in the estimation of biomass using remote sensing technology.

      PubDate: 2016-12-27T14:16:17Z
       
  • Crop yields under no-till farming in China: A meta-analysis
    • Abstract: Publication date: March 2017
      Source:European Journal of Agronomy, Volume 84
      Author(s): Xin Zhao, Sheng-Li Liu, Chao Pu, Xiang-Qian Zhang, Jian-Fu Xue, Yong-Xiang Ren, Xiu-Ling Zhao, Fu Chen, Rattan Lal, Hai-Lin Zhang
      No-till (NT) farming is popular globally, however, the effects on crop yields remain debatable. A meta-analysis was conducted on crop yield responses to NT in China based on 1006 comparisons from 164 studies. Results showed that a decrease of 2.1±1.8% on crop yield was observed under NT with residue removed (NT0) compared with that under plow tillage with residue removed (PT0), but the decreases can be diminished to 1.9±1.0% when residue retention was combined with both the two tillage practices. On the contrary, NT with residue retention (NTR) may significantly increase crop yields by 4.6±1.3% compared with that under PT0 (P <0.05). Along with improvements in crop yields, increases in soil organic carbon (SOC) by 10.2±7.2%, available nitrogen (N) by 9.4±5.4%, available potassium by 10.5±8.8%, and water storage by ∼9.3±2.4% was observed under NTR compared with PT0, indicating that improvements in soil quality could benefit crop productivity under NTR. Categorically, results on meta-analysis and regression indicated large variations in crop yields under NTR because of differences in crop species, temperature and precipitation, antecedent SOC level, N fertilizer input, duration of adoption, and with or without residue retention. For example, crop yields significantly increased with increase in duration (P <0.0001) under NTR, by 21.3% after 10 years of continuous NTR compared with PT0. Adoption of NTR under appropriate site-specific conditions can advance China’s food security, improve yield stability and alleviate soil-related constraints.

      PubDate: 2016-12-27T14:16:17Z
       
  • Farming systems analysis and design for sustainable intensification: New
           methods and assessments
    • Abstract: Publication date: January 2017
      Source:European Journal of Agronomy, Volume 82, Part B
      Author(s): Pytrik Reidsma, Marie-Hélène Jeuffroy


      PubDate: 2016-12-11T14:02:40Z
       
  • Review of yield gap explaining factors and opportunities for alternative
           data collection approaches
    • Abstract: Publication date: January 2017
      Source:European Journal of Agronomy, Volume 82, Part B
      Author(s): Eskender Beza , João Vasco Silva, Lammert Kooistra, Pytrik Reidsma
      Yield gap analysis is gaining increased scientific attention, as estimating and explaining yield gaps shows the potential for sustainable intensification of agricultural systems. Explaining yield gaps requires detailed information about the biophysical environment, crop management as well as farm(er) characteristics and socio-economic conditions in which farmers operate. However, these types of data are not always available, mostly because they are costly to collect. The main objective of this research is to assess data availability and data collection approaches for yield gap analysis, and to summarize the yield gap explaining factors identified by previous studies. For this purpose, a review of yield gap studies (50 agronomic-based peer-reviewed articles) was performed to identify the most commonly considered and explaining factors of the yield gap. Besides a global comparison, differences between regions, crops and methods were analysed as well. The results show that management and edaphic factors are more often considered to explain the yield gap compared to farm(er) characteristics and socio-economic factors. However, when considered, both farm(er) characteristics and socio-economic factors often explain the yield gap. Fertilization and soil fertility factors are the most often considered management and edaphic factors. In the fertilization group, factors related to quantity (e.g. N fertilizer quantity) are more often considered compared to factors related to timing (e.g. N fertilizer timing). However, when considered, timing explained the yield gap more often. Explaining factors vary among regions and crops. For example, while soil fertility is considered relatively much both in Africa and Asia, it is often explaining in Africa, but not in Asia. Agronomic methods like crop growth simulation models are often used for yield gap analysis, but are limited in the type and number of factors that can be included. Qualitative methods based on expert knowledge can include the largest range of factors. Although the data included in yield gap analysis also depends on the objective, knowledge of explaining factors, and methods applied, data availability is a major limiting factor. Bottom-up data collection approaches (e.g. crowdsourcing) involving agricultural communities can provide alternatives to overcome this limitation and improve yield gap analysis.

