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  Subjects -> AGRICULTURE (Total: 772 journals)
    - AGRICULTURAL ECONOMICS (74 journals)
    - AGRICULTURE (524 journals)
    - CROP PRODUCTION AND SOIL (94 journals)
    - DAIRYING AND DAIRY PRODUCTS (30 journals)
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AGRICULTURE (524 journals)            First | 1 2 3 4 5 6     

The South African Journal of Economics     Hybrid Journal   (Followers: 3)
Trends in Agricultural Economics     Open Access   (Followers: 5)
Tropical Agricultural Research     Open Access   (Followers: 1)
Tropical Agricultural Research and Extension     Open Access   (Followers: 1)
Tropical and Subtropical Agroecosystems     Open Access  
Tropical Grasslands - Forrajes Tropicales     Open Access  
Turkish Journal of Agriculture and Forestry     Open Access  
Ubisi Mail     Full-text available via subscription  
UMK Procedia     Open Access  
Universal Journal of Agricultural Research     Open Access  
Universidad y Ciencia     Open Access   (Followers: 1)
Walailak Journal of Science and Technology     Open Access   (Followers: 2)
Warm Earth     Full-text available via subscription  
Wartazoa. Indonesian Bulletin of Animal and Veterinary Sciences     Open Access  
Water Resources and Rural Development     Hybrid Journal  
Weed Biology and Management     Hybrid Journal   (Followers: 1)
Weed Research     Hybrid Journal   (Followers: 2)
West African Journal of Applied Ecology     Open Access  
Wildlife Australia     Full-text available via subscription   (Followers: 2)
Wine Studies     Open Access   (Followers: 6)
Wirtschaftsdienst     Hybrid Journal   (Followers: 3)
World Journal of Agricultural Research     Open Access   (Followers: 1)
World Mycotoxin Journal     Full-text available via subscription   (Followers: 6)
World's Poultry Science Journal     Full-text available via subscription   (Followers: 5)
Zootecnia     Open Access  

  First | 1 2 3 4 5 6     

Journal Cover European Journal of Agronomy
  [SJR: 1.381]   [H-I: 60]   [9 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 1161-0301
   Published by Elsevier Homepage  [2801 journals]
  • Nitrogen use efficiency of cotton (Gossypium hirsutum L.) as influenced by
           wheat–cotton cropping systems
    • Abstract: Publication date: April 2016
      Source:European Journal of Agronomy, Volume 75
      Author(s): Xiangbei Du, Binglin Chen, Yuxiao Zhang, Wenqing Zhao, Tianyao Shen, Zhiguo Zhou, Yali Meng
      Wheat–cotton rotations largely increase crop yield and improve resources use efficiency, such as the radiation use efficiency. However, little information is available on the nitrogen (N) utilization and requirement of cotton under wheat–cotton rotations. This study was to determine the N uptake and use efficiency by evaluating the cotton (Gossypium hirsutum L.) N use and the soil N balances, which will help to improve N resource management in wheat–cotton rotations. Field experiments were conducted during 2011/2012 and 2012/2013 growing seasons in the Yangtze River region in China. Two cotton cultivars (Siza 3, mid-late maturity with 130 days growth duration; CCRI 50, early maturity with 110 days growth duration) were planted under four cropping systems including monoculture cotton (MC), wheat/intercropped cotton (W/IC), wheat/transplanted cotton (W/TC) and wheat/direct-seeded cotton (W/DC). The N uptake and use efficiency of cotton were quantified under different cropping systems. The results showed that wheat–cotton rotations decreased the cotton N uptake through reducing the N accumulation rate and shortening the duration of fast N accumulation phase as compared to the monoculture cotton. Compared with MC, the N uptake of IC, TC and DC were decreased by 12.0%, 20.5% and 23.4% for Siza 3, respectively, and 7.3%, 10.7% and 17.6% for CCRI 50, respectively. Wheat–cotton rotations had a lower N harvest index as a consequence of the weaker sink capacity in the cotton plant caused by the delayed fruiting and boll formation. Wheat–cotton rotations used N inefficiently relative to the monoculture cotton, showing consistently lower level of the N agronomic use efficiency (NAE), N apparent recovery efficiency (NRE), N physiological efficiency (NPE) and N partial factor productivity (NPFP), particularly for DC. Relative to the mid–late maturity cultivar of Siza 3, the early maturity cultivar of CCRI 50 had higher N use efficiency in wheat–cotton rotations. An analysis of the crop N balance suggested that the high N excess in preceding wheat (Triticum aestivum L.) in wheat–cotton rotations led to significantly higher N surpluses than the monoculture cotton. The N management for the cotton in wheat–cotton rotations should be improved by means of reducing the base fertilizer input and increasing the bloom application.


      PubDate: 2016-01-30T21:10:23Z
       
  • Can arbuscular mycorrhizal fungi improve competitive ability of
           dill+common bean intercrops against weeds?
    • Abstract: Publication date: April 2016
      Source:European Journal of Agronomy, Volume 75
      Author(s): Weria Weisany, Saeid Zehtab-Salmasi, Yaghoub Raei, Yousef Sohrabi, Kazem Ghassemi-Golezani
      Competition for soil resources plays a key role in the crop yield of intercropping systems. There is a lack of knowledge on the main factors involved in competitive interactions between crops and weeds for nutrients uptake. Hence, the purpose of this work was to compare the effects of arbuscular mycorrhial fungi (Funneliformis mosseae) colonization in interspecific competitive relations and its effect on nutrients uptake and weed control in dill and common bean intercropping. Two field experiments were carried out with factorial arrangements based on randomized complete block design with three replications during 2013–2014. The factors were cropping systems including a) common bean (Phaseolus vulgaris L.) sole cropping (40 plantsm−2), b) dill (Anethum graveolens L.) sole cropping at different densities (25, 50 and 75 plantsm−2) and c) the additive intercropping of dill+common bean (25+40, 50+40 and 75+40 plantsm−2). All these treatments were applied with (+AM) or without (-AM) arbuscular mycorrhiza colonization. In both cropping systems, inoculation with F. mosseae increased the P, K, Fe and Zn concentrations of dill plants by 40, 524, 57 and 1.0μgkg−1 DW, respectively. Intercropping increased Mn concentration in common bean (4.0μgkg−1 DW) and dill (3.0μgkg−1 DW), and also seed yields of both crops (198gm−2 and161gm−2, respectively). AM colonization improved seed yields of dill and common bean by 169 and 177gm−2 in 2013 and 2014, respectively. Moreover, AM application enhanced competitive ability of dill+common bean intercrops against weeds at different intercropping systems. Intercropping significantly changed weed density compared to sole cropping, as weed density was decreased in the dill+common bean intercropping. Diversity (H), Evenness (E) and richness of weed species of weeds for intercrops were higher than those for sole crops.


      PubDate: 2016-01-30T21:10:23Z
       
  • Dense planting with less basal nitrogen fertilization might benefit rice
           cropping for high yield with less environmental impacts
    • Abstract: Publication date: April 2016
      Source:European Journal of Agronomy, Volume 75
      Author(s): Xiangcheng Zhu, Jun Zhang, Zhenping Zhang, Aixing Deng, Weijian Zhang
      Dense planting and less basal nitrogen (N) fertilization have been recommended to further increase rice (Oryza sativa L.) grain yield and N use efficiency (NUE), respectively. The objective of this study was to evaluate the integrative impacts of dense planting with reduced basal N application (DR) on rice yield, NUE and greenhouse gas (GHG) emissions. Field experiments with one conventional sparse planting (CK) and four treatments of dense planting (increased seedlings per hill) with less basal N application were conducted in northeast China from 2012 to 2013. In addition, a two-factor experiment was conducted to isolate the effect of planting density and basal N rate on CH4 emission in 2013. Our results show that an increase in planting density by about 50% with a correspondingly reduction in basal N rate by about 30% (DR1 and DR2) enhanced NUE by 14.3–50.6% and rice grain yield by 0.5–7.4% over CK. Meanwhile, DR1 and DR2 reduced GWP by 6.4–12.6% and yield-scaled GWP by 7.0–17.0% over CK. According to the two-factor experiment, soil CH4 production and oxidation and CH4 emission were not affected by planting density. However, reduced basal N rate decreased CH4 emission due to it significantly reduced soil CH4 production with a smaller reduction in soil CH4 oxidation. The above results indicate that moderate dense planting with less basal N application might be an environment friendly mode for rice cropping for high yield and NUE with less GHG emissions.


      PubDate: 2016-01-30T21:10:23Z
       
  • Low-input cropping systems to reduce input dependency and environmental
           impacts in maize production: A multi-criteria assessment
    • Abstract: Publication date: Available online 29 January 2016
      Source:European Journal of Agronomy
      Author(s): Simon Giuliano, Matthew R. Ryan, Grégory Véricel, Gaël Rametti, François Perdrieux, Eric Justes, Lionel Alletto
      Intensification of cropping systems in recent decades has increased their productivity but affected air, soil and water quality. These harmful environmental impacts are exacerbated in Maize Monoculture (MM) and hasten the need for solutions to overcome the trade off between crop yield and environmental impacts. In a three-year cropping systems experiment, a conventional intensive maize monoculture (MMConv), with a winter bare fallow, deep soil tillage, non-limiting irrigation was compared to three Low Input Cropping Systems (LI-CS) designed as alternatives to the conventional system. They were managed with decision-rules implemented to reach specific objectives of input reduction. The LI-CS designed with Integrated Weed Management (IWM) techniques and other sustainable cropping practices, were:(i) MMLI—an IWM Low Input MM; (ii) MMCT—a Conservation Tillage combined with cover crop MM; and (iii) Maize-MSW—an IWM maize grown in rotation with soybean and wheat. A comprehensive multi-criteria assessment was carried out to quantify the agronomic, economic, social, and environmental performances of each system. A canonical discriminant analysis of performance metrics revealed large differences between the four systems. Yields were significantly higher in MMConv (11.0Mgha−1) and MMLI (10.3Mgha−1) than in Maize-MSW (8.6Mgha−1) and MMCT (7.8Mgha−1). MMCT had the largest weed infestation (density and biomass) despite the greatest use of herbicides. The Herbicide Treatment Frequency Index (HTFI), used to indicate differences in herbicide use, revealed that the MMLI (HTFI=1.0) and Maize-MSW (1.1) halved the herbicide use as compared to the MMConv (2.1), despite having similar weed abundance levels. The LI-CS, especially MMCT, produced high biomass winter cover crops and then less nitrogen fertilization was required as compared to MMConv. Gross margins in the MMLI (1254 €ha−1) and MMConv (1252 €ha−1) were higher than the MMCT (637 €ha−1) and Maize-MSW (928 €ha−1). MMLI and MMConv had similar labour requirements. Water drainage, pesticide leaching, energy use, and estimated greenhouse gas emissions were higher in MMConv than in the LI-CS in most years. Results from this research show good potential for the MMLI to reduce the environmental impacts of MMConv while maintaining its economic and social performance.
      Graphical abstract image

      PubDate: 2016-01-30T21:10:23Z
       
  • Attributes of wheat cultivars for late autumn sowing in genes expression
           and field estimates
    • Abstract: Publication date: April 2016
      Source:European Journal of Agronomy, Volume 75
      Author(s): Anna Wenda-Piesik, Ludmila Holková, Eva Solařová, Radovan Pokorný
      Due to the growing interest in Central and Eastern Europe on cropping of wheat in optional late autumn terms, called facultative, genetic research and field evaluation were taken on four spring cultivars: Tybalt (NL), Monsun (DE), Ostka Smolicka (PL) and Bombona (PL), currently being recommended by breeders. The PPD gene analyze, expression level of dehydrine genes (WCS120 and WDHN13) in cooling test, and qPCR for RNA isolation and analyses of WCS120 and WDHN13 gene expression at the BBCH12 stage of wheat were estimated. Molecular analysis of PPD-D1 gene confirmed the presence of photoperiod sensitive allele ppd-D1b in all tested genotypes. The highest level of NRE WCS120 gene was detected in cultivars Tybalt and Bombona. Two-year field experimental study assessed the growth, development and productivity of facultative and spring crops of studied cultivars. Based on our results from field experiments and result of molecular analysis of alleles of PPD-D1 gene, the tested genotypes can be considered as potentially facultative genotypes.


