Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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    Assessing multifunctionality of agricultural soils : Reducing the biodiversity trade-off
    Vazquez, Carmen ; Goede, Ron G.M. de; Rutgers, Michiel ; Koeijer, Tanja J. de; Creamer, Rachel E. - \ 2020
    European Journal of Soil Science (2020). - ISSN 1351-0754
    cropland - grassland - land management - nutrient cycling - primary productivity - soil biodiversity - soil functions - yield

    Soils are indispensable for the provision of several functions. Agricultural intensification and its focus on increasing primary productivity (PP) poses a threat to soil quality, due to increases in nutrient loads, greenhouse gas emissions and declining biodiversity. The EU Horizon 2020 Landmark project has developed multi-criteria decision models to assess five soil functions: PP, nutrient cycling (NC), soil biodiversity and habitat provision (B-HP), climate mitigation and water regulation, simultaneously in agricultural fields. Using these algorithms, we evaluated the supply of PP, NC and B-HP of 31 grasslands and 21 croplands as low, medium or high. The multi-criteria decision models showed that 38% of the farms had a medium to high supply of all three soil functions, whereas only one cropland had a high supply for all three. Forty-eight per cent of the farms were characterized by a high supply of PP and NC. We observed a clear trade-off between these two functions and B-HP. Multivariate statistical analyses indicated that higher organic inputs combined with a lower mineral fertilization concur with higher biodiversity scores while maintaining a medium delivery of PP and NC. Additionally, we compared the outputs of the model predictions to independent variables that served as proxies for the soil functions and found: (a) croplands (but not grasslands) with high PP had a higher standardized yield than those with medium PP; (b) grasslands (but not croplands) with high NC had a significantly lower fungal to bacterial biomass ratio, suggesting faster decomposition channels; and (c) a positive though non-significant trend between B-HP score and rank according to soil invertebrate biodiversity. These comparisons suggest a successful upscaling of the models from field to farm level. Our study highlights the need for systematic collection of management-related data for the assessment of soil functions. Multifunctionality can be achieved in agricultural soils; however, without specifically managing for it, biodiversity might come at a loss. Highlights: We study how well soils can provide primary productivity, nutrient cycling and biodiversity. We study trade-offs and synergies among soil functions, as well as the drivers of these relationships. Soil biodiversity is largely sacrificed for primary productivity and nutrient cycling Changes in pesticide and fertilizer management can increase soil multifunctionality.

    Responses of Lowland, Upland and Aerobic Rice Genotypes to Water Limitation During Different Phases
    Vijayaraghavareddy, Preethi ; Xinyou, Yin ; Struik, Paul C. ; Makarla, Udayakumar ; Sreeman, Sheshshayee - \ 2020
    Rice Science 27 (2020)4. - ISSN 1672-6308 - p. 345 - 354.
    Aerobic - Oryza sativa - Phenology - Upland - Water limitation - yield

    Rice yield reduction due to water limitation depends on its severity and duration and on the phenological stage of its occurrence. We exposed three contrasting rice genotypes, IR64, UPLRi7 and Apo (adapted to lowland, upland and aerobic conditions, respectively), to three water regimes (puddle, 100% and 60% field capacity) in pots during the vegetative (GSI), flowering (GSII) and grain filling (GSIII) stages. Stress at all the three stages significantly reduced yield especially in lowland genotype IR64. Effect of water limitation was more severe at GSII than at the other two stages. Stress at GSI stage reduced both source activity (leaf area and photosynthetic rate) and sink capacity (tiller number or panicle number per pot). When stress was imposed at GSII, spikelet fertility was most affected in all the three genotypes. In both GSII and GSIII, although leaf area was constant in all the three water regimes, estimated relative whole-plant photosynthesis was strongly associated with yield reduction. Reduced photosynthesis due to stress at any given stage was found to have direct impact on yield. Compared to the other genotypes, Apo had deeper roots and maintained a better water relation, thus, higher carbon gain and spikelet viability, and ultimately, higher biomass and productivity under water-limited conditions. Therefore, screening for these stage-dependent adaptive mechanisms is crucial in breeding for sustained rice production under water limitation.

