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  • Closing yield gaps in oil palm production systems in Ghana through Best Management Practices
    Eur. J. Agron. (IF 3.384) Pub Date : 2020-02-20
    Tiemen Rhebergen; Shamie Zingore; Ken E. Giller; Charles Adu Frimpong; Kwame Acheampong; Francis Tetteh Ohipeni; Edward Kofi Panyin; Victor Zutah; Thomas Fairhurst

    The area under oil palm in Ghana has expanded but average fruit bunch yields remained low, resulting in large yield gaps. This study assessed the potential for increasing yield with 'Best Management Practices (BMP)' on plantations and smallholder farms in southern Ghana, compared with current standard practices, i.e. reference (REF) yield. We evaluated short-term (≤1 year) yield increases with 'yield taking' (improved crop recovery), and long-term increases (>1 year) with 'yield making' (better agronomy) practices and identified the factors that contributed most to yield improvements. Average fruit bunch yield increases with BMP were 2.1 t ha−1 (+19%) and 4.7 t ha−1 (+89%) with yield taking and 4.7 t ha−1 (+36%) and 7.6 t ha−1 (+76%) with yield making at plantations and smallholder farms respectively. Short-term yield improvements were achieved with more frequent harvesting events and improved field access, which can help finance inputs needed for the yield making phase. Our analysis suggests more balanced palm nutrition could contribute considerably to yield making, particularly on smallholder farms. Improved fertilizer recommendations are therefore essential for sustainable oil palm production in Ghana. Increasing yields to 21.0 t ha−1 on land already planted to oil palm, can increase national fruit bunch production from 2.5 Mt to 6.9 Mt, sparing 600,000 ha of land. However, labour constraints on plantations and lack of access to credit and agricultural inputs on smallholder farms are major hurdles that need to be overcome to increase production.

    更新日期:2020-02-21
  • Variability in the potential effects of climate change on phenology and on grape composition of Tempranillo in three zones of the Rioja DOCa (Spain)
    Eur. J. Agron. (IF 3.384) Pub Date : 2020-02-13
    María Concepción Ramos; Fernando Martínez de Toda

    The objective of this research was to analyse the potential effect of climate change on phenology and berry composition of the variety Tempranillo cultivated in areas of the Rioja DOCa (Spain) with different climatic characteristics. Three zones were selected within the DOCa, which were located at elevations between 325 and 650 m a.s.l. Phenology and the evolution of berry composition during ripening was analysed for the period 2008-2018. This information included the dates of the phenological stages H (separated flowers), M (veraison) and maturity (based in a fixed value of the probable alcoholic degree (PVAD)) and as well as pH, total acidity, malic acid, total anthocyanins, total polyphenols index and colour intensity, recorded in two plots at each location. The climatic conditions recorded during the period of study were evaluated from meteorological stations located close to the vineyards. The average predicted changes in temperature (maximum and minimum) and in precipitation, under two Representative Concentration Pathway (RCP) emission scenarios (RCP4.5 and RCP8.5) and simulated using an ensemble of 10 models were analysed by 2050 and 2070 for each zone. These data were obtained using the MarkSim™ DSSAT weather file generator. The relationship found at present between climate characteristics and the phenology and grape composition were considered in order to project the changes under climate change. The results indicated projected increase of temperature higher in the warmer than in the cooler area, and changes in average precipitation, which although being small will contribute to increase water deficits. The results predict that all evaluated phenological stages will suffer an advance, which will be higher for veraison and maturity than for the stage related to flowering. The advance of the stage H, M and maturity for the three zones by 2050 could be up to 5, 8, and 12 days, respectively under the RCP4.5 emission trajectory, and up to 8, 12 and 15, respectively under the RCP8.5 emission trajectory. The predicted advances indicate that the differences in timing that already exists between zones will be maintained or even increase, which will imply reaching maturity in the second half of August in the warmer area and in earlier September in the coolest one. Grape composition could also suffer changes, reaching the required PVAD earlier with a decoupling between anthocyanins and sugars and with lower acidity caused by the increase of temperatures.

    更新日期:2020-02-20
  • Analysis of the significant drop in protein content in Danish grain crops from 1990-2015 based on N-response in fertilizer trials
    Eur. J. Agron. (IF 3.384) Pub Date : 2020-02-12
    Merete E. Styczen; Per Abrahamsen; Søren Hansen; Leif Knudsen

    A significant drop of 2.4–2.9 percentage-points (%-p) in crude protein content (on dry matter basis) in Danish grain crops was observed from around 1990 to 2015. The aim of the analysis was to quantify the effect of the change in N-response of varieties of winter wheat (WW) and spring barley (SB) under farmers’ conditions based on approx. 1000 fertilizer trials with WW and 500 with SB carried out in farmers’ fields from 1987 to 2015. Results indicated that for WW receiving 129−190 kg N/ha, DM yield increased 0.8-0.9 Mg/ha. The amount of harvested N in grain increased 5−11 kg N/ha, and % N in grain dropped by 0.1-0.05 %-points; the largest drop was found for low N-additions. For SB, receiving 93−129 kg N/ha, DM yield increased by 0.9–1.1 Mg/ha. The amount of harvested N in grain increased by 4−6 kg while the N % in grain dropped 0.2-0.24 %-points. For both crops, the effect of plant breeding is likely to be confounded with the effect of increased CO2. Adding up effects of changed N-response and fertilizer rates only explained part of the observed reduction in crude protein content.

    更新日期:2020-02-20
  • Yield and quality changes in lucerne of different fall dormancy ratings under three defoliation regimes
    Eur. J. Agron. (IF 3.384) Pub Date : 2020-02-12
    Hung T. Ta; Edmar I. Teixeira; Hamish E. Brown; Derrick J. Moot

    This study determined how fall dormancy rating (FD2, FD5 or FD10) of lucerne genotypes affected crop yield and quality. One field experiment was measured for three growing seasons as a seedling crop and then three defoliation frequency regimes (DF) of 28 (DF28), 42 (DF42) or 84 (DF84) days were imposed (October 2014 to April 2017). Annual shoot dry matter (DM) yields ranged from 5.2 t DM/ha in DF28 crops to 17.5 t DM/ha in DF84 crops. Higher shoot DM was associated with greater shoot elongation which was modified by photoperiod (Pp). In an increasing Pp environment, the rate of DM accumulation in shoots was ∼ 91 kg/ha for each 1.0 cm increase in shoot height. In a decreasing Pp environment, the rate of DM accumulation in shoots was constant at ∼50 kg/ha/cm. In the DF84 crops, shoot yield declined due to leaf senescence by ∼31 kg/ha/cm when lucerne was ≥65 cm height. The leaf stem ratio (LSR) declined by 0.56 for each 1.0 cm increase in plant height. The crude protein (CP) and metabolisable energy (ME) accumulation in whole shoots or in leaf, soft stem and hard stem followed an allometric relationship. As DM increased, CP and ME increased in a similar pattern for all treatments. Thus the relationship between the yield and quality of lucerne was independent of genotype and phenological stage and was explained allometrically by the leaf and stem ratio, associated with changes in plant height, as affected by photoperiod. These results suggest universal defoliation management strategies can be developed based on ontogeny and independently of genotype, growth stage and growing conditions.

    更新日期:2020-02-20
  • Biological nitrogen fixation in field pea and vetch: Response to inoculation and residual effect on maize in the Pampean region
    Eur. J. Agron. (IF 3.384) Pub Date : 2020-02-13
    Juan Martín Enrico; Carlos Fabian Piccinetti; Mirian Raquel Barraco; Maria Belén Agosti; Roxana Paola Eclesia; Fernando Salvagiotti

    Including legumes in winter, both as cover crop or for grain harvest, is recommended for avoiding long periods of bare fallow and supplying N for succeeding crops in the rotation. The aims of this study were to i) quantify the contribution of N derived from biological nitrogen fixation (N_BNF) in vetch (Vicia sativa L. or Vicia villosa L.) and field pea (Pisum sativum) in the Central Pampas region of Argentina, ii) evaluate the response to seed inoculation in terms of %N derived from air (%Ndfa), biomass production and N_BNF in both crops and iii) determine grain yield response to nitrogen fertilization of maize (Zea mays L.) sown after field pea and vetch with and without inoculation. %Ndfa was assessed in 16 experimental sites using the natural 15N abundance method. Response to inoculation in vetch and field pea and the residual effects on the following maize was evaluated during two years. On average, 60 % of N demand of vetch and field pea was met by BNF. Seed inoculation increased %Ndfa in field pea and vetch, and a positive impact on aboveground biomass and N_BFN was observed in vetch. Maize yield did not respond to N fertilization when planted after inoculated vetch, and the largest responses to N fertilization were observed when vetch and field pea were not inoculated. Legume inoculation had a strong impact at the system level, especially in fields that vetch or field pea was not previously cultivated, reducing the economic optimal nitrogen fertilizer rate in the succeeding maize.

    更新日期:2020-02-20
  • A framework to type crop management strategies within a production situation to improve the comprehension of weed communities
    Eur. J. Agron. (IF 3.384) Pub Date : 2020-02-13
    Séverin Yvoz; Sandrine Petit; Luc Biju-Duval; Stéphane Cordeau

    Farmers facing the same production situation may have different farming objectives and thus farming practices. However, the latter are rarely precisely described since studies often use a unique indicator of soil use intensity, showing a weak explanatory value of biotic pressures. Our aim was to develop a framework to identify crop management strategies based on (i) 14 indicators of farming practices collected in 203 fields from 2004 to 2016 through interviews with the 23 farmers managing the fields, and (ii) a discussion with the farmers to assess to what extent they are valid. Then, we assessed how much these strategies helped improving our understanding of 412 weed communities surveyed in their fields. Indicators of farming intensity (e.g. treatment frequency index) was converted into ratios by dividing with the mean value of all the fields cultivated with the same crop in the same year. We identified eight crop management strategies with cluster analysis within a 950-ha area exposed to the same production situation. They differed, in decreasing order of importance, by the diversity of crops, tillage intensity, pesticide and fertiliser uses. The interviews of the farmers validated their assignment to each strategy. The interviews revealed the reasons why farmers implement a single or various strategies in their fields (seven farmers practiced two or three strategies because of differences in soil types or history of fields). The outputs of the classification gave them additional information on how their farming system differed from those of their neighbours. Using crop management strategies improved the quality of the statistical models predicting weed richness, cumulated weed richness over the 2008–2013 period, weed abundance and the frequency of weeding failure. This framework is useful to identify crop management strategies and to share information with farmers in order to be used to redesign cropping systems toward a more environmentally friendly agriculture.

    更新日期:2020-02-20
  • Triticale cultivar mixtures: Productivity, resource use and resource use efficiency in a Mediterranean environment
    Eur. J. Agron. (IF 3.384) Pub Date : 2020-02-13
    Francesco Giunta; Francesco Cadeddu; Francesca Mureddu; Adriana Virdis; Rosella Motzo

    Cultural systems based on mixtures of varieties may be more successful in resource use and resource use efficiency than those based on single varieties. Two triticale cultivars of different phenology (Bienvenu, intermediate; and Oceania, spring) grown in pure stands were compared with mixtures of the two (25:75; 50:50 and 75:25). Field experiments were carried out in Sardinia (Italy) in five experiments created by combining seasons, sowing date and sites. At the terminal spikelet of Bienvenu, the best mixtures produced 38, 89 and 82 % more biomass than Bienvenu in pure stand, depending on the experiment, due to a higher crop growth rate associated with a higher RUE (r = 0.60*). In the case of dual purpose utilization, this means that the winter herbage production of triticale at the terminal spikelet stage of an intermediate or winter cultivar is improved when mixed with a spring cultivar, at least in the Mediterranean environment explored here. Complementarity and differences between mixtures and pure stands in biomass production by anthesis were the exception rather than the rule. By the anthesis of Oceania, mixtures only produced more biomass than the Oceania pure stand on three occasions (11.8 and 11.9 t ha−1 vs. 9.3 t ha−1 and 10.7 t ha−1 vs. 8.7 t ha−1). In these cases, the superiority of the mixtures was due to a higher intercepted PAR (also reflected in greater transpiration), attributable to the pattern of LAI development. Differences in grain yield were only expressed when a cold stress during anthesis compromised the grain set of the spring cultivar. Here, mixtures played a fundamental role in increasing the stability in grain yield, suggesting that differences in the developmental rate between mixture components reduced the mixture sensitivity to specific abiotic stresses.

