Effects of sward botanical composition on nitrogen and potassium leaching in cut grassland

The leaching of nutrients in regions where annual precipitation considerably exceeds evaporation needs to be minimised. Our objective was to study the dependence of leached nitrogen and potassium on botanical composition of grassland sward. Mini-lysimeters filled with loamy sand were embedded in three swards (a mixture of three grass species, grasses mixed with white clover and grasses mixed with lucerne). Annual nitrogen application rates (0, 60, 120 and 180 kg ha(-1)) in conjunction with three fertilizers (mineral fertilizer, cattle slurry and sewage sludge) were applied. The nitrogen and potassium leaching was measured monthly during three years. We concluded that nitrogen and potassium leaching are affected by sward botanical composition. The leaching of both elements was the lowest from grass-clover sward.