Staff Publications

Staff Publications

  • external user (warningwarning)
  • Log in as
  • language uk
  • About

    '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.

    We have a manual that explains all the features 

Current refinement(s):

Records 1 - 20 / 43

  • help
  • print

    Print search results

  • export

    Export search results

  • alert
    We will mail you new results for this query: keywords==Nitrogen
Check title to add to marked list
Agricultural nitrogen and phosphorus emissions to water and their mitigation options in the Haihe Basin, China
Zhao, Zhanqing ; Qin, Wei ; Bai, Zhaohai ; Ma, Lin - \ 2019
Agricultural Water Management 212 (2019). - ISSN 0378-3774 - p. 262 - 272.
Crop-livestock system - Haihe Basin - Nitrogen - NUFER - Phosphorus - Water pollution

Agricultural nitrogen (N) and phosphorus (P) emissions to water bodies remain largely unknown in China, mainly due to the lack of reliable data sources and quantification tools. In this study, we constructed a grid-based NUFER (NUtrient Flow in food chains, Environment and Resources use) model in order to quantify a high-resolution agricultural N and P emissions to water bodies in Haihe Basin in 2012, based on data collected from county-level statistics, farm interview, and spatial data of topography, climate, soil texture, and land use. We also explored the mitigation strategies in 2030 via scenario analysis. The results showed that total agricultural N emission to water bodies in Haihe Basin was 1079 Gg N in 2012, of which cropland contributed 54%; total agricultural P emission to water bodies was 208 Gg P, livestock contributed 78%. There were large spatial variations in agricultural N and P emissions. Overall, the plain areas accounted for around 80% of the total agricultural N and P emissions to water in 2012. The highest N and P emission intensities were 10 t N km−2 and 2 t P km−2, respectively. N and P emissions were significantly related to anthropogenic factors (such as the livestock density and cropland) in the plain areas; whereas in mountainous areas, both anthropogenic and natural factors (e.g., slope deviation and soil texture) significantly affected N and P emissions. Our scenario analysis suggests that agricultural N and P emissions can be reduced by up to 45% and 77%, respectively for N and P in 2030, via improved agricultural and environmental policies, technologies and managements. The prohibition of direct animal manure discharge to the water system seems to be the most effective measure to mitigate the emissions. Our study provided a high-resolution agricultural N and P emissions to the water bodies of Haihe Basin and identified the most effective options to reduce these emissions in highly intensified agricultural areas.

Simulation of soil organic carbon effects on long-term winter wheat (Triticum aestivum) production under varying fertilizer inputs
Ghaley, Bhim B. ; Wösten, Henk ; Olesen, Jørgen E. ; Schelde, Kirsten ; Baby, Sanmohan ; Karki, Yubaraj K. ; Børgesen, Christen D. ; Smith, Pete ; Yeluripati, Jagadeesh ; Ferrise, Roberto ; Bindi, Marco ; Kuikman, Peter ; Lesschen, Jan Peter ; Porter, John R. - \ 2018
Frontiers in Plant Science 9 (2018). - ISSN 1664-462X
Crop productivity - DAISY model - Grain yield - Long-term experiment - Nitrogen - Pedotransfer functions - Plant available water

Soil organic carbon (SOC) has a vital role to enhance agricultural productivity and for mitigation of climate change. To quantify SOC effects on productivity, process models serve as a robust tool to keep track of multiple plant and soil factors and their interactions affecting SOC dynamics. We used soil-plant-atmospheric model viz. DAISY, to assess effects of SOC on nitrogen (N) supply and plant available water (PAW) under varying N fertilizer rates in winter wheat (Triticum aestivum) in Denmark. The study objective was assessment of SOC effects on winter wheat grain and aboveground biomass accumulation at three SOC levels (low: 0.7% SOC; reference: 1.3% SOC; and high: 2% SOC) with five nitrogen rates (0–200 kg N ha−1) and PAW at low, reference, and high SOC levels. The three SOC levels had significant effects on grain yields and aboveground biomass accumulation at only 0–100 kg N ha−1 and the SOC effects decreased with increasing N rates until no effects at 150–200 kg N ha−1. PAW had significant positive correlation with SOC content, with high SOC retaining higher PAW compared to low and reference SOC. The mean PAW and SOC correlation was given by PAW% = 1.0073 × SOC% + 15.641. For the 0.7–2% SOC range, the PAW increase was small with no significant effects on grain yields and aboveground biomass accumulation. The higher winter wheat grain and aboveground biomass was attributed to higher N supply in N deficient wheat production system. Our study suggested that building SOC enhances agronomic productivity at only 0–100 kg N ha−1. Maintenance of SOC stock will require regular replenishment of SOC, to compensate for the mineralization process degrading SOC over time. Hence, management can maximize realization of SOC benefits by building up SOC and maintaining N rates in the range 0–100 kg N ha−1, to reduce the off-farm N losses depending on the environmental zones, land use and the production system.

