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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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
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
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.
Effect of the DGAT1 K232A genotype of dairy cows on the milk metabolome and proteome
Lu, J. ; Boeren, S. ; Hooijdonk, A.C.M. van; Vervoort, J.J.M. ; Hettinga, K.A. - \ 2015
Journal of Dairy Science 98 (2015)5. - ISSN 0022-0302 - p. 3460 - 3469.
h-1-nmr spectroscopy - sample preparation - identification - stomatin - membrane - proteins - gene - cattle - yield
Diglyceride O-acyltransferase 1 (DGAT1) is the enzyme that catalyzes the synthesis of triglycerides from diglycerides and acyl-coenzyme A. The DGAT1 K232A polymorphism was previously shown to have a significant influence on bovine milk production characteristics (milk yield, protein content, fat content, and fatty acid composition). The mechanism of this influence has, however, not been elucidated. In this study, metabolomics (1H-nuclear magnetic resonance) and proteomics (laser chromatography-tandem mass spectrometry) were applied to determine the serum and lipid metabolite composition and milk fat globule membrane proteome of milk samples from cows with the DGAT1 KK and AA genotypes. The milk samples from cows with the DGAT1 KK genotype contained more stomatin, sphingomyelin, choline, and carnitine, and less citrate, creatine or phosphocreatine, glycerol-phosphocholine, mannose-like sugar, acetyl sugar phosphate, uridine diphosphate (UDP)-related sugar, and orotic acid compared with milk samples from cows with the DGAT1 AA genotype. Based on these results, we propose that the differences between the DGAT1 genotypes may be related to stomatin-sphingomyelin lipid rafts as well as structural (cell membrane) differences in epithelial cells of the mammary gland. In conclusion, our study shows that, in addition to previously described changes in triglyceride composition, cows differing in DGAT1 polymorphism differ in their milk proteome and metabolome, which may help in further understanding the effect of the DGAT1 K232A polymorphism on milk production characteristics.
A novel protocol for assessment of aboveground biomass in rangeland environments
Mundava, C. ; Schut, A.G.T. ; Helmholtz, P. ; Stovold, R.G.H. ; Donald, G. ; Lamb, D.W. - \ 2015
The Rangeland Journal 37 (2015)2. - ISSN 1036-9872 - p. 157 - 167.
rising-plate-meter - dry tropical savanna - standing crop - herbage mass - grazing strategies - pasture biomass - vegetation - grassland - yield - management
Current methods to measure aboveground biomass (AGB) do not deliver adequate results in relation to the extent and spatial variability that characterise rangelands. An optimised protocol for the assessment ofAGBis presented that enables calibration and validation of remote-sensing imagery or plant growth models at suitable scales. The protocol combines a limited number of destructive samples with non-destructive measurements including normalised difference vegetation index (NDVI), canopy height and visual scores of AGB. A total of 19 sites were sampled four times during two growing seasons. Fresh and dry matter weights of dead and green components ofAGBwere recorded. Similarity of responses allowed grouping into Open plains sites dominated by annual grasses, Bunch grass sites dominated by perennial grasses and Spinifex (Triodia spp.) sites. Relationships between non-destructive measurements and AGB were evaluated with a simple linear regression per vegetation type. Multiple regression models were first used to identify outliers and then cross-validated using a 'Leave-One-Out' and 'Leave-Site-Out' (LSO) approach on datasets including and excluding the identified outliers. Combining all non-destructive measurements into one single regression model per vegetation type provided strong relationships for all seasons for total and green AGB (adjusted R2 values of 0.65-0.90) for datasets excluding outliers. The model provided accurate assessments of total AGB in heterogeneous environments for Bunch grass and Spinifex sites (LSO-Q2 values of 0.70-0.88), whereas assessment of green AGB was accurate for all vegetation types (LSO-Q2 values of 0.62-0.84). The protocol described can be applied at a range of scales while considerably reducing sampling time
Exploring climate change impacts and adaptation options for maize production in the Central Rift Valley of Ethiopia using different climate change scenarios and crop models
Kassie, B.T. ; Asseng, S. ; Rotter, R.P. ; Hengsdijk, H. ; Ruane, A.C. ; Ittersum, M.K. van - \ 2015
Climatic Change 129 (2015)1-2. - ISSN 0165-0009 - p. 145 - 158.