      PubDate: 2016-12-11T14:02:40Z
       
  • Explaining rice yields and yield gaps in Central Luzon, Philippines: An
           application of stochastic frontier analysis and crop modelling
    • Abstract: Publication date: January 2017
      Source:European Journal of Agronomy, Volume 82, Part B
      Author(s): João Vasco Silva, Pytrik Reidsma, Alice G. Laborte, Martin K. van Ittersum
      Explaining yield gaps is crucial to understand the main technical constraints faced by farmers to increase land productivity. The objective of this study is to decompose the yield gap into efficiency, resource and technology yield gaps for irrigated lowland rice-based farming systems in Central Luzon, Philippines, and to explain those yield gaps using data related to crop management, biophysical constraints and available technologies. Stochastic frontier analysis was used to quantify and explain the efficiency and resource yield gaps and a crop growth model (ORYZA v3) was used to compute the technology yield gap. We combined these two methodologies into a theoretical framework to explain rice yield gaps in farmers’ fields included in the Central Luzon Loop Survey, an unbalanced panel dataset of about 100 households, collected every four to five years during the period 1966–2012. The mean yield gap estimated for the period 1979–2012 was 3.2tonha−1 in the wet season (WS) and 4.8tonha−1 in the dry season (DS). An average efficiency yield gap of 1.3tonha−1 was estimated and partly explained by untimely application of mineral fertilizers and biotic control factors. The mean resource yield gap was small in both seasons but somewhat larger in the DS (1.3tonha−1) than in the WS (1.0tonha−1). This can be partly explained by the greater N, P and K use in the highest yielding fields than in lowest yielding fields which was observed in the DS but not in the WS. The technology yield gap was on average less than 1.0tonha−1 during the WS prior to 2003 and ca. 1.6tonha−1 from 2003 to 2012 while in the DS it has been consistently large with a mean of 2.2tonha−1. Varietal shift and sub-optimal application of inputs (e.g. quantity of irrigation water and N) are the most plausible explanations for this yield gap during the WS and DS, respectively. We conclude that the technology yield gap explains nearly half of the difference between potential and actual yields while the efficiency and resource yield gaps explain each a quarter of that difference in the DS. As for the WS, particular attention should be given to the efficiency yield gap which, although decreasing with time, still accounted for nearly 40% of the overall yield gap.

      PubDate: 2016-12-11T14:02:40Z
       
  • Effects of changing farm management and farm structure on energy balance
           and energy-use efficiency—A case study of organic and conventional
           farming systems in southern Germany
    • Abstract: Publication date: January 2017
      Source:European Journal of Agronomy, Volume 82, Part B
      Author(s): Hung-Chun Lin, Julia A. Huber, Georg Gerl, Kurt-Jürgen Hülsbergen
      Fossil energy input, energy output, and energy use- efficiency (EUE) are important indicators of the environmental effects, resource consumption and economic performance of farming systems. In this study, the energy balance (process analysis) and EUE of different organic and conventional farming systems – mixed farming, arable farming, and agroforestry (AGFS) systems – were analyzed due to their importance in Germany. The analysis was based on long-term experiments at the Scheyern Research Farm in southern Germany. The results showed that the conversion from multi-structured organic mixed farming to a specialized organic arable farming system reduced the fossil energy input in crop production only marginally (from 5.9 to 5.5GJha−1 yr−1), but considerably decreased dry matter yield (from 5.4 to 2.5Mgha−1 yr−1), energy output (from 99 to 46GJha−1 yr−1) and EUE (from 16.8 to 8.3). Improved management in the conventional arable farming system (with high-yielding varieties and better N management) reduced the energy input from 14.0 to 12.2GJha−1 yr−1, increased the energy output from 155 to 179GJha−1 yr−1, and elevated the EUE from 11.1 to 14.6. The establishment of AGFS with short rotation trees (without fertilization and pesticide use) led to the reduction of energy input. Based on the results, we concluded that mixed farming is one of the best ways of producing food with high EUE under the conditions of organic farming. Therefore the conversion from organic mixed farming to an organic arable farming system is not recommended. Our AGFS results were from the first stage of a long-term experiment; it showed no negative effects on DM yield and energy output and positive effects on energy-use efficiency at this stage. However, further research is needed to know the long-term influence of AGFS.