      PubDate: 2016-01-24T20:53:39Z
       
  • Productivity and profitability of cotton–wheat system as influenced
           by relay intercropping of insect resistant transgenic cotton in bed
           planted wheat
    • Abstract: Publication date: April 2016
      Source:European Journal of Agronomy, Volume 75
      Author(s): Muhammad Asghar Shah, Muhammad Farooq, Mubshar Hussain
      Cotton (Gossypium hirsutum L.) is the leading cash crop being grown across the globe including Pakistan. By the inclusion of insect resistant transgenic cotton (BT cotton), the cotton production has mounted many folds in Pakistan. BT cotton is mostly grown in Southern Punjab in cotton–wheat cropping system of Pakistan; however there exists a time conflict among wheat harvest and BT cotton sowing in this system. Wheat is harvested during late April but the ideal sowing time of BT cotton is early-mid March indicating a time conflict of 4–6 weeks which is becoming the main concern leading to wheat exclusion from this system. Intercropping of BT cotton in standing wheat is one of the possible options to manage this overlapping period. This two year field study was, therefore, conducted at two locations (Multan, Vehari) to evaluate the economic feasibility of relay intercropping of BT cotton through different sowing methods in BT cotton–wheat cropping system. BT cotton–wheat cropping systems included in the study were: conventionally tilled cotton (CTC) on fallow land during early and late March, CTC during late April after harvest of flat sown wheat (FSW), bed sown wheat (BSW)+intercropped cotton during early and late March, and ridge sown wheat (RSW)+intercropped cotton during early and late March. Planting cotton in fallow land with conventional tillage during early March had more seed cotton yield; whereas planting in the same way during April after wheat harvest had minimum seed cotton yield. Likewise, FSW had more yield than ridge and bed sown wheat with intercropped BT cotton during early or late March. However, the system productivity in terms of net income, benefit: cost ratio and marginal rate of return of BSW+intercropped BT cotton during early March was the highest during both years at both locations. However, the system with sole crop of BT cotton sown on fallow land during late or early March was the least economical even than the system with CTC during late April after harvest of FSW. In conclusion, BSW+intercropped cotton during early March may be opted to manage the time conflict and improve the economic productivity of BT cotton–wheat cropping system without wheat exclusion from the system.


      PubDate: 2016-01-19T20:30:27Z
       
  • How do timing, duration, and intensity of drought stress affect the
           agronomic performance of winter rye?
    • Abstract: Publication date: April 2016
      Source:European Journal of Agronomy, Volume 75
      Author(s): Lorenz Kottmann, Peer Wilde, Siegfried Schittenhelm
      Winter rye (Secale cereale L.) will be especially affected by drought induced yield losses in Central and Eastern Europe in the future because it is predominantly cultivated on low-fertile soils with a poor water-holding capacity. In order to examine the performance of winter rye under different drought conditions, field experiments were carried out during the years 2011, 2012, and 2013 near Braunschweig, Germany. Two sets of genotypes were tested under severe, mild, pre-anthesis, and post-anthesis drought stress in rain-out shelters as well as under rainfed and well-watered conditions. The grain, straw, and total above ground biomass yields, harvest index, grain yield components, leaf area index (LAI), and phenological characteristics were examined, as well as phenotypic correlations between grain yield and further characteristics. Drought induced grain yield reduction ranged from 14 to 57%, while straw yield and harvest index were lesser affected by drought than the grain yield. Under drought conditions, fully ripe was reached up to twelve days earlier than under non water-limited conditions. Pre-anthesis drought mainly reduced spikes m−2 and kernels spike−1 while drought during grain filling reduced the 1000-kernel weight (TKW) only. The grain yield was positively associated with straw yield, spikes m−2, and kernels spike−1 under water limited conditions while the TWK was only positively associated with grain yield under drought during grain filling. Consequently, high pre-anthesis biomass as well as high numbers of spikes m−2 and kernels spike−1 are especially important for obtaining high grain yields under water-limited conditions. Focusing on these traits is, therefore, recommendable for developing drought tolerant rye genotypes.


      PubDate: 2016-01-15T20:06:28Z
       
  • Optimized single irrigation can achieve high corn yield and water use
           efficiency in the Corn Belt of Northeast China
    • Abstract: Publication date: April 2016
      Source:European Journal of Agronomy, Volume 75
      Author(s): Zizhong Li, Zenghui Sun
      Decreasing the corn (Zea mays L.) gap between the potential yield and farm yield and reducing the risk of grain yield of drought are very important for corn production in the Corn Belt of Northeast China (CBNC). To achieve a high and stable corn yield, the effects of supplementary irrigation on yield, water use efficiency (WUE) and irrigation water use efficiency (IWUE) were studied using a modelling approach. The Root Zone Water Quality Model 2 was parameterized and evaluated using two years of experimental data in aeolian sandy soil and black soil. The evaluated model was then used to investigate responses to various irrigation strategies (rainfed, full irrigation and 12 single irrigation scenarios) using long-term weather data from 1980 to 2012. Full irrigation guarantees a high and stable corn grain yield (12.92Mgha−1 and has a coefficient of variation (CV) of 14.8% in aeolian sandy soil; 12.30kgMa−1 and CV of 11.1% in black soil), but has a low water use efficiency (19.92 and 21.81kgha−1 mm−1) and a low irrigation water use efficiency (10.01 and 11.03kgha−1 mm−1). A single irrigation can increase corn yields by 3–35% for aeolian sandy soil and 5–35% for black soil over different irrigation dates compared with no irrigation. The most suitable single irrigation date was during late June to early July for aeolian sandy soil (yield=10.73Mgha−1 and WUE=27.94kgha−1 mm−1) and early to mid-July for black soil (yield=11.20Mgha−1 and WUE=27.70kgha−1 mm−1). The lowest yield risk of falling short of the yield goal of 8, 9, and 10Mgha−1 were 9.1%, 18.2%, and 33.33% in aeolian sandy soil and 3.0%, 15.25, and 21.2% in black soil when an optimized single irrigation was applied in late June or early July, respectively. Therefore, an optimized single irrigation should be applied in late June to early July with the irrigation amount to refill soil water storage of root zone to field capacity in CBNC.


      PubDate: 2016-01-15T20:06:28Z
       
  • Long-term atmospheric CO2 enrichment impact on soil biophysical properties
           and root nodule biophysics in chickpea (Cicer arietinum L.)
    • Abstract: Publication date: April 2016
      Source:European Journal of Agronomy, Volume 75
      Author(s): Saurav Saha, D. Chakraborty, Vinay K. Sehgal, Lata Nain, Madan Pal
      Impact of atmospheric CO2 enrichment on soil aggregation, carbon and other nutrient availability and soil enzyme activities in relation to root and nodule biophysics in chickpea (Cicer arietinum L.; Pusa-1105 genotype) was studied in an open top chamber experiment at IARI, New Delhi, India, continuing since 2003. Soil samples were collected at the end of the crop growing seasons of 2010–11 and 2011–12, and analyzed. Root growth and nodulation were also studied in these seasons. Soil C and P pools, and associated enzyme activities responded differently to CO2 enrichment, while total soil N did not change. Soil labile C fractions viz., water soluble carbohydrate (WSC) and microbial biomass C (MBC) significantly increased, although recalcitrant C fraction declined marginally. The soil-CO2 flux increased by 28%. Dehydrogenase and fluorescein diacetate hydrolysis activity in soil increased by 44% and 67% respectively; and the β-glucosidase activity enhanced by 20% under enriched CO2 condition. The CO2 enrichment induced root growth and N2-fixation by root nodules, which were evidenced by increase in legheamoglobin content and nitrogenase activity. Nodules were bulky and had higher starch and soluble sugar contents under enriched atmospheric CO2 condition, allowing for greater N2-fixation. The rhizosphere C:N ratio, however, remained unaffected. It could be possible that larger partitioning of C to roots along with greater N2-fixation by nodules in chickpea might stabilize the net C:N ratio in the soil. Moreover, the increased soil biological activity under CO2 enrichment resulted in marginal depletion of soil recalcitrant C with increase in labile C pools. These are likely to offset the stability of soil C pools in a legume-based agroecosystems under the enriched CO2 condition in the semi-arid climate.


      PubDate: 2016-01-10T19:47:12Z
       
  • Mapping crop diseases using survey data: The case of bacterial wilt in
           bananas in the East African highlands
    • Abstract: Publication date: March 2016
      Source:European Journal of Agronomy, Volume 74
      Author(s): H. Bouwmeester, G.B.M. Heuvelink, J.J. Stoorvogel
      Globally, crop diseases result in significant losses in crop yields. To properly target interventions to control crop diseases, it is important to map diseases at a high resolution. However, many surveys of crop diseases pose challenges to mapping because available observations are only proxies of the actual disease, observations often are not normally distributed and because typically convenience sampling is applied, leading to spatially clustered observations and large areas without observations. This paper addresses these challenges by applying a geostatistical methodology for disease incidence mapping. The methodology is illustrated for the case of bacterial wilt of banana (BWB) caused by Xanthomonas campestris pv. musacearum in the East African highlands. In a survey using convenience sampling, 1350 banana producing farmers were asked to estimate the percentage yield loss due to bacterial wilt. To deal with the non-normal distribution of the data, the percentages were classified into two binary variables, indicating whether or not the disease occurred and whether or not the yield loss was severe. To improve the spatial prediction of disease incidence in areas with low sampling density, the target variables were correlated in a logistic regression to a range of environmental variables, for which maps were available. Subsequently, the residuals of the regression analysis were interpolated using simple kriging. Finally, the interpolated residuals were added to the regression predictions. This so-called indicator regression kriging approach resulted in continuous maps of disease incidence. Cross-validation showed that the method yields unbiased predictions and correctly assesses the prediction accuracy. The geostatistical mapping is also more accurate than conventional mapping, which uses the mean of observations within districts as the predicted value for all locations within the district, although the accuracy improvement is not very large. The maps were also spatially aggregated to district level to support regional decision-making. The analysis showed that the disease is widespread on banana farms throughout the study area and can locally reach severe levels.


      PubDate: 2016-01-10T19:47:12Z
       
  • A simple Bayesian method for adjusting ensemble of crop model outputs to
           yield observations
    • Abstract: Publication date: Available online 4 January 2016
      Source:European Journal of Agronomy
      Author(s): David Makowski
      Multi-model forecasting has drawn some attention in crop science for evaluating effect of climate change on crop yields. The principle is to run several individual process-based crop models under several climate scenarios in order to generate ensembles of output values. This paper describes a simple Bayesian method – called Bayes linear method – for updating ensemble of crop model outputs using yield observations. The principle is to summarize the ensemble of crop model outputs by its mean and variance, and then to adjust these two quantities to yield observations in order to reduce uncertainty. The adjusted mean and variance combine two sources of information, i.e., the ensemble of crop model outputs and the observations. Interestingly, with this method, observations collected under a given climate scenario can be used to adjust mean and variance of the model ensemble under a different scenario. Another advantage of the proposed method is that it does not rely on a separate calibration of each individual crop model. The uncertainty reduction resulting from the adjustment of an ensemble of crop models to observations was assessed in a numerical application. The implementation of the Bayes linear method systematically reduced uncertainty, but the results showed the effectiveness of this method varied in function of several factors, especially the accuracy of the yield observation, and the covariance between the crop model output and the observation.


