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Detection and quantitification of nitrite in drainage waters from grassland - NT1911

Intensively managed grassland systems may provide opportunities for release of unacceptably high levels of nitrite (NO2-) to surface waters, resulting in detrimental effects on aquatic ecosystems. This study will aim to quantify the extent of NO2- leaving typical pasture soils in south west England. The study will be composed of 4 specific objectives outlined as follows, together with ways in which they might be achieved: 1. Development of sampling and analytical protocols appropriate to the analysis of NO2- in waters. An analytical methodology based on existing described protocols and using flow injection procedures will be developed. A sampling and storage protocol will also be determined in order to avoid problems of transformation in the sample vial during storage; 2. Perform routine measurements of NO2- concentrations in water draining from a number of experimental grassland systems encompassing a range of different N managements. Measurements will be based on the Rowden Drainage experiments with hydrologically isolated plots and will be conducted on a soil type with a hydrological classification which is representative of a large proportion of the soils used for grassland production in lowland Britain. A range of different grassland management systems will be investigated; 3. Provide an estimation of the annual losses of NO2- from these grassland soils during a winter's drainage season. Measurements of NO2- will be made weekly and the cumulative quantities of N leached in this state calculated for the complete drainage system for each of the N management treatments; and 4. Provide periodic measurements of NO2- in a transect of the River Taw and from sectors of the local rivers. Fortnightly samples of local river waters will be taken for analysis of NO2-; these will include a range of sites on the River Taw (from upland through agricultural landscapes) and from selected sites on a number of other local rivers. Results of the study will provide MAFF with baseline information on release of NO2- from UK grassland systems, so that any necessary remedial measures can be developed in accordance with EU standards for water quality.
Time-Scale and Cost
From: 1996

To: 1997

Cost: £19,698
Contractor / Funded Organisations
Institute of Grassland and Environment Research (IGER)
Fields of Study
Fertilisers and Nitrate Pollution