Relationship between home-field advantage of litter decomposition and priming of soil organic matter
Lonardo, D.P. di; Manrubia, M. ; Boer, W. de; Zweers, H. ; Veen, G.F. ; Wal, A. van der - \ 2018
Soil Biology and Biochemistry 126 (2018). - ISSN 0038-0717 - p. 49 - 56.
C-plant litter - Carbon cycling - Home field advantage - Nitrogen - Priming effect - Soil organic matter

Home field advantage (HFA; acceleration of plant litter decomposition in soils that receive their indigenous litter) and priming effects (PE; short-term changes in the turnover of soil organic matter caused by the addition of fresh organic carbon) are two aspects of decomposition processes that are driven by the composition and functioning of soil decomposer communities. Physicochemical similarity between added organic compounds and soil organic matter fractions has been indicated as an important steering factor of PE. It is unknown whether PE, like litter decomposition, experience HFA, i.e., whether PE are higher than expected in soils receiving their own litter due to specialization of the decomposer community. Here we studied both HFA and PE by measuring litter- and SOM-derived carbon (C) fluxes after the addition of fresh plant litter. We reciprocally incubated three 13C labelled litter types (maize, bent and beech) in soils from ecosystems where these litters are abundantly produced (e.g., arable sites, grasslands and forests), with and without the addition of mineral nitrogen (N). Generally, respiration of both litter-derived and SOM-derived C were lowest when beech litter was added, and were lower in forest soils than in arable or grassland soils. N addition generally slightly increased the respiration of litter-derived C, but had no effect on SOM-derived C. All litter types induced a positive PE in all soils. HFA effects were not significantly different from zero, but were significantly higher in grasslands than in maize fields amended with nitrogen. We found a positive relationship between litter and priming HFA, indicating that the rates of both litter decomposition and PE may be affected in the same manner by home combinations of plant and litter versus away combinations. This positive relationship disappeared when N was added. Our results provide a first indication that the extent to which indigenous soil microbes are specialized to breakdown home litter, not only accelerates or decelerates the decomposition of litter, but affects the breakdown of SOM in the same way. This could imply that a specialized litter decomposer community driving HFA can further accelerate soil C mineralization via enhanced induction of PE. Therefore, the impact of specialized decomposer communities on the dynamics of soil C pools may be bigger than expected from HFA of litter decomposition alone.

A comparison of disaggregated nitrogen budgets for Danish agriculture using Europe-wide and national approaches
Kros, Johannes ; Hutchings, Nicholas J. ; Kristensen, Inge Toft ; Kristensen, Ib Sillebak ; Børgesen, Christen Duus ; Voogd, Jan Cees ; Dalgaard, Tommy ; Vries, Wim de - \ 2018
Science of the Total Environment 643 (2018). - ISSN 0048-9697 - p. 890 - 901.
Agricultural soils - Budgets - Disaggregation - Modelling - National - Nitrogen

Spatially detailed information on agricultural nitrogen (N) budgets is relevant to identify regions where there is a need for a reduction in inputs in view of various forms of N pollution. However, at the scale of the European Union, there is a lack of consistent, reliable, high spatial resolution data necessary for the calculation of regional N losses. To gain insight in the reduction in uncertainty achieved by using higher spatial resolution input data. This was done by comparing spatially disaggregated agricultural N budgets for Denmark for the period 2000–2010, generated by two versions of the European scale model Integrator, a version using high spatial resolution national data for Denmark (Integrator-DK) and a version using available data at the EU scale (Integrator-EU). Results showed that the national N fluxes in the N budgets calculated by the two versions of the model were within 1–5% for N inputs by fertilizer and manure excretion, but inputs by N fixation and N mineralisation differed by 50–100% and N uptake also differed by ca 25%, causing a difference in N leaching and runoff of nearly 50%. Comparison with an independently derived Danish national budget appeared generally to be better with Integrator-EU results in 2000 but with Integrator-DK results in 2010. However, the spatial distribution of manure distribution and N losses from Integrator-DK were closer to observed distributions than those from Integrator-EU. We conclude that close attention to local agronomic practices is needed when using a leaching fraction approach and that for effective support of environmental policymaking, Member States need to collect or submit high spatial resolution agricultural data to Eurostat.

Drought and soil fertility modify fertilization effects on aphid performance in wheat
Tamburini, Giovanni ; Gils, Stijn van; Kos, Martine ; Putten, Wim van der; Marini, Lorenzo - \ 2018
Basic and Applied Ecology 30 (2018). - ISSN 1439-1791 - p. 23 - 31.
Agricultural intensification - Cereals - Climate change - Grain aphid - Nitrogen - Soil organic matter - Water availability

Agricultural intensification and climate change are expected to affect pest performance through excessive inputs of chemical fertilizers and increased probability of extreme drought events. Potential interactive effects of fertilization and water availability on aboveground pest performance may depend on soil fertility because of its effect on nutrient availability. In a greenhouse experiment, we examined the effects of inorganic fertilization on the performance of the grain aphid (Sitobion avenae, F.), an important pest of wheat, under different conditions of soil fertility and water availability. We found soil fertility and water availability to influence the positive effects of inorganic fertilizers on aphid growth, i.e. fertilization promoted faster aphid development time and higher fecundity and biomass under low fertility and under well-watered conditions. Moreover, although increased soil fertility favored aphid growth under well-watered conditions, it simultaneously sustained plant development. The current practices promoting soil fertility do not have direct negative consequence on crop protection under conventional cropping systems.