      PubDate: 2016-01-05T16:21:49Z
       
  • Effect of panicle nitrogen on grain filling characteristics of
           high-yielding rice cultivars
    • Abstract: Publication date: Available online 4 January 2016
      Source:European Journal of Agronomy
      Author(s): Qi Jiang, Yonglin Du, Xiaoya Tian, Qiangsheng Wang, Ruiheng Xiong, Guochun Xu, Chuan Yan, Yanfeng Ding
      The effects of four levels of panicle nitrogen fertilizer on the grain filling characteristics of three rice (Oryza sativa L.) varieties (super japonica rice Ningjing 3, three-line japonica hybrid rice Changyou 3 and three-line indica–japonica hybrid rice Yongyou 12) were analyzed. The results showed that difference in time of maximum filling rate (T max) was the smallest between the superior and inferior spikelets of Ningjing 3, bigger between those of Changyou 3, the biggest between those of Yongyou 12. Ningjing 3 was of the synchronous grain-filling type, Yongyou 12 the asynchronous type, and the Changyou 3 the medium type. The grain filling rate, the initial filling power (R 0), the maximum filling rate (G max), and the average filling rate (G) of the superior and inferior spikelets of the three varieties under the treatment of panicle N with the amount of 120kgha−1 (middle panicle N, shortened as NM) treatment were higher than those of other treatments. NM treatment led to the highest increase in grain weight at the middle stage of filling for all the three varieties. The treatment shortened the early and late stages of grain filling, but extended the middle stage when the filling rate was the highest. However, the middle stage of grain filling of Changyou 3 and Yongyou 12 was much more extended than that of Ningjing 3, indicating a better effect of N on hybrid rice varieties.


      PubDate: 2016-01-05T16:21:49Z
       
  • Compactión produced by combine harvest traffic: Effect on soil and
           
    • Abstract: Publication date: March 2016
      Source:European Journal of Agronomy, Volume 74
      Author(s): G.F. Botta, A. Tolón-Becerra, D. Rivero, D. Laureda, M. Ramírez-Roman, X. Lastra-Bravo, D. Agnes, I.M. Flores-Parra, F. Pelizzari, V. Martiren
      Soil compaction is caused by the high traffic intensity and tyre ground pressures of tractor and combines in harvesting, especially when these operations are carried out on wet soil or with high ground pressure tyres. Our main objective was to compare the effect of three combine harvester traffic intensities on soil compaction and soybean (Glycine max L.) yields cultivated under direct sowing (DS) in a Typic Argiudoll soil in the east of the Rolling Pampa region, Argentina. The treatments were: (1) combine harvester with high axle load and low ground pressure (C1TLGP), (2) combine harvester with medium axle load and medium ground pressure (C2TMGP) and (3) combine harvester with low axle load and high ground pressure (C3THPG). We hypothesised that the application of the different combine harvester traffic intensities produced soybean yield reductions and subsoil compaction on soil under continuous DS. In the topsoil (0–20cm), the results show that after three years, the C3THGP treatment aplication produced higher cone index values than for the other treatments. In the subsoil (20–60cm), the results show that during three growing seasons, the C1TLGP (total load=152kN) treatment aplication produced higher cone index values than other treatments The highest average root dry matter per plant (RDM) was found in the first growing season under the C1TLGP treatment. The average dry matter per plant (DMP) measurement was 1.77g plant−1 in the C1TLGP treatment, followed by 1.55g plant−1 in the C2TMGP treatment and 1.40 g plant−1 in the C3THGP treatment. The C3THGP treatment resulted in a significantly higher soybean yield (15.3, 21.0 and 22.1% in 2010, 2011 and 2012, respectively) than the C2TMGP and C1TLGP treatments. The main conclusions were that when argiudoll soil under DS system was trafficked with a high axle load >79.70kN for three years, the cone index peaked in the subsoil to depths below 35 cm and soybean yields were significantly reduced. Soybean seedling emergence was not affected by high topsoil compaction produced by the tyre ground pressure of used combine harvesters. The soybean yield decreased with increased weight of the combine harvester.


      PubDate: 2016-01-05T16:21:49Z
       
  • Differences between wheat genotypes in damage from freezing temperatures
           during reproductive growth
    • Abstract: Publication date: March 2016
      Source:European Journal of Agronomy, Volume 74
      Author(s): David P. Livingston, Tan D. Tuong, Thomas G. Isleib, J. Paul Murphy
      Cereal crops in the reproductive stage of growth are considerably more susceptible to injury from freezing temperatures than during their vegetative growth stage in the fall. While damage resulting from spring-freeze events has been documented, information on genotypic differences in tolerance to spring-freezes is scarce. Ninety wheat genotypes were subjected to a simulated spring-freeze at the mid-boot growth stage under controlled conditions. Spring-freeze tolerance was evaluated as the number of seeds per head at maturity after plants were frozen at −6°C. Plants that froze, as confirmed by infrared (IR) thermography, died shortly after thawing and consequently the heads did not mature. Only in plants that had no visible freezing (super-cooled) were heads able to reach maturity and produce seeds. In plants that super-cooled four genotypes had significantly higher seed counts after being exposed to freezing than three with the lowest. In addition, significant differences between genotypes were found in whole plant survival among those that had frozen. Genotypes with high whole-plant freezing survival were not necessarily the same as the super-cooled plants with the highest seed counts. Spring-freeze tolerance was not correlated with maturity suggesting that improvement in freezing tolerance could be selected for without affecting heading date. Spring-freeze tolerance was not correlated with freezing tolerance of genotypes of plants in a vegetative state, either under non-acclimated or cold-acclimated conditions indicating that vegetative freezing tolerance is not a good predictor of spring-freeze tolerance.


      PubDate: 2016-01-05T16:21:49Z
       
  • Quantifying canopy formation processes in fodder beet (Beta vulgaris
           subsp. vulgaris var. alba L.) crops
    • Abstract: Publication date: March 2016
      Source:European Journal of Agronomy, Volume 74
      Author(s): E. Chakwizira, S.J. Dellow, E.I. Teixeira
      Fodder beet is a highly productive forage crop of expanding use in livestock production systems in temperate regions, notably in Europe and New Zealand. The main determinant of fodder beet productivity is the amount of light intercepted by the crop canopy, which is regulated by temperature and the availability of water and nitrogen (N) for plant development and growth. The quantitative understanding of canopy formation processes under constraining growth conditions is an essential step for the development of biophysical simulation models of new crops for research and predictive purposes. In this study, we provided the first estimates of key canopy formation parameters in fodder beet both under optimum and water- and N-limited supply, in two field experiments in Lincoln, Canterbury, New Zealand. Specifically, the base temperature for leaf appearance in fodder beet was estimated as 0°C. The range of the critical LAI (c. 90–95% of light interception) was 3–4m2/m2. The phyllochron was 48–53°Cd/leaf in unstressed crops and 60°Cd/leaf in water stressed crops, with no effect of N supply. Leaf senescence rates varied widely (from 42 to 260°Cd/leaf) depending on water availability and canopy cover. Leaf expansion, appearance and senescence rates fully recovered following a period of water stress to values similar to those observed in unstressed crops in response to late season rainfall events. Leaf area expansion rates (LAER) ranged from 0.0012 to 0.0034m2/m2/°Cd and was reduced both by limited water and N supply. Leaf area senescence rates (LASR) ranged from 0.0005 to 0.0019m2/m2/°Cd, with low values recorded during drought periods when crop growth was negligible. Canopy architecture, characterised by the extinction coefficient (k), was less sensitive to water stress than canopy expansion or senescence with a conservative value of 0.74. This first quantitative description of fodder beet canopy forming processes can assist the development of predictive approaches, such as biophysical simulation models, for application in research, extension and teaching.


      PubDate: 2016-01-01T15:54:04Z
       
  • Glyphosate accumulation, translocation, and biological effects in Coffea
           arabica after single and multiple exposures
    • Abstract: Publication date: March 2016
      Source:European Journal of Agronomy, Volume 74
      Author(s): Lars C. Schrübbers, Bernal E. Valverde, Bjarne W. Strobel, Nina Cedergreen
      In perennial crops like coffee, glyphosate drift exposure can occur multiple times during its commercial life span. Due to limited glyphosate degradation in higher plants, a potential accumulation of glyphosate could lead to increased biological effects with increased exposure frequency. In this study, we investigated glyphosate translocation over time, and its concentration and biological effects after single and multiple simulated spray-drift exposures. Additionally, shikimic acid/glyphosate ratios were used as biomarkers for glyphosate binding to its target enzyme. Four weeks after the exposure, glyphosate was continuously translocated. Shikimic acid levels were linear correlated with glyphosate levels. After two months, however, glyphosate appeared to have reduced activity. In the greenhouse, multiple applications resulted in higher internal glyphosate concentrations. The time of application, however, was more important regarding biological effects than the number of applications both in the greenhouse and in the field. In the field, berry yield, the most important biological response variable, was reduced 26% by the first out of four sequential applications of glyphosate at 64g a.e. ha−1 each. The three subsequent applications did not reduce yield any further.
      Graphical abstract image

      PubDate: 2016-01-01T15:54:04Z
       
  • Long-term effects of lime and phosphogypsum application on tropical
           no-till soybean–oat–sorghum rotation and soil chemical
           properties
    • Abstract: Publication date: March 2016
      Source:European Journal of Agronomy, Volume 74
      Author(s): Claudio Hideo Martins da Costa, Carlos Alexandre Costa Crusciol
      Root growth, nutrition and crop yield can be affected by soil chemical modifications caused by superficial limestone and phosphogypsum application in a no-till system. Using this approach, this study was conducted in southeastern Brazil, continuing an experiment that has been on-going since 2002 with the objective of evaluating the residual effects of the surface application of lime and phosphogypsum on the soil chemical characteristics and the root growth, nutrition and yield of soybean, black oat and sorghum in a dry winter region cultivated in 2008/2009 and 2009/2010. The experimental design was a randomized block with 4 replications. The treatments were applied in November 2004 and were as follows: original conditions, limestone application (2000kgha−1), phosphogypsum application (2100kgha−1), and limestone (2000kgha−1)+phosphogypsum (2100kgha−1) application. Superficial liming with or without phosphogypsum reduced the surface and subsurface soil acidity 5 years after application in the no-till system. The movement of Ca2+ and Mg2+ from the surface layer into the subsoil over time was evident. The phosphogypsum application associated with liming increased the Ca2+ levels throughout the soil profile. Liming maintained high levels of Mg2+ throughout the soil profile with or without phosphogypsum application. The organic matter content increased with liming with or without phosphogypsum, indicating that in the long term, these practices can increase the C accumulation. Phosphogypsum application had a residual effect on the SO4-S levels, and high sulphate concentrations were observed in the subsoil after 5 years. Superficial liming improved crop nutrition and, when associated with phosphogypsum, increased Ca absorption by soybean and sorghum, as reflected in the increased yields of these crops.


      PubDate: 2016-01-01T15:54:04Z
       
  • Leaf area development strategies of cover plants used in banana
           plantations identified from a set of plant traits
    • Abstract: Publication date: March 2016
      Source:European Journal of Agronomy, Volume 74
      Author(s): Gaëlle Damour, Chloé Guérin, Marc Dorel
      Cover crops introduced into cropping systems can lead to chemical input reductions and pollution mitigation because they enhance ecological functions. The choice of the best cover crops for a specific cropping system is, however, difficult because of the large range of potential cover species. A promising method involves functional traits as simplified indicators of plant functions. In banana cropping systems, cover crops are used especially to control weeds by development of their leaf area to boost competition for light. The aim of this study was to seek trait-based leaf area development strategies among tropical cover species, based on four plant traits chosen because of their mathematical link with leaf area development: specific leaf area (SLA), aboveground leaf mass fraction (LMFa), seed mass (SM) and aboveground relative growth rate (RGRa). We measured trait values and leaf areas of 17 tropical cover species grown for 1 month in a growth chamber. Strong positive and negative covariations were observed between SM, LMFa and RGRa, revealing a “syndrome” of traits and suggesting trade-offs between traits. Four groups of species were identified based on PCA and cluster analyses and were characterized by significantly different sets of trait values. They showed four leaf area development strategies: species that allocate a large part of biomass to leaf area (G1), species that develop large biomass and leaf area at emergence (G2), species with rapid biomass growth and low biomass investment in leaves (G3) and species with a non-specialized strategy (G4). After 1 month, species of groups G1 and G2 had higher leaf area, although not significantly, than species of groups G3 and G4. Comparisons between this functional classification and the taxonomic monocot/dicot classification showed that the functional classification captured a larger part of the variability in traits involved in leaf area development than the taxonomic monocot/dicot classification. This encourages the use of such a classification to describe plant functioning, to understand plant roles in plant–plant interactions and guide the choice of the best cover species to introduce into cropping systems.