    Yield and nitrogen uptake of sole and intercropped maize and peanut in response to N fertilizer input
    Gao, Huaxin ; Meng, Weiwei ; Zhang, Chaochun ; Werf, Wopke van der; Zhang, Zheng ; Wan, Shubo ; Zhang, Fusuo - \ 2020
    Food and Energy Security 9 (2020)1. - ISSN 2048-3694
    intercropping - land equivalent ratio - N input - N uptake - yield

    Chinese agriculture needs to become less dependent on fertilizer inputs to enhance sustainability. Cereal/legume intercropping is a potential pathway to lower fertilizer inputs, but there is insufficient knowledge on the nitrogen (N) response in species mixtures. Here, we investigated N response in maize/peanut intercropping. Maize showed a stronger yield response to N input than peanut both in sole cropping and in intercropping, and so did sole crops relative to intercrops. Maize yield was the highest at the maximum level tested: 360 kg N/ha. Agronomic efficiency (AE) of sole maize was 7.8 kg/kg N input, averaged across five N levels (0, 90, 180, 270, and 360 kg/ha). Partial land equivalent ratios (pLERs) for maize decreased with N input, from 0.70 at zero to 0.64 at 360 kg/ha. Sole peanut showed an optimum yield response to N input, with the highest yield at 270 kg/ha and lower yield at 360 kg/ha. The average AE of sole peanut was 1.3 kg/kg. The pLER of peanut declined from 0.43 at zero to 0.32 at 360 kg/ha while the overall LER decreased from 1.13 to 0.96, indicating relative better performance of intercropping at low than at high N input. Apparent recovery (RE) for N was 27.2% for sole maize, 12.4% for sole peanut, and 7.2% for intercrops. Mean N uptake was 179 kg/ha in sole maize, 199 kg/ha in intercropping, and 264 kg/ha in sole peanut. Partial economic budgeting indicated that with the current low Chinese N fertilizer prices, gross margin is maximized with high N input in sole crops; however, for intercropping, the highest gross margin was attained at intermediate N inputs of 180 or 270 kg/ha. Fertilizer price incentives may facilitate a transition to intercropping at moderate N input in China.

    The fertilization effect of global dimming on crop yields is not attributed to an improved light interception
    Shao, Liping ; Li, Gang ; Zhao, Qiannan ; Li, Yabing ; Sun, Yutong ; Wang, Weinan ; Cai, Chuang ; Chen, Weiping ; Liu, Ronghua ; Luo, Weihong ; Yin, Xinyou ; Lee, Xuhui - \ 2020
    Global Change Biology 26 (2020)3. - ISSN 1354-1013 - p. 1697 - 1713.
    acclimation - diffuse radiation - fertilization effect - global dimming - radiation use efficiency - rice - wheat - yield

    Global dimming, a decadal decrease in incident global radiation, is often accompanied with an increase in the diffuse radiation fraction, and, therefore, the impact of global dimming on crop production is hard to predict. A popular approach to quantify this impact is the statistical analysis of historical climate and crop data, or use of dynamic crop simulation modelling approach. Here, we show that statistical analysis of historical data did not provide plausible values for the effect of diffuse radiation versus direct radiation on rice or wheat yield. In contrast, our field experimental study of 3 years demonstrated a fertilization effect of increased diffuse radiation fraction, which partly offset yield losses caused by decreased global radiation, in both crops. The fertilization effect was not attributed to any improved canopy light interception but mainly to the increased radiation use efficiency (RUE). The increased RUE was explained not only by the saturating shape of photosynthetic light response curves but also by plant acclimation to dimming that gradually increased leaf nitrogen concentration. Crop harvest index slightly decreased under dimming, thereby discounting the fertilization effect on crop yields. These results challenge existing modelling paradigms, which assume that the fertilization effect on crop yields is mainly attributed to an improved light interception. Further studies on the physiological mechanism of plant acclimation are required to better quantify the global dimming impact on agroecosystem productivity under future climate change.