Reducing external costs of nitrogen pollution by relocation of pig production between regions in the European Union
Grinsven, Hans J.M. van; Dam, Jan D. van; Lesschen, Jan Peter ; Timmers, Marloes H.G. ; Velthof, Gerard L. ; Lassaletta, Luis - \ 2018
Regional Environmental Change (2018). - ISSN 1436-3798 - 13 p.
European Union - External cost - Nitrogen - Pig industry - Spatial optimization

This paper tests the hypothesis that relocation of pig production within the EU27 can reduce the external costs of nitrogen (N) pollution. The external cost of pollution by ammonia and nitrate from agriculture in the European Union (EU27) in 2008 was estimated at 61–215 billion € (0.5 to 1.8% of the GDP). Per capita it ranged from more than 1000 € in north-west EU27 to 50 € in Romania. The average contribution of pig production was 15%. Using provincial data (224 NUTS2 regions in EU27), the potential reduction of external N cost by relocation of pig production was estimated at 14 billion € (10% of the total). Regions most eligible for decreasing the pig stock were in western Germany, Flemish region, Denmark, the Netherlands and Bretagne, while Romania is most eligible for increasing pig production. Relocating 20 million pigs (13% of the total EU stock) decreased average external costs per capita from 900 to 785 € in the 13 NUTS2 regions where pigs were removed and increased from 69 to 107 € in 11 regions receiving pigs. A second alternative configuration of pig production was targeted at reducing exceedance of critical N deposition and closing regional nutrient cycles. This configuration relocates pigs within Germany and France, for example from Bretagne to Northern France and from Weser-Ems to Oberbayern. However, total external cost increases due to an increase of health impacts, unless when combined with implementation of best N management practices. Relocation of the pig industry in the EU27 will meet many socio-economic barriers and realisation requires new policy incentives.

