1,721,348 research outputs found
Synthesis of the research within the framework of the Mineral Concentrates Pilot
No full textThe agronomic, economic and environmental impacts of the production of mineral concentrate and its use as mineral fertilizer were examined in a pilot in 2009 and 2010. In this pilot, the mineral concentrates were applied as fertilizer above the application standard for manure, but within the nitrogen application standard of the Nitrates Directive. The study consisted of i) monitoring of products from slurry treatment, ii) research on agricultural and environmental impacts of application of mineral concentrate as fertilizer, iii) research on user experience and an economic analysis and iv) Life Cycle Assessment (LCA). This report is a synthesis of the results of the various studies. The research data will serve for consultation with the European Commission on a possible permanent permission to use of mineral concentrates as replacement of mineral fertilizers
Estimation of N2O emission factors for soils depending on environmental conditions and crop management
No full textNitrous oxide (N2O) contributes 8% to anthropogenic global warming, of which about one third are direct emissions of agricultural soils. These N2O emissions are often estimated using the default IPCC 2006 emission factor of 1% of the amount of N applied for mineral fertilizer, manure and crop residues. However, a large variation in emission factors exists due to differences in environment (e.g. weather and soil conditions), crops (grassland, arable land, crop residues) and management (e.g. type of manure and fertilizer, application rates, time of application). We developed a simple approach to determine N2O emission factors that depend on environmental, crop and management factors. The main factors controlling N2O emission are nitrate content, oxygen content, available C content, temperature and pH. The starting point of the method was a two-year monitoring study of Velthof et al. (1996), who found an emission factor of exactly 1% for grassland on a sandy soil fertilized with calcium ammonium nitrate. The conditions of this experiment were set as the reference from which the effects of other environmental conditions and management on the N2O emission factor were estimated. Based on literature and expert knowledge we determined for 19 sources of N input, three soil types, two land use types, three precipitation classes, two pH classes and three temperature classes the effect on the default emission factor. The calculated N2O emission factors ranged from 0 to 10%. The approach was applied to a European scale, using the INTEGRATOR model. The results were also produced with the standard IPCC approach and the empirical approach by Stehfest and Bouwman (2006). Differences in the overall results at EU27 scale and at regional scale are discussed. The emission factors derived from this inference scheme can improve predictions of N2O emissions with integrated large-scale model
Effects of ageing and cultivation of grassland on soil nitrogen
No full textNitrogen losses from agriculture in the Netherlands have to be strongly decreased because of national and international policy (e.g. Nitrate Directive). The cultivation of grassland when grassland is renewed or converted into arable land may enhance net nitrogen mineralization and, thereby, nitrogen losses via leaching and denitrification. These nitrogen losses can be decreased by adjustment of management, but a good insight into the soil processes during ageing and after cultivation of grassland is required. A literature study was carried out to quantify the effects of ageing and cultivation of grassland on nitrogen losses from the soil. The study shows that the risk on losses increases when grassland age increases, the period between cultivation and reseeding increases and the nitrogen uptake capacity of the next crop decreases. In the Netherlands, only a few studies have been carried out and, especially, a quantification of the effects of cultivation on nitrogen losses under Dutch conditions is lacking. It is recommended to set up integral field studies in which both the agricultural and environmental effects of grassland cultivation are quantified. The results must be used to develop measures and tools to achieve environmentally and agriculturally sound systems of permanent and temporal grasslands
Scheuren van grasland
No full textIn dit hoofdstuk wordt achtergrondinformatie gegeven over 1) de motieven om grasland te scheuren in de melkveehouderij en akkerbouw, 2) het areaal grasland dat jaarlijks wordt gescheurd, 3) de huidige wetgeving met betrekking tot scheuren en 4) de N-processen die na het scheuren van grasland optreden
Effects of nitrogen fertilization and grazing on the emission of nitrous oxide from grassland.
No full textUit de mest- en mineralenprogramma's : Verkenningen van stikstof- en fosfaatemissies uit de landbouw in vier regio's
No full textEr is behoefte aan een methodiek waarbij op eenvoudige wijze de interactie tussen landbouw-, milieu- en natuurrandvoorwaarden in kaart kan worden gebracht. In het project Milieugebruiksruimte (programma 398-III) wordt samen met andere programma's een beslissingsondersteunend syteem ontwikkeld voor integrale analyses van milieudruk uit de landbouw (zie informatieblad 398.6). Het integraal stikstofmodel INITIATOR vormt hiervoor de basis. Begin 2003 is INITIATOR uitgebreid met fosfaat. INITIATOR richt zich op de langere termijn effecten van ingrepen in het milieu. De met INITIATOR berekende milieukwaliteit betreft de toestand die na 30 jaar is bereikt. Dit in tegenstelling tot het model STONE dat wel dynamisch rekent. In dit infoblad worden resultaten weergegeven van de N- en P-emissies in vier regio's met behulp van INITIATO
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