      PubDate: 2016-01-01T15:54:04Z
       
  • Influence of leaf and silique photosynthesis on seeds yield and seeds oil
           quality of oilseed rape (Brassica napus L.)
    • Abstract: Publication date: March 2016
      Source:European Journal of Agronomy, Volume 74
      Author(s): Chunli Wang, Jiangbo Hai, Jianli Yang, Jianhua Tian, Wenjie Chen, Ting Chen, Hongbo Luo, Hao Wang
      With the purpose of enhancing oil production, the present work was carried out to elucidate relationships between photosynthesis of leaves, siliques and seeds yield and seeds oil accumulation of oilseed rape. Field trials, in which two repeated experiments was carried out during 2012–2014 growth season, a rape hybrids the “Qin You No.7” (Brassica napus L.) variety was taken into account. The results showed that, on rape plant the photosynthetic capacity and chlorophyll a, b, carotenoid contents of leaf were significantly higher than that of silique shell. Oil content of 94.7% was achieved in young seeds (sampled at 25th day after flowering ending stage of the tested rape plant) versus to mature seeds, saturated fatty acids percent was higher whereas oleic acid percent was lower of oil extracted from young seeds. During flowering period of the rape plants tested, area and dry weight of leaves attained maximum, treatments of removing leaves induced reduction in seeds number per silique, siliques number, seeds yield per plant and seeds oil content, these indexes were respectively decreased by 73.6%, 43.4%, 83.4% and 10.5% in maximum, and seeds oil composition was not significantly influenced; during seeds growing period of the tested plants, surface area and dry weight of siliques attained maximum, under shading siliques treatment, the 1000-seed weight, seeds yield per plant and seeds oil content were respectively reduced by 57.5%, 61.4% and 44.7% in maximum, and seeds oil oleic acid (C18:1) and linolenic acid (C18:3) percent was decreased, linolic acid (C18:2) and erucidic acid (C22:1) percent was increased. So for oilseed rape plant during flowering period, surface area and photosynthesis of leaves dramatically influenced siliques number, seeds number and seeds yield; while in seeds growth period, surface area and photosynthesis of siliques greatly influenced 1000-seed yield, seeds yield, seeds oil content and oil composition; oil accumulation in rape seeds initiated early since seeds commencing growth, seed mature degree influenced oil composition of seeds.


      PubDate: 2016-01-01T15:54:04Z
       
  • A dynamic model of potential growth of olive (Olea europaea L.) orchards
    • Abstract: Publication date: March 2016
      Source:European Journal of Agronomy, Volume 74
      Author(s): Alejandro Morales, Peter A. Leffelaar, Luca Testi, Francisco Orgaz, Francisco J. Villalobos
      A model of potential olive oil production is presented, based on a three-dimensional model of canopy photosynthesis and respiration and dynamic distribution of assimilates among organs. The model is used to analyse the effects of planting density (high and super-high density orchards with 408 and 1667 treesha−1, respectively) and climate change (ΔT of 4°C and CO2 concentration of 740ppm) on olive oil production. To evaluate its predictive power, the simulations were tested with published measurements of leaf area, growth and yield for a high density olive orchard cv. ‘Arbequina’ in Cordoba, Spain. The model slightly overestimated (less than 7%) the different measurements reported in the experiment. For all simulations, the maximum yields obtained were in agreement with literature. Simulations showed that climate change had a very small effect on yields due to compensation of the negative and positive effects of temperature and CO2 on photosynthesis and respiration. However, high temperatures led to some sterile years due to lack of vernalization. The model predicts that super-high density olive orchards achieve higher potential yields than high-density systems and that maximum yields are reached on the third year of the orchard. The advantage of a higher density is a higher interception of solar radiation, especially during the first years of the orchard. In all the simulations, the model predicted a small decrease of the radiation use efficiency for oil production with the age of the orchard as well as an important inter-annual variability (range of 0.11–0.19g (MJ PAR)−1), indicating that the use of a constant radiation use efficiency may not be adequate to predict oil production.


      PubDate: 2015-12-28T15:45:12Z
       
  • Are vegetation indices derived from consumer-grade cameras mounted on UAVs
           sufficiently reliable for assessing experimental plots?
    • Abstract: Publication date: March 2016
      Source:European Journal of Agronomy, Volume 74
      Author(s): Jesper Rasmussen, Georgios Ntakos, Jon Nielsen, Jesper Svensgaard, Robert N. Poulsen, Svend Christensen
      Recent technological advances in UAV (unmanned aerial vehicle) technology offer new opportunities for assessing agricultural plot experiments using UAV imagery. Vegetation indices (VIs) based on aerial images derived from consumer-grade cameras are a simple and cheap alternative compared to VIs derived from proximal (on-ground) sensors. The objective of this study was to assess whether VIs derived from consumer-grade cameras mounted on UAVs are reliable and whether there are any shortcomings in image acquisition and analysis that need to be addressed before their general application. This objective was investigated using a rotary-wing and a fixed-wing UAV, true colour (RGB) and colour-infrared (CIR) cameras, four different VIs (ExG, NGRDI, NDVI and ENDVI), altitudes in the range of 30–100m, different ambient lighting conditions and two different software packages for stitching images together. Results were compared with ground-based recordings by consumer-grade cameras and multispectral sensors. Field experiments in cereals were used to evaluate the assessments. The study showed that VIs based on UAV imagery have the same ability to quantify crop responses to experimental treatments as ground-based recordings with cameras and advanced sensors. However, there are shortcomings that need to be taken into consideration: (1) angular variation in reflectance (bidirectional reflectance), (2) stitching and (3) ambient light fluctuations. Bidirectional reflectance was so extensive that it could lead to misleading conclusions in sunny conditions and this effect could be amplified further by stitching. A procedure for avoiding impacts from bidirectional reflectance is demonstrated when plots were cropped from individual images and a procedure is suggested for stitching images. Camera, VIs and image acquisition altitude were of minor importance, but fluctuating ambient lighting conditions is an issue that should be addressed in future studies.


      PubDate: 2015-12-23T21:13:11Z
       
  • Determination of chilling and heat requirements of 69 Japanese apricot
           cultivars
    • Abstract: Publication date: March 2016
      Source:European Journal of Agronomy, Volume 74
      Author(s): Weibing Zhuang, Binhua Cai, Zhihong Gao, Zhen Zhang
      Chilling requirement, together with heat requirement, which has an impact on the climatic distribution of the genotypes of tree species, determines the flowering date. It also played an important role in the protected cultivation of fruit trees. In our study, we estimated chilling requirements for breaking of dormancy and heat requirements for flowering for 2 successive years in 69 Japanese apricot cultivars of Nanjing (China). The chilling requirements of those Japanese apricot cultivars ranged from 24 to 82 chill portions according to the dynamic model, and the heat requirements of those cultivars fluctuated between 691.9 and 2634.7 growing degree hours. The Japanese apricot cultivars were classified into three groups according to their chilling requirements: the low chilling requirement cultivars with less than 50 chill portions, the medium chilling requirement cultivar ranging from 50 to 70 chill portions, and the high chilling requirement cultivars with more than 70 chill portions. In our study, cultivars originated in Guangdong of China generally have a low chilling requirements, and originated in Zhejiang and Jiangsu of China have a high chilling requirements. Cultivars with lower or higher chilling requirement are not suitable for introduction of Nanjing due to their abnormal phenotype. We also observed that the heat requirement of Japanese apricot had no obvious relationship with their origins. The determination of chilling requirements of 69 Japanese apricot cultivars provided some basis for their rationalized introduction and distribution, and was also important in a breeding program. Those results also expanded our understanding of the temperature responses of flower bud in Japanese apricot during the dormancy progress.


      PubDate: 2015-12-20T21:06:06Z
       
  • On-farm evaluation of an active optical sensor performance for variable
           nitrogen application in winter wheat
    • Abstract: Publication date: March 2016
      Source:European Journal of Agronomy, Volume 74
      Author(s): Stanisław M. Samborski, Dariusz Gozdowski, Michał Stępień, Olga S. Walsh, Elżbieta Leszczyńska
      Winter wheat (Triticum aestivum L.) represents almost 50% of total cereal production in the European Union, accounting for approximately 25% of total mineral nitrogen (N) fertilizer applied to all crops. Currently, several active optical sensor (AOS) based systems for optimizing variable N fertilization are commercially available for a variety of crops, including wheat. To ensure successful adoption of these systems, definitive measurable benefits must be demonstrated. Nitrogen management strategies developed based on small-scale plot research are not always meaningful for large-scale farm conditions. In 2010–2012 (5 site-years) on-farm study was implemented in northern Poland utilizing a strip-trial design. The objective was to evaluate the performance of AOS in combination with a built-in algorithm for variable N rate fertilization. In this study, the reference uniform N rates (farmer’s practice) were comparable to optimum variable N rate recommendations. Side-by-side comparisons of uniform and variable N application revealed inconsistent benefits in terms of grain yield, grain protein content (GPC), N use and N use efficiency (NUE). Anticipated yield increases and/or reduced N rates are typical drivers for AOS adoption. Significant yield increases are not easily attained on farms with winter wheat yields already close to maximum yield potential. Thus, sensor-based variable N rate recommendations for fields previously fertilized with relatively low uniform N rates would often entail more appropriate allocation (redistribution) of the same amount of total N. This would minimize N surplus in areas of lower productivity and to improve the sustainability of N management overall.


      PubDate: 2015-12-12T20:31:19Z
       
  • Long-term effects of crop rotation, manure and mineral fertilisation on
           carbon sequestration and soil fertility
    • Abstract: Publication date: March 2016
      Source:European Journal of Agronomy, Volume 74
      Author(s): Loretta Triberti, Anna Nastri, Guido Baldoni
      Carbon sequestration, recently advocated to mitigate climate change, needs a thorough knowledge of the dynamics of soil organic carbon (SOC), whose study requires long-term experiments. A field trial started in 1967 is still in progress in the Southeast Po valley (Italy). It compares a 9-year rotation (corn–wheat–corn–wheat–corn–wheat–alfalfa–alfalfa–alfalfa), two 2-year successions (corn–wheat and sugarbeet–wheat), continuous corn and continuous wheat. During the first 18 years (up to 1984) wheat crops were always followed by catch crops of silage corn. Within each rotation, three rates of cattle manure have been factorially combined with three mineral NP rates. In 1984 the highest manure application was stopped. Wheat straw and corn stalks have always been removed from the field. Since 1972 up to now every year we have determined the organic C and total N contents in soil samples collected from 0.40-m depth. During the first 18 years (in the presence of the catch crop) SOC exponentially declined, probably as a consequence of the intensification of tillage depth and crop succession with respect to the previous conventional agriculture. The intensification regarded ploughing, which became deeper, the number of cropped species that in most treatments was reduced, and mineral N application, which, on average, increased. The drop was faster in the sugarbeet–wheat succession than in the 9-yr rotation and continuous wheat. After 1985, without the catch crop, SOC linearly increased, faster in the 9-yr rotation and continuous wheat than in sugarbeet–wheat. The results can be ascribed to the amount and C/N ratio of debris remaining in the field after each crop, even after having taken away wheat straw and corn stalks. The debris consisted of sugarbeet tops, with a low C/N ratio, and of roots and basal culms of the two cereal crops with higher C/N ratio. Mineral fertilizers significantly increased SOC, probably for the greater amount of cereal roots and sugarbeet tops in more fertilized plots. The influence of manure was less intense, but its benefits lasted longer than 18 years after its interruption. Soil N content was more related to accumulated organic matter than to mineral N fertilisation. In conclusion the highest C sequestration was obtained with manure addition, with the highest rate of mineral fertilizers, and in the rotation containing the alfalfa ley. The effects of these factors were not additive.