    更新日期:2020-02-20
  • Tracking on-farm innovative practices to support crop mixture design: The case of annual mixtures including a legume crop
    Eur. J. Agron. (IF 3.384) Pub Date : 2020-02-19
    Valentin Verret; Elise Pelzer; Laurent Bedoussac; Marie-Hélène Jeuffroy

    The use of crop mixtures can help to reduce environmental impacts of agriculture, while maintaining, or even increasing yield. However, farmers seldom use crop mixtures, due to a combination of obstacles characterizing a sociotechnical lock-in. The dominant system remains the cultivation of pure crops, with acknowledged environmental impacts, but some innovative farmers are experimenting crop mixtures. This study aimed to identify and analyze the crop mixtures grown by these farmers, with a view to creating cognitive resources to help other farmers to adopt and adapt this practice to their own context. The on-farm innovative practices tracking method was implemented in Center-West and Southwest France. We surveyed 47 farmers who were already growing crop mixtures. Semi-structured interviews were conducted to identify the crop mixtures grown by these farmers, the objectives targeted with these mixtures, the crop management applied, and the farmers’ satisfaction criteria. In total, 77 combinations involving 29 different species were found. Most of the mixtures included grain or forage legumes. We distinguished seven types of crop mixtures, based on their seasonal or temporal organization, and the target outlets for the mixtures. Each type of crop mixture was associated with a particular set of farmer’s objectives. Crop management practices for mixtures of similar species sometimes differed considerably between farmers. An analysis of the agronomic rationale of farmers revealed consistency between technical choices, farmer’s objectives and farm context. Based on an agronomic cross-analysis of these on-farm innovative practices, we generated actionable knowledge and cognitive resources to support farmers and agricultural extension workers wishing to redesign their cropping systems to make them more sustainable.

    更新日期:2020-02-20
  • Testing critical phosphorus dilution curves for potato cropped in tropical Oxisols of southeastern Brazil
    Eur. J. Agron. (IF 3.384) Pub Date : 2020-02-19
    Rogério P. Soratto; Patricio Sandaña; Adalton M. Fernandes; Jéssyca D.L. Martins; André L.G. Job

    One of the challenges of potato (Solanum tuberosum L.) production is to minimize phosphorus (P) fertilization without negatively affecting the yield progress. Therefore, critical P dilution curves [Pc = acW−b; where Pc is the critical P concentration (%); ac is the critical plant P concentration (%) for a total dry matter (DM) biomass of 1 Mg ha-1; W is the total DM biomass expressed in Mg ha-1; and coefficient b is dimensionless and represents the ratio between the relative decline in plant P concentration and the relative crop growth rate] have been developed recently to improve P fertilization management in potatoes. The aim of this study was to test critical P dilution curves for potato cultivated in São Paulo State, southeastern Brazil. Nine field experiments were conducted in Oxisols with Presin values ranging from 8 to 70 mg dm-3 (very low to high). In each experiment, treatments were different P rates (ranging from 0 to 448 kg P ha-1) or the combination of different cultivars and P rates. Wide ranges in tuber DM yield (0.7-7.9 Mg ha-1) and plant P concentration (0.13-0.36 %) were observed before vine killing in response to P rates, cultivars, and site-years. Tuber DM yields were related to total DM biomass (R2 = 0.98), while P uptake was related to both total DM biomass and total plant P concentration (p < 0.01). Relative tuber DM yields at harvest were closely related to P nutrition index (PNI) (p < 0.01, R2 = 0.82) calculated with the critical P dilution curve previously reported for potato under higher yielding environments. These results validate the critical P dilution curve (Pc = 0.391W-0.304) as a useful diagnostic tool for improving the P fertilization of potato crops systems in the tropical region of Brazil.

    更新日期:2020-02-20
  • N2O emissions during Brassica oleracea cultivation: Interaction of biochar with mineral and organic fertilization
    Eur. J. Agron. (IF 3.384) Pub Date : 2020-02-20
    M. Sánchez-García; M.A. Sánchez-Monedero; M.L. Cayuela

    The impact of different forms of nitrogen input, biochar amendments and their combination on the yield-scaled N2O emissions were investigated during the cultivation of a representative commercial crop. A field randomized block design with inorganic/organic fertilization and biochar amendment was established during a crop cycle of drip-irrigated broccoli. N2O emissions were measured with a static chamber in crop rows and in the bare soil control. N2O emissions were triggered by N fertigation and heavy rainfall events and increased as the plants grew. Organic fertilization resulted in higher N2O emissions than mineral fertilization and these treatments also resulted in the highest peak emissions after fertigation events. Biochar had a significant mitigation effect in hot moments registered immediately after fertilization in organic fertilization treatments. However, biochar caused a slight but not significant reduction in cumulative N2O emissions in all treatments. Peak emissions after heavy rainfall were similar in all the treatments and were not affected by the biochar amendment. Biochar usage decreased the soil bulk density in the inorganic fertilization treatments and facilitated N uptake by the plants. Biochar addition resulted in a significant reduction in yield-scaled emissions, which was more pronounced in the inorganic fertilizer treatments.

    更新日期:2020-02-20
  • Nitrogen utilization efficiency in wheat: A global perspective
    Eur. J. Agron. (IF 3.384) Pub Date : 2020-02-01
    Amanda de Oliveira Silva; Ignacio A. Ciampitti; Gustavo A. Slafer; Romulo P. Lollato

    Understanding factors underpinning the variability in nitrogen (N) utilization efficiency (NUtE) [i.e. grain yield per unit of N uptake at maturity (NupMAT)] is critical to direct future improvements in breeding and agronomic management. To our knowledge, no study has summarized changes in wheat NUtE across a wide range of experimental conditions. We performed a synthesis-analysis using published data to provide a global perspective of NUtE trends in wheat by (i) benchmarking against yield limited by NupMAT, and (ii) assessing factors contributing to the variation in NUtE. The final database encompassed 55 studies (n = 529). A nonlinear model explained yield as a function of NupMAT. The gap between actual yield and NupMAT-limited yield was negligible at the lowest range of NupMAT and increased to ∼2000 kg ha−1 as NupMAT levels increased. Hence, opportunities to enhance yield through improving NUtE would be more likely at greater-than-average yield and NupMAT levels. The negative correlation between grain protein concentration and the residuals between NUtE and NupMAT indicated a challenge to increase yield without penalizing grain protein. Further, there are greater opportunities to increase NUtE in fall- than winter-sown wheat. Identifying the determinants of NUtE will enable to narrow the gap between actual and NupMAT-limited yields.

    更新日期:2020-02-03
  • Reducing yield-scaled global warming potential and water use by rice plastic film mulching in a winter flooded paddy field
    Eur. J. Agron. (IF 3.384) Pub Date : 2020-01-23
    Guangbin Zhang; Yuting Yang; Qiong Huang; Jing Ma; Haiyang Yu; Kaifu Song; Yujiao Dong; Shihua Lv; Hua Xu
    更新日期:2020-01-23
  • Response of cotton fruit growth, intraspecific competition and yield to plant density
    Eur. J. Agron. (IF 3.384) Pub Date : 2020-01-16
    Xiaofei Li; Yingchun Han; Guoping Wang; Lu Feng; Zhanbiao Wang; Beifang Yang; Wenli Du; Yaping Lei; Shiwu Xiong; Xiaoyu Zhi; Fangfang Xing; Zhengyi Fan; Minghua Xin; Yabing Li

    Increasing plant density has been an effective way for cotton yield improvements. The density of plants in a community also determines competition intensity and the efficiency to exploit available resources. However, the competition response as well as optimal density for yields and the mechanisms of which in terms of fruit growth rate are poorly known. A field experiment was conducted on cotton (Gossypium hirsutum L. SCRC 28) at a wide range of plant densities from 1.5–10.5 plants m−2. The results indicated that intraspecific competition between cotton plants increased nonlinearly with increasing plant density. Seedcotton yield per unit ground area declined precipitously at plant densities below the 4.0 plants m−2 threshold and yield did not further increase above this threshold, which is interpreted as the minimum plant density at which yield should be maximized. Moreover, maximum fruit production and fruit growth rate were also recorded at the same density threshold, above which there was no significant response. Cotton yield was positively correlated with fruit production and fruit growth rate. We thus conclude that high fruit production and fruit growth rate are responsible for maximum yield under optimal plant density in cotton.

    更新日期:2020-01-17
  • Native pastures and beef cattle show a spatially variable response to a changing climate in Queensland, Australia
    Eur. J. Agron. (IF 3.384) Pub Date : 2020-01-17
    David H Cobon; Grant Stone; John Carter; Greg McKeon; Baisen Zhang; Hanna Heidemann

    Queensland’s rangelands are an important source for Australia’s pastoral food production. However, they are subject to significant climate variability and will be under increasing pressure as the climate changes, potentially leading to loss of productivity. Pasture growth fluctuates greatly due to rainfall variability, which unfortunately is the climate variable with the largest uncertainties in future projections for northern and eastern Australia. This sensitivity study examines the effect of climate change and its interaction with soil fertility and trees on pasture and livestock production in Queensland. Nine climate change sensitivities were tested in various combinations; an increase in air temperatures by a median projected value of +3 °C, rainfall changes of -20 %, -10 % and +10 % and an increase of carbon dioxide concentrations to 700 ppm. The GRASP model was used to assess the responses of pasture growth, pasture quality and cattle liveweight change per head. The most arid areas in western and south-western Queensland were the most sensitive to changes in rainfall. In contrast, the tropical north was the most resilient region. Southern and south-eastern Queensland benefitted from higher air temperatures producing greater pasture growth, quality and liveweight gain per head by extending the growing season and reducing frost during the winter months. The presence of trees competing for water and nitrogen increased the sensitivity of pasture to climate change, especially at higher carbon dioxide levels and lower rainfall. Increased carbon dioxide enhanced pasture growth and mitigated rainfall reductions by improving the water use efficiency of the plants. Thus, a warmer climate may create new opportunities in the south and south-east, but a warmer and drier climate in the western regions of Queensland is likely to reduce pasture and livestock production.

    更新日期:2020-01-17
  • The cover crop termination choice to designing sustainable cropping systems
    Eur. J. Agron. (IF 3.384) Pub Date : 2020-01-10
    María Alonso-Ayuso; José Luis Gabriel; Chiquinquirá Hontoria; Miguel Ángel Ibáñez; Miguel Quemada

    The use of winter cover crops (CCs) in annual rotations is a tool to increase agroecosystem sustainability. To optimize their benefits, the choice of how to terminate CCs in spring is crucial, because this decision may lead to differences in soil–plant variables and affect cash crop productivity. The use of a roller-crimper is an emerging option in both conservation and organic agriculture but its adoption in Mediterranean regions is still rare. In this work the objective was to identify best CC termination practices to maximize benefits and increase agro-ecosystem resilience. To this end a field experiment with a barley/vetch (Hordeum vulgare L. / Vicia villosa L.) CC mixture followed by an irrigated corn (Zea mays L.) was conducted in Central Spain in three consecutive years. Each year, three CC termination methods (roller-crimper, glyphosate + roller-crimper, and CC residue incorporation) and four post-emergence operations to reduce weed pressure in summer (post-emergence herbicide, inter-row cultivator, the combination of the two, or without operation) were compared. The effect on the spring soil water content and temperature, weed control, soil inorganic N and the corn grain yield and N content were evaluated. Energy and economic analyses were conducted. An ineffective CC termination by roller-crimper was overcome when using glyphosate or post-emergence herbicides. However, the roller-crimper was less dependent on post-emergence operations than residue incorporation to achieve proper weed control and attain good productivity. The results showed that in early corn growth stages, roller-crimper use enhanced the soil’s water conservation and decreased soil temperature compared to CC residue incorporation. Moreover, the energy cost was lower for roller-crimper termination. Our findings suggest that the roller-crimper increases the environmental sustainability in Mediterranean regions, but farmers may encounter economic risks. Further research is needed to find proper conditions that maximize the potential of this CC termination method under Mediterranean conditions.

