The effect of fertilizer and N application rate on nitrogen and potassium leaching in cut grassland

Although fertilization has a positive effect on agricultural productivity, its negative side effect can be the leaching of plant nutrients. Our objectives were to study the impact of fertilizer type and nitrogen application rate on the nitrogen and potassium leaching from grassland during and after the vegetative period. Within three years (20082011) mini-lysimeters experiment was conducted on grassland swards receiving mineral NPK, mineral PK, cattle slurry and sewage sludge based on nitrogen rate 0, 60, 120 and 180 kg ha(-1) year(-1). Nitrogen and potassium leaching was measured monthly throughout the experimental period. From our results it can be concluded that nitrogen leaching is lower with the use of mineral NPK, because it increases the sward yield most efficiently. Potassium leaching in grassland can be reduced when using nitrogen containing fertilizers, as the fertilizer N: K ratio has a great effect on its leaching potential. Fertilizers are not the only N and K leaching source. It can be high also from unfertilized soil at the expense of soil reserves. Injection of slurry at rational amounts can be an effective method for the reduction of nitrogen leaching in grassland.