africa - yield - agriculture - risks - opportunities - vulnerability - temperatures - uncertainty - variability - projections
Exploring adaptation strategies for different climate change scenarios to support agricultural production and food security is a major concern to vulnerable regions, including Ethiopia. This study assesses the potential impacts of climate change on maize yield and explores specific adaptation options under climate change scenarios for the Central Rift Valley of Ethiopia by mid-century. Impacts and adaptation options were evaluated using three General Circulation Models (GCMs) in combination with two Representative Concentration Pathways (RCPs) and two crop models. Results indicate that maize yield decreases on average by 20 % in 2050s relative to the baseline (1980–2009) due to climate change. A negative impact on yield is very likely, while the extent of impact is more uncertain. The share in uncertainties of impact projections was higher for the three GCMs than it was for the two RCPs and two crop models used in this study. Increasing nitrogen fertilization and use of irrigation were assessed as potentially effective adaptation options, which would offset negative impacts. However, the response of yields to increased fertilizer and irrigation will be less for climate change scenarios than under the baseline. Changes in planting dates also reduced negative impacts, while changing the maturity type of maize cultivars was not effective in most scenarios. The multi-model based analysis allowed estimating climate change impact and adaptation uncertainties, which can provide valuable insights and guidance for adaptation planning.
Letter : Rising temperatures reduce global wheat production
Asseng, S. ; Ewert, F. ; Martre, P. ; Rötter, R.P. ; Cammarano, D. ; Kimball, B.A. ; Ottman, M.J. ; Wall, G.W. ; White, J.W. ; Reynolds, M.P. ; Alderman, P.D. ; Prasad, P.V.V. ; Lobell, D.B. ; Aggarwal, P.K. ; Anothai, J. ; Basso, B. ; Biernath, C. ; Challinor, A.J. ; Sanctis, G. De; Doltra, J. ; Fereres, E. ; Garcia-Vila, M. ; Gayler, S. ; Hoogenboom, G. ; Hunt, L.A. ; Izaurralde, C. ; Jabloun, M. ; Jones, C.D. ; Kersebaum, K.C. ; Koehler, A.K. ; Müller, C. ; Naresh Kumar, S. ; Nendel, C. ; O’Leary, G. ; Olesen, J.E. ; Palosuo, T. ; Priesack, E. ; Eyshi Rezae, E. ; Ruane, A.C. ; Semenov, M.A. ; Shcherbak, I. ; Stöckle, C.O. ; Stratonovitch, P. ; Streck, T. ; Supit, I. ; Tao, T. ; Thorburn, P. ; Waha, K. ; Wang, E. ; Wallach, D. ; Wolf, J. ; Zhao, Z. ; Zhu, Y. - \ 2015
Nature Climate Change 5 (2015). - ISSN 1758-678X - p. 143 - 147.
climate-change - spring wheat - dryland wheat - yield - growth - drought - heat - co2 - agriculture - adaptation
Crop models are essential tools for assessing the threat of climate change to local and global food production(1). Present models used to predict wheat grain yield are highly uncertain when simulating how crops respond to temperature(2). Here we systematically tested 30 different wheat crop models of the Agricultural Model Intercomparison and Improvement Project against field experiments in which growing season mean temperatures ranged from 15 degrees C to 32 degrees C, including experiments with artificial heating. Many models simulated yields well, but were less accurate at higher temperatures. The model ensemble median was consistently more accurate in simulating the crop temperature response than any single model, regardless of the input information used. Extrapolating the model ensemble temperature response indicates that warming is already slowing yield gains at a majority of wheat-growing locations. Global wheat production is estimated to fall by 6% for each degrees C of further temperature increase and become more variable over space and time.
Assessing the impact of changes in the electricity price structure on dairy farm energy costs
Upton, J.R. ; Murphy, M. ; Shalloo, L. ; Groot Koerkamp, P.W.G. ; Boer, I.J.M. de - \ 2015
Applied energy 137 (2015). - ISSN 0306-2619 - p. 1 - 8.
demand-side management - once-daily milking - consumption - buildings - yield - model - cows
This study aims to provide information on the changes in electricity consumption and costs on dairy farms, through the simulation of various electricity tariffs that may exist in the future and how these tariffs interact with changes in farm management (i.e. shifting the milking operation to an earlier or later time of the day). A previously developed model capable of simulating electricity consumption and costs on dairy farms (MECD) was used to simulate five different electricity tariffs (Flat, Day&Night, Time of Use Tariff 1 (TOU1), TOU2 and Real Time Pricing (RTP)) on three representative Irish dairy farms: a small farm (SF), a medium farm (MF) and a large farm (LF). The Flat tariff consisted of one electricity price for all time periods, the Day&Night tariff consisted of two electricity prices, a high rate from 09:00 to 00:00 h and a low rate thereafter. The TOU tariff structure was similar to that of the Day&Night tariff except that a peak price band was introduced between 17:00 and 19:00 h. The RTP tariff varied dynamically according to the electricity demand on the national grid. The model used in these simulations was a mechanistic mathematical representation of the electricity consumption that simulated farm equipment under the following headings; milk cooling system, water heating system, milking machine system, lighting systems, water pump systems and the winter housing facilities. The effect of milking start time was simulated to determine the effect on electricity consumption and costs at farm level. The earliest AM milking start time and the latest PM milking start time resulted in the lowest energy consumption. The difference between the lowest and highest electricity consumption within a farm was 7% for SF, 5% for MF and 5% for LF. This difference was accounted for by the variation in the milk cooling system coefficient of performance. The greatest scope to reduce total annual electricity costs by adjusting milking start times was on TOU2 (39%, 34% and 33% of total annual electricity costs on the SF, MF and LF) and the least scope for reductions using this method was on the Flat tariff (7%, 5% and 7% of total annual electricity costs). The potential for reduction of annual electricity consumption and related costs per litre of milk produced by adjusting milking times was higher for the LF than the SF or MF across all electricity tariffs. It is anticipated that these results and the use of the MECD will help support the decision-making process at farm level around increasing energy efficiency and electricity cost forecasts in future electricity pricing tariff structures
Farmers’ views on the future prospects of aerobic rice culture in Pakistan
Awan, M.I. ; Oort, P.A.J. van; Ahmad, R. ; Bastiaans, L. ; Meinke, H.B. - \ 2015
Land Use Policy 42 (2015). - ISSN 0264-8377 - p. 517 - 526.