    更新日期:2020-01-11
  • Crop response of greenhouse soil-grown cucumber to total available N in a Nitrate Vulnerable Zone
    Eur. J. Agron. (IF 3.384) Pub Date : 2020-01-08
    Marisa Gallardo; Francisco M. Padilla; M. Teresa Peña-Fleitas; Romina de Souza; Alejandra Rodríguez; Rodney B. Thompson

    Intensive vegetable production in soil is commonly associated with low N use efficiency (NUE) and consequently appreciable N losses that have negative environmental impacts. Improved N management practices for intensive vegetable crops require detailed knowledge of crop response to N supply. This study evaluated the effects of increasing total available N (TAN, i.e. the sum of soil mineral N at planting, N mineralized from organic matter, and mineral fertilizer N applied by fertigation) on cucumber grown in soil in a greenhouse. Parameters assessed were: yield, dry matter production (DMP), crop N uptake, nitrogen use efficiency (NUE) and potential NO3− leaching loss. The study was conducted in three growing seasons, in autumn, spring and late spring. Three commercial cultivars were examined, in the Late Spring crop, to assess possible cultivar differences. Five N treatments were applied, in the Autumn and Spring crops, as different N concentrations in nutrient solution that were applied in all irrigations throughout the crops. The applied N concentrations were N1: 0.7–1.0 mmol L-1, N2: 4.7–5.7 mmol L-1, N3: 12.1–13.8 mmol L-1, N4: 16.3–17.6 mmol L-1 and N5: 19.7–21.1 mmol L-1. The cultivar ´Strategos´ was used in both crops. Three N treatments (N1: 2.4 mmol L-1; N2: 8.5 mmol L-1and N3: 14.8 mmol L-1) were continuously applied throughout the Late Spring crop to three different cultivars (´Strategos´, ´Padrera´, and ´Mitre´). Total and marketable yield, relative to maximum value, and DMP were strongly related to TAN in linear-plateau relationships for the three growing seasons and three cultivars. Using relationships that include data from the three cropping seasons and the three cultivars, TAN values for maximum DMP, total yield, and marketable yield were 222 ± 15 kg ha−1, 221 ± 14 kg ha−1 and 228 ± 15 kg ha−1, respectively, for the Autumn, Spring and Late Spring crops. The relationships of crop N uptake to TAN, and DMP to crop N uptake, were described by a logarithmic equation. The relationship of N uptake efficiency to TAN (i.e. N uptake/TAN) was described by an exponential decay equation. Considering all crops and cultivars, these relationships were described by individual equations with R2 values of 0.75-0.96. The consistency of these relationships indicate that there are general responses of greenhouse-grown cucumber to N, which is not affected by growing season or cultivar. Measured NO3− leaching losses were low because of good irrigation management. Residual mineral N was considered to be indicative of the potential NO3− leaching loss; residual soil mineral N increased exponentially with TAN, being 196 and 330 kg N ha−1 for the highest N treatments in the Autumn and Spring crops, respectively. The information provided by this study will enable the total N supply (TAN) to be matched to cucumber crop N requirements thereby reducing excessive N supply and consequent negative environmental impacts.

    更新日期:2020-01-09
  • How good are the models available for estimating sugar content in sugarcane?
    Eur. J. Agron. (IF 3.384) Pub Date : 2019-12-27
    Monique Pires Gravina de Oliveira; Luiz Henrique Antunes Rodrigues

    While sugarcane growth models could assist farmers in harvesting fields as close as possible to peak maturity, few of them are available to the industry. Even in those that are available, either there is room for improvement in sugar content estimation, or they were not properly assessed as to how they would perform given weather variability. In this work, we show that when developed with a dataset comprised of typical weather patterns, the outputs of empirical models that have been recently developed are qualitatively analogous to those of a process-based model and have smaller errors. However, when the training data is not representative, the same doesn’t happen and they are not consistent with known responses from sugarcane and with the output of mechanistic models. We used data from three years of harvests of a sugarcane mill to develop and evaluate the performance of machine learning models, as well as to evaluate an empirical model recently developed and DSSAT/Canegro. All models’ performances were evaluated in each of the three years separately, as well as through sensitivity analysis, to observe the effects of unknown weather in the estimates obtained by the model. This evaluation suggests that while machine learning techniques applied to industry data may be a promising tool for decision-makers, by themselves they are not capable of capturing all the effects that influence sucrose accumulation in sugarcane stalks.

    更新日期:2019-12-27
  • Individual and combined effects of jointing and booting low-temperature stress on wheat yield
    Eur. J. Agron. (IF 3.384) Pub Date : 2019-12-19
    Leilei Liu; Yumin Xia; Bing Liu; Chunyi Chang; Liujun Xiao; Juan Shen; Liang Tang; Weixing Cao; Yan Zhu

    Low temperature greatly affects wheat production, while low-temperature pretreatments may enhance plant tolerance to subsequent low-temperature stress. However, the knowledge on grain yield formation responses to multiple low-temperature stresses under natural conditions is still limited. Here, two years of environment-controlled phytotron experiments were carried out with two wheat cultivars under different low-temperature levels, periods and frequencies, and the temperature regimes in this study were designed to be similar to the daily variation in natural temperature. Spring frost (canopy temperature fall below 0 °C or Stevenson screen air temperatures below 2 °C) had negative effects on grain yield and yield components for both cultivars. Moreover, wheat yield was more sensitive to low temperatures at booting than at jointing. The reduction in grain yield under low-temperature conditions was mainly attributed to the decreased spike number per plant (SNPP) and grain number per spike (GNPS). Furthermore, grains in the apical spikelets were the most sensitive to spring frost, followed by those in the basal and central spikelets. Compared to the non-low-temperature-pretreated plants, the low-temperature-pretreated plants did not have an increased grain yield, except at T4 (Tmin/Tmax/Tmean, −6 °C/4 °C/−1 °C). Grain yield under T4 probably increased because severe low temperatures killed parts of the tillers, which resulted in carbon and nitrogen relocation to the roots, young tillers and axillary buds. As a result, the young and new tillers in the axillary buds grew rapidly and eventually formed spikes.

    更新日期:2019-12-19
  • Yield gain, complementarity and competitive dominance in intercropping in China: A meta-analysis of drivers of yield gain using additive partitioning
    Eur. J. Agron. (IF 3.384) Pub Date : 2019-12-05
    Chunjie Li, Ellis Hoffland, Thomas W. Kuyper, Yang Yu, Haigang Li, Chaochun Zhang, Fusuo Zhang, Wopke van der Werf

    Intercropping is known to increase the efficiency of land use, but no meta-analysis has so far been made on the yield gain of intercropping compared to sole cropping in terms of absolute yield per unit area. Yield gain could potentially be related to a relaxation of competition, due to complementarity or facilitation, and/or to the competitive dominance of the higher yielding species. The contributions of competitive relaxation and dominance were here estimated using the concepts of complementarity effect (CE) and selection effect (SE), respectively. We compiled a dataset on intercropping of grain-producing crops from China, a hotspot of strip intercropping in the world. We quantified the yield gain and its components and analysed the contribution to yield gain of species traits (C3, C4, legume, non-legume), complementarity in time and nutrient input. Total yield in intercrops exceeded the expected yield, estimated on the basis of sole crop yields, by 2.14 ± 0.16 Mg ha−1 (mean ± standard error). Ninety percent of this yield gain was due to a positive CE while the remaining 10 % was due to SE. The net yield gain increased with temporal niche differentiation (TND) which is the proportion of the total growing period of the crop mixture during which species grow alone. The mechanism underlying yield gain shifted from competitive dominance of the higher yielding species when there was more overlap in growth period between the two species, to competitive relaxation when there was less overlap, while competitive relaxation remained the major component of the yield gain. The yield gain was substantially greater in intercrops with maize than in intercrops without maize, but there was no difference in yield gain between systems with and without legumes. The yield gain increased with nitrogen (N) input in maize/C3-cereal intercrops but not in cereal/legume intercrops, illustrating the ability of legumes to compensate for low N input, and highlighting the need for N input for high productivity in intercropping systems without legumes. Yield gain did not respond to phosphorus (P) input. We conclude that competitive relaxation is the main contributing factor to yield gain in the investigated Chinese intercropping systems, which were mostly relay strip intercropping systems. The underlying drivers of yield gain were related to presence of maize and species complementarity in time, but we did not find strong evidence for the selection effect.

    更新日期:2019-12-05
  • Protein-rich legume and pseudo-cereal crop suitability under present and future European climates
    Eur. J. Agron. (IF 3.384) Pub Date : 2019-11-29
    Rhys Manners, Consuelo Varela-Ortega, Jacob van Etten

    Replacing animal proteins with plant proteins in diets has been demonstrated to have both health and environmental advantages, driving a debate about the potential of protein-rich crops as dietary replacements for animal products. However, there is a lack of knowledge on how climate change could influence the potential for producing protein-rich crops. This study addresses this knowledge gap for the European Union. We analysed 13 protein-rich crops, using the crop suitability model EcoCrop and climate projections for the 2050s, based on 30 Global Circulation Models, under the Representative Concentration Pathway 4.5. The results suggest that current protein-rich crop distributions reflect climatic suitability. We demonstrate the heterogeneous impacts of climate change on crop suitability. In general, conditions in northern Europe were modelled to become more favourable for protein-rich crops, while in southern Europe modelled future climates limit the production of traditional protein-rich crops commonly grown there, including chickpea and lentil. Model results show an expanded area of high suitability for quinoa. Our results confirm the need for concerted breeding and research planning strategies to improve the tolerance of faba bean, lentil, and chickpea to the abiotic stresses that are predicted to become more common with climate change. At the same time, production in northern Europe can benefit from experimentation with protein-rich crops predicted to become more suitable there. Production planning and agricultural policy should consider these likely impacts, to encourage shifts that follow the emerging geographic patterns of crop suitability, and to support the resilience of protein-rich crop production in regions that may be negatively impacted by climate change.

    更新日期:2019-11-30
  • Performance of wheat-based cropping systems and economic risk of low relative productivity assessment in a sub-dry Mediterranean environment
    Eur. J. Agron. (IF 3.384) Pub Date : 2019-11-30
    A. Nasrallah, H. Belhouchette, N. Baghdadi, M. Mhawej, T. Darwish, S. Darwich, G. Faour

    The promotion of optimum rotations and agricultural management of winter wheat-based cropping systems is very critical, as wheat is considered an essential component in the Mediterranean diet. Considering the delicate economic situation of farmers in the Mediterranean area, recommending a low risk, sustainable farming system is desirable. In this study, an innovative application of a multi-criteria field-level approach is presented, targeting food security, farmer profitability and environmental sustainability. The CropSyst biophysical simulation model was calibrated and implemented for the study site. It was chosen for its agro-environmental robustness to simulate four rotations (wheat-wheat, wheat-fallow, wheat-potato, and wheat-fava bean). Four types of wheat agricultural management systems (full fertilization and full irrigation, full fertilization and zero irrigation, zero fertilization and full irrigation, and zero fertilization and irrigation) were tested in low and high soil water holding capacity (WHC) types. The effects of soil conditions, management practices and rotation type on wheat grain yields were assessed. Furthermore, the performance of each winter wheat-based cropping system was evaluated in terms of productivity (protein production and profitability) and the efficient use of resources (nitrogen and water), as well as the economic risk of low relative productivity each one engenders. The results show that there is no particular optimal scenario that can simultaneously ensure high productivity, reduce economic risk of low relative productivity, and achieve high wheat- water- and nitrogen-use efficiency. However, the wheat-fava bean rotation cultivated with no wheat fertilization appeared to be a better substitute to the wheat-wheat rotation in terms of protein production (0.93 t/ha versus 0.8 t/ha in low WHC soil and 1.34 t/ha versus 1.17 t/ha in high WHC). This cropping system achieved a higher net profit (2111 US$/ha versus 1222US$/ha in low WHC and 3550 US$/ha versus 2450 US$/ha in high WHC), showing high resource-use efficiency and was less risky for farmers. Moreover, a very high profit could only be attained with the wheat-potato rotation (8640 US$/ha and 12,170 US$/ha in low and high WHC, respectively), yet with low input-efficiency and high economic risk of low relative productivity.

    更新日期:2019-11-30
  • Expanding row ratio with lowered nitrogen fertilization improves system productivity of maize/pea strip intercropping
    Eur. J. Agron. (IF 3.384) Pub Date : 2019-11-29
    Yan Tan, Falong Hu, Qiang Chai, Guang Li, Jeffrey A. Coulter, Cai Zhao, Aizhong Yu, Zhilong Fan, Wen Yin

    Intercropping is increasingly applied to confront food security issues in a sustainable manner. However, whether changing of row ratio and lowering N fertilization will affect interspecific interactions in maize (Zea mays L.)/pea (Pisum sativum L.) strip intercropping is unknown. Here we determined interspecific competition and yield response of pea and maize in a substitutive strip intercropping field experiment with irrigation in arid northwestern China from 2009–2011. Expanding the maize-to-pea row ratio from 2 : 4 to 3 : 4 intensified interspecific competition by 39, 96 and 154 % at 45, 60 and 75 d after maize sowing, and increased crop growth dynamics index of maize by 102, 89 and 16 % during 75–105, 105–135, and 135–165 d after maize sowing. Accordingly, grain yield of pea and maize with row ratio 3 : 4 was improved by 12 and 8 %, respectively, compared to row ratio 2 : 4. Meanwhile, the overyielding effect of pea and maize with row ratio 3 : 4 at 28 and 35 %, respectively, was significantly greater than row ratio 2 : 4. Lowering N fertilizer rate from 450 to 300 kg N ha−1 intensified interspecific competition without affecting grain yield of pea and maize in the intercropping system. Grain yield of pea was positively correlated with interspecific competition, while that of maize was positively correlated with crop growth dynamics index of maize. Consequently, expanding row ratio with reduced N fertilizer rate could optimize interspecific interactions and improve system productivity of maize/pea strip intercropping.