      PubDate: 2016-12-11T14:02:40Z
       
  • Mitigating N2O emissions from cropping systems after conversion from
           pasture − a modelling approach
    • Abstract: Publication date: January 2017
      Source:European Journal of Agronomy, Volume 82, Part B
      Author(s): Henrike Mielenz, Peter J. Thorburn, Robert H. Harris, Peter R. Grace, Sally J. Officer
      Converting pasture to cropping is common in many of the world’s agricultural systems. This conversion results in substantial net mineralisation of soil organic matter that builds up during a phase of pasture. A few studies have shown that this mineralisation leads to increased nitrous oxide (N2O) emissions compared to long-term pasture or long-term cropping. Understanding of interactions leading to these significant emissions is still scarce but is needed to identify mitigation options for this situation. In this study, the Agricultural Production Systems sIMulator (APSIM) was used to investigate the optimal timing of pasture termination (relative to crop planting) and management of nitrogen (N) in crops after pasture termination to maximise crop yield and limit N2O emissions. Beforehand, APSIM’s performance in simulating yields and N2O emissions was tested against data from field experiments conducted in the temperate high-rainfall zone of southern Australia where N2O emissions were monitored with automatic gas collection chambers during the first year of cropping wheat after terminating long-term pasture on two adjacent sites in two consecutive years. Field experiments and simulation scenarios showed very high N2O emissions (up to 48kgN2O-Nha−1 yr−1) in the first year of wheat after pasture termination, even without N fertiliser application. Measured cumulative N2O emissions, crop yields and soil mineral N and water content dynamics were simulated well with APSIM. Including a routine into APSIM to account for N2O transport through the soil profile improved the simulation of daily N2O emissions considerably, leading to up to 67% of the measured variability in daily N2O emissions being explained by the model. We predicted that a short fallow between termination of pasture and sowing wheat, instead of a long fallow which is the common practice, reduces N2O emissions by more than half in the first year of cropping without a noteworthy impact on crop yield. Reducing N fertiliser applications in the first few years after pasture termination by taking available soil mineral N into account, and applying the fertiliser six to twelve weeks after sowing instead of at sowing was predicted to further reduce N2O emissions. Since the model was calibrated against experimental data during the first year after pasture termination only, experiments determining N2O emissions in the first two or three years after terminating pasture are needed to confirm our predictions.

      PubDate: 2016-12-11T14:02:40Z
       
  • Modelling soil tillage and mulching effects on soil water dynamics in
           raised-bed vegetable rotations
    • Abstract: Publication date: January 2017
      Source:European Journal of Agronomy, Volume 82, Part B
      Author(s): F. Alliaume, W.A.H. Rossing, P. Tittonell, S. Dogliotti
      Reduced tillage and mulching may bring about new production systems that combine better soil structure with greater water use efficiency for vegetable crops grown in raised bed systems. These are especially relevant under conditions of high rainfall variability, limited access to irrigation and high soil erosion risk. Here we evaluate a novel combination of empirical models on water interception and infiltration, with a soil-water balance model to evaluate water dynamics in raised bed systems on fine Uruguayan soils to analyze the effect of reduced tillage, cover crops and organic matter addition on soil physical properties and water balance. In the experiment mulching increased water capture by 9.5% and reduced runoff by 37%, on average, leading to less erosion risk and greater plant available water over four years of trial. Using these data we calibrated and evaluated different models that predicted interception+infiltration efficiently (EF=0.93 to 0.95), with a root mean squared error (RMSE) from 0.32 to 0.40mm, for an average observed interception+infiltration of 28.8mm per day per rainfall event. Combining the best model with a soil water balance resulted in predictions of total soil water content to 1m depth (SWCT) with RMSE ranging from 4.5 to 10.3mm for observed SWCT ranging from 180.4 to 380.6mm. Running the model for a four-year crop sequence under 10 years of Uruguayan historical weather revealed that reduced tillage required on average 141mmyr−1 less irrigation water than conventional tillage combined with organic matter application, thus enabling a potential increase in irrigated area of vegetable crops and crop yields. Results also showed the importance of inter-annual rainfall variability, which caused up to 3-fold differences in irrigation requirements. The model is easily adaptable to other soil and weather conditions.

