Main research question/goal
The project is geared towards measuring the effect of the timing of ploughing down grassland on the risk of nitrate nitrogen leaching (by measuring the nitrate concentration in the soil profile) and on the yield level when grassland is resown. We want to detect the most suitable forage crop to sow after the grassland has been ploughed down in spring and the optimal fertilization level (combination of high yield and low risk of nitrate leaching). Previous observations show very often high- very high nitrate nitrogen concentrations in the soil during the official sampling period (1 October – 15 November) and a considerable risk of nitrate leaching when ploughing down grassland in autumn. Research approach
We are carrying out empirical field experiments on Sandy (Bocholt) and Sandy loam soils (Merelbeke). We are renovating grassland at several points in time in spring and autumn and we are measuring grass production and evolution of nitrate nitrogen concentrations in the soil. We are cultivating silage maize, fodder beets and perennial ryegrass with 3 levels of N-fertilisation: 0 N/ha, 170 Navailable from slurry and Nmax. following current legislation. We are measuring yield and nitrate nitrogen concentrations in the soil.Relevance/Valorisation
The results will be made available for farmers in a brochure “Grassland amelioration and renovation”. In this brochure environmental aspects will be an important topic. The problem is clarified. On the one hand, autumn is the best period for grassland renovation from an agricultural point of view, on the other hand grassland ploughing in spring minimizes the risk of nitrate leaching. In spring other crops than grass can be sown after ploughing grassland down. The type of (forage) crop and the fertilization applied have a significant impact on the balance between yield and nitrate residue in the soil at the end of the season.