      PubDate: 2015-12-12T20:31:19Z
       
  • Climate change trends in Malta and related beliefs, concerns and attitudes
           toward adaptation among Gozitan farmers
    • Abstract: Publication date: March 2016
      Source:European Journal of Agronomy, Volume 74
      Author(s): C. Galdies, A. Said, L. Camilleri, M. Caruana
      In this study we report the results obtained from an island-wide survey aimed at researching an under-emphasized key feature of climate change adaptation—namely willingness to adapt on the basis of the perceptions and beliefs held by the Gozitan livestock and crop farmers. Some of the main objectives of this study included the: (1) determination of whether the current perception is in line with the observed climatic changes at the local scale, and (2) identification of the typology of these farmers, together with those factors that affect both skepticism and acceptance of climate change. This study provided an important first step in the objective validation of local farmers' perceptions of climate change, as well as in the development of a comprehensive understanding of their attitude, beliefs, willingness and capacity to adjust their practices in response to climate change. The results pointed to several important conclusions that can be used to inform research, outreach strategies and policy formulation, targeting the Gozitan farming sector to adapt to climate change without delay. The forgoing analysis showed a dire need for more information both on impacts and risks, as well as on ways how to introduce new farming techniques and practices.


      PubDate: 2015-12-12T20:31:19Z
       
  • New approach to determine biological and environmental factors influencing
           mass of a single pea (Pisum sativum L.) seed in Silesia region in Poland
           using a CART model
    • Abstract: Publication date: March 2016
      Source:European Journal of Agronomy, Volume 74
      Author(s): Mariusz Dacko, Tadeusz Zając, Agnieszka Synowiec, Andrzej Oleksy, Agnieszka Klimek-Kopyra, Bogdan Kulig
      There are many factors that influence the mass of a single pea seed. Because peas are an important edible legume crop of high biological value, we aimed at assessing the determinants of a single pea-seed mass based on thirteen predictors, grouped as: morphological, weather and Rhizobium vaccines. In a three-year field experiment, the biological and habitat characteristics of the yielding of two edible peas, i.e., semi-leafless cv. ‘Tarchalska’ and traditional foliage cv. ‘Klif’, were studied. A collection of 8446 observations was used to construct a CART regression tree. The CART model allowed us to build a regression tree with 14 terminal nodes and produced a Pearson correlation coefficient, between predicted and actual masses of seeds, of 0.71. The model satisfactorily explained the variation in the mass of a single pea-seed. It was found that the single pea-seed mass is affected mostly by 4 predictors: ‘K index’, which describes the hydrothermal conditions during pea sowing-emergence (K s-e) and emergence-maturity (K e-m) periods, ‘length of pod’ and 'cultivar'. In the CART model, the optimal K s-e index and long pods were always associated with higher seed mass. The mass of a single pea-seed also depended on the ‘Fruiting node’—larger seeds developed on the lowest nodes of a stem. Two factors had a marginal effect on the mass of single pea-seeds: ‘Rhizobium vaccine’ and ‘pod position per node’.


      PubDate: 2015-12-12T20:31:19Z
       
  • Dry matter partitioning and canopy traits in wheat and barley under
           varying N supply
    • Abstract: Publication date: March 2016
      Source:European Journal of Agronomy, Volume 74
      Author(s): Klaus Sieling, Ulf Böttcher, Henning Kage
      The prediction of the allocation of carbon and nitrogen into the different organs, e.g., leaves, stems, roots of a growing plant is a pivotal part of mechanistic growth models. Based on 2 year (winter wheat) and 3 year (winter barley) field trials with different N treatments (0–240kgNha−1), the objectives of this study were to verify currently used parameters for (i) specific leaf area, and (ii) allometric relationships between leaf and stem dry matter (DM). Green area index (GAI) differed between years and increased with N supply rate. The course of the specific leaf area (SLA) within the growth period after winter showed a large variation between the years as well as between the N treatments. During stem elongation, SLA positively correlated with GAI in both crops, indicating that leaves became thinner when the canopy was denser. The allometric relationships between stem and leaf dry DM clearly varied with the growth stages. Stem DM of wheat showed a higher proportion of the total above-ground biomass compared to barley. The effect of N fertilization on allometry remained small during early growth stages in barley, whereas in wheat, an increased N supply significantly decreased the proportion of stem DM. Our results suggest similar GAI and SLA patterns for wheat and barley, albeit depending on the N supply. Especially, using a constant SLA in plant growth models seems to be not suitable.


      PubDate: 2015-12-12T20:31:19Z
       
  • Intercropping maize and wheat with conservation agriculture principles
           improves water harvesting and reduces carbon emissions in dry areas
    • Abstract: Publication date: March 2016
      Source:European Journal of Agronomy, Volume 74
      Author(s): Falong Hu, Yantai Gan, Hongyan Cui, Cai Zhao, Fuxue Feng, Wen Yin, Qiang Chai
      In arid and populated areas or countries, water shortage and heavy carbon emissions are threatening agricultural sustainability with food security severely, and becoming a major issue. It is unclear whether improved farming systems can be developed to tackle those issues through a sustainable agriculture. Here three farming practices that have proven to be essential and successful, which were: (a) crop intensification through strip intercropping, (b) water harvesting through conservation tillage; and (c) carbon sequestration through improved crop residue management options, were integrated in one cropping system. We hypothesize that the integrated system allows the increase of crop yields with improved water use efficiency, while reducing carbon emissions from farming. The hypothesis was tested in field experiments at Hexi Corridor (37°96′N, 102°64′E) in northwest China. We found that the integrated system increased soil moisture (mm) by 7.4% before sowing, 10.3% during the wheat–maize co-growth period, 8.3% after wheat harvest, and 9.2% after maize harvest, compared to the conventional sole cropping systems. The wheat/maize intercrops increased net primary production by 68% and net ecosystem production by 72%; and when combined with straw mulching on the soil surface, it decreased carbon emissions by 16%, compared to the monoculture maize without mulch. The wheat/maize intercrops used more water but increased grain yields by 142% over the monoculture wheat and by 23% over the monoculture maize, thus, enhancing water use efficiency by an average of 26%. We conclude that integrating strip intercropping, conservation tillage as well as straw mulching in one cropping system can significantly boost crop yields, improve the use efficiency of the limited water resources in arid areas, while, lowering the carbon emissions from farming. The integrated system may be considered in the development of strategies for alleviating food security issues currently experienced in the environment-damaged and water-shortage areas.


      PubDate: 2015-12-12T20:31:19Z
       
  • Weed communities in Italian maize fields as affected by pedo-climatic
           traits and sowing time
    • Abstract: Publication date: March 2016
      Source:European Journal of Agronomy, Volume 74
      Author(s): Francesco Vidotto, Silvia Fogliatto, Marco Milan, Aldo Ferrero
      This study examined relationships between weed communities and some pedo-climatic traits in Italian maize cultivation areas. A weed dataset was amassed from studies conducted independently by research groups during 1998–2013. Included were herbicide efficacy field trials and weed surveys from about 600 sites representing 175 northern and central Italy maize fields. The dataset was honed to results from untreated plots in which weed data were collected at least once (June/July) each season. For sites observed more often, only the survey with the highest weed species count was used. Of the approximate 120 species found, just five were present on more than 50% of sites: Chenopodium album, Echinochloa crus-galli, Amaranthus retroflexus, Solanum nigrum, and Persicaria maculosa. Indices were calculated to describe weed community structure: total weed species count, monocotyledonous and dicotyledonous species counts, and total weed density. Additional soil and climate site data were collected or obtained from regional databases: pH reaction, texture, organic matter content, total nitrogen, Mg/K ratio, assimilable phosphorus, cation exchange capacity (CEC), and C/N ratio, annual total precipitation, annual mean temperature, and Thornthwaite climate classification. Pedo-climatic traits and weed indices relationships were investigated using linear correlation analysis (CA), discriminant analysis (DA), and principal component analysis (PCA). CA and PCA highlighted a weak bias (higher count and density) by monocotyledonous species for sand and alkaline soils, while clay and alkaline soils favored dicotyledonous species. DA classified the sites well based on weed indices using soil parameters as predictor variables, in particular for a Piemonte region (northwest Italy) data subset. Soil texture, CEC, pH, and some nutrient contents significantly predicted some weed indices. This study pointed out that Italian maize field weed communities are influenced by some pedoclimatic traits; the weak relationships observed might be mitigated by the overall influence of crop practices on weed dynamics.


      PubDate: 2015-12-12T20:31:19Z
       
  • A conceptual model of farmers' decision-making process for nitrogen
           fertilization and irrigation of durum wheat
    • Abstract: Publication date: Available online 7 December 2015
      Source:European Journal of Agronomy
      Author(s): Solenne Guillaume, Céline Bruzeau, Eric Justes, Bernard Lacroix, Jacques-Eric Bergez
      With a 2 millions of tons production, France is the second country in the European Union to produce durum wheat. Durum wheat production requires high grain nitrogen concentration. Irrigation and nitrogen fertilization must be managed simultaneously to maximize grain yield and also avoid low protein concentration and environmental impacts. To help advisors and farmers to better manage together these two agricultural operations and to develop innovative managements, developing a biodecisional model is an interesting possibility. However, knowledge is still missing on how farmers already managed these operations and how these two operations are linked. We developed the conceptual model for the decision part of this computer model. We performed a survey of 28 farmers conducted over the five French production areas investigating a diversity of growing conditions to identify the set of possible constraints and farmers' decision rules. To analyze the survey, we first used a general inductive approach on individual cases and then built a conceptual model of the decision with a bottom-up approach. We identified four decision sequences for fertilization (N splitting, choice of N fertilizer, rate of application, fertilization triggering) and five for irrigation (irrigation period, anticipated number of irrigation cycles, irrigation cycles organization, irrigation triggering and irrigation cycle specificities). For each operation, the first three decision sequences refer to strategic decisions. The other decision sequences refer to tactical decisions. Coupling this model with a crop model could provide guidelines for managing durum wheat in the current climatic and economic changing context.


      PubDate: 2015-12-08T06:16:06Z
       
  • Detecting interactive effects of N fertilization and heat stress on maize
           productivity by remote sensing techniques
    • Abstract: Publication date: February 2016
      Source:European Journal of Agronomy, Volume 73
      Author(s): Abdelhalim Elazab, Raziel A. Ordóñez, Roxana Savin, Gustavo A. Slafer, José Luis Araus
      The objective of this study was to compare the performance of two different remotely sensed techniques in detecting the effects of terminal heat stress and N fertilization on final maize aerial biomass (AB) and grain yield (GY). The study was conducted under field conditions for two consecutive growing seasons. Six N treatments combining three doses [0, 100, 200KgNha−1] and two timings [at V4 and at 15 days before silking] were applied. Within each N treatment three heat treatments were applied (pre-flowering, post-flowering and the control treatment at ambient air temperature). Remote sensing measurements were taken with a multispectral band camera to measure the normalized difference vegetation index (NDVI) and a digital Red/Green/Blue (RGB) camera to measure the normalized green red difference index (NGRDI). Both indices failed to predict the GY of pre-flowering heat-treated plants due to grain set establishment problems that could not be detected by vegetation indices which are designed to capture differences in green canopy area. In contrast, both the NGRDI and the NDVI correlated positively with GY and AB in the control heat treatment and to a lesser extent in the post-flowering heat treatment. Under the control heat treatment, the NGRDI exhibited higher correlations with AB and GY than the NDVI across the N fertilization treatments. Since the NGRDI is formulated based only on the reflectance in the visible regions (VIS) of the spectrum (Green and Red) without dependence on the near infrared regions (NIR), it performs better than the NDVI. This is because it overcame the reported saturation patterns at high leaf area index and was more efficient at capturing even small differences in leaf colour (chlorophyll content) due to the different applied N treatments. Also, the NGRDI seemed to be a more seasonally independent parameter than the NDVI, which is more affected by temporal variability within the field, and thus the NGRDI predicted AB and GY better than the NDVI when combining the data of the two growing seasons.