Animal manure use in vegetable production in the Netherlands
Haan, J. de; Geel, W. van - \ 2018
In: 5th International Symposium on Ecologically Sound Fertilization Strategies for Field Vegetable Production. - International Society for Horticultural Science (Acta Horticulturae ) - ISBN 9789462611887 - p. 73 - 80.
Manure - Nitrogen - Organic matter - Phosphate - Regulations - Vegetables
Application of animal manure in vegetables, when used right, can improve soil quality, crop production and financial returns on the long term. Use of animal manure closes nutrient and carbon cycles and contributes to several ecosystem services. The composition of animal manure varies considerably depending on animal species, housing system and feeding of animals. It is important to account for the composition of the manure when using it in vegetable production. Important aspects are the right selection of manure type, matching crop needs in nutrients and organic matter, and the right application of manure in time and place with minimum emissions. Animal manure is ample available in the Netherlands. It is widely used to cover nutrient needs and to sustain soil fertility in the intensive crop rotations in the Netherlands. Manure use in the Netherlands is severely restricted by legislation on nitrogen and phosphorus to prevent emissions to ground and surface water. Processing of animal manure is emerging to be able to use more manure in crop production efficiently next to other advantages for the animal farmer. Important processing techniques developed are 1) anaerobic digestion and 2) separation of manure in a liquid and a solid fraction combined with reversed osmosis making mineral concentrates. The value of animal manure for arable and vegetable crop production is difficult to calculate, especially for organic matter as it affects multiple processes in soil and plant growth. A first estimation of the value of animal manure for arable and vegetable farming on sandy soils is made based on a long-term experiment with different organic matter input treatments. Total value of slurry in the Netherlands is estimated between € 35 and 57 t-1 or € 430 and 2240 ha-1 based on input of 60 kg ha-1 of phosphate with slurry.
Plant species occurrence patterns in Eurasian grasslands reflect adaptation to nutrient ratios
Roeling, Ineke S. ; Ozinga, Wim A. ; Dijk, Jerry van; Eppinga, Maarten B. ; Wassen, Martin J. - \ 2018
Oecologia 186 (2018)4. - ISSN 0029-8549 - p. 1055 - 1067.
Niche - Nitrogen - Phosphorus - Species composition - Stoichiometry
Previous studies of Eurasian grasslands have suggested that nutrient ratios, rather than absolute nutrient availabilities and associated productivity, may be driving plant species richness patterns. However, the underlying assumption that species occupy distinct niches along nutrient ratio gradients remains to be tested. We analysed plant community composition and nutrient status of 644 Eurasian wet grassland plots. The importance of nutrient ratios driving variation in species composition was analysed using ordination methods (DCA and CCA). Subsequently, we assessed the niche position and width along the most important nutrient ratio gradient [N:P] for each species. We found that the N:P ratio explained part of the variation in species composition independent from conventional explanatory variables. The N:P ratio explained less variation than soil moisture or pH, but more than productivity or the availability of N and P separately, highlighting its importance for grassland species composition. Species occupied distinct niches along the N:P gradient, and species’ niche widths decreased toward extreme nutrient limitation. After correcting for niche position, there was no overall difference in niche width between endangered and non-endangered species. Surprisingly, endangered species with niche optima at the extreme P-limited end of the gradient had broader niches than their non-endangered counterparts. As species occupied distinct niches along a nutrient ratio gradient, future grassland conservation efforts may benefit from targeting changes in nutrient ratios, i.e. the balance between N and P, rather than only focussing on a general reduction in nutrient availability. However, what management interventions can be used for this purpose remains unclear.
Feasibility of coupled empirical and dynamic modeling to assess climate change and air pollution impacts on temperate forest vegetation of the eastern United States
McDonnell, T.C. ; Reinds, G.J. ; Sullivan, T.J. ; Clark, C.M. ; Bonten, L.T.C. ; Mol-Dijkstra, J.P. ; Wamelink, G.W.W. ; Dovciak, M. - \ 2018
Environmental Pollution 234 (2018). - ISSN 0269-7491 - p. 902 - 914.
Acidification - Biodiversity - Climate change - Forest understory - Nitrogen
Changes in climate and atmospheric nitrogen (N) deposition caused pronounced changes in soil conditions and habitat suitability for many plant species over the latter half of the previous century. Such changes are expected to continue in the future with anticipated further changing air temperature and precipitation that will likely influence the effects of N deposition. To investigate the potential long-term impacts of atmospheric N deposition on hardwood forest ecosystems in the eastern United States in the context of climate change, application of the coupled biogeochemical and vegetation community model VSD+PROPS was explored at three sites in New Hampshire, Virginia, and Tennessee. This represents the first application of VSD+PROPS to forest ecosystems in the United States. Climate change and elevated (above mid-19th century) N deposition were simulated to be important factors for determining habitat suitability. Although simulation results suggested that the suitability of these forests to support the continued presence of their characteristic understory plant species might decline by the year 2100, low data availability for building vegetation response models with PROPS resulted in uncertain results at the extremes of simulated N deposition. Future PROPS model development in the United States should focus on inclusion of additional foundational data or alternate candidate predictor variables to reduce these uncertainties. Climate change and elevated N deposition were simulated to be important factors for determining habitat suitability for plants, and are expected to interact with changes in soil chemistry.
Relationships between leaf mass per area and nutrient concentrations in 98 Mediterranean woody species are determined by phylogeny, habitat and leaf habit
Riva, Enrique G. de la; Villar, Rafael ; Pérez-Ramos, Ignacio M. ; Quero, José Luis ; Matías, Luis ; Poorter, Lourens ; Marañón, Teodoro - \ 2018
Trees-Structure and Function 32 (2018)2. - ISSN 0931-1890 - p. 497 - 510.
Functional traits - Leaf economics spectrum - Nitrogen - Phosphorus - Phylogenetic independent contrast (PIC) - Stoichiometry