    更新日期:2019-11-30
  • Yield gap analysis simulated for sugar beet-growing areas in water-limited environments
    Eur. J. Agron. (IF 3.384) Pub Date : 2019-11-30
    Esmaeil Mohammadi-Ahmadmahmoudi, Reza Deihimfard, Omid Noori

    Sugar beet is one of the main two field crops cultivated to extract sugar. In order to increase the production of sugar beet, it is necessary to identify limiting and reducing factors by quantifying and analyzing yield gap. For this purpose, a crop simulation model was evaluated and used to simulate the storage organ of the sugar beet as well as yield gaps due to water shortage, inappropriate sowing date, and other biotic and abiotic factors at 10 locations of Khorasan Razavi province in northeastern Iran. Results of long-term simulations indicated that the province has a good potential for sugar beet yield with the highest yield of 103.6 t ha−1. However, there is a huge difference between actual production level and simulated attainable one (65.4 t ha−1); the average actual yield was only 32.7 % of the simulated attainable yield. In spite of the large amount of water applied as irrigation by most farmers, there are still water limitations because of water mismanagement, high vapor pressure deficit, and the temperatures occurring during most sensitive the major sugar beet growth stages at most locations. On average, water limitation had a major influence on yield gap (47.5 % of total yield gap) compared with sowing date (15 %) and other limiting and reducing factors (37.5 %). Under these circumstances, farmers must focus on increasing the water productivity of the sugar beet agroecosystem by replacing the current furrow irrigation systems, sowing earlier crops, and substituting sugar beet with crops that have a shorter growing season and are better adapted to the hot and arid climate during summer.

    更新日期:2019-11-30
  • Inoculation with native Bradyrhizobium strains formulated with biochar as carrier improves the performance of pigeonpea (Cajanus cajan L.)
    Eur. J. Agron. (IF 3.384) Pub Date : 2019-11-27
    Juan Araujo, César-Antonio Díaz-Alcántara, Beatriz Urbano, Fernando González-Andrés

    Pigeonpea (Cajanus cajan) originated in India and is now a major source of protein in countries in tropical and subtropical regions worldwide. However, little is known about the effect on crop yields of inoculation with appropriate rhizobia strains. The objective of this study was to explore the possibility of improving pigeonpea yields in the Caribbean region, by inoculating with selected N-fixing symbionts. To achieve the study objective, we selected three elite strains of the genus Bradyrhizobium isolated from root nodules of pigeonpea in the Dominican Republic, we formulated them using innovative carriers, and finally we tested the formulated inoculant on eight farms located in the Dominican Republic. Three different carriers (sewage sludge, pine bark biochar and poultry litter) plus perlite as control were tested for the formulation. The first step was to test bacterial survival in the different carriers at different times up to one year (shelf-life). Pine bark biochar and the control resulted in the best shelf-life and were selected for the field experiment. The experimental design comprised two pigeonpea cultivars and five fertilisation strategies: Inoculation with three Bradyrhizobium strains without nitrogen (N) fertilisation, plus two non-inoculated controls one of them fertilised with 125 and 210 kg N ha−1 in non-irrigated and irrigated fields respectively. Nodule occupancy by the inoculated bacterial strain depended solely on the level of soil native nodulating bacteria and not on the bacterial strain or the carrier. Inoculation produced, on average, a significant yield increase compared to the non-inoculated non-N-fertilised control. Furthermore, the yield with the inoculated treatments did not significantly differ from the yield of the N-fertilised control. However, either inoculation or N-fertilisation were ineffective in two out of the eight fields with more than 104 nodulating bacteria g soil−1, compared to the non-inoculated non-N-fertilised control. Yield was neither significantly affected by the bacterial strain nor by the cultivar-strain interaction, and therefore, the two cultivars can be considered promiscuous. Neither carrier had a significant effect on yield. Thus, inoculants based on strains of Bradyrhizobia isolated from the root nodules of pigeonpea, formulated with pine bark biochar or perlite as carrier, are recommended as a good strategy to ensure food security in tropical agroecosystems with pigeonpea.

    更新日期:2019-11-28
  • Seasonal and climatic variation of weighted VPD for transpiration estimation
    Eur. J. Agron. (IF 3.384) Pub Date : 2019-11-20
    Michel Edmond Ghanem, Zakaria Kehel, Hélène Marrou, Thomas R. Sinclair

    Vapor pressure deficit (VPD) is one of the critical variables that drives evapotranspiration, and is of fundamental importance in crop physiology and modeling in the face of climate change. Unfortunately, direct records of atmospheric moisture are rarely available at short temporal scales, e.g. hourly, and country or regional scales. Most models use approximations to estimate daily transpiration-weighted VPD. Tanner and Sinclair (1983) suggested an approach to calculate weighted daily VPD as a fraction (0.75) of the difference between daily maximum and minimum vapor pressure based on estimates calculated from daily maximum and minimum temperatures, respectively. A test of the Tanner-Sinclair suggestion is reported by obtaining daily weighted VPD from hourly measurements of humidity and temperature. The objective of this study was to assess the fractional value to obtained daily weighted VPD estimations. This study was based on ten years of hourly weather data collected at thirty five stations across the wide diversity of environments that exist in France.

    更新日期:2019-11-21
  • Crop yield stability and sustainability in a rice-wheat cropping system based on 34-year field experiment
    Eur. J. Agron. (IF 3.384) Pub Date : 2019-11-19
    Xuemei Han, Cheng Hu, Yunfeng Chen, Yan Qiao, Donghai Liu, Jun Fan, Shuanglai Li, Zhi Zhang

    Little is known about the effects of different fertilizers and manure use on the yield stability and sustainability of crop in a rice-wheat cropping system. Therefore, a 34-year field experiment (conducted from 1982 to 2015) was used to evaluate the effect of continuous application of inorganic fertilizers and organic manure, supplied at different combinations, on the stability and sustainability of rice and wheat yields. Eight treatments consisted of unfertilized control (CK), inorganic fertilizers (N, NP, NPK) and organic manure (M) either alone or in combination (MN, MNP, MNPK). There was no significant trend of rice grain yield over time for any of the treatments. Wheat yield had an increasing tendency in all the fertilization treatments, including the unfertilized control. Organic manure in combination with chemical fertilizer supported high rice and wheat yields and sustainable yield index (SYI), with decreased coefficient of variance (CV) of rice and wheat yields. The SYI value clearly indicates that rice yield was more sustainable than wheat yield. In conclusion, the combined use of both organic manure and inorganic fertilizer can improve not only crop grain yield but also yield stability and sustainability.

    更新日期:2019-11-20
  • Joint optimization of irrigation and planting pattern to guarantee seed quality, maximize yield, and save water in hybrid maize seed production
    Eur. J. Agron. (IF 3.384) Pub Date : 2019-11-19
    Jintao Wang, Shanshan Guo, Shaozhong Kang, Yufeng Wang, Taisheng Du, Ling Tong

    Severe water scarcity necessitates the development of a scientifically informed basis for efficient crop irrigation. Both irrigation and crop planting pattern (the planting dates and the planting ratio for male to female maize inbred lines) affect the yield components in hybrid maize production. A high kernel weight, which affects seed germination, is critical in maize seed production. Therefore, the aim of this study was to build a system that jointly optimizes irrigation and planting pattern (JOIPP) to guarantee a suitable kernel weight, maximizes yield, and saves water. The JOIPP was based on a model which could simulate flowering, predict kernel number and estimate the upper and lower limits of kernel weight based on the evapotranspiration and planting pattern. Parameters in JOIPP were calibrated and validated using data from experiments conducted from 2014 to 2016 in Hexi Corridor, northwestern China. A weighted sum method was used to maximize yield and minimize irrigation. A genetic algorithm with a modified initial population generation module was used to solve this optimization problem. Results showed that when the minimum lower limit of kernel weight (LowKWmin) increased, there was decreased irrigation at the flowering stage, increased irrigation at the grain-filling stage, less optimal yield and water use efficiency when the available water insufficient. However, the associated risk of seed germination failure decreased. The optimized planting pattern, compared with the crop planting pattern used by local farmers, increased yield by about 10% and water use efficiency by about 7.3% when LowKWmin was 260 mg/kernel. JOIPP is a useful tool that enables farmers and seed companies to save water and improve yield and seed quality when planting and irrigating maize for hybrid seed production.

    更新日期:2019-11-20
  • Simulating alfalfa regrowth and biomass in eastern Canada using the CSM-CROPGRO-perennial forage model
    Eur. J. Agron. (IF 3.384) Pub Date : 2019-11-18
    Qi Jing, Budong Qian, Gilles Bélanger, Andrew VanderZaag, Guillaume Jégo, Ward Smith, Brian Grant, Jiali Shang, Jiangui Liu, Wentian He, Kenneth Boote, Gerrit Hoogenboom

    Alfalfa (Medicago sativa L.) is the predominant forage legume species in Canada and is considered a prioritized option for sustainable cropping under climate change. Crop growth models provide an opportunity to explore the potential impacts of climate change on alfalfa and for evaluating potential adaptation options. For this study, six experimental datasets in eastern Canada were used to parameterize the newly adapted CSM-CROPGRO-Perennial Forage Model (CSM-CROGRO-PFM) in simulating alfalfa regrowth and to identify areas for further model improvement needed for climate change assessments in the northern agricultural regions of North America. Estimated air temperatures under snow cover were used successfully to drive the CSM-CROPGRO-PFM model for simulating alfalfa regrowth in eastern Canada. The simulated values of aboveground biomass across all sites and years were acceptable with a root mean square error (RMSE) of 936 kg dry matter (DM) ha−1 and a normalized RMSE of 24%. A sensitivity analysis of the model revealed that with no change in the number of harvests per year, the simulated annual herbage yield (harvestable biomass) declined with increasing temperature, increased with elevated atmospheric CO2 concentration, and changed little with increased precipitation. However, the increase in the number of harvests made possible by warmer temperatures may increase the simulated annual herbage yield. Although most alfalfa physiological processes were successfully simulated, some additional model functions may be required to further improve the simulation of alfalfa regrowth for climate change studies conducted in Canada. These functions include quantifying plant density decline and its relationship with biomass in post-seeding years, estimating temperatures surrounding alfalfa crowns during the overwintering period, and simulating herbage nutritive attributes.

    更新日期:2019-11-18
  • Weed regulation by crop and grassland competition: critical biomass level and persistence rate
    Eur. J. Agron. (IF 3.384) Pub Date : 2019-11-15
    Mauricio Z. Schuster, François Gastal, Diana Doisy, Xavier Charrier, Anibal de Moraes, Safia Médiène, Corentin M. Barbu

    It is widely agreed that competition is an important factor that regulates plant populations and shapes communities in agricultural landscapes. Many studies have suggested that crop and grassland competition can be used for cost-effective sustainable weed control. However, effective weed management requires a precise knowledge of the effects of agronomic practices and there is a lack of quantitative indicators to compare and predict the success of weed control by competition. Here, we studied weed abundance dynamics over a 12-year period in crop-grassland rotations (rotation treatments consisted of maize, wheat and barley crops, alternating with temporary grassland maintained for three or six years in the rotation and fertilised with ∼30 or ∼230 kg ha−1 year−1 of nitrogen). In addition to classical statistical analysis of the different rotation treatments, we modelled weed abundance as a function of the crop and grassland competition, expressed here by biomasses harvested in the preceding years. We show that weed abundance decreases over the years in grassland and subsequent crops only if the grassland receives sufficient nitrogen fertiliser. Our model had a greater explanatory power than the rotation treatments. This model estimates a critical biomass level above which weeds are suppressed in subsequent years, and below which they tend to thrive. This critical biomass level was 24.3 and 4.7 tonnes ha−1 of dry matter for crops and grassland, respectively, highlighting the greater competitiveness of grasslands than of crops. Several clear differences between weed functional groups emerged. This new modelling approach directly links the interannual dynamics of weed populations to current and previous biomass production levels. This approach facilitates the development of environment-friendly weed management strategies and paves the way for comparisons of the competitiveness against weeds of crops and grassland under various pedoclimatic conditions and agronomic practices.