    FOODSECURE Scenario Driver Database
    Dijk, Michiel van; Gramberger, M. ; Laborde, D. ; Mandryk, Maryia ; Shutes, Lindsay ; Stehfest, Elke ; Valin, H. ; Zellmer, K. - \ 2019
    Wageningen University & Research
    food security - scenarios - drivers - population - yield - gdp - gross domestic product - storylines
    The FOODSECURE Scenario Driver Database contains projections for key drivers that, in combination with storylines, describe four scenarios for the assessment of global food security. The database provides information for 19 regions that together have global coverage for the period 2010-2050.
    Do diverse landscapes provide for effective natural pest control in subtropical rice?
    Zou, Y. ; Kraker, Joop de; Bianchi, F.J.J.A. ; Xiao, Haijun ; Huang, Jikun ; Deng, Xiangzheng ; Hou, Lingling ; Werf, W. van der - \ 2019
    Wageningen University & Research
    agroecosystem - biological pest control - China - natural enemy - pest - planthopper - yield
    This datasets comprises data from 20 rice fields embedded in a gradient of landscapes from crop-dominated to semi-natural habitat-dominated, in the Jiangxi Province in China in 2014 and 2015. Each field was split into two plots: in one plot no pesticides were applied and in the other plot farmers applied pesticides according to their normal pest management practices. The dataset comprises information on the focal rice fields, the land use surrounding the focal rice fields, arthropod abundances and diversity, crop damage, an exclusion experiment to assess the potential of natural enemies to suppress pests, pest management practices and rice yield
    The interplay of landscape composition and configuration: new pathways to manage functional biodiversity and agroecosystem services across Europe
    Martin, Emily A. ; Dainese, Matteo ; Clough, Yann ; Báldi, András ; Bommarco, Riccardo ; Gagic, Vesna ; Garratt, Michael P.D. ; Holzschuh, Andrea ; Kleijn, David ; Kovács-Hostyánszki, Anikó ; Marini, Lorenzo ; Potts, Simon G. ; Smith, Henrik G. ; Hassan, Diab Al; Albrecht, Matthias ; Andersson, Georg K.S. ; Asís, Josep D. ; Aviron, Stéphanie ; Balzan, Mario V. ; Baños-Picón, Laura ; Bartomeus, Ignasi ; Batáry, Péter ; Burel, Francoise ; Caballero-López, Berta ; Concepción, Elena D. ; Coudrain, Valérie ; Dänhardt, Juliana ; Diaz, Mario ; Diekötter, Tim ; Dormann, Carsten F. ; Duflot, Rémi ; Entling, Martin H. ; Farwig, Nina ; Fischer, Christina ; Frank, Thomas ; Garibaldi, Lucas A. ; Hermann, John ; Herzog, Felix ; Inclán, Diego ; Jacot, Katja ; Jauker, Frank ; Jeanneret, Philippe ; Kaiser, Marina ; Krauss, Jochen ; Féon, Violette Le; Marshall, Jon ; Moonen, Anna Camilla ; Moreno, Gerardo ; Riedinger, Verena ; Rundlöf, Maj ; Rusch, Adrien ; Scheper, Jeroen ; Schneider, Gudrun ; Schüepp, Christof ; Stutz, Sonja ; Sutter, Louis ; Tamburini, Giovanni ; Thies, Carsten ; Tormos, José ; Tscharntke, Teja ; Tschumi, Matthias ; Uzman, Deniz ; Wagner, Christian ; Zubair-Anjum, Muhammad ; Steffan-Dewenter, Ingolf - \ 2019
    Ecology Letters 22 (2019)7. - ISSN 1461-023X - p. 1083 - 1094.
    Agroecology - arthropod community - biological control - edge density - pest control - pollination - response trait - semi-natural habitat - trait syndrome - yield

    Managing agricultural landscapes to support biodiversity and ecosystem services is a key aim of a sustainable agriculture. However, how the spatial arrangement of crop fields and other habitats in landscapes impacts arthropods and their functions is poorly known. Synthesising data from 49 studies (1515 landscapes) across Europe, we examined effects of landscape composition (% habitats) and configuration (edge density) on arthropods in fields and their margins, pest control, pollination and yields. Configuration effects interacted with the proportions of crop and non-crop habitats, and species’ dietary, dispersal and overwintering traits led to contrasting responses to landscape variables. Overall, however, in landscapes with high edge density, 70% of pollinator and 44% of natural enemy species reached highest abundances and pollination and pest control improved 1.7- and 1.4-fold respectively. Arable-dominated landscapes with high edge densities achieved high yields. This suggests that enhancing edge density in European agroecosystems can promote functional biodiversity and yield-enhancing ecosystem services.

    What root traits determine grass resistance to phosphorus deficiency in production grassland?
    Ros, Mart B.H. ; Deyn, Gerlinde B. de; Koopmans, Gerwin F. ; Oenema, Oene ; Groenigen, Jan Willem van - \ 2018
    Journal of Plant Nutrition and Soil Science 181 (2018)3. - ISSN 1436-8730 - p. 323 - 335.
    P acquisition - root characteristics - root length - structural equation modeling - yield

    Grasslands are a major form of agricultural land use worldwide. Current and future declines of phosphorus (P) inputs into production grasslands necessitate a shift towards selecting grass species based on high efficiency under suboptimal, rather than optimal P conditions. It is therefore imperative to identify key root traits that determine P acquisition of grasses in soils with a low P status. In a 9-month greenhouse experiment, we grew eight common grass species and cultivars on a soil with a low P status and related root morphological traits to their performance under P-limiting conditions. We applied (P1) or withheld (P0) P fertilization while providing adequate amounts of all other nutrients. Omitting P fertilization greatly reduced yield and nutrient acquisition for the various grass species. Biomass production differed significantly (P < 0.1%) among species and P fertilization treatments, varying from 17.1 to 72.1 g pot−1 in the P0 treatment and from 33.4 to 85.8 g pot−1 in the P1 treatment. Root traits were species-specific and unresponsive to P fertilization, but overall we observed a trade-off between root biomass and specific root length. Structural equation modeling identified total root length as key factor with respect to resistance to P deficiency, especially when roots explored the subsoil. Optimizing root length and subsoil exploration could be the key to maintaining high productivity of production grasslands with decreasing P availability. This is relevant for both plant breeding programs and for composing seed mixtures.