Key message: This study reinforces the existence of the leaf economics spectrum in Mediterranean woody species, and demonstrates the strong influence of phylogeny, leaf habit and environmental context as main drivers of variability in structural and nutrient traits of leaves. Abstract: Leaf structural and nutrient traits are key attributes of plant ecological strategies, as these traits are related to resource-use strategies and plant growth. However, leaf structure and nutrient composition can vary among different habitats, leaf habits or phylogenetic groups. In this study, we measured 13 leaf traits (one structural—leaf mass per area, LMA—and 12 nutrient traits) in 98 Mediterranean woody species growing over a wide range of environmental conditions, with the final aim of discerning the main causes of leaf trait variability. The variance decomposition results show that phylogeny, leaf habit and habitat type affected in several ways the structural and nutrient traits studied. Leaf nutrient concentrations are strongly positively correlated amongst themselves, and negatively correlated with LMA, in accordance with the “leaf economics spectrum”. We found that leaf habit and phylogeny were important causes of variation in LMA and in a broad number of leaf nutrients (i.e., C, N, Mg, S, K), while other micronutrients seemed to be more dependent on the environment (i.e., Cu and Mn). In summary, our study reinforces the existence of the leaf economics spectrum in a broad pool of Mediterranean woody species, and demonstrates the strong influence of phylogeny, leaf habit and environmental context as the main drivers of variability in some leaf structural and nutrient traits.
Sink-source relationship during rice grain filling is associated with grain nitrogen concentration
Wei, Huanhe ; Meng, Tianyao ; Li, Xiaoyun ; Dai, Qigen ; Zhang, Hongcheng ; Yin, Xinyou - \ 2018
Field Crops Research 215 (2018). - ISSN 0378-4290 - p. 23 - 38.
Grain filling - Model - Nitrogen - Oryza sativa - Source/sink ratio
High grain nitrogen (N) concentration in crops may require to translocate more N from the vegetative tissues, cause faster plant senescence, alter sink-source balance during grain filling, and ultimately lower grain yield. Previous studies have shown that indica hybrid rice (IH) have shorter grain-filling period, and lower biomass and grain yield, compared with japonica/indica hybrid rice (JIH) and japonica conventional inbred rice (JC) in China. We hypothesise that these are caused by early senescence and poor sink-source balance after heading in IH as a result of its high grain N concentration. In this study, two JIH, two JC, and two IH varieties were grown in 2013 and 2014 at Ningbo, and in 2015 and 2016 at Yangzhou, China, and the observed dynamics of grain and crop biomass were fitted to mathematical equations to quantify sink-source relationships during grain filling. Compared with JC and IH varieties, JIH varieties showed higher sink growth and source capacity and 7.5–21.6% higher grain yield across years and sites. In JIH and JC genotypes, total source during grain filling was higher than the total sink value, whereas opposite was observed for IH genotypes. Source-sink difference, source/sink ratio, and grain-filling duration all negatively (P < 0.01) correlated with grain N concentration at maturity. Compared with JIH and JC, IH accumulated more N in grains and translocated more N from leaf during the period from heading to maturity. We conclude that early senescence and poor sink-source balance after heading of IH was linked to its high grain N concentration, and sink-source relationships during rice grain filling were associated with grain N concentration. Further breeding and cultivation programmes should aim at improving sink-related traits in JIH and JC genotypes, whereas for IH varieties, whether yield was set by sink size or by any limited availability of pre-heading reserves remains to be further examined.
Can our global food system meet food demand within planetary boundaries?
Conijn, J.G. ; Bindraban, P.S. ; Schröder, J.J. ; Jongschaap, R.E.E. - \ 2018
Agriculture, Ecosystems and Environment 251 (2018). - ISSN 0167-8809 - p. 244 - 256.
Food system - GHG emission - Land use - Nitrogen - Phosphorus - Planetary boundaries - Sustainability
Global food demand is expected to increase, affecting required land, nitrogen (N) and phosphorus (P) inputs along with unintended emissions of greenhouse gasses (GHG) and losses of N and P. To quantify these input requirements and associated emissions/losses as a function of food demand, we built a comprehensive model of the food system and investigated the effects of multiple interventions in the food system on multiple environmental goals. Model outcomes are compared to planetary boundaries for land system change, climate change and the global N and P cycles to identify interventions that direct us towards a safe operating space for humanity. Results show a transgression of most boundaries already for 2010 and a drastic deterioration in the reference scenario for 2050 in which no improvements relative to 2010 were implemented. We defined the following improvements for 2050: reduction of waste, less consumption of animal products, higher feed conversion efficiency, higher crop and grassland yields, reduction of N and P losses from agricultural land and reduction of ammonia (NH3) volatilization. The effects of these measures were quantified individually and in combination. Significant trade-offs and synergies in our results underline the importance of a comprehensive analysis with respect to the entire food system, including multiple measures and environmental goals. The combination of all measures was able to partly prevent transgression of the boundaries for: agricultural area requirement, GHG emission and P flow into the ocean. However, global mineral N and P fertilizer inputs and total N loss to air and water still exceeded their boundaries in our study. The planetary boundary concept is discussed in relation to the selected variables and boundary values, including the additional necessity of eliminating the dependency of our food production on finite P reserves. We argue that total N loss is a better indicator of the environmental impacts of the global N cycle than fertilizer N input. Most measures studied in this paper are also on the agenda of the United Nations for Sustainable Development, which gives added support to their implementation.
Balanced N and C input recommendations for rain-fed maize production in northern China based on N balances and grain yields
Wang, Xiaobin ; Cai, Dianxiong ; Zhao, Quansheng ; Xie, Xiaohong ; Hoogmoed, Willem B. ; Oenema, Oene - \ 2018
Journal of the Science of Food and Agriculture 98 (2018)3. - ISSN 0022-5142 - p. 872 - 883.
Carbon - Dryland - Maize - Nitrogen - Rain-fed farming

