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To provide guidelines for improved nitrogen use on potatoes, oilseed rape & sugar beet..... (New code NT1307) - NT0201

See NT1307.

NT0201. Potatoes, oilseed rape & sugar beet/nitrate leaching.

N fertiliser loss from arable crops, due to leaching though soils, could result in an increase in the nitrate content of drinking water sources to levels greater than those set by EC legislation; current fertilisation and irrigation practices for potatoes and sugar beet may pose high risks of nitrate leaching. This study will aim to develop better N fertilisation practices for potato, oil seed rape and sugar beet crops and to formulate improved guidelines for irrigation of potatoes and sugar beet. Methods for reducing N leaching from irrigated potato crops will be developed as a result of experiments to determine the critical soil moisture deficit of potatoes grown in beds and the N requirement of irrigated vs unirrigated potatoes; the possibility of reducing irrigation inputs for the control of common scab Streptomyces scabies will also be evaluated. Improved N management techniques will be established for potatoes so that applied N is balanced by crop offtake, in order to minimise risk from nitrate leaching post harvest. Irrigation requirements of sugar beet on light soils will be determined in relation to crop growth stage, whilst minimising the risk of nitrate leaching and any adverse effects on crop yields; effects of drought-induced stress on crop growth and development will also be quantified. In addition, nitrate losses by leaching from autumn N applications to winter oilseed rape will be determined for coarse-textured and shallow soils and amounts of residual N will be measured after harvest of the crop. The need for seedbed/autumn applied N fertiliser will be evaluated when straw from the preceding cereal crop is incorporated into the soil. Influence of changes in N fertilisation source, timing and application method will be investigated as a means of reducing nitrate leaching from potato crops. It is anticipated that data from this study will lead to improved understanding of the N cycle.
To determine the effect of irrigation on the nitrogen requirement of potatoes. To determine whether nitrate leaching post-harvest of potatoes can be reduced by the manipulation of crop maturity, as affected by physiological age and planting date. To determine whether lower yielding unirrigation sugar beet is prone to nitrate leaching. To quantify, for coarse-textured and shallow soils, the losses of nitrate by leaching from autumn nitrogen applications to winter oilseed rape, and the influence of incorporated cereal straw on autumn nitrogen. To measure the effect of slow release nitrogen fertilizers on post-harvest leaching of N. To evaluate changes in nitrogen source, timing and application method as a means of reducing nitrate leaching from the potato crop.
Time-Scale and Cost
From: 1990

To: 1995

Cost: £1,499,000
Contractor / Funded Organisations
Fields of Study
Fertilisers and Nitrate Pollution