    Physical mapping of QTL for tuber yield, starch content and starch yield in tetraploid potato (Solanum tuberosum L.) by means of genome wide genotyping by sequencing and the 8.3 K SolCAP SNP array
    Schönhals, Elske Maria ; Ding, Jia ; Ritter, Enrique ; Caldas Paulo, M.J. ; Cara, Nicolás ; Tacke, Eckhard ; Hofferbert, Hans Reinhardt ; Lübeck, Jens ; Strahwald, Josef ; Gebhardt, Christiane - \ 2017
    Max Planck Institute for Plant Breeding Research
    Potato - Solanum tuberosum - tuber - yield - starch content - complex trait - genome wide genotyping - SNP - GWAS - candidate gene
    Background Tuber yield and starch content of the cultivated potato are complex traits of decisive importance for breeding improved varieties. Natural variation of tuber yield and starch content depends on the environment and on multiple, mostly unknown genetic factors. Dissection and molecular identification of the genes and their natural allelic variants controlling these complex traits will lead to the development of diagnostic DNA-based markers, by which precision and efficiency of selection can be increased (precision breeding). Results Three case-control populations were assembled from tetraploid potato cultivars based on maximizing the differences between high and low tuber yield (TY), starch content (TSC) and starch yield (TSY, arithmetic product of TY and TSC). The case-control populations were genotyped by restriction-site associated DNA sequencing (RADseq) and the 8.3 k SolCAP SNP genotyping array. The allele frequencies of single nucleotide polymorphisms (SNPs) were compared between cases and controls. RADseq identified, depending on data filtering criteria, between 6664 and 450 genes with one or more differential SNPs for one, two or all three traits. Differential SNPs in 275 genes were detected using the SolCAP array. A genome wide association study using the SolCAP array on an independent, unselected population identified SNPs associated with tuber starch content in 117 genes. Physical mapping of the genes containing differential or associated SNPs, and comparisons between the two genome wide genotyping methods and two different populations identified genome segments on all twelve potato chromosomes harboring one or more quantitative trait loci (QTL) for TY, TSC and TSY. Conclusions Several hundred genes control tuber yield and starch content in potato. They are unequally distributed on all potato chromosomes, forming clusters between 0.5–4 Mbp width. The largest fraction of these genes had unknown function, followed by genes with putative signalling and regulatory functions. The genetic control of tuber yield and starch content is interlinked. Most differential SNPs affecting both traits had antagonistic effects: The allele increasing TY decreased TSC and vice versa. Exceptions were 89 SNP alleles which had synergistic effects on TY, TSC and TSY. These and the corresponding genes are primary targets for developing diagnostic markers.
    Supplementary material from "Increased SBPase activity improves photosynthesis and grain yield in wheat grown in greenhouse conditions"
    Driever, S.M. ; Simkin, Andrew J. ; Alotaibi, Saqer ; Fisk, Stuart J. ; Madgwick, Pippa J. ; Sparks, Caroline A. ; Jones, Huw D. ; Lawson, Tracy ; Parry, Martin A.J. ; Raines, Christine A. - \ 2017
    Wageningen University & Research
    sedoheptulose-1 - 7-biphosphatase - Calvin-Benson cycle - transgenic - biomass - yield
    To meet the growing demand for food, substantial improvements in yields are needed. This is particularly the case for wheat, where global yield has stagnated in recent years. Increasing photosynthesis has been identified as a primary target to achieve yield improvements. To increase leaf photosynthesis in wheat, the level of the Calvin–Benson cycle enzyme sedoheptulose-1,7-biphosphatase (SBPase) has been increased through transformation and expression of a Brachypodium distachyon SBPase gene construct. Transgenic lines with increased SBPase protein levels and activity were grown under greenhouse conditions and showed enhanced leaf photosynthesis and increased total biomass and dry seed yield. This showed the potential of improving yield potential by increasing leaf photosynthesis in a crop species such as wheat. The results are discussed with regards to future strategies for further improvement of photosynthesis in wheat.This article is part of the themed issue ‘Enhancing photosynthesis in crop plants: targets for improvement’.
    A methodical approach for the assessment of waste sorting plants
    Feil, Alexander ; Pretz, Thomas ; Vitz, Philipp ; Thoden van Velzen, Ulphard - \ 2017
    Waste Management and Research 35 (2017)2. - ISSN 0734-242X - p. 147 - 154.
    assessment - back-calculation - beverage cartons - decision tree - modelling - sample taking options - separation coefficient - Waste sorting plants - yield

