Landbouwpraktijk en waterkwaliteit op landbouwbedrijven aangemeld voor de derogatie. Beschrijving van de meetnetopzet voor de periode 2006-2009 en de inhoud van de rapportages vanaf 2008

Translation of RIVM report 680717001. Alleen digitaal verschenenHet RIVM en het LEI hebben in 2006 in Nederland een monitoringnetwerk opgezet dat de gevolgen meet als landbouwbedrijven mogen afwijken (derogatie) van de Europese gebruiksnorm voor dierlijke mest. Het meetnet volgt driehonderd landbouwbedrijven die zich hebben aangemeld voor derogatie. Het legt de gevolgen vast voor de landbouwpraktijk en de waterkwaliteit. In dit rapport is de opzet van het monitoringnetwerk beschreven, evenals de wijze waarop vanaf 2008 over de resultaten zal worden gerapporteerd. Het rapport geeft onder andere aan wanneer welke cijfers beschikbaar zijn, en welke rekenmethoden gebruikt zullen worden om onder andere de bemesting en gewasopbrengst te berekenen. De Europese Nitraatrichtlijn verplicht lidstaten het stikstofgebruik via dierlijke mest te beperken tot maximaal 170 kg per hectare. Een lidstaat kan de Europese Commissie vragen hiervan onder voorwaarden af te wijken. Nederland heeft in december 2005 toestemming gekregen om vanaf 2006 tot en met 2009 onder voorwaarden af te mogen wijken van de gestelde norm. Dit betekent dat landbouwbedrijven 250 kilo stikstof per hectare mogen toedienen via dierlijke mest afkomstig van graasdieren (vooral koeien). Een van die voorwaarden is dat minimaal 70 procent van het totale areaal grasland is. Daarnaast is de Nederlandse overheid verplicht een monitoringnetwerk in te richten en de Commissie over de resultaten daarvan te rapporteren. De driehonderd deelnemers die worden gevolgd, zijn een steekproef van de circa 27.000 Nederlandse landbouwbedrijven die zich hebben aangemeld voor derogatie. Het netwerk is een onderdeel van het Landelijk Meetnet effecten Mestbeleid (LMM).In 2006 RIVM and LEI set up a monitoring network that measures the consequences of the option for farmers to deviate from the European use-standard for animal manure (derogation). The monitoring network follows three hundred farms benefiting from individual derogations and records the consequences for agricultural practice and water quality. This report describes the design and set-up of the monitoring network, as well as the content and layout of the annual reports from 2008 onwards containing results of the monitoring network. The report indicates, for example, what data will be available at a certain point in time, and what methods will be used to calculate such factors as fertilisation and yield. The Nitrates Directive obliges Member States to limit the use of animal manure to a maximum of 170 kg of nitrogen per hectare. A Member State may request the European Commission to deviate from this obligation under certain conditions. In December 2005, the European Commission granted the Netherlands the right to derogate from the obligation from 2006 till 2009 inclusive, implying that farmers could use up to 250 kg of nitrogen via manure of grazing livestock (particularly cows). One of the conditions is that 70% or more of the acreage available for manure application is grass. The Netherlands authorities are also obliged to set up a monitoring network and to report the results of this network to the European Commission. The 300 farms participating in the monitoring represent a sample taken from the approximately 27,000 Netherlands farms benefiting from individual derogations. The network is part of the National Programme for Monitoring the Effectiveness of the Minerals Policy (LMM).VROM-BWLLNV-D

Measured and Simulated Nitrous Oxide Emissions from Ryegrass- and Ryegrass/White Clover-Based Grasslands in a Moist Temperate Climate

There is uncertainty about the potential reduction of soil nitrous oxide (N2O) emission when fertilizer nitrogen (FN) is partially or completely replaced by biological N fixation (BNF) in temperate grassland. The objectives of this study were to 1) investigate the changes in N2O emissions when BNF is used to replace FN in permanent grassland, and 2) evaluate the applicability of the process-based model DNDC to simulate N2O emissions from Irish grasslands. Three grazing treatments were: (i) ryegrass (Lolium perenne) grasslands receiving 226 kg FN ha−1 yr−1 (GG+FN), (ii) ryegrass/white clover (Trifolium repens) grasslands receiving 58 kg FN ha−1 yr−1 (GWC+FN) applied in spring, and (iii) ryegrass/white clover grasslands receiving no FN (GWC-FN). Two background treatments, un-grazed swards with ryegrass only (G–B) or ryegrass/white clover (WC–B), did not receive slurry or FN and the herbage was harvested by mowing. There was no significant difference in annual N2O emissions between G–B (2.38±0.12 kg N ha−1 yr−1 (mean±SE)) and WC-B (2.45±0.85 kg N ha−1 yr−1), indicating that N2O emission due to BNF itself and clover residual decomposition from permanent ryegrass/clover grassland was negligible. N2O emissions were 7.82±1.67, 6.35±1.14 and 6.54±1.70 kg N ha−1 yr−1, respectively, from GG+FN, GWC+FN and GWC-FN. N2O fluxes simulated by DNDC agreed well with the measured values with significant correlation between simulated and measured daily fluxes for the three grazing treatments, but the simulation did not agree very well for the background treatments. DNDC overestimated annual emission by 61% for GG+FN, and underestimated by 45% for GWC-FN, but simulated very well for GWC+FN. Both the measured and simulated results supported that there was a clear reduction of N2O emissions when FN was replaced by BNF