    更新日期:2019-11-15
  • Co-limitation and stoichiometry capture the interacting effects of nitrogen and sulfur on maize yield and nutrient use efficiency
    Eur. J. Agron. (IF 3.384) Pub Date : 2019-11-15
    Walter D. Carciochi, Victor O. Sadras, Agustín Pagani, Ignacio A. Ciampitti

    Nitrogen (N) and sulfur (S) deficiencies, individually and in combination, produce gaps between actual and potential yields in maize (Zea mays L.). Our objectives were to evaluate the effect of N and S status and their interaction on yield gap, and nutrient use efficiency (yield per unit of nutrient supply) using frameworks of co-limitation and stoichiometry. Factorial trials were established combining two N (unfertilized, N-fertilized) and two S (unfertilized, S-fertilized) treatments in five site-years. Yield ranged from 6.7 to 15.4 Mg ha−1. In a scale from 0 (no stress) to 1 (maximum stress), N stress varied from 0 to 0.67, and S stress from 0 to 0.66. Yield gap varied from 0 to 10 Mg ha−1, diminished as both N and S stresses reduced, and with higher N-S co-limitation. Both N and S use efficiencies increased with reductions in nutrient stresses and with increases in some of the N-S co-limitation indices. Co-limitation between N and S was maximized with N:S ratio ∼9.6 in shoot biomass and ∼11.2 in grain, indicating the balanced nutrient ratio in each plant organ at maturity. Both co-limitation and stoichiometry frameworks captured the interacting N and S effects on yield and nutrient use efficiency.

    更新日期:2019-11-15
  • Analysis of soybean germination, emergence, and prediction of a possible northward establishment of the crop under climate change
    Eur. J. Agron. (IF 3.384) Pub Date : 2019-11-15
    Jay Ram Lamichhane, Julie Constantin, Céline Schoving, Pierre Maury, Philippe Debaeke, Jean-Noël Aubertot, Carolyne Dürr

    Soybean (Glycine max (L.) Merr.) has the potential to improve sustainability of agricultural production systems. A higher focus on this crop is needed to re-launch its production in the EU. A better understanding of key determinants affecting soybean establishment represents a first step to facilitate its adoption in cropping systems. To this objective, we conducted laboratory and field experiments in order to better characterize seed germination and seedling growth in relation to temperatures, water content, and soil structure. We then used these data to parametrize the SIMPLE crop emergence model and to evaluate its prediction quality, by comparing observed field germination and emergence data with the predicted ones. Finally, we performed a simulation study over the 2020–2100 period, for three sowing dates, from mid-March to mid-April, in the northern climate of France to evaluate whether soybean will successfully establish in the Northern part of the country under future climate change. Experimental results showed that soybean germination was very fast, taking only 17 °C days to reach 50% germination at optimal conditions. The base, optimum and maximum temperatures were determined as 4, 30 and 40 °C, respectively while the base water potential was −0.67 MPa, indicating a high sensitivity to water stress. The SIMPLE model finely predicted germination and emergence courses and their final rates, compared with the observed field data. The simulation study showed average emergence rate ranging from 61 to 78% with little variability among sowing dates and periods, but a high variability between years. Main causes of non-emergence were: i) seedling mortality due to clods or soil surface crust, followed by ii) non-germination, and iii) seedling mortality due to drought. When sown in mid-April, seedling mortality due to drought was higher compared with earlier sowing dates. These results provide a better knowledge of soybean establishment that are encouraging to introduce soybean with early sowings to diversify current cropping systems.

    更新日期:2019-11-15
  • Productivity of intercropping with maize and common bean over five cropping seasons on smallholder farms of Tanzania
    Eur. J. Agron. (IF 3.384) Pub Date : 2019-11-14
    Eliakira Kisetu Nassary, Frederick Baijukya, Patrick Alois Ndakidemi

    Intercropping with maize (Zea mays L.) and common bean (Phaseolus vulgaris L.) is one of the widely used practices of producing food crops on smallholder farms in Sub-Saharan Africa (SSA). However, the knowledge on the options toward intensification of available practices in order to optimize systems productivity using intercrops is generally lacking. Therefore, this study evaluated the effects of intercropping, cropping seasons, and different varieties of common bean on productivity of the maize-common bean based intercrop through 5 cropping seasons from 2015 to 2017. Experimental site is located at 03°18 ′03.74′' S and 37°12′13.94′ E and an altitude of 956 m above sea level in the northern highlands of Tanzania. Hybrid maize Dekalb brand (DK 8031) and two varieties of common bean (improved Lyamungu 90 and local Mkanamna) were used. The treatments within a replicate were: (1) sole crops: (i) maize, (ii) local bean, (iii) improved bean, and (2) intercrops: (i) maize + local bean, (ii) maize + improved bean. Interaction and individual effects of cropping seasons (S) (periods of years – short and long rains), varieties of common bean (V), and cropping systems (C) (sole and intercrop) were studied. Results indicated that S × V interaction was significant on bean grain yield and 100-seed weight. Improved bean outweighed the local bean with grain yields ranging from 2.2–3.5 t ha-1 and 0.2–2.5 t ha-1, respectively. The effect of S was significant on all measured variables in beans and the effect of M was only significant on total biomass. Further, S significantly affected all measured variables in maize and grain yields ranged from 2.3–2.6 t ha-1. In maize, correlations were strong (r = 0.48*; P = 0.0325) between maize grain yield and ground coverage of leaf canopy measured 42–56 days after sowing. The land equivalent ratios (LERs) for maize intercropped with improved and local beans were 1.48 and 1.55, respectively but LER values did not differ significantly between bean varieties. In this study, both common bean varieties were sown simultaneously with the maize, which might have resulted in their differential performance. It is recommended that studies are conducted to evaluate time of introducing this legume crop to a maize system such as early sowing, sowing mid in the season after a maize crop is well established, and sowing late in the season when the leaves in maize plant have started to senesce.

    更新日期:2019-11-14
  • Determination of the post-anthesis nitrogen status using ear critical nitrogen dilution curve and its implications for nitrogen management in maize and wheat
    Eur. J. Agron. (IF 3.384) Pub Date : 2019-11-13
    Ben Zhao, Xiaoli Niu, Syed Tahir Ata-Ul-Karim, Laigang Wang, Aiwang Duan, Zhandong Liu, Gilles Lemaire

    Nitrogen (N) accumulation in plant reproductive organs during the post-anthesis growth phase of maize and wheat plays a crucial role in the formation of grain yield and quality. However, little is known about the effect of crop pre-anthesis and post-anthesis N status on ear N accumulation (NAE). This study endeavored to extend the crop N dilution theory already developed for vegetative growth period to determine ear critical N concentration (%NcE) during post-anthesis period of crop growth for analyzing the difference of NAE under various N levels. The data including the weight of dry mass (W) and N concentration of entire plant and ear, post-anthesis plant N uptake (PANU) from soil, grain number (GN), and grain weight (GW) were collected on wheat (two cultivars) and maize (three cultivars) from eight N rates (0–300 kg N ha−1) field experiments. The results revealed that the process of %N dilution exists in ear and it is plausible to extend the concept of %NcE curve till crop post-anthesis period. The %NcE curves as function of ear dry mass (WE) of wheat (%NcE = 2.85WE-0.17) and maize (%NcE = 2.22WE-0.26) were lower than those developed in maize and wheat on whole plant basis. This study revealed that the ear has the potential to diagnose ear N status under different N conditions and the increases in ear N nutrition index (NNIE) during the post-anthesis period with increasing N rate were well synchronized with plant NNI (NNIp) at anthesis. GN and GW of maize and wheat showed significantly positive correlation with NNIp at anthesis and NNIE at maturity under N-limiting treatments, and GN and GW could keep relatively stable under non-N limiting treatments. NNIp and NNIE showed the potential capacity to predict GN and GW of maize and wheat under N limiting condition. Ear critical N accumulation (NAcE) was calculated using ear Nc curve to investigate the differences mechanism of NAE under different N conditions. The difference of NAcE under different N treatments was deduced from the pre-anthesis N status of maize and wheat by determining GN. The ear N deficiency (NDE) between NAcE and NAE was co-regulated by plant pre-anthesis and post-anthesis N status, which in turn have potential to explain the variance of GW at maturity in both crops. The significantly attenuated effect of pre-anthesis N deficiency on ear potential N demand in maize and wheat indicated that the post-anthesis N management must consider the pre-anthesis N status and the corresponding reduction of the post-anthesis N input to prevent N loss under N limiting treatment in both crops. Maize was more dependent on post-anthesis N status while wheat was more reliant on pre-anthesis N status for satisfying ear growth and producing optimum GN owing to the differential values of PANU/NAE in maize and wheat during post-anthesis period. This study provides a new viewpoint on post-anthesis N management of maize and wheat for enhancing N use efficiency and grain yield.

    更新日期:2019-11-13
  • Plant structure as a determinant of coriander (Coriandrum sativum L.) seed and straw yield
    Eur. J. Agron. (IF 3.384) Pub Date : 2019-11-10
    Alessandra Carrubba, Alberto Lombardo

    Coriander (Coriandrum sativum L., Apiaceae) is a Mediterranean aromatic plant that is mainly cultivated for its fruits. Understanding the association between various vegetative and reproductive structures as they pertain to yield can help addressing efforts for achieving the highest productivity levels, by improving both cropping techniques and breeding. Multiple Regression (MR) analysis is a suitable tool to understand this association; notwithstanding, due to the plant’s inherent “weedy” growth, the interpretation of MR results in coriander is often difficult. Therefore, in our analysis we also calculated additional indicators of variable contribution to the model and to one another. We analyzed data (n = 193) obtained from field experiments on coriander carried out in Sicily from 1999 to 2007. Nine plant variables were submitted to different MR approaches, including Path Analysis (PA), Commonality Analysis (CA) and Dominance Analysis (DA). All MR analyses attributed to the number of umbels per plant the highest importance in assessing both seed and straw yield. Additionally, the mass of one umbel proved to be a strong determinant of fruit yield per plant, whereas the umbel diameter was relevant for the assessment of plant straw production. This information will be useful for addressing coriander cropping technique and breeding.

    更新日期:2019-11-11
  • Effects of strip width on yields in relay-strip intercropping: A simulation study
    Eur. J. Agron. (IF 3.384) Pub Date : 2019-11-06
    P.A.J. van Oort, F. Gou, T.J. Stomph, W. van der Werf
    更新日期:2019-11-06
  • Future development of apricot blossom blight under climate change in Southern France
    Eur. J. Agron. (IF 3.384) Pub Date : 2019-10-12
    Paul Tresson, Laurent Brun, Iñaki García de Cortázar-Atauri, Jean-Marc Audergon, Sophie Buléon, Hélène Chenevotot, Freddy Combe, Doriane Dam, Maxime Jacquot, Baptiste Labeyrie, Vincent Mercier, Claude-Eric Parveaud, Marie Launay

    Climate change will have several consequences for agro-systems, one of which will concern changes to the development of pathogens. Because of the losses it causes, particularly in organic farming, Monilinia laxa is an important pathogen affecting apricot crops. This study focuses on the consequences of climate change regarding blossom and twig blight (Monilinia laxa) of apricot. To achieve this, a Climatic Index of cumulated Blight risk (CIB) was built, to obtain the weighted sum of blossom blight incidence throughout the blooming period. An epidemiological model to calculate the incidence of blossom blight during every potentially infectious episode and based on biological parameters, was calibrated using a trap pot experiment where trees were placed in orchards and subject to various meteorological conditions. The CIB derived from this model was evaluated on field data, and was shown to be a robust and useful tool to predict the effects of climate change on the development of apricot blight. Then, using the CIB with a phenological model to predict blooming periods in the future, we estimated the risks of apricot blight until 2100 on four contrasted apricot cultivars and in three geographical zones under climate change scenarios RCP 4.5 and 8.5. This study revealed different effects of climate change depending on the cultivar and altitude. Apricot trees would bloom earlier (up to a difference of 50 days between 1950 and 2100) under climate change. Under the combined effects of these shifts of blooming period and changing climatic conditions, late cultivars such as Bergarouge might see a reduction in the risk of blossom blight (down to 31%) because of warmer but dryer blooming periods. Other varieties (e.g.: Bergeron) could experience an increase in this risk by up to 27% with a shift of the blooming period towards rainier conditions at the highest altitudes. The results of this study could be used to anticipate future changes as well as be used at present as a decision-support tool for farmers.

