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Effects of fertiliser nitrogen additions on soil quality and fertility - SP0504

Medium-term effects of addition of inorganic N fertilisers on soil quality and sustainability will be investigated, with particular emphasis on impact of N fertiliser on returns and turnover of organic C and N. Studies will be conducted at 3 sites of contrasting soil types (Ropsley (medium loam), ADAS Gleadthorpe (sandy) and Morley Research Centre (light loam)); sites will be managed as part of a conventional crop rotation for the duration of the study. C balances will be constructed at each site in order to establish the level of C inputs and associated N fertiliser additions required to maintain soil organic matter status; this will involve measurements of total above-ground dry matter production by the crop and estimates of C root returns. Measurements of C returns will then be compared with changes in total soil organic matter, the light organic matter fraction and N soil content. Effects of inorganic N fertilisers on key indicators of soil quality (e.g. structural stability, soil strength/density, water holding capacity, microbial biomass of C and N, microbial respiration and total C and N) will be measured on experimental sites. Moreover, influence of N fertilisers on potential N mineralization will be evaluated and compared with the amount of N taken up by the crop at harvest in the absence of N fertiliser. Finally, effects of addition of inorganic N fertiliser on C and N turnover will be compared with models that predict organic matter turnover such as CENTURY. Results from the study will be used to provide recommendations on the use of inorganic N fertilisers in maintaining soil fertility and quality.
Project Documents
• Final Report : Effects of fertiliser nitrogen additions on soil quality and fertility   (579k)
Time-Scale and Cost
From: 1998

To: 2003

Cost: £217,222
Contractor / Funded Organisations
Agricultural Land              
Environmental Protection              
Sustainable Production              
Waste Management              
Fields of Study
Soil Protection