      PubDate: 2015-12-02T05:55:07Z
       
  • Crop yields and N losses tradeoffs in a garlic–wheat rotation in
           southern Spain
    • Abstract: Publication date: Available online 29 November 2015
      Source:European Journal of Agronomy
      Author(s): C. Giménez, C.O. Stöckle, E.M. Suárez-Rey, M. Gallardo
      The CropSyst model was parameterized and verified for garlic with data from six field experiments carried out in southern Spain from 2008 to 2011. The model simulated well crop dry matter production, N uptake, and yield from field plots with different N fertilization treatments. A garlic–wheat rotation was then simulated for a 30-year period to evaluate the role of wheat after garlic as a catch crop that utilizes and reduces the loss of residual soil N left at the time of garlic harvest. The scenarios studied were the combination of seven rates of mineral N fertilization in garlic (0, 50, 100, 150, 200, 250 and 300kgN/ha) and three rates in wheat (30, 70 and 110kgN/ha). Fertilization rates of 150kgN/ha in garlic and 70kgN/ha in wheat were found to provide the best tradeoff between N loss reductions (N leaching and N gas emissions) while attaining near-maximum yields. Increasing fertilization to 200 and 110kgN/ha for garlic and wheat, respectively, rates not atypical in the region, had a minimum effect on yields but increased average N losses over the rotation by 19kgN/ha/2-year (29%). Further reductions of N losses by decreasing N fertilization below the best tradeoff point are possible at the expense of crop yield.


      PubDate: 2015-12-02T05:55:07Z
       
  • Effects of plant density on grain yield, protein size distribution, and
           breadmaking quality of winter wheat grown under two nitrogen fertilisation
           rates
    • Abstract: Publication date: February 2016
      Source:European Journal of Agronomy, Volume 73
      Author(s): Yu Zhang, Xinglong Dai, Dianyong Jia, Huaying Li, Yuechao Wang, Chuanxing Li, Haicheng Xu, Mingrong He
      Nitrogen (N) and plant density are two crucial factors that affect winter wheat (Triticum aestivum L.) yield and quality, but little is known regarding the effects of interactions between these two factors on the amount and size distribution of protein fractions and quality traits. We grew the bread wheat cultivar Jinan17 in two successive seasons (2012–2013 and 2013–2014) at three densities of 120plantsm−2 (low), 180plantsm−2 [the usual rate for a multiple-spike cultivar with high tillering ability in the North China Plain (NCP)], and 240plantsm−2 (high) and two levels of N fertilisation of 0 (low N availability treatment without N fertilisation) and 240kgha−1 (the usual N rate for winter wheat production in the NCP) to evaluate the effect of N level×plant density interaction on grain yield, grain protein concentration, the amount and composition of protein fractions, dough development time, dough stability time, and loaf volume. The effect of plant density on Jinan 17 grain yield and quality differed between the two N levels. As plant density increased, all the parameters listed above decreased under 0kgha−1 N fertilisation, but increased under 240kgha−1 N fertilisation. Stepwise regression analysis showed that the dough rheological properties and breadmaking quality of Jinan 17 were affected by plant density under both N levels, primarily through changes in the polymerisation degree of glutenins in the flour.


      PubDate: 2015-12-02T05:55:07Z
       
  • Proximal optical sensing of cucumber crop N status using chlorophyll
           fluorescence indices
    • Abstract: Publication date: Available online 19 November 2015
      Source:European Journal of Agronomy
      Author(s): Francisco M. Padilla, M.Teresa Peña-Fleitas, Marisa Gallardo, Rodney B. Thompson
      Sustainable N management of intensive vegetable crops requires accurate and timely on-farm assessment of crop N status. Proximal fluorescence-based sensors are promising tools for monitoring crop N status, by providing non-destructive optical measurements of N-sensitive indicator compounds such as chlorophyll and flavonols. The ability of the Multiplex® fluorescence sensor to determine crop N status was evaluated in two indeterminate cucumber crops grown in contrasting seasons (autumn and spring). Three fluorescence indices, leaf chlorophyll (SFR) and flavonols (FLAV) contents, and their ratio (Nitrogen Balance Index, NBI) were evaluated, and their consistency between the two crops compared. Actual crop N status was assessed by the Nitrogen Nutrition Index (NNI), calculated as the ratio between the actual and the critical crop N contents (i.e., the minimum N content for maximum growth). There were strong relationships between each of SFR, FLAV and NBI with crop NNI, for most weekly measurements made throughout the two crops. For the three indices, coefficients of determination (R 2) were mostly 0.65–0.91 in the autumn crop, and 0.71–0.99 in the spring crop. SFR values were generally comparable between the two crops, which enabled the derivation of common relationships with NNI for individual phenological phases that applied to both cropping seasons. FLAV and NBI values were not comparable between the two crops; FLAV values were appreciably higher throughout the spring crop, which was attributed to the higher solar radiation. Consequently, phenological relationships of FLAV and NBI with NNI were established for each individual cropping season. Our findings suggested that SFR was the most consistent index between cropping seasons, and that NBI was the most sensitive index within each season. Regardless of the index and crops, all fluorescence indices were weakly related to crop NNI during the short vegetative phase while stronger relationships were found in the reproductive and harvest phases. This study also showed that the three fluorescence indices were sensitive to and able to distinguish deficient from optimal crop N status, but that they were insensitive to discriminate optimal from slightly excessive N status. Overall, this study demonstrated that fluorescence indices of chlorophyll content (SFR), flavonols content (FLAV) and nitrogen sufficiency (NBI) can be used as reliable indicators of crop N status in cucumber crops; however, there was variability in FLAV and NBI values between cropping seasons and a lack of sensitivity in the range of optimal to slightly excessive crop N status.


      PubDate: 2015-11-24T10:15:45Z
       
  • Genotype-by-environment interaction analysis of rice (Oryza spp.) yield in
           a floodplain ecosystem in West Africa
    • Abstract: Publication date: Available online 19 November 2015
      Source:European Journal of Agronomy
      Author(s): Keisuke Katsura, Yasuhiro Tsujimoto, Masato Oda, Ken-ichi Matsushima, Baba Inusah, Wilson Dogbe, Jun-Ichi Sakagami
      West Africa has large areas of river floodplains, most of which are not currently used for farmland. Rice (Oryza spp.) is a promising crop for farming in floodplains because of its high adaptability to a wide range of water environments. On the other hand, there is great variation in soil fertility and water availability even in a small area within a floodplain. Hence, we evaluated 27 rice genotypes in four fields in three years in a floodplain of the Northern Region of Ghana to investigate genotype×environment (G×E) interactions for rice yield and to identify stable, high-yielding genotypes. The genotypes consisted of O. sativa, O. glaberrima and New Rice for Africa (NERICA), and many were selected for their reported submergence resistance because of the anticipated submergence damage in the floodplain. There were large variations in yield, which ranged from 0.14 to 5.35tha−1 depending on the location within a floodplain, genotype and year, and there were significant genotype, environment and G×E interaction effects on yield, accounting for 24.8%, 20.2%, and 28.2%, respectively, of the total variation. The results suggested that selection of suitable location with high soil fertility and low risk of submergence is necessary to achieve high yield in a floodplain. In addition, early sowing would be effective high-yielding crop management, which reduced the risk of submergence-induced damage just after sowing and secured sufficient growth duration to achieve high yield. Genotype IR42 showed the highest average yield among environments, but its yield stability was low. On the other hand, several genotypes including Amankwatia, a local aromatic cultivar adapted to irrigated and lowland environments, and IRBL9-W[RL], a blast-tolerant variety containing the Sub1 gene for submergence tolerance, showed high, stable yield. To put these results to practical use in other floodplain areas in West Africa, physiological mechanisms causing G×E interaction for rice yield should be further studied.


      PubDate: 2015-11-24T10:15:45Z
       
  • Estimating canopy leaf nitrogen concentration in winter wheat based on
           multi-angular hyperspectral remote sensing
    • Abstract: Publication date: Available online 21 November 2015
      Source:European Journal of Agronomy
      Author(s): Li He, Hai-Yan Zhang, Yuan-Shuai Zhang, Xiao Song, Wei Feng, Guo-Zhang Kang, Chen-Yang Wang, Tian-Cai Guo
      Real-time, nondestructive estimation of crop nitrogen (N) status is highly important for precision N management in winter wheat production. Developing a new N indicator based on the direct link between spectral index and chlorophyll content is important for crop N diagnosis. In this study, we investigated the quantitative relationships between leaf N concentration (LNC) and ground-based multi-angular remote sensing hyperspectral reflectance in winter wheat (Triticum aestivum L.). Field experiments were conducted from 2011 to 2014 across different sites, cultivars, growth stages, N rates, and planting densities, and a novel Multi-angular vegetation index (MAVISR) was developed to improve the prediction accuracy and stability of LNC measurement. The optimum vegetation indices (VIs) obtained from 40 traditional indices reported in the literature, as well as normalized difference spectral indices (ND) and Simple Ratio Indices (SR), were tested for their stability in estimating LNC at 13 viewing zenith angles (VZAs). Overall, the coefficient of determination (r 2) of spectral reflectance and traditional VIs with LNC decreased with increasing VZA in both the forward and backward scattering directions and reached maximum values at a viewing angle of −20°. Ratio index (RI-1dB) exhibited the best linear relationship to LNC (r 2 of 0.837) at the −20° viewing angle, but Enhanced vegetation index (EVI-1) showed the highest r 2 (0.819) with LNC at the nadir direction. The relationships between the LNC and two-band combinations indicate that there are three sensitive regions with high r 2, which vary with VZA, usually comprising combinations of blue–red wavelengths, green–red edge wavelengths, and between-red edge wavelengths. To further analyze the relationship between the combination of the three sensitive regions and the sensitive VZAs with LNC, the MAVISR index in the form of MAVISR =(R538/R768)−20 −(R478/R634)+10 was calculated and found to be highly correlated with LNC (r 2 =0.897). When independent data were fit to the derived equations, the average relative error (RE) values were 15.5%, 14.3%, and 12.6% between measured and estimated LNC using EVI-10°, RI-1dB−20°, and MAVISR, respectively. These results suggest that the models can accurately estimate LNC in wheat, and the novel MAVISR is more effective for estimating LNC than previously reported VIs, independent of years, sites, and growth periods. The results also indicate the importance of taking into account angle effects when analyzing VIs.


      PubDate: 2015-11-24T10:15:45Z
       
  • Nitrogen uptake and N-use efficiency of Mediterranean cotton under varied
           deficit irrigation and N fertilization
    • Abstract: Publication date: Available online 21 November 2015
      Source:European Journal of Agronomy
      Author(s): S. Stamatiadis, C. Tsadilas, V. Samaras, J.S. Schepers, K. Eskridge
      Efficient N management is essential to optimize yields and reduce degradation of the environment, but requires knowledge of deficit irrigation effects on crop yields and crop N outputs. This study assessed the N content and N-use efficiency of cotton over the 2008 and 2009 growing seasons in a single field site of the Thessaly Plain (central Greece). The experiment consisted of nine treatments with three fertilizer rates (60, 110 and 160kg Nha−1) split into three irrigation levels (approx. 1.0, 0.7 and 0.4 of the amount applied by the producer). Reduced water supply induced a shift in the distribution of N within the plant with seeds becoming an N sink under conditions of water stress. Total crop N increased linearly with irrigation level and reached a maximum average of 261 and 192kg Nha−1 in 2008 and 2009, respectively. Fertilizer application did not trigger a crop N or yield response and indicated that N inputs were in excess of crop needs. Variation in weather patterns appeared to explain annual differences of nitrate-N in the top soil and N uptake by the crop. The index of lint production efficiency (iNUE) detected crop responses caused by irrigation and annual effects, but failed to account for excessive N inputs due to mineral fertilizer applications. A maximum average iNUE of 9.6 was obtained under deficit irrigation, whereas an iNUE of 8.1 was obtained under 40cm irrigation when crop N uptake was not excessive (192kgha−1 in 2009). In contrast, NUE, as an estimator of N recovery efficiency, identified excessive fertilizer inputs as N losses to the environment and indicated that 60kg Nha−1 was a rate of high N removal efficiency and long-term N balance. However, NUE failed to account for crop N responses to irrigation and weather/management patterns. In this case study, neither index was able to detect all the factors influencing the N mass balance and both were required in order to provide a comprehensive evaluation of the environmental performance of our cropping system.