    更新日期:2019-10-12
  • Estimation of the harvest index and the relative water content – Two examples of composite variables in agronomy
    Eur. J. Agron. (IF 3.384) Pub Date : 2019-10-10
    Signe M. Jensen, Jesper Svensgaard, Christian Ritz

    Composite variables are variables derived from measurable traits. They are commonly used in agronomy: two well-known examples being the harvest index and the relative water content. There are two approaches for finding estimated averages of such variables that are derived from direct measurements: They can be found either based on a calculation using individual measurements (“pre-processing”) or from a calculation using averages or estimates (“after-fitting”). The former needs to be done prior to fitting a statistical model whereas the latter is carried out after a statistical model has been fitted to the original measurements. We show that the commonly used pre-processing approach results in biased estimates. Moreover, the bias depends on both the correlation between and the uncertainty associated with the variables used for the composite variable. This finding is shown in two examples and a simulation study.

    更新日期:2019-10-10
  • Response of rice yield and yield components to elevated [CO2]: A synthesis of updated data from FACE experiments
    Eur. J. Agron. (IF 3.384) Pub Date : 2019-10-03
    Chunhua Lv, Yao Huang, Wenjuan Sun, Lingfei Yu, Jianguo Zhu
    更新日期:2019-10-04
  • Re-designing organic grain legume cropping systems using systems agronomy
    Eur. J. Agron. (IF 3.384) Pub Date : 2019-10-03
    Moritz Reckling, Göran Bergkvist, Christine A. Watson, Frederick L. Stoddard, Johann Bachinger

    Crop production in Europe is intensive, highly specialized and responsible for some negative environmental impacts, raising questions about the sustainability of agricultural systems. The (re)integration of grain legumes into European agricultural systems could contribute to the transition to more sustainable food production. While the general benefits from legume cultivation are widely known, there is little evidence on how to re-design specific cropping systems with legumes to make this option more attractive to farmers. The objectives of this study were to describe the constraints and opportunities of grain legume production perceived by farmers, explain the agronomic impacts of current grain legume cropping, explore technical options to improve grain legume agronomy, and to re-design current grain legume cropping systems in a participatory process with farmers. A co-design approach was implemented with farmers, advisors and scientists on 25 farms in northern Germany, that were part of two large demonstration networks of about 170 farms supporting grain legumes across Germany. We used the DEED research cycle (Describe, Explain, Explore and Design) as a conceptual framework combining on-farm research, crop rotation modelling, and on-station experiments. From it, we identified nine agronomic practices that either were novel or confirmed known strategies under new conditions, to re-design grain legume cropping systems at the field and farm level. The practices included (i) inter-row hoeing, (ii) direct seeding into a cover-crop, (iii) species-specific inoculation, (iv) cover crops to reduce leaching, (v) reduced tillage, (vi) soybean for increased gross margins, (vii) cultivars for food and feed use, (viii) flexible irrigation, (ix) grain legumes with cover crop to enhance subsequent crop yields. We also demonstrate how to complement knowledge of farmers’ perceptions (Describe step) and formal knowledge from classical on-station experiments and modelling (Explain step) with on-farm research including the local views of farmers (Explore step) to identify tailored options for specific farm contexts rather than prescriptive solutions (Design step) to intensify legume production. This approach therefore contrasts with traditional methods that are often solely participatory and qualitative or model/experimental-based and quantitative. Hence, our results provide new insights in how to re-design cropping systems using a combination of participatory and quantitative approaches. While participatory approaches are common in developing countries, this study shows their potential in an industrialized context with large-scale farmers in Europe. These novel findings can be used as a starting point for further adaptations of cropping systems and contribute to making grain legume production economically and environmentally more sustainable.

    更新日期:2019-10-03
  • High-resolution assessment of French grassland dry matter and nitrogen yields
    Eur. J. Agron. (IF 3.384) Pub Date : 2019-10-03
    A.-I. Graux, R. Resmond, E. Casellas, L. Delaby, P. Faverdin, C. Le Bas, D. Ripoche, F. Ruget, O. Thérond, F. Vertès, J.-L. Peyraud

    Grasslands offer many environmental and economic advantages that put them at the heart of future sustainable ruminant production systems. This study aimed to quantify and map the dry matter yield (DMY) and nitrogen yield (NY) of French grasslands resulting from cutting and grazing practices, based on the existing diversity of grassland vegetation, management, soil and climate conditions, using a research version of the STICS crop model called PâturSTICS. This model simulates daily dry matter (DM), nitrogen (N) and water fluxes involved in the functioning of grasslands and crops in response to management and environmental conditions. It was improved to represent deposition of animal waste on grassland soils during grazing and to simulate DM production and N content of grasses and legumes more accurately. Simulations were performed for locations across France on a high-resolution grid composed of pedoclimatic units (PCU) obtained by combining the spatial resolutions of climate and soil. The main grassland types and associated management types were determined for each PCU and then simulated over 30 years (1984–2013). Using the simulated values, predictive metamodels of annual grassland DMY and NY were developed from easily accessible explanatory variables using a random forest approach. Annual model predictions were aggregated and averaged at the PCU scale, then compared to regional observations. Predicted DMY agreed with available observations, except in semi-mountainous and mountainous regions, where PâturSTICS tended to overpredict DMY, probably because it ignores effects of snow, frost and slope, and due to how it represents effects of temperature and water stress on plant growth. According to results, three-quarters of French grasslands produce and export at least 7.6 t DM ha−1 yr−1 and 172 kg N ha−1 yr−1, respectively. One-quarter of French grasslands produce and export at least 10.7 t DM ha−1 yr−1 and 254 kg N ha−1 yr−1, respectively. The latter are located mainly in north-western France, the north-western Massif Central, the French Alps and the western Pyrénées, all of which have environmental conditions favourable for grass growth. The metamodels developed are interesting proxies for PâturSTICS’ predictions of grassland DMY and NY. Our results provided valuable knowledge that promotes better use of the potential forage production of French and European grasslands to improve protein self-sufficiency and N fertilisation management in ruminant livestock systems.

    更新日期:2019-10-03
  • Simulation using the STICS model of C&N dynamics in alfalfa from sowing to crop destruction
    Eur. J. Agron. (IF 3.384) Pub Date : 2019-10-03
    L. Strullu, N. Beaudoin, P. Thiébeau, B. Julier, B. Mary, F. Ruget, D. Ripoche, L. Rakotovololona, G. Louarn
    更新日期:2019-10-03
  • Maize-bean intercropping yields in Northern Germany are comparable to those of pure silage maize
    Eur. J. Agron. (IF 3.384) Pub Date : 2019-10-01
    Jenny Fischer, Herwart Böhm, Jürgen Heβ
    更新日期:2019-10-01
  • Integrated Pest Meadow-ploughing timing as an integrated pest management tactic to prevent soil-pest damage to maize
    Eur. J. Agron. (IF 3.384) Pub Date : 2019-09-28
    Lorenzo Furlan, Isadora Benvegnù, Francesca Chiarini, Donato Loddo, Francesco Morari

    The management of soil-pests still largely relies on conventional chemical insecticides despite the provisions of Integrated Pest Management (IPM). Long-term research was carried out in north-eastern Italy to assess the potential of meadow ploughing just before maize sowing to prevent wireworm damage. The research was based on the observation that no serious wireworm damage occurred in 20 years when meadows were ploughed just before maize sowing. The research hypothesis was that soil-incorporated fresh meadow turf would be a more attractive wireworm food source than seeds, emerging seedlings and young plants. Meadow plots with a sufficiently homogeneous wireworm density were alternately ploughed the previous autumn and a few days before maize sowing. The same conditions were simulated in pots into which known numbers of cage-reared wireworms had been introduced. Results showed very consistently that plant damage in plots ploughed just before maize sowing was much lower than the damage in plots ploughed in autumn-winter, and always below the economic risk threshold (15% of damaged plants). In controlled conditions, plant damage in pots with soil-incorporated fresh meadow turf was significantly lower than that observed in pots without. In both field and controlled conditions, this major effect on plant protection is likely to be caused by the incorporation of meadow turf living plant parts into the soil. Therefore, the ploughing timing of meadows in rotation may be a viable alternative to chemical insecticides when rotation includes meadow.

    更新日期:2019-09-29
  • High potential of variable rate fertilization combined with a controlled released nitrogen form at affecting cv. Barbera vines behavior
    Eur. J. Agron. (IF 3.384) Pub Date : 2019-09-24
    M. Gatti, M. Schippa, A. Garavani, C. Squeri, T. Frioni, P. Dosso, S. Poni

    Variable rate technologies allow site-specific management of parcels characterized by different levels of vigor and/or yield. Fertilization based on actual plant needs is one of the most promising applications of precision farming aiming at improving efficiency, optimizing vine balance, as well as limiting environmental impact. Although this strategy appears suitable for developing new vineyard management models, few experiences validating this hypothesis are available in the literature. Based on a pre-trial remotely sensed vigor map (NDVI-derived, 5 m resolution), a three-year study was performed in a Vitis vinifera L. cv. Barbera vineyard situated in the Colli Piacentini area. Vigor level (L = low, M = medium and H = high) and fertilization technique (Standard, Variable Rate Application, and unfertilized Control) were the main factors in a randomized block design. The controlled release fertilizer Multicote™ Agri ([NPK fertilizer 13-5-21 + 7MgO+14SO3 (Controlled Release Nitrogen >46% on the total nitrogen, with longevity 2÷4 months), low in chloride] was used and the input rate calculated according to the N-supply. For each vigor level the study compared no fertilization (0 kg/ha), standard supply (40 kg of N /ha) and Variable Rate Application (VRA) supply delivering 0, 40 and 80 kg of N/ha to H, M and L, respectively. Vine growth, yield, leaf nutritional status and fruit composition were assessed. Results show that the classified L vigor plots had significantly less growth (i.e leaf area or pruning weight per vine) than M and H vigor plots, whereas yield components and grape composition followed a linear variation with vigor. There was a large prevalence of vigor x technique interactions suggesting that VRA had a differential impact on vine behavior depending upon the initial level of vigor. For vegetative and yield parameters, in the L vigor vines, increased Multicote™ Agri dosage delivered as control (0 kg of N/ha), standard (40 kg of N/ha) and VRA (80 kg of N/ha) caused a very close and linear increase in total leaf and yield per vine, whereas, within the M and H vigor plots, the effect due to fertilization technique was very mild. Such a behavior was nicely mirrored by grape composition at harvest as, in L vines, applying 40 or 80 kg of N in the form of Multicote™ Agri induced a progressive and significant reduction in both must soluble solids and total anthocyanins concentration, although the oenological quality of the resulting must was still satisfactory and in compliance with the oenological target. The novelty of the present work is that, unlike previous variable rate fertilization attempts where a rapid nitrogen release fertilizer such as urea was used, L vigor vines showed a very prompt response to the amount of Multicote™ Agri application, confirming higher effectiveness of this chemical form and higher flexibility in adjusting the level of vigor and yield according to specific needs. Conversely, when the initial level of vigor was medium or high, differential fertilization resulted in overall minor modifications of the vine behavior.

    更新日期:2019-09-25
  • Super-resolution enhancement of Sentinel-2 image for retrieving LAI and chlorophyll content of summer corn
    Eur. J. Agron. (IF 3.384) Pub Date : 2019-09-07
    Mingzheng Zhang, Wei Su, Yuting Fu, Dehai Zhu, Jing-Hao Xue, Jianxi Huang, Wei Wang, Jiayu Wu, Chan Yao

    Sentinel-2 satellite is a new generation of multi-spectral remote sensing technique with high spatial, temporal and spectral resolution. Especially, Sentinel-2 incorporates three red-edge bands with central wavelength at 705, 740 and 783 nm, which are very sensitive to vegetation changing, heath and variations. Unfortunately, their spatial resolution is only 20 m, which is lower comparably. This spatial resolution brings difficulties for mining the potential of Sentinel-2 image in vegetation monitoring. Therefore, we focus on enhancing the spatial resolution of Sentinel-2 red edge band images to 10m using the SupReME algorithm. Furthermore, the summer corn canopy leaf area index (LAI), leaves chlorophyll content (LCC) and canopy chlorophyll content (CCC) were retrieved by the linear and physical models for the corn growth monitoring purpose. The results showed that the spatial resolution of Sentinel-2 images had been enhanced to 10m from original 20m, and the estimation accuracy (EA) was over 97% for pixels planted by summer corn. Moreover, the accuracy of summer corn canopy LAI, LCC and CCC was improved respectively using enhanced Sentinel-2 images by SupReME method. During these three parameters retrieval, the red-edge bands or SWIR bands were introduced into optimal cost function and vegetation index which the accuracy of these models was high. The SupReME algorithm provides a valuable way for Sentinel-2 images enhancement, which is of great potential to mining Sentinel-2 images and multitude its application.