agricultural technology - seeded rice - water-use - systems - irrigation - adoption - performance - growth - punjab - yield
In parts of Pakistan, the sustainability of conventional flooded rice systems is threatened by diminishingresources, particularly – land, water, and labour. The adoption of aerobic rice system (ARS), an alterna-tive to the conventional systems, could considerably increase resource-use efficiencies. Information onfarmer perceptions is vital to identify socio-technological factors of adoption. Our aim was to under-stand and analyse farmer perceptions about ARS in regards to future adoption. We conducted our studyin the Pakistani Punjab with three groups of farmers: (I) informant farmers in rice–wheat system whotrialled ARS in a participatory research trial (n = 70), (II) rice farmers in rice–wheat, mixed-cropping andcotton–wheat system with no experience of ARS (n = 97), and (III) non-rice farmers in mixed-croppingand cotton–wheat system (n = 48). Data were collected using a pretested semi-structured questionnaireand analysed by using descriptive statistics and chi-square tests. More than half of respondents in groupsII and III had never heard of ARS, though, 76% were open to experimenting. Across three groups, farmersperceived ARS as a means of increasing resource-use efficiency particularly for labour, net profitabil-ity, and an option for crop diversification in the mixed-cropping system. Perceived threats were weeds,diseases, poor germination, spikelet sterility, low yields, and frequent irrigation requirement. Decidingfactors for repeat ARS plantings by group I were: ease of operation due to direct seeding, good income,and low input requirement. Deciding factors against repeat plantings were: unavailability of suitable finegrain basmati varieties, falling water table, weed problem, and unsuitable soil type. The results suggestthat aerobic rice is an interesting alternative to traditional rice production as evident from the willingnessto plant again by 73% group I demonstration households but the unavailability of well-adapted basmativarieties hampers its expansion. Farmers’ appreciation of risks and benefits can pave the way for large-scale adoption. Associated risks can be reduced by filling the identified knowledge or technological gapsthrough additional research and farmer awareness programmes.
On-farm impact of the System of Rice Intensification (SRI): Evidence and knowledge gaps
Berkhout, E.D. ; Glover, D.B.A. ; Kuyvenhoven, A. - \ 2015
Agricultural Systems 132 (2015). - ISSN 0308-521X - p. 157 - 166.
identifying changes - timor leste - technology - madagascar - productivity - cultivation - adoption - india - yield - dynamics
The System of Rice Intensification (SRI) is being promoted worldwide, but relatively little is yet known about its impacts at farm level. This article reviews available evidence on the impact of SRI practices in terms of yield and productivity. Adoption of SRI practices necessarily changes the mix and allocation of inputs, in particular of water, seeds, fertiliser and labour. However, SRI impact studies have generally failed to distinguish between technological change – a more productive use of inputs, evidenced by a change in total factor productivity – increases in input use, or selection effects and their respective effects on yields. The studies reviewed point not only to modest increases in rice yields associated with SRI adoption, but also to concurrent increases in labour and fertiliser use. Often SRI is selectively practised on more fertile plots. As a result, no firm evidence on changes in total factor productivity can be discerned, while partial productivities of land and labour show mixed results. Though yields tend to be higher under SRI management, risk also seems to increase, which initially favours adoption by better-endowed farmers and on better soils. Evidence on SRI impact is further complicated by the large diversity of SRI practices associated with different biophysical, socio-economic and institutional circumstances. We conclude by identifying knowledge gaps surrounding the SRI phenomenon, encompassing agro-technical aspects, socio-economic issues and (dis)adoption behaviour.
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