    A techno-economical evaluation of the processing result of waste sorting plants should at least provide a realistic assessment of the recovery yields of valuable materials and of the qualities of the obtained products. This practical data is generated by weighing all the output products and sampling these products. Due to the technological complexity of sorting plants, for example, lightweight packaging waste treatments plants and the high expenditures concerning time and costs of sampling with subsequent manual sorting for quality determination, usually only final products undergo such an investigation. Thereby, the transferability of the results depends decisively on the boundary conditions (extent, throughput of the plant, process parameterization). Given that the process is too complex, not all relevant information of the process steps can be determined by sampling. By model calculations and/or adjustment of reasonable assumptions, information concerning weak points in the process can be identified, which can be used for further plant optimization. For the example of the recovery of beverage cartons from co-collected and mechanically recovered mixtures of lightweight packaging waste, a methodical approach for the assessment of processing results will be presented.

    Fruit load governs transpiration of olive trees
    Bustan, Amnon ; Dag, Arnon ; Yermiyahu, Uri ; Erel, Ran ; Presnov, Eugene ; Agam, Nurit ; Kool, Dilia ; Iwema, Joost ; Zipori, Isaac ; Ben-Gal, Alon - \ 2016
    Tree Physiology 36 (2016)3. - ISSN 0829-318X - p. 380 - 391.
    Olea europaea - photosynthesis - stomatal regulation - vegetative growth - water potential - yield

    We tested the hypothesis that whole-tree water consumption of olives (Olea europaea L.) is fruit load-dependent and investigated the driving physiological mechanisms. Fruit load was manipulated in mature olives grown in weighing-drainage lysimeters. Fruit was thinned or entirely removed from trees at three separate stages of growth: early, mid and late in the season. Tree-scale transpiration, calculated from lysimeter water balance, was found to be a function of fruit load, canopy size and weather conditions. Fruit removal caused an immediate decline in water consumption, measured as whole-plant transpiration normalized to tree size, which persisted until the end of the season. The later the execution of fruit removal, the greater was the response. The amount of water transpired by a fruit-loaded tree was found to be roughly 30% greater than that of an equivalent low- or nonyielding tree. The tree-scale response to fruit was reflected in stem water potential but was not mirrored in leaf-scale physiological measurements of stomatal conductance or photosynthesis. Trees with low or no fruit load had higher vegetative growth rates. However, no significant difference was observed in the overall aboveground dry biomass among groups, when fruit was included. This case, where carbon sources and sinks were both not limiting, suggests that the role of fruit on water consumption involves signaling and alterations in hydraulic properties of vascular tissues and tree organs.