Estimation of incidence and social cost of colon cancer due to nitrate in drinking water in the EU: a tentative cost-benefit assessment

<p>Abstract</p> <p>Background</p> <p>Presently, health costs associated with nitrate in drinking water are uncertain and not quantified. This limits proper evaluation of current policies and measures for solving or preventing nitrate pollution of drinking water resources. The cost for society associated with nitrate is also relevant for integrated assessment of EU nitrogen policies taking a perspective of welfare optimization. The overarching question is at which nitrogen mitigation level the social cost of measures, including their consequence for availability of food and energy, matches the social benefit of these measures for human health and biodiversity.</p> <p>Methods</p> <p>Epidemiological studies suggest colon cancer to be possibly associated with nitrate in drinking water. In this study risk increase for colon cancer is based on a case-control study for Iowa, which is extrapolated to assess the social cost for 11 EU member states by using data on cancer incidence, nitrogen leaching and drinking water supply in the EU. Health costs are provisionally compared with nitrate mitigation costs and social benefits of fertilizer use.</p> <p>Results</p> <p>For above median meat consumption the risk of colon cancer doubles when exposed to drinking water exceeding 25 mg/L of nitrate (NO₃) for more than ten years. We estimate the associated increase of incidence of colon cancer from nitrate contamination of groundwater based drinking water in EU11 at 3%. This corresponds to a population-averaged health loss of 2.9 euro per capita or 0.7 euro per kg of nitrate-N leaching from fertilizer.</p> <p>Conclusions</p> <p>Our cost estimates indicate that current measures to prevent exceedance of 50 mg/L NO₃are probably beneficial for society and that a stricter nitrate limit and additional measures may be justified. The present assessment of social cost is uncertain because it considers only one type of cancer, it is based on one epidemiological study in Iowa, and involves various assumptions regarding exposure. Our results highlight the need for improved epidemiological studies.</p

Mild and Moderate Extraction Methods to Assess Potentially Available Soil Organic Nitrogen

ABSTRACT The use of chemical methods to assess the soil organic nitrogen (N) potentially available to plants is not a common practice in Brazil. However, associated with others, this tool might improve efficiency in the use of waste and nitrogen fertilizers. In our study, chemical methods were tested to assess potentially available soil N in samples of 17 representative soils of the western plateau of the state of São Paulo (10 Oxisols and 7 Ultisols). Available soil N was extracted from the collected soil samples using moderate (ISNT-Illinois Soil Nitrogen Test) and mild (hot water and heated solutions of 2 mol L-1 KCl and 0.01 mol L-1 CaCl2) extraction methods. The levels of potentially available N obtained from these chemical methods were correlated with dry matter (DM) and N uptake (Nup) by corn plants grown in pots in a greenhouse experiment carried out with the same 17 soil samples. The ISNT method showed the highest available N extraction capacity, whereas hot water showed the lowest capacity, followed closely by the hot 0.01 mol L-1 CaCl2 solution. Despite the differences among the quantities of available N extracted, the methods correlated with each other and with DM and Nup, but the values from the ISNT method showed the lowest correlation with plant variables (rDM = 0.67** and rNup = 0.81**). Procedures of extraction with water or 0.01 mol L-1 CaCl2 heated for 16 h, and 2 mol L-1 KCl heated for 4 h, resulted in similar correlation values (r) with plant DM and Nup. Thus, water (rDM = 0.77** and rNup = 0.90**) and 0.01 mol L-1 CaCl2 (rDM = 0.82** and rNup = 0.93**) heated for 16 h can be recommended as the best options for N extraction.considering the possibility for predicting N availability, lower generation of waste, and lower cost of analysis