      PubDate: 2016-12-11T14:02:40Z
       
  • The farming system component of European agricultural landscapes
    • Abstract: Publication date: January 2017
      Source:European Journal of Agronomy, Volume 82, Part B
      Author(s): Erling Andersen
      Agricultural landscapes are the outcome of combined natural and human factors over time. This paper explores the scope of perceiving the agricultural landscapes of the European Union (EU) as distinct patterns of farming systems and landscape elements in homogeneous biophysical and administrative endowments. The focus is on the farming systems component of the agricultural landscapes by applying a typology to the sample farms of the Farm Accountancy Data Network and scaling up the results to the landscape level for the territory of the EU. The farming system approach emphasises that agricultural landscapes evolve from the praxis of the farmers and takes into account the scale, intensity and specialisation of the agricultural production. From farming system design point of view, the approach can be used to integrate the landscape in the design process. From a policy point of view, the approach offers handles to implement policies that design agricultural landscapes by targeting the farming system pattern.

      PubDate: 2016-12-11T14:02:40Z
       
  • From stakeholders narratives to modelling plausible future agricultural
           
    • Abstract: Publication date: January 2017
      Source:European Journal of Agronomy, Volume 82, Part B
      Author(s): Sylvestre Delmotte, Vincent Couderc, Jean-Claude Mouret, Santiago Lopez-Ridaura, Jean-Marc Barbier, Laure Hossard
      European farmers are facing challenges that call for important transformations on their agricultural production systems, including an increasing number of regulations aimed at reducing environmental impacts from farming practices. Climate change is also expected to affect agricultural production in most European regions, and in Southern Europe this effect is expected to negatively impact yields. In this study, we present the application of an innovative participatory approach to assess the potential of innovative agricultural systems to reconcile environmental sustainability with economic viability while contributing to local and global food security. Our approach consisted of combining (1) the participation of local stakeholders in the design of narrative scenarios, and (2) an integrated assessment of scenarios through the calculation of indicators at different scale with a bio-economic model. We tested our approach with a case study situated in the Camargue region of Southern France. Rice is currently the main crop in this region, but farmers there face adverse economic conditions linked to the recent reform of European Common Agriculture Policy. After identifying the main drivers of change, local stakeholders developed narrative scenarios and described how farmers would adapt within the context of those changes. These elements were then translated into model inputs. At the regional level, the four scenarios led to variations in farmland acreage (28,000–33,000ha), as well as the proportion of rice crops (19–75%) and areas cultivated under organic farming standards (8–43%). The four scenarios also led to different values for indicators of agricultural economic welfare, food production, and environmental impacts. Trade-offs between these indicators and the associated objectives assigned to agriculture were identified and discussed with the stakeholders. We end with a discussion of the limitations and advantages of our approach to the participatory development and assessment of locally developed narrative scenarios.

      PubDate: 2016-12-11T14:02:40Z
       
  • Methodology to design agroecological orchards: Learnings from on-station
           and on-farm experiences
    • Abstract: Publication date: January 2017
      Source:European Journal of Agronomy, Volume 82, Part B
      Author(s): Sylvaine Simon, Magalie Lesueur-Jannoyer, Daniel Plénet, Pierre-Éric Lauri, Fabrice Le Bellec
      Agricultural research has to tackle complex questions such as the design of sustainable cropping systems. System experiments are innovative approaches to address this challenge and a framework to iteratively design annual cropping systems has been proposed by Debaeke et al. (2009). However, specificities of some other cropping systems are not considered. Orchards are complex perennial agroecosystems formed of grass and tree layers aiming at the production of fresh fruit that require specific design and management over space and time. To identify orchard specificities and adapt the design framework to such perennial systems, we used two case studies of orchards aiming at decreasing pesticide use in temperate (apple, system experiment) and tropical (citrus, on-farm network) fruit productions. Specificities to take into account in the design framework are: (1) the spatial heterogeneity of the orchard with grass and tree layers, and tree rows and alleys; (2) the succession and interrelations among a young unproductive and then a productive stage; (3) the permanency of the fruit-tree crop constraining the management of soil fertility, (4) ground cover and (5) pest control, especially for pests that complete their lifecycle in the orchard and can build up important populations or inoculum across years. This is especially true in tropical areas where there is no dormant season. (6) Conversely, the permanency of the orchard habitats facilitates the sowing, planting or conservation of plant assemblages (e.g., ground covers, lining hedgerows) to enhance conservation biocontrol and/or compete weeds, provided non-disruptive practices are applied. Because of their longevity, orchards contribute to foster both plant-mediated (e.g., bottom-up) and natural enemy-mediated (e.g., top-down) processes in the foodweb to avoid direct measures against pests. Interactions among the orchard life stages, spatial and functional dimensions and practices need to be explicitly considered to optimize the efficiency of the system as a whole. Using the generic framework proposed by Debaeke et al. (2009) to design annual cropping systems, our framework includes adaptations to account for orchard specificities: (i) Agronomic objectives have to be fixed for each orchard stage; (ii) The cultivar choice and the composition and spatial arrangement of plants within the orchard are key elements to provide the expected services in the long term. This entails to include an additional step of perennial spatial design; (iii) Within-time and −space interactions have to be considered in the decisional system; (iv) Evaluation has to consider all the orchard stages in the global impact or performance, to account for carry-over effects and possible ‘paybacks’ of a given stage or period to the orchard whole lifetime. Last, to handle such complex interactions, design needs knowledge from many stakeholders in the food system (growers, advisors, scientists etc.) and requires more and renewed interactions among those stakeholders in a co-design process.

