Nitrogen Management for Profitable Farming with Minimal Environmental Impact: The Challenge for Mixed Farms in the Cotswold Hills, England

Abstract

A detailed nitrogen (N) budget was constructed for a mixed farm in the Cotswold Hills, England, situated on thin, well drained soils prone to leaching. The study covered all stages of the farm's seven-year rotation and included the removal of the dairy herd. All inputs and outputs of N were measured or estimated and a balanced budget achieved, but only by including relatively expensive measurements of soluble organic nitrogen (SON) leached. Leaching was the main loss process. Given the nature of the soil and the influence of the weather, it would be difficult to reduce losses without drastic reductions in fertiliser inputs or stocking rates. Nitrogen use efficiency averaged 46%. The mean N surplus declined from 141 kg N ha⁻¹ to 117 kg N ha⁻¹ with the removal of the dairy herd. However, the farm to which the herd moved had an N surplus of 392 kg N ha⁻¹. Simple farm gate N budgets were constructed for neighbouring Cotswold farms to encourage farmers to consider ways to improve N use. Implications for policy to reduce losses of N while maintaining farm profitability are discussed.

Keywords:

• mixed farming systems
• nitrate leaching
• nitrogen budget
• nitrogen management