    How Sensitive Are Ecosystem Services in European Forest Landscapes to Silvicultural Treatment?
    Biber, P. ; Borges, J.G. ; Moshammer, R. ; Barreiro, S. ; Botequim, B. ; Brodrechtová, Y. ; Brukas, V. ; Chirici, G. ; Cordero-Debets, R. ; Corrigan, E. ; Eriksson, L.O. ; Favero, M. ; Galev, E. ; Garcia-Gonzalo, J. ; Hengeveld, G.M. ; Kavaliauskas, M. ; Marchetti, M. ; Marques, S. ; Mozgeris, G. ; Navrátil, R. ; Nieuwenhuis, M. ; Orazio, C. ; Paligorov, I. ; Pettenella, D. ; Sedmák, R. ; Smrecek, R. ; Stanislovaitis, A. ; Tomé, M. ; Trubins, R. ; Tucek, J. ; Vizzarri, M. ; Wallin, I. ; Pretzsch, H. ; Sallnäs, O. - \ 2015
    Forests 6 (2015)5. - ISSN 1999-4907 - p. 1666 - 1695.
    scenario analysis - simulator silva - climate-change - management - growth - tree - impacts - regions - yield - stand
    While sustainable forestry in Europe is characterized by the provision of a multitude of forest ecosystem services, there exists no comprehensive study that scrutinizes their sensitivity to forest management on a pan-European scale, so far. We compile scenario runs from regionally tailored forest growth models and Decision Support Systems (DSS) from 20 case studies throughout Europe and analyze whether the ecosystem service provision depends on management intensity and other co-variables, comprising regional affiliation, social environment, and tree species composition. The simulation runs provide information about the case-specifically most important ecosystem services in terms of appropriate indicators. We found a strong positive correlation between management intensity and wood production, but only weak correlation with protective and socioeconomic forest functions. Interestingly, depending on the forest region, we found that biodiversity can react in both ways, positively and negatively, to increased management intensity. Thus, it may be in tradeoff or in synergy with wood production and forest resource maintenance. The covariables species composition and social environment are of punctual interest only, while the affiliation to a certain region often makes an important difference in terms of an ecosystem service’s treatment sensitivity.
    Estimating genetic parameters for fertility in dairy cows from in-line milk progesterone profiles
    Tenghe, A.M.M. ; Bouwman, A.C. ; Berglund, B. ; Strandberg, E. ; Blom, J. ; Veerkamp, R.F. - \ 2015
    Journal of Dairy Science 98 (2015)8. - ISSN 0022-0302 - p. 5763 - 5773.
    experimental research herds - body condition score - luteal activity - postpartum ovulation - cattle - holstein - traits - interval - yield - endocrine
    The aim of this study was to define endocrine fertility traits from in-line milk progesterone (P4) records and to estimate genetic parameters for these traits. Correlations of classical fertility (calving interval and calving to first service) and milk production traits with endocrine fertility traits were also estimated. In-line milk P4 records (n = 160,952) collected from June 2009 through November 2013 for 2,273 lactations of 1,561 Holstein-Friesian cows in 12 commercial herds in the Netherlands were analyzed for (the log of) the number of days from calving till commencement of luteal activity (lnC-LA), proportion of samples between 25 and 60 d in milk with luteal activity (PLA), presence or absence of luteal activity for a cow between 25 and 60 d in milk, interval from commencement of luteal activity to first service (CLAFS), first luteal phase length, length of first interluteal interval, and length of first interovulatory interval. Milk P4 records were sampled, on average, every 2 d. Genetic parameters were estimated using a mixed linear animal model. Heritability estimates (±SE) of endocrine fertility traits were 0.12 ± 0.05 for lnC-LA, 0.12 ± 0.05 for PLA, and 0.11 ± 0.06 for CLAFS, and their repeatability estimates were 0.29 ± 0.04, 0.21 ± 0.04, and 0.15 ± 0.06, respectively. The genetic correlation of lnC-LA with PLA was -0.91 ± 0.06 and with CLAFS was -0.56 ± 0.25. The genetic correlations of lnC-LA were 0.26 ± 0.33 with calving interval and 0.37 ± 0.21 with calving to first service. Genetic correlations of the milk production traits with lnC-LA ranged from 0.04 to 0.18 and 0.07 to 0.65 with classical fertility traits. The phenotypic correlations of all endocrine fertility traits with milk production traits were close to zero (0.01 to 0.07). This study shows that in-line P4 records can be used to define and explore several heritable endocrine fertility traits in dairy cows and might help in selection for improved fertility.
    Resource use efficiency, ecological intensification and sustainability of intercropping systems
    Mao, L. ; Zhang, L. ; Zhang, S. ; Evers, J.B. ; Werf, W. van der; Wang, J. ; Sun, H. ; Su, Z. ; Spiertz, J.H.J. - \ 2015
    Journal of Integrative Agriculture 14 (2015)8. - ISSN 2095-3119 - p. 1542 - 1550.
    growth - maize - yield - wheat - water - agriculture - radiation - capture - cotton - model
    The rapidly growing demand for food, feed and fuel requires further improvements of land and water management, crop productivity and resource-use efficiencies. Combined field experimentation and crop growth modelling during the past five decades made a great leap forward in the understanding of factors that determine actual and potential yields of monocrops. The research field of production ecology developed concepts to integrate biological and biophysical processes with the aim to explore crop growth potential in contrasting environments. To understand the potential of more complex systems (multi-cropping and intercropping) we need an agro-ecosystem approach that integrates knowledge derived from various disciplines: agronomy, crop physiology, crop ecology, and environmental sciences (soil, water and climate). Adaptation of cropping systems to climate change and a better tolerance to biotic and abiotic stresses by genetic improvement and by managing diverse cropping systems in a sustainable way will be of key importance in food security. To accelerate sustainable intensification of agricultural production, it is required to develop intercropping systems that are highly productive and stable under conditions with abiotic constraints (water, nutrients and weather). Strategies to achieve sustainable intensification include developing tools to evaluate crop growth potential under more extreme climatic conditions and introducing new crops and cropping systems that are more productive and robust under conditions with abiotic stress. This paper presents some examples of sustainable intensification management of intercropping systems that proved to be tolerant to extreme climate conditions.