      PubDate: 2015-11-24T10:15:45Z
       
  • Stable isotope technique in the evaluation of tillage and fertilizer
           effects on soil carbon and nitrogen sequestration and water use efficiency
           
    • Abstract: Publication date: Available online 23 November 2015
      Source:European Journal of Agronomy
      Author(s): M.A. Busari, F.K. Salako, C. Tuniz
      Agricultural soil could be made to serve as a sink rather than a source of greenhouse gases by suitable soil management. This study was, therefore, conducted to assess the impact of tillage and fertilizer application on soil and plant carbon and nitrogen fractionation and intrinsic water use efficiency (iWUE). The experiment was a split–split-plot factorial design with three replications. The main plot consisted of two tillage treatments: zero tillage (ZT) and conventional tillage (CT). The sub-plot contained four NPK fertilizer treatments (0, 90, 120 and 150kgNha−1), while the sub–sub-plot comprised three poultry manure (PM) treatments (0, 10 and 20Mgha−1). Soil carbon and nitrogen sequestration were evaluated using stable isotope of carbon (δ 13C) and nitrogen (δ 15N). The δ 13C in maize plant was used to obtain iWUE. It was observed that soil δ 13C and δ 15N were more depleted under ZT than CT and in plots treated with 20Mgha−1 PM (PM20) implying carbon and nitrogen sequestration under ZT and by PM20. Relative to the control, application of PM20 raised soil δ 15N enrichment by 82% and 96% under CT and ZT, respectively. Higher iWUE of 25.7% was obtained under CT and was significantly higher than the iWUE values under ZT in the second year of the study while the iWUE was significantly lower with PM20 application than other fertilizer treatments. The significant δ 13C depletion and hence lower iWUE with combination of NPK fertilizer and PM under CT than the control implied that soil disturbance under tilled plots was mediated by combined nutrient management thereby limiting soil C available for fractionation resulting in lower iWUE. This suggests that conservation tillage such as zero tillage and integrated application of organic and inorganic fertilizers are good strategies for reducing soil carbon and nitrogen emission.


      PubDate: 2015-11-24T10:15:45Z
       
  • Identifying the impact of multi-hazards on crop yield—A case for
           heat stress and dry stress on winter wheat yield in northern China
    • Abstract: Publication date: Available online 17 November 2015
      Source:European Journal of Agronomy
      Author(s): Yi Chen, Zhao Zhang, Pin Wang, Xiao Song, Xing Wei, Fulu Tao
      Winter wheat production in northern China severely suffered from high temperatures and low relative humidity. However, the spatio-temporal pattern of heat stress and dry stress and the impacts of these multi-hazards on winter wheat yield have rarely been investigated. Using historical climate data, phenology data and yield records from 1980 to 2008, an analysis was performed to characterize the spatio-temporal variability of heat stress and dry stress in the post-heading stages of wheat growth in northern China. Additionally, these stresses’ impacts on winter wheat yield fluctuations were evaluated. Spatially, the central and northern parts of northern China have seen more serious heat stress, while greater dry stress has been observed in the northwest and north of the research area. Temporally, the heat stress has increased in the western part but decreased in the central and eastern parts of research area. Dry stress has aggravated in the entire northern China during the past decades, indicating the complexity of the exposure to adverse climate conditions. These two hazards (heat stress and dry stress) have contributed significant yield loss (up to 1.28% yieldyr−1) in most parts of the research region. The yield in the west was more sensitive to heat stress, and dry stress was the main hazard in the south. Additionally, the opposite spatial pattern between the sensitivity and exposure revealed that the climate is not the only factor controlling the yield fluctuation, the local adaptation measures used to mitigate negative influences of extreme events should not be ignored. In general, this study highlighted a focus on the impacts of multi-hazards on agricultural production, and an equal importance of considering local adaptation ability during the evaluation of agricultural risk in the future. Additionally, paying more attention to higher sensitive areas and to more reasonable and practical adaptive strategies is critical and significant for food supply security.


      PubDate: 2015-11-19T09:54:53Z
       
  • Growth response and active constituents of Cynara cardunculus plants to
           the number of leaves harvests
    • Abstract: Publication date: Available online 17 November 2015
      Source:European Journal of Agronomy
      Author(s): Hend E. Wahba, Atef Z. Sarhan, Adel B. Salama, Mahmoud A. Sharaf-Eldin, Heba M. Gad
      Cardoon (Cynara cardunculus) is a highly promising medicinal plant that has been used to treat several diseases, but there remains a great need for research into both the agriculture and chemical composition of the plant. For this study, cardoon was cultivated for two successive seasons (2009/2010 and 2010/2011) at the experimental farm of the Faculty of Agriculture, Cairo University. Specifically, the study investigated the effect of numerous harvests of leaves (one, two, three and four harvests/cuts) on both the growth and the active constituents of C. cardunculus plants. Both the fresh and the dry weight of the harvested leaves were measured and the active constituents, such as carbohydrate, flavonoid, polyphenol and chlorogenic acid content, were measured. It was found that as the number of harvests increased (up to three harvests) the values of these parameters also increased in both seasons.


      PubDate: 2015-11-19T09:54:53Z
       
  • Yield and nitrogen use efficiency of fodder and sugar beet (Beta vulgaris
           L.) in contrasting environments of northwestern Europe
    • Abstract: Publication date: Available online 18 November 2015
      Source:European Journal of Agronomy
      Author(s): D. Laufer, O. Nielsen, P. Wilting, H.-J. Koch, B. Märländer
      Yield and nitrogen (N) use efficiency (NUE) are important traits for the evaluation of crops used for renewable energy production. Contrary to other bio-energy crops, data on NUE are not available for beet crops from the Beta genus for high yielding conditions of northwestern Europe. Thus, our study aimed to provide such information for one current representative of the cultivar groups sugar and fodder beet. Field experiments were conducted with six mineral fertilizer N doses (0–200kg Nha−1, 40kg steps) at one site in Germany (DE), The Netherlands (NL) and Denmark (DK) in 2010 and 2011; each combination of site and year (DE10, DE11, NL10, NL11, DK10, DK11) was evaluated as distinct environment. The environments strongly differed in yield (dry matter, sugar), N uptake, harvest indices and N-utilization efficiency (NUtE) parameters. Increasing the fertilizer N dose increased dry matter yield and sugar yield in the environments NL10, NL11, DK10 and DK11, but not at DE10 and DE11. Harvest indices decreased with increasing fertilizer N dose in the environments NL10, NL11, DK10 and DK11 only, which were characterized by a 70–110kg Nha−1 lower N uptake at zero fertilizer N than DE10 and DE11. The N uptake continuously increased while NUtE decreased with increasing fertilizer N dose at all environments. When regarding environmental and fertilizer N effects, yield was neither related to harvest indices nor NUtE. Despite several significant interactions between environment and cultivar, the data clearly reveal that yield, sucrose concentration in taproot dry matter, total plant N uptake, NUtE and apparent fertilizer N recovery were considerably higher for sugar beet (SB) than for fodder beet (FB). Contrastingly, harvest index on taproot dry matter basis and N harvest index were higher in FB than in SB, while harvest index for sugar was similar. An improved harvest index was obviously not the cause for the higher sugar yield of SB compared to FB, while sucrose concentration in taproot dry matter was clearly favourable for SB. Although SB crops incorporated more N into the leaves than FB, NUtE was considerably higher in SB, especially when focusing on sugar instead of dry matter production. In conclusion, SB offers a higher potential for producing bio-energy per unit of arable land with less N use related greenhouse gas emissions per unit of energy gain than FB.


      PubDate: 2015-11-19T09:54:53Z
       
  • The influence of nitrogen and phosphorous status on glyphosate hormesis in
           Lemna minor and Hordeum vulgare
    • Abstract: Publication date: Available online 17 November 2015
      Source:European Journal of Agronomy
      Author(s): Nina Cedergreen, Natascha K.K. Hansen, Birgitte W. Arentoft
      The herbicide glyphosate has been shown to stimulate growth and photosynthetic capacity of barley and other plant species. The growth increase, however, only takes place under certain, yet undefined, growth conditions. We hypothesise that glyphosate growth stimulation only takes place, when growth is nutrient limited. Nutrient limitation was induced in this study by limiting nitrogen and phosphorous availability. The experiments were performed on hydroponically grown lesser duckweed and barley and on barley in the field. Hydroponic duckweed and barley grown under a range of N- and P-availabilities displayed glyphosate induced growth increases in plants which were slightly stressed by N-deficiency, but not in response to P-deficiency in the case of barley. The growth increase found for P-deficient duckweed was hypothesised to be caused by glyphosate derived P, acting as a nutrient source. No growth increase was found in the 2012 field experiment, which was in contrast to earlier year’s findings. Our hypothesis that nutrient limitation makes plants susceptible to glyphosate induced growth was only confirmed for nitrogen but not for phosphorous and not under field conditions in 2012. Mechanisms related to high C:N ratios might be of importance, as this trait varies depending on N- and P-availability during plant growth.
      Graphical abstract image

      PubDate: 2015-11-19T09:54:53Z
       
  • Pollen-based predictive modelling of wine production: application to an
           arid region
    • Abstract: Publication date: Available online 11 November 2015
      Source:European Journal of Agronomy
      Author(s): Mário Cunha, Helena Ribeiro, Ilda Abreu
      A wine forecast model for one of the most arid wine regions of the Europe—Alentejo was improved and tested for the period 1998–2014. During this period, Alentejo region had strong upward trends in wine production associated to the increase of vineyard area. The forecast model was supported on a hierarchical analysis, including the determination of the potential production at flowering by quantifying airborne pollen concentration, followed by a climate based evaluation of the possible impact of fruit-set conditions in the limitation of production. Through the monitoring of airborne pollen flows it is possible to define an accurate main pollen season and determine the regional pollen index that will be used as independent variable in the regional forecast model. The time trend, which was initially removed from data, was then added back to obtain the forecast. Stepwise regression and cross-validation were employed during the period 1998–2014 for calibration of the model used for predicting annual wine production. The developed model explained about 86% of wine variance over the years with absolute average error of 6% for the cross validation and 87% of cases had differences between actual and forecasted wine production below 10%. The reliability and early-indication ability of the proposed forecast model justify their use to respond to a number of government agencies and wine industry concerns and activities.
      Graphical abstract image

      PubDate: 2015-11-15T09:42:02Z
       
  • A new sunflower high oleic mutation confers stable oil grain fatty acid
           composition across environments
    • Abstract: Publication date: Available online 11 November 2015
      Source:European Journal of Agronomy
      Author(s): Constanza Alberio, Natalia G. Izquierdo, Teresa Galella, Sebastián Zuil, Roberto Reid, Andrés Zambelli, Luis A.N. Aguirrezábal
      The oil industry demands sunflower oils with high oleic acid content. New varieties producing high oleic oils independently of the growing environment are needed as growers could receive an extra prime for offering them. Oil fatty acid composition of high oleic sunflower hybrids currently available carrying the Pervenets mutation could however be affected by the temperature during the grain filling period. A new high oleic mutation has been obtained to attain oils with ultra-high oleic levels (>90%oleic acid content). This new structural mutation would be able to reduce the variation in oleic acid percentage to changes in the minimum night temperature (MNT). The aim of this work was to assess the response of oil fatty acid composition of the new high oleic mutation to MNT compared to traditional and Pervenets genotypes. Field experiments in different sowing dates and locations and one growth chambers experiment were performed to explore a wide range of temperatures (11.8–23.2°C) during grain filling. The oleic acid percentage in traditional and high oleic Pervenets genotypes varied between 15.0–50.9% and 87.4–91.2%, respectively, while the new mutation genotype presented values of oleic acid between 91.3 and 92.5%. Moreover, the oleic acid percentage of traditional and Pervenets genotypes showed a linear and positive response to temperature (slopes 2.95 and 0.28%oleic acid °C−1, respectively). No response to temperature was detected in the new mutation genotype. The ultra-high oleic quality from the new high oleic sunflower mutant could be obtained in a wide range of environments as the fatty acid composition was not affected by temperature during grain filling, representing an advantage over the high oleic Pervenets and traditional genotypes.