    更新日期:2019-09-07
  • Wheat grain number and yield: The relative importance of physiological traits and source-sink balance in southern Australia
    Eur. J. Agron. (IF 3.384) Pub Date : 2019-08-26
    Heping Zhang, Richard Richards, Penny Riffkin, Jens Berger, Brendan Christy, Garry O’Leary, Tina Botwright Acuña, Angela Merry

    Grain number (GN) is determined by spike growth rate (SGR), fruiting efficiency (FE) and the duration of spike growth period (Ds). However, these three traits are not independent of each other and therefore quantifying their relative contribution to GN is important for improving yield potential. This study aimed to model GN as a function of SGR, FE and Ds in bread wheat and investigate the relative importance of these three traits in determining GN. A large number of commercial varieties, elite wheat breeding lines, and a Multiparent Advanced Generation InterCross population were evaluated for GN, SGR, Ds, and FE in six Australian environments in 2014 and 2015. The model explained 43–98% of the variation in GN in individual environments and 88% of the variation in GN across the six environments. The percentage of GN variance explained by the model was significantly higher than those explained by correlating GN to individual traits. The relative importance of the contribution of the three traits to GN was different and ranked as SGR > FE > Ds. The negative correlation between FE and spike dry weight at anthesis (SDWa) appears to be spurious, suggesting that there was no causality between high FE and low SDWa and vice versa. Thus, FE can be used as an independent trait to increase GN in addition to SGR and Ds. We also investigated if the wheat crop had enough source to fill the increased sink size in the southern Australian high rainfall environment. The source-sink balance analysis indicates that the available source, consisting of concurrent photosynthetic assimilate and stored water-soluble carbohydrate at anthesis, was sufficient to fill the established sink but no surplus assimilates were available to fill a larger sink in southwestern Australia. However, the opportunity to increase yield potential by further increasing grain number might exist in south-eastern Australia environments.

    更新日期:2019-08-26
  • Double-cropping systems based on rye, maize and sorghum: Impact of variety and harvesting time on biomass and biogas yield
    Eur. J. Agron. (IF 3.384) Pub Date : 2019-08-09
    Lukas Wannasek, Markus Ortner, Hans-Peter Kaul, Barbara Amon, Thomas Amon

    Climate change affects the frequency and intensity of extreme weather, the results of which include production losses and climate-induced crop productivity fluctuations. Double-cropping systems (DCSs) have been suggested as a way to increase biomass-production while simultaneously delivering environmental benefits. In a three-year field-test, two DCSs based on maize and sorghum as the main crop and rye as the preceding winter crop were compared with each other and compared with 2 single-cropping systems (SCSs) of maize or sorghum; there were comparisons of growth dynamics, optimal harvesting and growing time as well as biomass and methane yield. In addition, the impact of variety and harvest time on the winter rye optimal biomass yield was studied. The experiments clearly showed the superiority of the DCS over the SCS. Within the DCS, the rye/sorghum combination achieved significantly higher biomass yields compared to those of the rye/maize combination. The highest dry matter biomass yield was achieved during year 1 at 27.5 ± 2.4 t∙ha−1, during which winter rye contributed 8.3 ± 0.7 t∙ha−1 and sorghum contributed 19.2 ± 1.8 t∙ha−1. At the experimental location, which is influenced by a Pannonia climate (hot and dry), the rye/sorghum DCS was able to obtain average methane yields per hectare, 9300 m3, whereas the rye/maize combination reached 7400 m3. In contrast, the rye, maize and sorghum SCSs achieved methane yields of 4800, 6100 and 6500 m3 ha−1, respectively. The study revealed that the winter rye and sorghum DCS is a promising strategy to counteract climate change and thus guarantee crop yield stability.

    更新日期:2019-08-09
  • The critical period for yield determination in common buckwheat (Fagopyrum esculentum Moench)
    Eur. J. Agron. (IF 3.384) Pub Date : 2019-08-08
    Antonio C. Guglielmini, Juan I. Forcat, Daniel J. Miralles

    The aim of this study was to identify the critical period for yield determination in buckwheat by applying successive shading periods (of 14-days duration) throughout the crop cycle, from nine days after emergence to crop maturity. Experiments were carried out under field conditions during the 2017 and 2018 growing seasons. The critical period was defined as the interval when crop yield was significantly reduced by the shading treatments. This period extended from 74 °C days after the first open flowers to the first brown fruits stage (i.e. 390 °C days duration). Aerial biomass and its partitioning to the achenes (i.e. harvest index) were also reduced by shading. Achene number was reduced in a similar way to that of yield, and crop yield was highly associated with this yield component, while the shading treatments did not affect achene weight. The main cause of achene number reduction was the lower number of achenes per raceme, as the number of racemes was not affected. It is possible to speculate that radiation restriction imposed during the critical period could have increased floret mortality and thereby the number of achenes per raceme. However, further studies are required to determine the causes of reductions in the number of achenes per raceme during the critical period.

    更新日期:2019-08-08
  • On-farm diagnosis for greenhouse tomato in south Uruguay: Explaining yield variability and ranking of determining factors
    Eur. J. Agron. (IF 3.384) Pub Date : 2019-08-07
    Cecilia Berrueta, Alejandra Borges, Gustavo Giménez, Santiago Dogliotti
    更新日期:2019-08-07
  • Banana leaf pruning to facilitate annual legume intercropping as an intensification strategy in the East African highlands
    Eur. J. Agron. (IF 3.384) Pub Date : 2019-07-23
    W. Ocimati, J. Ntamwira, J.C.J. Groot, G. Taulya, P. Tittonell, B. Dhed’a, P. van Asten, B. Vanlauwe, B. Ruhigwa, G. Blomme

    Banana leaf pruning is a common practice to facilitate intercropping with legumes on farmers’ fields. It is however not clear if this practice improves farmers land-use and economic efficiency, especially after full canopy formation. To analyze pruning effects, three legumes viz. bush bean (Phaseolus vulgaris L), climbing bean (Phaseolus vulgaris L) and soybean (Glycine max), were planted under three banana leaf pruning levels in which four, seven and all fully grown leaves were retained. Sole banana or legume plots served as controls. Each treatment combination was replicated three times. Banana growth and yield attributes were measured for the plant and first ratoon crops while legume biomass and yields determined over five consecutive cropping seasons. Significant (P < 0.001) reductions in banana growth and yield were associated with leaf pruning. Banana yield reductions of 31% and 10% for the four- and seven-leaf retention treatments, respectively occurred. The vigorous intercrops (climbing beans and soybeans) more often depressed the growth and yield of banana. Legume grain and biomass yields increased with leaf pruning levels. Weed biomass and associated management costs increased with decline in shade intensity. The land-use efficiency measured using the land equivalence ratio (LER) was far lower in the treatment with four-leaves (1.10) compared to when all leaves were retained (1.4) but higher (1.54) for the seven-leaf treatment. Severe banana leaf pruning could thus be detrimental to banana performance and inefficient. Moderate banana leaf pruning could however be promoted were land is limiting and farmers want to maximize diversity/nutrition. However, the highest values for gross revenue and benefit-cost ratio were realized for sole banana-all-leaf retention treatment due to a higher labor productivity and lower input costs attributed to the perennial nature of banana. The higher economic efficiency in sole banana plots suggests that reliance on LER only may be insufficient for guiding intercropping decisions.

    更新日期:2019-07-24
  • Comparison of milk thistle (Silybum marianum) and cardoon (Cynara cardunculus) productivity for energy biomass under weedy and weed-free conditions
    Eur. J. Agron. (IF 3.384) Pub Date : 2019-07-17
    Athanasia Tsiaousi, Ioannis Vasilakoglou, Ioannis Gravalos, Spyridon D. Koutroubas

    Milk thistle (Silybum marianum [L.] Gaertn.) and cardoon (Cynara cardunculus L.) are energy plants. However, no studies have been conducted to investigate which of these crops could provide sufficient biomass under reduced inputs (regarding irrigation, fertilization and weed management), although this knowledge is essential for the farmers for decision-making. A 3-year field study was conducted in central Greece to compare the productivity of milk thistle (native ecotype) with that of cardoon (var. C12) under weedy and weed-free conditions, without fertilization and irrigation. During the 3 years of cultivation, cardoon and milk thistle produced a total of 24.56 t ha−1 and 20.89 t ha−1 dry biomass, respectively, in weed-free treatments. Weed competition slightly reduced the productivity of both crops. Therefore, the corresponding biomass yields in weedy treatments were 19.70 and 15.49 t ha−1. The gross calorific value of milk thistle and cardoon biomass ranged from 15.5 to 16.1 MJ kg-1 and 16.5 to 17.3 MJ kg−1, respectively. The average across-year potential energy yield in weed-free treatments was 111,870 MJ ha-1 for the milk thistle and 135,330 MJ ha-1 for the cardoon. The corresponding potential energy yields in weedy treatments were 80,130 MJ ha-1 and 113,550 MJ ha−1. Conclusively, milk thistle and cardoon could provide satisfactory dry biomass for energy use in semi-arid Mediterranean fields without irrigation or weed control inputs (assisted by their high allelopathic potential). Additionally, the cardoon outperformed the milk thistle in productivity.

    更新日期:2019-07-17
  • Effective population size (Ne) of organically and conventionally grown composite cross winter wheat populations depending on generation
    Eur. J. Agron. (IF 3.384) Pub Date : 2019-07-01
    S. Brumlop, O. Weedon, W. Link, M.R. Finckh

    Effective Population Sizes (Ne) of three winter wheat composite cross populations (CCPs) that had been maintained under organic and conventional conditions from the F7 to the F12 were analysed. The number of plants (N) needed to maintain an Ne of 5000 for each population was calculated based on the mean variation in the number of gametes per parent Sk2. Variability in kernel number per plant was high, leading to large variations in the contribution of single plants to the next generation. Also, N required for an Ne of 5000 individuals was somewhat variable among the CCPs, but changed little from the F7 (mean N of 11,955) to the F9 (mean N 11,854) under the assumption of 2% outcrossing. There was, however, an increase to a mean N of 14,374 between the F9 and the F12, most likely due to an extreme winterkill in the F11. The calculation of N using demographic data can only give general estimations but was well suited to show changes in the populations over time as affected by generation and year. Results show that drift was limited even under disruptive climatic events.

    更新日期:2019-07-01
  • Benchmarking break-crops with wheat reveals higher risk may limit on farm adoption
    Eur. J. Agron. (IF 3.384) Pub Date : 2019-06-18
    Andrew Fletcher

    Typically dryland rain fed cropping systems in much of the world (Australia, North America, Europe and the Middle East) are dominated by cereals, such as wheat, even though the rotational benefits of other crops are well documented. Presumably farmers see an advantage to wheat and this paper tested the hypothesis that on-farm break-crop yields are lower compared to wheat, and more variable. Farm level yields for wheat, barley, hay, oats, triticale, canola, lupin, chickpea, and field pea were taken from a survey of Western Australian grain farms (180–302 farms per year). In general, the yield of broad leaf crops was less than cereals and more variable. Additional data were sourced from published experiments and then yields were compared with wheat using linear regression with wheat as the x-axis and break crop as the y-axis. All break -crops were more sensitive to low yielding environments than wheat, as indicated by a positive intercept with the x-axis. Barley and wheat yields were closely related (R2 = 0.63), but in environments where yield was less than 1.25 t/ha wheat tended to yield more, while barley out yielded wheat when yields were greater than 1.25 t/ha. There was a poor relationship between either oat grain (R2 = 0.26) or hay (R2 = 0.10) yields and wheat indicating that these maybe potential income diversification options. Canola was the least variable (R2 = 0.54) broadleaf crop compared to wheat, with an intercept of 0.15 t/ha and for every 1 t/ha increase in wheat yield, canola yield increased by 0.56 t/ha. If increased diversity of crop species on-farm is the objective, then varieties and management packages that increase the yield and reliability of broadleaf crops relative to wheat will need to be developed.