      PubDate: 2016-12-11T14:02:40Z
       
  • Spatial distribution of soil water, soil temperature, and plant roots in a
           drip-irrigated intercropping field with plastic mulch
    • Abstract: Publication date: February 2017
      Source:European Journal of Agronomy, Volume 83
      Author(s): Xianyue Li, Jiří Šimůnek, Haibin Shi, Jianwen Yan, Zunyuan Peng, Xuewen Gong
      Intercropping and drip irrigation with plastic mulch are two agricultural practices used worldwide. Coupling of these two practices may further increase crop yields and land and water use efficiencies when an optimal spatial distribution of soil water contents (SWC), soil temperatures, and plant roots is achieved. However, this coupling causes the distribution of SWCs, soil temperatures, and plant roots to be more complex than when only one of these agricultural practices are used. The objective of this study thus was to investigate the effects of different irrigation treatments on spatial distributions of SWCs, soil temperatures, and root growth in a drip-irrigated intercropping field with plastic mulch. Three field experiments with different irrigation treatments (high T1, moderate T2, and low T3) were conducted to evaluate the spatial distribution of SWCs, soil temperatures, and plant roots with respect to dripper lines and plant locations. There were significant differences (p <0.05) in SWCs in the 0–40cm soil layer for different irrigation treatments and between different locations. The maximum SWC was measured under the plant/mulch for the T1 treatment, while the minimum SWC was measured under the bare soil surface for the T3 treatment. This was mainly due to the location of drippers and mulch. However, no differences in SWCs were measured in the 60100cm soil layer. Significant differences in soil temperatures were measured in the 05cm soil layer between different irrigation treatments and different locations. The soil temperature in the subsoil (1525cm) under mulch was higher than under the bare surface. The overlaps of two plant root systems in an intercropping field gradually increased and then decreased during the growing season. The roots in the 030cm soil layer accounted for about 60%70% of all roots. Higher irrigation rates produced higher root length and weight densities in the 030cm soil layer and lower densities in the 30100cm soil layers. Spatial distributions of SWCs, soil temperatures, and plant roots in the intercropping field under drip irrigation were significantly influenced by irrigation treatments and plastic mulch. Collected experimental data may contribute to designing an optimal irrigation program for a drip-irrigated intercropping field with plastic mulch.