BACKGROUND: This study aimed to assess longer-term (1993-2009) effects of combined applications of fertiliser, maize stover, and cattle manure on maize yields, partial nitrogen (N) and carbon (C) balances, and water and N-use efficiencies, to guide N and C input recommendations for rain-fed maize production in northern China. RESULTS: The field trial, with three factors at five levels and 12 treatments, was conducted at Shouyang Dryland-Farming Experimental Station, Shanxi, China. Data analysis revealed higher N balances but lower C balances significantly occurred in a dry year than in a wet year. Positive N balances related to higher N inputs resulted in higher soil available N, even downward to deep layers with increasing N inputs, while positive C balances due to higher C inputs could be benefit to increase soil organic C. Based on partial N balances and grain yields, N and C inputs at ranges of 100kg N ha-1 and 1.9-2.9Mg C ha-1 could be recommended for target yields of 6.7-7.2Mg ha-1 in rain-fed maize production. CONCLUSION: The study suggests that N balances close to neutral be given priority to improving N-use efficiency, and more positive C balances also be important for sustaining target yields and soil fertility levels.

Nitrogen fertiliser replacement values for organic amendments appear to increase with N application rates
Hijbeek, R. ; Berge, H.F.M. ten; Whitmore, A.P. ; Barkusky, D. ; Schroder, J.J. ; Ittersum, M.K. van - \ 2018
Nutrient Cycling in Agroecosystems 110 (2018)1. - ISSN 1385-1314 - p. 105 - 115.
Crop yield - Mineral fertiliser - Mineral fertiliser equivalent - Nitrogen - Nitrogen fertiliser replacement value - Organic amendments - Soil fertility

Nitrogen (N) supply from organic amendments [such as farmyard manure (FYM), slurries or crop residues] to crops is commonly expressed in the amendment’s Nitrogen Fertiliser Replacement Value (NFRV). Values for NFRV can be determined by comparison of crop yield or N uptake in amended plots against mineral fertiliser-only plots. NFRV is then defined as the amount of mineral fertiliser N saved when using organic amendment-N (kg/kg), while attaining the same crop yield. Factors known to affect NFRV are crop type cultivated, soil type, manuring history and method or time of application. We investigated whether long-term NFRV depends on N application rates. Using data from eight long term experiments in Europe, values of NFRV at low total N supply were compared with values of NFRV at high total N supply. Our findings show that FYM has a significant higher NFRV value at high total N supply than at low total N supply (1.12 vs. 0.53, p = 0.04). For the other amendment types investigated, NFRV was also higher at high total N supply than at low total N supply, but sample sizes were too small or variations too large to detect significant differences. Farmers in Europe usually operate at high rates of total N applied. If fertiliser supplements are based on NFRV of the manure estimated at low total N supply, N fertiliser requirements might be overestimated. This might lead to overuse of N, lower N use efficiency and larger losses of N to the environment.

What plant functional traits can reduce nitrous oxide emissions from intensively managed grasslands?
Abalos Rodriguez, Diego ; Groenigen, Jan Willem van; Deyn, Gerlinde B. De - \ 2018
Global Change Biology 24 (2018)1. - ISSN 1354-1013 - p. e248 - e258.
Functional traits - Grassland - Nitrogen - Nitrous oxide - Plant traits - Plant-microbe interactions

Plant species exert a dominant control over the nitrogen (N) cycle of natural and managed grasslands. Although in intensively managed systems that receive large external N inputs the emission of the potent greenhouse gas nitrous oxide (N2O) is a crucial component of this cycle, a mechanistic relationship between plant species and N2O emissions has not yet been established. Here we use a plant functional trait approach to study the relation between plant species strategies and N2O emissions from soils. Compared to species with conservative strategies, species with acquisitive strategies have higher N uptake when there is ample N in the soil, but also trigger N mineralization when soil N is limiting. Therefore, we hypothesized that (1) compared to conservative species, species with acquisitive traits reduce N2O emissions after a high N addition; and (2) species with conservative traits have lower N2O emissions than acquisitive plants if there is no high N addition. This was tested in a greenhouse experiment using monocultures of six grass species with differing above- and below-ground traits, growing across a gradient of soil N availability. We found that acquisitive species reduced N2O emissions at all levels of N availability, produced higher biomass and showed larger N uptake. As such, acquisitive species had 87% lower N2O emissions per unit of N uptake than conservative species (p < .05). Structural equation modelling revealed that specific leaf area and root length density were key traits regulating the effects of plants on N2O emission and biomass productivity. These results provide the first framework to understand the mechanisms through which plants modulate N2O emissions, pointing the way to develop productive grasslands that contribute optimally to climate change mitigation.

