Nitrogen and potassium leaching from grassland

In the first part of this work the effects of four fertilizer regimes on the dynamics of N and K on mown grassland on a sandy soil were investigated. The swards differed in the source of N input and related K fertilization. After six years, the swards showed distinctive features in terms of nutrient balances and leaching, nutrient contents in the soil, and botanical composition.
These swards then formed the basis of a mini-lysimeter study of the fate of mainly N and K at urine patches on grazed grassland, which makes up part two and three of this work. Late urine applications led to increased N leaching losses and losses were higher from poor swards and productive grass-clover swards compared to grassland that received mineral fertilizer. Macropore flow played a role during summer for N and K leaching. High plant uptake and retention in the soil alleviated leaching losses of K, while leaching of Ca and Mg was substantially increased.