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Leaching of soluble organic N - NT1916

Recent MAFF-funded research has determined that substantial amounts of soluble organic nitrogen (SON) occur at depth in agricultural soils under certain circumstances. Data collected under project NT1518 analysed samples from over 50 fields and measured SON levels (0--90 cm) ranging from <10 to >300 kg/ha; these measurements were based on KCl extracts because samples from another project were used for the additional measurements. Although some calibration against water extractable SON was made, these were inconclusive; further research is needed to determine the relationship between KCl and water extractable SON, because the latter is more representative of soil SON content. This study will be composed of 3 specific objectives outlined as follows, together with ways in which they might be achieved: 1. Determination of the relationship between water and KCl extractable SON. 50 soil samples collected under project CTE9603 will be analysed using both extraction techniques; 2. Conduct soil and water sampling to quantify the depth of any SON movement from the topsoil. On established experimental plots that have received known application rates of poultry manure for 6 years, soil SON concentrations at depths up to 1.5 m will be determined; lysimeter leachates from these plots will also be analysed during the main drainage period (December to February); and 3. Summarise findings in a report to MAFF (to aid policy decisions) and as a scientific paper. Experimental data obtained will be incorporated into the partially written paper from project NT1518. An assessment of this newly collected data will be made before deciding its route for publication - conference or refereed paper.
Time-Scale and Cost
From: 1997

To: 1998

Cost: £16,500
Contractor / Funded Organisations
Fields of Study
Fertilisers and Nitrate Pollution