      PubDate: 2015-11-15T09:42:02Z
       
  • Nitrogen fertilizer replacement value of undigested liquid cattle manure
           and digestates
    • Abstract: Publication date: Available online 11 November 2015
      Source:European Journal of Agronomy
      Author(s): Daniele Cavalli, Giovanni Cabassi, Lamberto Borrelli, Gabriele Geromel, Luca Bechini, Luigi Degano, Pietro Marino Gallina
      Accurate estimation of animal manure nitrogen (N) availability is required to maximize crop N use efficiency and reduce environmental N losses. Many field and laboratory experiments have shown that first-year net mineralization of manure organic N is often negligible, which often causes crop available N to approximate the ammonium N content of the manure. Anaerobic digestion increases the ammonium share and reduces the C to organic N ratio of animal manures, potentially increasing their N fertilizer value. In 2011, we undertook a three-year field experiment in Northern Italy to estimate the N fertilizer value of four manures: undigested cattle slurry, digested cattle slurry-maize mix, and liquid and solid fractions of the digested slurry-maize mix. The experiment also allowed us to test if ammonium recovery was similar among manures, and between manures and ammonium sulphate. Fertilizers were applied annually to plots before silage maize cultivation that was followed by an unfertilized Italian ryegrass crop. Results showed that the recovery of ammonium from manure in maize did not differ significantly compared to ammonium sulphate among all the fertilizers in 2013; however, in 2011 and 2012 it was significantly lower for all manures except digested slurry-maize mix and its liquid fraction in 2011. The increased recovery of applied N in 2012 and 2013 for solid fraction and undigested manure were likely due to the residual effect of previously applied organic N.


      PubDate: 2015-11-15T09:42:02Z
       
  • Effect of spring fertilization on ecosystem services of organic wheat and
           clover relay intercrops
    • Abstract: Publication date: Available online 10 November 2015
      Source:European Journal of Agronomy
      Author(s): Sylvain Vrignon-Brenas, Florian Celette, Camille Amossé, Christophe David
      Nitrogen (N) deficiency and weed infestation are main factors limiting yield and yield stability in organic wheat. Organic fertilizers may be used to improve crop performance but off-farm input costs tend to limit profitability. Instead, forage legumes may be inserted into the crop rotation to improve the N balance and to control weed infestation. In opposition to simultaneous cropping, relay intercropping of legumes in organic winter wheat limits resource competition for the legume cover crop, without decreasing the performance of the associated wheat. The aim of this study is to evaluate the effect of spring organic fertilization on the performance of intercropped legumes and wheat, and on services provided by the legume cover. Two species of forage legumes (Trifolium pratense L. and Trifolium repens L.) were undersown in winter wheat (Triticum aestivum L. cv Lona) in five organic fields during two consecutive crop seasons. Organic fertilizer was composed of feather meal and applied on wheat at legume sowing. The cover crop was maintained after the wheat harvest and destroyed just before sowing maize. Spring organic nitrogen fertilization increased wheat biomass (+35%), nitrogen (+49%), grain yield (+40%) and protein content (+7%) whatever the intercropping treatment. At wheat harvest, red clover biomass was significantly higher than white clover one (1.4 vs. 0.7tha−1). Nitrogen fertilization decreased forage legume above-ground biomass at wheat harvest, at approximately 0.5tha−1 whatever the specie. No significant difference in forage legume biomass production was observed at cover killing. Nitrogen accumulation in legume above-ground tissues was significantly higher for white clover than for red clover. Both red and white clover species significantly decreased weed infestation at this date. Nitrogen fertilization significantly increased weed biomass whatever the intercropping treatment and decreased nitrogen accumulation in both clover species (−12%). We demonstrated that nitrogen fertilization increased yield of wheat intercropped with forage legume while the performance of legumes was decreased. Legume growth was modified by spring fertilization whatever the species.


      PubDate: 2015-11-10T22:13:37Z
       
  • Modeling sugar content of pineapple under agro-climatic conditions on
           Reunion Island
    • Abstract: Publication date: Available online 10 November 2015
      Source:European Journal of Agronomy
      Author(s): Elodie Dorey, Patrick Fournier, Mathieu Léchaudel, Philippe Tixier
      A process-based model simulating the change in total soluble solids (TSS (%)) in fruit flesh was developed to describe the effect of climatic conditions on the sugar content of ‘Queen Victoria’ pineapple at harvest on Reunion Island. Sugar content varies throughout fruit development according to three processes (the supply of carbohydrates to the fruit, fruit metabolism, and dilution) which are affected by environmental factors, mainly temperature, rainfall and fertilization. The ecophysiological model of soluble sugar accumulation was linked to SIMPIÑA, a crop model that accurately predicts the daily increases in flesh dry and fresh weight. When the process-based model and crop model were linked, the dry and fresh matter of the pineapple flesh, as affected by climatic conditions, could be used as inputs to predict the TSS (%) at harvest. The relative rate of transformation of carbon as sugars in the fruit flesh for the synthesis of compounds other than sugars was estimated during fruit growth. TSS (%) were compared for harvested fruit grown under eight agro-climatic conditions. In the flesh of fruit harvested close to maturity, i.e., at 1400 degree-days after flowering, TSS (%) were significantly related (r 2 =0.55, P <0.001) to total soluble sugar content. The variability of TSS (%) between the eight agro-climatic groups ranged from 16.9 for pineapples grown in dry locations irrigated, under N-deficit conditions to 19.4 for pineapples grown in dry locations, without irrigation and without N deficiency. The variability of TSS (%) was substantial within each of the eight agro-climatic groups: standard deviations ranged from 0.9 to 1.5 for pineapples grown in dry locations, irrigated, without N deficiency and in dry locations, without irrigation and without N deficiency, respectively. For data from 14 experiments conducted under different climatic conditions, N fertilization, and irrigation conditions, the model predicted the TSS (%) at harvest with an RRMSE of 0.04. By linking this sugar model to the SIMPIÑA crop model, the impact of environmental conditions and cultural practices on the growth and development of pineapple are taken into account to predict the gustatory quality of pineapple grown on Reunion Island. The model could have a practical application to manage fruit quality, plan harvest, and marketing.


      PubDate: 2015-11-10T22:13:37Z
       
  • Assessing the sustainability of cropping systems in single- and multi-site
           studies. A review of methods
    • Abstract: Publication date: Available online 4 November 2015
      Source:European Journal of Agronomy
      Author(s): Violaine Deytieux, Nicolas Munier-Jolain, Jacques Caneill
      The multiple new challenges facing agriculture require the development of innovative cropping systems with high environmental, economic and social performances. Many research programmes are currently focusing on the design of such cropping systems. Some include the multicriteria assessment of cropping systems by diverse methods and approaches. Some of these research programmes are supported by experimental or farmers’ networks, generating new opportunities for data analysis and raising new research and methodological questions. In this article, we provide an overview based on a review of 56 articles, comparing the various methods for sustainability assessment in single- and multi-site studies. Articles were classified according to three characteristics: (i) their objectives, (ii) the study design (single- vs. multi-site), (iii) the type of system assessed (fictitious vs. real). Our analysis was structured around four items: (i) the variables used to describe cropping systems and production situations and the use of these variables in the assessment process, (ii) the criteria and associated indicators assessed, (iii) the methods used to explore multiple aspects of the performance of cropping systems, (iv) the use of reference values. We identified key points to be taken into account in multi-site studies. The application of the proposed guidelines to experimental networks should facilitate the identification of high-performance cropping systems and the identification of the drivers of cropping system performance.


      PubDate: 2015-11-06T21:59:24Z
       
  • The intercropping common bean with maize improves the rhizobial
           efficiency, resource use and grain yield under low phosphorus availability
           
    • Abstract: Publication date: January 2016
      Source:European Journal of Agronomy, Volume 72
      Author(s): Mourad Latati, Adnane Bargaz, Baroudi Belarbi, Mohamed Lazali, Samia Benlahrech, Siham Tellah, Ghiles Kaci, Jean Jacques Drevon, Sidi Mohamed Ounane
      In order to better understand how mixed crop cultures mitigate stressful conditions, this study aims to highlight the beneficial effect of the intercropping legume-cereal in enhancing soil phosphorus (P) availability for plant growth and productivity in a P-deficient soil of a northern Algerian agroecosystem. To address this question, common bean (Phaseolus vulgaris L. cv. El Djadida) and maize (Zea mays L. cv. Filou), were grown as sole- and inter-crops in two experimental sites; S1 (P-deficient) and S2 (P-sufficient) during two growing seasons (2011 and 2012). Growth, nodulation and grain yield were assessed and correlated with the rhizosphere soil P availability. Results showed that P availability significantly increased in the rhizosphere of both species, especially in intercropping under the P-deficient soil conditions. This increase was associated with high efficiency in use of the rhizobial symbiosis (high correlation between plant biomass and nodulation), plant growth and resource (nitrogen (N) and P) use efficiency as indicated by higher land equivalent ratio (LER>1) and N nutrition index (for maize) in intercropping over sole cropping treatments. Moreover, the rhizosphere P availability and nodule biomass were positively correlated (r 2 =0.71, p <0.01 and r 2 =0.62, p <0.01) in the intercropped common bean grown in the P-deficient soil during 2011 and 2012. The increased P availability presumably improved biomass and grain yield in intercropping, though it mainly enhanced grain yield in intercropped maize. Our findings suggest that modification in the intercropped common bean rhizosphere-induced parameters facilitated P uptake, plant biomass and grain yield for the intercropped maize under P-deficiency conditions.


      PubDate: 2015-10-25T15:13:33Z
       
  • Broccoli yield response to environmental factors in sustainable
           agriculture
    • Abstract: Publication date: January 2016
      Source:European Journal of Agronomy, Volume 72
      Author(s): Simona Ciancaleoni, Andrea Onofri, Renzo Torricelli, Valeria Negri
      A reduced rank factorial regression was carried out to assess effects of environmental factors in sustainable agriculture on yield performances of homogeneous (one F1 hybrid) and heterogeneous (one landrace, LR, and two derived synthetics) broccoli varieties under Organic Agriculture (OA) and Low-Input (LI) management systems. The study was motivated by a general lack of data on environmental variables that affect broccoli yield. Agronomic trials were carried out for three years in three locations in Central Italy with different pedo-climatic conditions. Reduced rank factorial regression was efficient in summarising the effect of environmental variables on the pattern of Genotype (G)×Environment (E) interactions. Nitrogen content, together with rainfall, minimum temperature and clay content, were the most important environmental variables and explained 91% of the variability in the G×E interaction matrix. A mild and nitrogen-rich environment allowed good performances to be achieved with all genotypes and maximised the F1 hybrid yield. The synthetic varieties and the LR tolerated a high clay content, even though broccoli crops prefer, in general, alluvial, deep and permeable soils without water stagnation. This suggests that the above mentioned varieties are the best materials for these yield-limiting environments, possibly because they were selected under those conditions. The results highlight the needs (i) to carry out further agronomy research aimed at identifying the most suitable areas and optimizing the control of environmental variables in OA and LI (in particular, type, quantity and time of application of N fertilization), (ii) to develop specific breeding programs for OA and LI and, while carrying them out, (iii) to evaluate the responses of the genotypes under selection to limiting environmental variables.


      PubDate: 2015-10-03T15:09:50Z
       
 
 
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