Hydroponically grown leek : Slowly growing to maturity
Os, E.A. van; Weel, P.A. van; Wilms, J.A.M. ; Bruins, M.A. ; Verhoeven, J. ; Wijk, K. van - \ 2017
In: Proceedings of the ICESC2015. - International Society for Horticultural Science (Acta Horticulturae ) - ISBN 9789462611726 - p. 79 - 86.
Deep flow technique - Floating panels - Nitrogen - Nitrogen efficiency - Water

Leek traditionally grows in a sandy soil in the open field in The Netherlands. However, the vulnerability of sandy soils to leaching of nutrients to ground- and surface water is high. Therefore leek was chosen for experiments to be grown out of the soil in the open field. Investigations took place to certain aspects of system development which were reported in 2011. During the following years the research focused on commercializing the design (supporting tubes in floating panels in a DFT system), upscaling the system to several ponds of 200 m2, marketing the product, solving specific problems which appear during those experiments (oxygen content of the nutrient solution, continuous circulation, virus symptoms) and economic aspects. The semi-commercial system developed was based on various trials at which a plant density of more than 70 plants m-2 is needed to achieve plants of more than 200 g which are thicker than 2.0 cm. Hydroponically grown leek should be graded before planting on the panels. Fast growing cultivars should be chosen year round. Uniform planting material is needed for a uniform, single date, harvest. The age of the plant is of less importance for the quality of the harvested product. This gives flexibility in the planting date which often depends on the harvesting date of the former crop and, consequently the weather before. Besides the plants should be >20 g to be planted in the 20 cm long tubes, otherwise the growth is delayed (no catchment of light inside the tube). The cultivation period was similar to earlier trials (50-75 d). The taste of hydroponically grown leek was comparable with leeks raised in soil. During cultivation, symptoms of the yellow stripe virus were seen more frequent compared to soil grown leek. Reuse of the nutrient solution during 4 crops a year saves about 50% of the fertilizers required. Another aspect of importance in The Netherlands is the surplus of rainfall (800 mm average year-1) during the growing season compared to the water uptake (300-500 mm). Adaptation of the system or discharge strategy was investigated Hydroponically grown leek slowly grows to a mature cultivation system by solving the topics mentioned-above, therefor it can be used by commercial growers now. The importance of a slow upscale was proven by the appearance of several unforeseen aspects (oxygen, rainfall, duration of irrigation), while in marketing a first step is taken to bring hydroponically grown leek as a distinguishable product.

Agronomic effects of bovine manure : A review of long-term European field experiments
Zavattaro, Laura ; Bechini, Luca ; Grignani, Carlo ; Evert, Frits K. van; Mallast, Janine ; Spiegel, Heide ; Sandén, Taru ; Pecio, Alicja ; Giráldez Cervera, Juan Vicente ; Guzmán, Gema ; Vanderlinden, Karl ; Hose, Tommy D'; Ruysschaert, Greet ; Berge, Hein F.M. ten - \ 2017
European Journal of Agronomy 90 (2017). - ISSN 1161-0301 - p. 127 - 138.
Efficiency - Farmyard manure - Nitrogen - Response ratio - Slurry - Soil organic carbon

To evaluate the agronomic value of animal manure, we quantified the effects of pedo-climatic, crop and management factors on crop productivity, N use efficiency, and soil organic matter, described with simple indicators that compare manures with mineral fertilizers. We selected 80 European long-term field experiments that used bovine farmyard manure or bovine liquid slurry, alone (FYM and SLU) or combined with mineral fertilizers (FYMm and SLUm), and compared them to mineral fertilizer only reference treatments. We collected 5570 measurements from 107 papers. FYM produced slightly lower crop yields (−9.5%) when used alone and higher (+11.3%) yields when used in combination with N fertilizer (FYMm), compared to those obtained using mineral fertilizers only. Conditions promoting manure-N mineralization (lighter soil texture, warmer temperature, longer growing season, and shallower incorporation depth) significantly increased the effect of FYM/FYMm on crop yield and yield N. The production efficiency of FYM (yield:N applied ratio) was slightly lower than that of mineral fertilizers (-1.6%). The apparent N recoveries of FYM and FYMm were 59.3% and 78.7%, respectively, of mineral fertilizers. Manured soils had significantly higher C (+32.9% on average for FYM and FYMm) and N (+21.5%) concentrations. Compared to mineral fertilizers, yield was reduced by 9.1% with SLU, but not with SLUm. Influencing factors were similar to those of FYM/FYMm. Efficiency indicators indicated SLU (but not SLUm) was less effective than mineral fertilizers. Slurry significantly increased SOC (on average for SLU and SLUm by +17.4%) and soil N (+15.7%) concentrations. In conclusion, compared to mineral N fertilizers, bovine farmyard manure and slurry were slightly less effective on the crop, but determined marked increases to SOC and soil N, and thus, to long-term soil fertility maintenance.