    Long-term decline in soil fertility and responsiveness to fertiliser as mitigated by short fallow periods in sub-Sahelian area of Togo
    Kintché, K. ; Guibert, H. ; Bonfoh, B. ; Tittonell, P.A. - \ 2015
    Nutrient Cycling in Agroecosystems 101 (2015)3. - ISSN 1385-1314 - p. 333 - 350.
    organic-matter dynamics - nitrogen dynamics - burn agriculture - tropical fallows - no-tillage - carbon - management - biomass - productivity - yield
    Using 40-year experiment data from a mono-modal rainfall area of northern Togo, we analyzed soil fertility dynamics when 2 and 3-year fallows were alternated with 3-year rotation of groundnut, cotton and sorghum. The control treatment consisted to continuous cultivate the soil in a rotation of groundnut/cotton/sorghum without fallow periods. For each rotation, two fertilisation rates were applied: no fertilisation and mineral fertiliser application during the cropping and/or the fallow periods. Yields of unfertilised crops, which averaged 1 t ha-1 during the first years of cultivation, were often nil in the long-term. In the long-term, yields of fertilised cotton and sorghum decreased by 32 and 50 %, respectively compared to the average of 2.4 and 1.6 t ha-1 obtained during the first decade of cultivation. The long-term decline in crop productivity was mitigated when fallow periods were alternated with cropping periods, and consequently there was partial compensation in terms of production for the unproductive fallowed plots. Long-term yields of fertilised cotton and sorghum in the periodically fallowed plots were 40 and 50 % higher than those in continuously cropped plots, respectively; they were 90 and 60 % higher than those in continuously cropped plots without fertilisation. Like for crop productivity, soil C, N and exchangeable Ca and Mg decreased less in periodically fallowed plots than in continuously cropped plots. The limited soil C decline when fallows were alternated with crops appears to be the consequence of no-tillage period rather than the effect of the highest C inputs to the soil.
    Cumulative ozone effect on canopy stomatal resistance and the impact on boundary layer dynamics and CO2 assimilation at the diurnal scale: A case study for grassland in the Netherlands
    Super, I. ; Vilà-Guerau De Arellano, J. ; Krol, M.C. - \ 2015
    Journal of Geophysical Research: Biogeosciences 120 (2015). - ISSN 2169-8953 - p. 1348 - 1365.
    climate-change - soil-moisture - vegetation - exposure - drought - yield - l. - conductance - sensitivity - atmosphere
    Biological, chemical, and dynamical processes occurring at the surface strongly interact at diurnal scales. Therefore, this study examines the seasonal ozone impact on stomatal resistance, surface energy balance, boundary layer dynamics, and CO2 assimilation at this (sub)diurnal scale under changing conditions. We combine a seasonal canopy resistance module with a surface-boundary layer model that solves the diurnal evolution of dynamical and chemical variables in a well-mixed, convective boundary layer. The model is constrained with observations from Cabauw (Netherlands) for the dry year 2003, representing a well-mixed boundary layer at midlatitudes over water-stressed grassland. To quantify the ozone impact, the Cumulative Uptake of Ozone is calculated over a growing season, which gives an estimate of the reduction in stomatal aperture and photosynthesis. From a sensitivity analysis with mixed-layer temperature and soil moisture content we conclude that drought is the dominant factor that determines the surface energy partitioning and limits CO2 assimilation. Although drought causes stomatal closure, the results indicate that ozone damage, nevertheless, occurs. A second sensitivity analysis with CO2 and ozone shows that ozone damage causes an increase in stomatal resistance of up to 40% under high ozone levels and that CO2-induced stomatal closure limits ozone damage. The impact on boundary layer development through the effect of CO2 and ozone on the stomatal resistance is much smaller. At the diurnal scale soil moisture influences the surface energy partitioning, which affects the entrainment of ozone-rich air. Due to ozone damage, the CO2 assimilation flux is reduced by about 15%.
    Selecting crop models for decision making in wheat insurance
    Castaneda Vera, A. ; Leffelaar, P.A. ; Alvaro-Fuentes, J. ; Cantero-Martinez, C. ; Minguez, M.I. - \ 2015
    European Journal of Agronomy 68 (2015). - ISSN 1161-0301 - p. 97 - 116.
    use efficiency - management-practices - farming systems - field-capacity - soil - yield - evaporation - photosynthesis - transpiration - irrigation
