Ploughing down and reseeding grassland in April or at the end of May after one cut: effects on crop yield and nitrate nitrogen concentration in the soil

摘要

Reseeding grassland in spring is less productive in the first year than reseeding in autumn, but it is better for environmental reasons because it represents a lower risk for nitrate leaching. In experiments at Mcrelbeke and Bocholt (Belgium), grassland was reseeded either in April or at the end of May after one cut of grass. Evolution of NO^-N in the soil and dry matter yield in the sowing year were measured to determine the best period of grassland reseeding both for the farmer and for the environment. In this experiment the dry matter yield of grassland reseeded on June 1st after one cut of the original sward was 0.9 t ha'1 higher in comparison with grassland reseeded on 15 April, but it was only significantly higher at one location and in one year. Moving the ploughing date from April to June 1st resulted in significantly higher NO^-N concentrations in the soil during October - December 2012 and in October 2013, but the risk of nitrate leaching was still low.