Estimating the energetic cost of feeding excess dietary nitrogen to dairy cows
Reed, K.F. ; Bonfá, H.C. ; Dijkstra, Jan ; Casper, D.P. ; Kebreab, E. - \ 2017
Journal of Dairy Science 100 (2017)9. - ISSN 0022-0302 - p. 7116 - 7126.
Energetics - Nitrogen - Nutrient requirements
Feeding N in excess of requirement could require the use of additional energy to metabolize excess protein, and to synthesize and excrete urea; however, the amount and fate of this energy is unknown. Little progress has been made on this topic in recent decades, so an extension of work published in 1970 was conducted to quantify the effect of excess N on ruminant energetics. In part 1 of this study, the results of previous work were replicated using a simple linear regression to estimate the effect of excess N on energy balance. In part 2, mixed model methodology and a larger data set were used to improve upon the previously reported linear regression methods. In part 3, heat production, retained energy, and milk energy replaced the composite energy balance variable previously proposed as the dependent variable to narrow the effect of excess N. In addition, rumen degradable and undegradable protein intakes were estimated using table values and included as covariates in part 3. Excess N had opposite and approximately equal effects on heat production (+4.1 to +7.6 kcal/g of excess N) and retained energy (-4.2 to -6.6 kcal/g of excess N) but had a larger negative effect on milk gross energy (-52 to -68 kcal/g of excess N). The results suggest that feeding excess N increases heat production, but more investigation is required to determine why excess N has such a large effect on milk gross energy production.
Symbiotic soil fungi enhance ecosystem resilience to climate change
Martínez-García, Laura B. ; Deyn, Gerlinde B. de; Pugnaire, Francisco I. ; Kothamasi, David ; Heijden, Marcel G.A. van der - \ 2017
Global Change Biology 23 (2017)12. - ISSN 1354-1013 - p. 5228 - 5236.
Arbuscular mycorrhizal fungi - Climate change - Nitrogen - Nutrient leaching - Phosphorus - Rainfall regimes

Substantial amounts of nutrients are lost from soils through leaching. These losses can be environmentally damaging, causing groundwater eutrophication and also comprise an economic burden in terms of lost agricultural production. More intense precipitation events caused by climate change will likely aggravate this problem. So far it is unresolved to which extent soil biota can make ecosystems more resilient to climate change and reduce nutrient leaching losses when rainfall intensity increases. In this study, we focused on arbuscular mycorrhizal (AM) fungi, common soil fungi that form symbiotic associations with most land plants and which increase plant nutrient uptake. We hypothesized that AM fungi mitigate nutrient losses following intensive precipitation events (higher amount of precipitation and rain events frequency). To test this, we manipulated the presence of AM fungi in model grassland communities subjected to two rainfall scenarios: moderate and high rainfall intensity. The total amount of nutrients lost through leaching increased substantially with higher rainfall intensity. The presence of AM fungi reduced phosphorus losses by 50% under both rainfall scenarios and nitrogen losses by 40% under high rainfall intensity. Thus, the presence of AM fungi enhanced the nutrient interception ability of soils, and AM fungi reduced the nutrient leaching risk when rainfall intensity increases. These findings are especially relevant in areas with high rainfall intensity (e.g., such as the tropics) and for ecosystems that will experience increased rainfall due to climate change. Overall, this work demonstrates that soil biota such as AM fungi can enhance ecosystem resilience and reduce the negative impact of increased precipitation on nutrient losses.

Modeling sources of nutrients in rivers draining into the Bay of Bengal—a scenario analysis
Pedde, Simona ; Kroeze, Carolien ; Mayorga, Emilio ; Seitzinger, Sybil Putnam - \ 2017
Regional Environmental Change 17 (2017)8. - ISSN 1436-3798 - p. 2495 - 2506.
Bay of Bengal - Coastal eutrophication - Nitrogen - Phosphorus - River pollution - Silica

We model future trends in river export of nutrients to the Bay of Bengal, and the sources of this pollution. We focus on total nitrogen (TN), total phosphorus (TP), and dissolved silica (DSi) inputs to the Bay of Bengal Large Marine Ecosystem (BOB LME) in the years 2000, 2030, and 2050. In 2000, rivers exported 7.1 Tg N and 1.5 Tg P to the BOB LME. Three rivers (Ganges, Godavari, Irrawaddy) account for 75–80% of the total river export of N and P. For 2050, we calculate an increase in river export of N to 8.6 Tg, while P export stabilizes at the 2000 level. Future trends are the net effect of increasing river export of dissolved N (by 40%) and P (by 80%), and decreasing river export of particulate N and P. The increases in dissolved N and P loads are associated primarily with increased N and P losses from agriculture and sewage systems. The decreasing export of particulate N and P is associated with damming of rivers and increased human water consumption. There are large differences in nutrient export among rivers. Rivers draining into the western BOB LME generally export more N and P than eastern BOB LME rivers. Most N and P in western BOB LME rivers are from anthropogenic sources. Future increases in dissolved inorganic N and P (DIN and DIP) export can be large for individual rivers: up to more than a factor of five for DIP and more than a doubling for DIN. The calculated nutrient export ratios (N and P relative to DSi) indicate an increasing risk for blooms of non-siliceous algal species, which can potentially produce toxins and otherwise disrupt coastal ecosystems. Our results indicate that basin-specific management may be the most effective approach towards reducing the risk of coastal eutrophication in the BOB LME.

Check title to add to marked list
<< previous | next >>

Show 20 50 100 records per page

 
Please log in to use this service. Login as Wageningen University & Research user or guest user in upper right hand corner of this page.