      PubDate: 2016-12-05T09:41:44Z
       
  • Assessment of soybean yield with altered water-related genetic improvement
           traits under climate change in Southern Brazil
    • Abstract: Publication date: February 2017
      Source:European Journal of Agronomy, Volume 83
      Author(s): Rafael Battisti, Paulo C. Sentelhas, Kenneth J. Boote, Gil M. de S. Câmara, José R.B. Farias, Claudir J. Basso
      Water deficit is a major factor responsible for soybean yield gap in Southern Brazil and tends to increase under climate change. An alternative to reduce such gap is to identify soybean cultivars with traits associated to drought tolerance. Thus, the aim of this study was to assess soybean adaptive traits to water deficit that can improve yield under current and future climates, providing guidelines for soybean cultivar breeding in Southern Brazil. The following soybean traits were manipulated in the CSM-CROPGRO-Soybean crop model: deeper root depth in the soil profile; maximum fraction of shoot dry matter diverted to root growth under water stress; early reduction of transpiration under mild stress; transpiration limited as a function of vapor pressure deficit; N2 fixation drought tolerance; and sensitivity of grain filling period to water deficit. The yields were predicted for standard and altered traits using climate data for the current (1961–2014) and future (middle-century) scenarios. The traits with greater improvement in soybean yield were deeper rooting profile, with yield gains of ≈300kgha−1, followed by transpiration limited as a function of vapor pressure deficit and less drought-induced shortening of the grain filling period. The maximum fraction of shoot dry matter diverted to root and N2 fixation drought tolerance increased yield by less than 75kgha−1, while early reduction of transpiration resulted in a small area of country showing gains. When these traits were combined, the simulations resulted in higher yield gains than using any single trait. These results show that traits associated with deeper and greater root profile in the soil, reducing transpiration under water deficit more than photosynthesis, creating tolerance of nitrogen fixation to drought, and reducing sensitivity of grain filling period to water deficit should be included in new soybean cultivars to improve soybean drought tolerance in Southern Brazil.

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

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

      PubDate: 2016-11-28T02:21:13Z
       
  • Sowing date and N application effects on tap root and above-ground dry
           matter of winter oilseed rape in autumn
    • Abstract: Publication date: February 2017
      Source:European Journal of Agronomy, Volume 83
      Author(s): Klaus Sieling, Ulf Böttcher, Henning Kage
      In many parts of Europe, farmers often replace winter barley by winter wheat as preceding crop for winter oilseed rape (WOSR) resulting in a delayed WOSR sowing and poor autumn growth. Based on data from a field trial running in 2009/10, 2010/1l, and 2012/13, this study aims i) to investigate how a delayed sowing impairs autumnal above-ground and tap root growth of winter WOSR and ii) to test the ability of an additional N supply in autumn to compensate for the negative effects of an unfavorable sowing date. In order to create sufficiently differentiated canopies, 4 sowing dates (first decade of August till the third decade of September) and 4 autumn N treatments (0, 30, 60, and 90kgNha−1) combined. Above-ground and tap root dry matter (DM) as well as green area index (GAI) were determined in autumn. On average of the three years, delaying sowing date significantly decreased above-ground and tap root DM accumulation and GAI of oilseed rape at the end of autumn growth. The reduction in tap root DM was more pronounced compared to that in above-ground DM. N supply in autumn significantly boosted above-ground and tap root DM. However, the N effect was less distinct compared to that of the sowing date. Green area of all autumn N treatments increased according to a logistic function, reaching its maximum at a thermal time (Tbase =3°C) of about 650°d. N supply in autumn significantly enhanced GAI formation. The current results clearly revealed that a delayed sowing date of OSR decreased both the above-ground and tap root DM. An additional N supply was only partly able to compensate for a poor autumn growth, especially that of the tap root.

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

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

      PubDate: 2016-11-14T09:49:20Z
       
  • Comparison of regression techniques to predict response of oilseed rape
           yield to variation in climatic conditions in Denmark
    • Abstract: Publication date: Available online 31 October 2016
      Source:European Journal of Agronomy
      Author(s): Behzad Sharif, David Makowski, Finn Plauborg, Jørgen E. Olesen
      Statistical regression models represent alternatives to process-based dynamic models for predicting the response of crop yields to variation in climatic conditions. Regression models can be used to quantify the effect of change in temperature and precipitation on yields. However, it is difficult to identify the most relevant input variables that should be included in regression models due to the high number of candidate variables and to their correlations. This paper compares several regression techniques for modeling response of winter oilseed rape yield to a high number of correlated input variables. Several statistical regression methods were fitted to a dataset including 689 observations of winter oilseed rape yield from replicated field experiments conducted in 239 sites in Denmark, covering nearly all regions of the country from 1992 to 2013. Regression methods were compared by cross-validation. The regression methods leading to the most accurate yield predictions were Lasso and Elastic Net, and the least accurate methods were ordinary least squares and stepwise regression. Partial least squares and ridge regression methods gave intermediate results. The estimated relative yield change for a +1°C temperature increase during flowering was estimated to range between 0 and +6 %, depending on choice of regression method. Precipitation was found to have an adverse effect on yield during autumn and winter. It was estimated that an increase in precipitation of +1 mm/day would result in a relative yield change ranging from 0 to −4 %. Soil type was also important for crop yields with lower yields on sandy soils compared to loamy soils. Later sowing was found to result in increased crop yield. The estimated effect of climate on yield was highly sensitive to the chosen regression method. Regression models showing similar performance led in some cases to different conclusions with respect to effect of temperature and precipitation. Hence, it is recommended to apply an ensemble of regression models, in order to account for the sensitivity of the data driven models for projecting crop yield under climate change.

