Phosphorus concentration and export by silage maize and cut grassland under temperate climate

摘要

Algal blooming caused by phosphorus (P) losses from agricultural soils to ground- and surface water is a major problem as P is typically the limiting factor for eutrophication in freshwater systems. To fine-tune the advice on P fertilisation and increase P-use efficiency, it is important to have up to date information on amounts of phosphate (P_20_5) exported by crops. We re-analysed Flemish nitrogen fertilisation experiments on silage maize (Zea mays) and cut grassland (Poaceae) to derive their quantities of exported P_20_5. The median P_20_5 export by silage maize increased significantly from 78 kg P_20_5 ha~(-1) in the last decade of the 20th century to 94 kgP_20_5 ha~(-1) in recent years (median of 2.1 g P kg~(-1)1 dry matter (DM)). This increase is due to the higher crop yields. The medianP_20_5 export for cut grassland remained at approximately 110 kg P_20_5 ha~(-1) with a median of 4.1 g P kg~(-1) DM.