    In crop insurance, the accuracy with which the insurer quantifies the actual risk is highly dependent on the availability on actual yield data. Crop models might be valuable tools to generate data on expected yields for risk assessment when no historical records are available. However, selecting a crop model for a specific objective, location and implementation scale is a difficult task. A look inside the different crop and soil modules to understand how outputs are obtained might facilitate model choice. The objectives of this paper were (i) to assess the usefulness of crop models to be used within a crop insurance analysis and design and (ii) to select the most suitable crop model for drought risk assessment in semi-arid regions in Spain. For that purpose first, a pre-selection of crop models simulating wheat yield under rainfed growing conditions at the field scale was made, and second, four selected models (Aquacrop, CERES-Wheat, CropSyst and WOFOST) were compared in terms of modelling approaches, process descriptions and model outputs. Outputs of the four models for the simulation of winter wheat growth are comparable when water is not limiting, but differences are larger when simulating yields under rainfed conditions. These differences in rainfed yields are mainly related to the dissimilar simulated soil water availability and the assumed linkages with dry matter formation. We concluded that for the simulation of winter wheat growth at field scale in such semi-arid conditions, CERES-Wheat and CropSyst are preferred. WOFOST is a satisfactory compromise between data availability and complexity when detail data on soil is limited. Aquacrop integrates physiological processes in some representative parameters, thus diminishing the number of input parameters, what is seen as an advantage when observed data is scarce. However, the high sensitivity of this model to low water availability limits its use in the region considered. Contrary to the use of ensembles of crop models, we endorse that efforts be concentrated on selecting or rebuilding a model that includes approaches that better describe the agronomic conditions of the regions in which they will be applied. The use of such complex methodologies as crop models is associated with numerous sources of uncertainty, although these models are the best tools available to get insight in these complex agronomic systems.
    Method Development to Increase Protein Enrichment During Dry Fractionation of Starch-Rich Legumes
    Pelgrom, P.J.M. ; Boom, R.M. ; Schutyser, M.A.I. - \ 2015
    Food Bioprocess Technology 8 (2015)7. - ISSN 1935-5130 - p. 1495 - 1502.
    air-classified protein - functional-properties - flours - bodies - seeds - pea - efficiency - yield - food
    A facile method was developed to establish milling settings that optimally separate starch granules from protein bodies and cell wall fibres for starch-rich legumes. Optimal separation was obtained for pea, bean, lentil and chickpea when the particle size distribution curve of flour and isolated starch granules overlap maximally. This outcome was based on scanning electron microscopy, protein content of the fine fraction and particle size distribution curves. Milling settings differed between legumes due to variances in seed hardness and starch granule size. The protein content of the fine fraction was legume specific as well and could be explained by differences in particle density, seed hardness, starch granule size, fat content and flour dispersibility.
    Quantifying the source-sink balance and carbohydrate content in three tomato cultivars
    Li, T. ; Heuvelink, E. ; Marcelis, L.F.M. - \ 2015
    Frontiers in Plant Science 6 (2015). - ISSN 1664-462X
    dry-matter production - leaf photosynthesis - plant-growth - leaves - strength - yield - metabolism - simulation - storage - light
    Supplementary lighting is frequently applied in the winter season for crop production in greenhouses. The effect of supplementary lighting on plant growth depends on the balance between assimilate production in source leaves and the overall capacity of the plants to use assimilates. This study aims at quantifying the source-sink balance and carbohydrate content of three tomato cultivars differing in fruit size, and to investigate to what extent the source/sink ratio correlates with the potential fruit size. Cultivars Komeet (large size), Capricia (medium size), and Sunstream (small size, cherry tomato) were grown from 16 August to 21 November, at similar crop management as in commercial practice. Supplementary lighting (High Pressure Sodium lamps, photosynthetic active radiation at 1 m below lamps was 162 mu mol photons m(-2) s(-1); maximum 10 h per day depending on solar irradiance level) was applied from 19 September onward. Source strength was estimated from total plant growth rate using periodic destructive plant harvests in combination with the crop growth model TOMSIM. Sink strength was estimated from potential fruit growth rate which was determined from non-destructively measuring the fruit growth rate at non-limiting assimilate supply, growing only one fruit on each truss. Carbohydrate content in leaves and stems were periodically determined. During the early growth stage, Komeet' and Capricia' showed sink limitation and 'Sunstream' was close to sink limitation. During this stage reproductive organs had hardly formed or were still small and natural irradiance was high (early September) compared to winter months. Subsequently, during the fully fruiting stage all three cultivars were strongly source-limited as indicated by the low source/sink ratio (average source/sink ratio from 50 days after planting onward was 0.17, 0.22, and 0.33 for 'Komeet, 'Capricia,' and 'Sunstream,' respectively). This was further confirmed by the fact that pruning half of the fruits hardly influenced net leaf photosynthesis rates. Carbohydrate content in leaves and stems increased linearly with the source/sink ratio. We conclude that during the early growth stage under high irradiance, tomato plants are sink-limited and that the level of sink limitation differs between cultivars but it is not correlated with their potential fruit size. During the fully fruiting stage tomato plants are source-limited and the extent of source limitation of a cultivar is positively correlated with its potential fruit size.
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