      PubDate: 2016-11-07T09:30:10Z
       
  • Maternal environment and dormancy in sunflower: The effect of temperature
           during fruit development
    • Abstract: Publication date: Available online 25 October 2016
      Source:European Journal of Agronomy
      Author(s): María Paula Bodrone, María Verónica Rodríguez, Sebastián Arisnabarreta, Diego Batlla
      A rapid and uniform germination in the field is an important requirement for commercial hybrid sunflower seed. Persistence of dormancy after harvest can negatively affect this aspect of seed quality, and seed lots with some degree of dormancy cannot be commercialized. Seed dormancy intensity and duration can vary greatly among sunflower genotypes, but it is also subject to strong interactions with the maternal environment. In this paper we report results of investigations into the effect of temperature during sunflower fruit development on the level of dormancy after harvest. After conducting controlled (greenhouse) and field experiments (sowing dates and plastic tents), we found that higher temperatures during later stages of achene development significantly increased the level of dormancy at harvest and its persistence during storage. The impact of the maternal (thermal) environment on embryo and coat-imposed dormancy was also investigated. Results showed that although maturation under warmer environments reduced embryo dormancy, this effect was overcompensated for by the enhancement of inhibition imposed by the pericarp and the seed coat. In addition, the results obtained suggest that observed changes in dormancy in response to the maternal environment could be at least partially explained by changes in achene and/or embryo sensitivity to ABA. Results presented here should be useful when choosing a proper environment for the production of hybrid sunflower seed of high quality, avoiding high temperatures during later stages of fruit development.

      PubDate: 2016-10-30T21:49:42Z
       
  • Crop rotation effects on yield, technological quality and yield stability
           of sugar beet after 45 trial years
    • Abstract: Publication date: Available online 22 October 2016
      Source:European Journal of Agronomy
      Author(s): Philipp Götze, Jan Rücknagel, Monika Wensch-Dorendorf, Bernward Märländer, Olaf Christen
      Long-term field trials constitute an essential basis for research into the effects of agricultural management practices on yield and soil properties. The long-term field trial Etzdorf (Germany) was set up in 1970 and uses various crop rotations with sugar beets (Beta vulgaris L., SB) to investigate the influence of increasing cropping concentrations (20 %–100 %) and decreasing cropping intervals (0–4 years) on the yield and quality parameters of SB. However, evaluation of the yield stability of SB in diverse crop rotations has not been conducted in this context so far. For this reason, the yield for the last 13 years of the trial (2002 until 2014) was subjected to such an evaluation. Besides cropping interval and cropping concentration, the crop rotations investigated also differed in terms of the complementary crops cultivated (winter wheat, Triticum aestivum L.; alfalfa, Medicago ssp.; potato, Solanum tuberosum L. and grain maize, Zea mays L.). Both SB root yield and white sugar yield increased with an increasing cropping interval or decreasing cropping concentration of SB in the crop rotation. In addition, a positive effect on root yield and white sugar yield was seen when integrating alfalfa, while cultivating SB after SB displayed the lowest root yield and white sugar yield. Sugar content was lowest in SB monoculture. In order to assess stability of white sugar yield, the coefficient of variation and ecovalence were calculated, and a linear regression analysis of the individual crop rotations’ annual yield was performed for the annual average of all crop rotations. When considering these three parameters, the crop rotations with a cropping interval of at least 2 years displayed higher yield stability, with simultaneously higher white sugar yield, than the crop rotations with a cropping interval of 0 and 1year. By integrating alfalfa into the crop rotation, it was also possible to achieve above-average white sugar yield with high yield stability for a cropping interval of 1year.