    更新日期:2019-06-18
  • Potential of indicators to unveil the hidden side of cropping system classification: Differences and similarities in cropping practices between conventional, no-till and organic systems
    Eur. J. Agron. (IF 3.384) Pub Date : 2019-06-10
    Lucie Büchi, Florent Georges, Florian Walder, Samiran Banerjee, Thomas Keller, Johan Six, Marcel van der Heijden, Raphaël Charles

    To compare different cropping systems, it is crucial to describe explicitly the associated cropping practices. A set of 31 indicators and six composite indexes addressing farm structure, crop diversification, soil disturbance, organic matter inputs, nitrogen fertilisation, crop protection, and yield was used to describe 59 winter wheat fields belonging to conventional, no-till and organic systems, in Switzerland. The aim of this study was to investigate the complementarity and redundancy of the indicators and their potential to characterise these cropping systems. In general, weak correlations were observed between the studied indicators, showing the importance of using a set of indicators to fully characterise cropping practices. The complex indicators were often correlated with simpler ones, but it cannot be excluded that they can prove to be more useful in different contexts. Retaining a combination of simple and complex indicators to obtain a broad picture of cropping practices is thus recommended. The indicators highlighted differences but also similarities between the three systems. For example, the input of organic matter and crop rotation diversification were similar between the three systems. In contrast, total nitrogen fertilisation (lower for organic systems) and soil disturbance (lower for no-till systems) were different. A high within-system variability was observed for some indicators, suggesting that using quantitative indicators rather than simple classifications based on a general description of the systems allows a better characterisation of these systems. Overall, the use of indicators has the potential to improve our understanding of the influence of cropping practices on the soil and environment.

    更新日期:2019-06-11
  • Is it feasible to reduce tillage and N use while improving maize yield in irrigated Mediterranean agroecosystems?
    Eur. J. Agron. (IF 3.384) Pub Date : 2019-05-31
    E. Pareja-Sánchez, D. Plaza-Bonilla, J. Álvaro-Fuentes, C. Cantero-Martínez

    Mediterranean rainfed areas are transformed into irrigation to stabilize or increase crop yields. The gradual occupation of irrigation leads to an increase in nitrogen use and intensity of tillage. The aim of this work was to evaluate the combined impact of tillage systems and mineral N fertilization rates on maize grain yield, water and nitrogen use efficiencies (WUE and NUE) under Mediterranean irrigated conditions. The study was carried out in NE Spain during three maize growing seasons (i.e. years 2015, 2016 and 2017). A long-term (LTE) tillage and N rate field experiment established in 1996 under rainfed conditions was transformed into irrigation with maize (Zea mays L.) monocrop as cropping system in 2015. Three types of tillage (conventional tillage, CT; reduced tillage, RT; no-tillage, NT) and three mineral N fertilization rates (0, 200, 400 kg N ha−1) were compared. In 2015, an adjacent experiment (short-term experiment, STE) with the same layout was set up in an area previously managed under long-term rainfed NT for the last 21 years. In the long-term tillage and N fertilization combination (LTE), the reduction of tillage (NT and RT) led to greater grain yield when applying 200 and 400 kg N ha−1 compared to the use of the same rates under CT. Differently, in the sort-term experiment with preceding NT (STE), tillage systems did not influence grain yields, while N application led to greater yields than the control (0 kg N ha−1). In both situations (LTE and STE), NT and RT enhanced soil water content before planting leading to greater crop growth compared to CT. The lack of available water under CT caused lower maize stover, yield, and yield components in LTE and, therefore, lower WUEB (for biomass) and WUEY (for yield). In LTE, the use of long-term CT led to a significant accumulation of nitrate compared to NT. Differently, in the STE, soil nitrate content did not show differences between tillage systems. In the LTE, water and N were used more efficiently to produce aboveground biomass and grain yield in RT and NT. Our study shows that in Mediterranean agroecosystems transformed into irrigation the use of NT and RT with medium rates of N leads to greater maize yield, WUE and NUE than the traditional management based on CT with high rates of mineral N. In rainfed areas with long-term history of no-till, this soil management system can be successfully maintained if transformed into irrigation.

    更新日期:2019-05-31
  • Above- and belowground dry matter partitioning of four warm-season annual crops sown on different dates in a semiarid region
    Eur. J. Agron. (IF 3.384) Pub Date : 2019-05-22
    Zhixin Zhang, Kailiang Yu, Xiuliang Jin, Zhibiao Nan, Jianfeng Wang, Xueli Niu, Jeremy P.M. Whish, Lindsay W. Bell, Kadambot H.M. Siddique

    Biomass production and partitioning are important for crop production and is influenced by environmental conditions. Sowing date can profoundly influence biomass production and portioning in crop plants depending upon the local climatic conditions. However, the accumulation of biomass in different plant components in annual forages in response to changes in sowing date has not been quantified, especially for semiarid farming systems. A field experiment was conducted during 2011–2013 to investigate how sowing date (early, mid, late) influences biomass partitioning and the interrelationships with environments in four warm-season annual crops in the Loess Plateau of China. The aboveground biomass of all four crops was more reliant on rainfall and solar radiation at flowering and temperature and rainfall at maturity. Solar radiation, rainfall, and temperature had a combined effect on belowground biomass (0–0.3 m), depending on the forage crop. Reductions in biomass in the late-sown treatment were mostly attributed to plant size; the ‘allometry’ among plant components did not change. The changes of shoot: root and leaf: stem ratios were related to the relationship between biomass accumulation and rainfall, temperature and intercepted radiation. It is evident that dry matter allocation patterns in crops must be analyzed using a dynamic approach (allometry) and relate with environmental conditions, rather than a static approach using ratios. The results from this study provide references for crop management in forage production and breeding in semiarid areas.

    更新日期:2019-05-22
  • Residual effect of synthetic nitrogen fertilizers and impact on Soil Nitrifiers
    Eur. J. Agron. (IF 3.384) Pub Date : 2019-05-20
    Miguel Quemada, María Alonso-Ayuso, Antonio Castellano-Hinojosa, Eulogio J. Bedmar, Jose L. Gabriel, Irene García González, Francisco Valentín, Manuel Calvo

    The residual effect of nitrogen (N) fertilizers on subsequent crops might affect N efficiency and soil microorganisms, but little is known about the underlying reasons. Our goal was to elucidate the origin of the residual effect of synthetic N fertilizers, with and without a nitrification inhibitor, in three field experiments located in different regions of Spain that shared a common design in a maize (Zea mays L.) /wheat (Triticum aestivum L.) rotation. Maize was fertilized with ammonium sulphate nitrate (ASN) or with ASN blended with 3,4 dimethylpyrazole phosphate (DMPP) (ASN + DMPP) or was not fertilized with N. Wheat after maize received the recommended N dose, a low N dose or no N application. Yield and N content were determined for each crop and treatment and soil samples were taken to determine non-exchangeable NH4+ as well as C and N in the microbial biomass. DNA extraction was conducted in soil samples at different times. In the two locations where a residual effect occurred as a result of fertilizer application on the previous crop, either as ASN or ASN + DMPP, the C retained in the microbial biomass increased. The abundance of bacterial and archaeal communities was related to the soil’s C biomass, and the quantitative PCR approach was a more sensitive biomarker of the microbial activity than C and N in the microbial biomass. The residual effect was associated with a temporal increase of soil microorganisms caused by fertilizer application. Optical sensors identified the residual effect, opening the opportunity for adjusting the fertilizer rate to actual crop requirements.

    更新日期:2019-05-21
  • Adapting irrigated and rainfed wheat to climate change in semi-arid environments: Management, breeding options and land use change
    Eur. J. Agron. (IF 3.384) Pub Date : 2019-05-20
    Ixchel M. Hernandez-Ochoa, Diego Notello Luz Pequeno, Matthew Reynolds, Md Ali Babar, Kai Sonder, Anabel Molero Milan, Gerrit Hoogenboom, Ricky Robertson, Stefan Gerber, Diane L. Rowland, Clyde W. Fraisse, Senthold Asseng

    Mexico’s 3.3 million tons current wheat production is projected to decline due to climate change. To counteract these negative impacts, we explored a range of plausible adaptation measures including change in crop management (early sowing and nitrogen fertilizer applications), crop genetic traits (early vigor, late flowering and heat tolerance) and wheat growing area expansion. Adaptation measures were simulated individually and in various combinations with a multi-crop model and multi-Global Climate Model ensemble across representative wheat growing regions and aggregated to national wheat production. Under both baseline (current) and future climate scenarios, most of the suggested individual and combined genetic traits resulted in a positive impact on irrigated wheat but were less beneficial in rainfed systems, with the largest responses observed with late flowering and increased N fertilizer. Increased N fertilizer applications on its own, but particularly combined with crop genetic traits showed the highest yield increase in the baseline, with further positive impacts in the future scenarios. Yield benefits from new crop genetic traits combined with increased N fertilizer applications could add about 672,000 t year−1 to national wheat production, after losing 200,000 t year−1 due to climate change by 2050s. Most effectively, expanding wheat to include all areas where wheat was previously grown during the last two decades could add 1.5 million t year−1 now and 1.2 million t year−1 in the future. Breeding for new crop genetic traits will reduce some of the negative impacts from future climate change, but improved cultivars need to be implemented with suitable crop management, especially N fertilizer management.

    更新日期:2019-05-20
  • Soil compaction effects on grassland silage yields and soil structure under different levels of compaction over three years
    Eur. J. Agron. (IF 3.384) Pub Date : 2019-05-20
    P.R. Hargreaves, K.L. Baker, A. Graceson, S. Bonnett, B.C. Ball, J.M. Cloy

    Soil compaction has been estimated to be responsible for 33 million ha of soil degradation in Europe, reducing crop yields, however there is limited data on grassland silage yields loss. Extended grazing periods, increased size and weight of farm vehicles and more extreme weather have fostered concern over the consequences of grassland management on reduced grass yield and soil quality. This work aimed at studying the effect of increased animal trampling and mechanical (tractor) soil compaction on grassland silage mean dry matter (DM) yields and soil structure over a three year period at two UK sites. These sites were on two established perennial ryegrass fields with contrasting soil textures; an imperfectly drained silty clay loam in SW Scotland and a well drained sandy loam from central England. Results showed trampling and tractor compaction decreased mean DM yields over three years and by the third year DM yield for the trampled area was 11.4% less on the soil with greater clay content soil and 12.0% less on the more sandier soil than the no compaction control. DM yield for the tractor compaction, by the third year, was 14.5% less than no compaction DM yield, on both soil types. Compaction treatments gave the greatest reductions for the first silage cut DM yields annually, for both soil types. The largest reductions (19.0% for trampling and 37.7% for tractor) were on the soil with the greater clay content in the second year, with the coolest start to the growing season. Compaction reduced N uptake, decreased drainage and increased water filled pore spaces (WFPS). Linear regression of visual evaluation of soil structure (VESS) scores and bulk densities provided evidence that VESS is an effective tool for detecting grassland compaction and would assist with the management of moderately compacted soils where deteriorate soil conditions may result in yield loss.

    更新日期:2019-05-20
  • Prognosis and diagnosis of sulfur status in maize by plant analysis
    Eur. J. Agron. (IF 3.384) Pub Date : 2019-05-08
    Walter D. Carciochi, Nahuel I. Reussi Calvo, Nicolás Wyngaard, Guillermo A. Divito, Mercedes Eyherabide, Hernán E. Echeverría

    The analysis of sulfur concentration (SC) and nitrogen to S ratio (N/S) in plant tissue are some of the suggested tools to evaluate S deficiency in maize (Zea mays L.). However, the convenience of one over the other and the tissue that should be analyzed (upper leaf or shoot) is still questioned. Therefore, the objectives of our study were to: i) evaluate the stability of shoot and upper leaf N/S ratio with increasing shoot biomass (BM), ii) compare SC vs N/S in shoot or upper leaf as S prognosis tools, and iii) evaluate the use of SC simultaneously with grain N/S as a S diagnostic method in maize. Different S fertilization rates (0–32 kg S ha−1) were evaluated in nine field experiments where S and N concentration were determined in maize shoot, uppermost fully developed leaf, and grain samples. The main results of our study were: i) the N/S ratio in shoot and upper leaf was not stable with increasing BM; ii) the S prognosis capacity was similar when measuring SC or N/S on the shoot or upper leaf in vegetative growth stages, and iii) SC in grain allowed an adequate S diagnosis, which was not improved by including N/S in the prediction. In conclusion, based on its simplicity and reliability, we suggested the use of SC in the upper leaf at ≈V6 stage as a S prognosis tool (2.1 g kg−1 threshold). In addition, a 1.12 g S kg−1 threshold in grain was adequate for S diagnosis.

    更新日期:2019-05-08
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