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

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

      PubDate: 2016-10-25T00:19:59Z
       
  • PhenoGlad: A model for simulating development in Gladiolus
    • Abstract: Publication date: Available online 17 October 2016
      Source:European Journal of Agronomy
      Author(s): Lilian Osmari Uhlmann, Nereu Augusto Streck, Camila Coelho Becker, Natalia Teixeira Schwab, Rômulo Pulcinelli Benedetti, Andrea Schwertner Charão, Bruna San Martin Rolim Ribeiro, Waleska Bolson Silveira, Fernanda Alice Antonello Londero Backes, Cleber Maus Alberto, Martina Muttoni, Gizelli Moiano de Paula, Regina Tomiozzo, Leosane Cristina Bosco, Dislaine Becker
      Crop simulation models are important tools to help farmers in planning management practices and flowering time of cut flowers, like Gladiolus (Gladiolus x grandiflorus Hort.). The objective of this study was to develop a robust Gladiolus phenology model, named PhenoGlad, for field applications. The model describes the timing of developmental stages, including harvest point, the vase life of Gladiolus spikes and the low (chilling) and high (heat) temperature effects on spike quality. The Gladiolus developmental model simulates on a daily basis the cumulative leaf number and the phenology using a non-linear temperature response function and genotype-specific coefficients considering three main phases: corms sprouting phase, vegetative phase, and reproductive phase. Data from nine field experiments conducted during five years (2011–2015) in three locations across the Rio Grande do Sul State and in one location in Santa Catarina State, Brazil, were used. These cultivar x planting dates x years x locations experiments provided a rich data set for parameterizing and evaluating the Gladiolus model. The PhenoGlad model accurately simulated the dynamics of leaf development, final leaf number and the timing of developmental stages among cultivars, planting dates, years and locations, with an overall RMSE of 0.5 leaves for leaf development and final leaf number, 6.5days for the date of reproductive developmental stages, and 1.3days for simulating the vase life of harvested spikes. PhenoGlad was also accurate in predicting the effects of chilling and high temperatures damage on florets.

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

      PubDate: 2016-10-16T23:15:31Z
       
  • Effects of shade, altitude and management on multiple ecosystem services
           in coffee agroecosystems
    • Authors: Rolando Cerda; Clémentine Allinne; Christian Gary; Philippe Tixier; Celia A. Harvey; Louise Krolczyk; Charlie Mathiot; Eugénie Clément; Jean-Noel Aubertot; Jacques Avelino
      Abstract: Publication date: Available online 6 October 2016
      Source:European Journal of Agronomy
      Author(s): Rolando Cerda, Clémentine Allinne, Christian Gary, Philippe Tixier, Celia A. Harvey, Louise Krolczyk, Charlie Mathiot, Eugénie Clément, Jean-Noel Aubertot, Jacques Avelino
      Agroforestry systems provide diverse ecosystem services that contribute to farmer livelihoods and the conservation of natural resources. Despite these known benefits, there is still limited understanding on how shade trees affect the provision of multiple ecosystem services at the same time and the potential trade-offs or synergies among them. To fill this knowledge gap, we quantified four major ecosystem services (regulation of pests and diseases; provisioning of agroforestry products; maintenance of soil fertility; and carbon sequestration) in 69 coffee agroecosystems belonging to smallholder farmers under a range of altitudes (as representative of environmental conditions) and management conditions, in the region of Turrialba, Costa Rica. We first analyzed the individual effects of altitude, types of shade and management intensity and their interactions on the provision of ecosystem services. In order to identify potential trade-offs and synergies, we then analyzed bivariate relationships between different ecosystem services, and between individual ecosystem services and plant biodiversity. We also explored which types of shade provided better levels of ecosystem services. The effectiveness of different types of shade in providing ecosystem services depended on their interactions with altitude and coffee management, with different ecosystem services responding differently to these factors. No trade-offs were found among the different ecosystem services studied or between ecosystem services and biodiversity, suggesting that it is possible to increase the provision of multiple ecosystem services at the same time. Overall, both low and highly diversified coffee agroforestry systems had better ability to provide ecosystem services than coffee monocultures in full sun. Based on our findings, we suggest that coffee agroforestry systems should be designed with diversified, productive shade canopies and managed with a medium intensity of cropping practices, with the aim of ensuring the continued provision of multiple ecosystem services.

      PubDate: 2016-10-12T12:36:48Z
      DOI: 10.1016/j.eja.2016.09.019
       
 
 
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