Innovative methods to maintain or to improve the soil fertility to meet fertilizer policy objectives (ORGANIC_P_MATTERS)

This research focuses on more sustainable soil management. What is the long-term and short-term influence of various fertilizer strategies on the soil organic matter, soil phosphorus fractions, crop yield and phosphorus leaching? This research is based on long-term field trials, technical analyses of soil and plant samples, and incubation experiments. ILVO is searching for optimal fertilizer strategies to maintain the levels of soil organic matter content and the crop yield while still meeting the restrictions of the fertilizer legislations (“Mestactieplan” or MAP).

Ghent University runs annual long-term fertilizer field experiments. ILVO and Ghent University both make observations of these experiments. Potatoes, maize, beets and cabbage are included in the crop rotation. Evolution in crop yield, phosphorus uptake by plants, soil organic matter level, soil phosphorus conditions and plant availability of phosphorus are observed in consecutive growing seasons. Besides the field trials, lab experiments are done to measure phosphorus leaching from soil samples from these field trials. In other lab experiments we test the influence on phosphorus availability and phosphorus leaching of mixing green manure into the soil.

The data reveal which fertilizer strategies are most promising. This research contributes to the fundamental knowledge about the links between sustainable soil, fertilizer strategies and phosphorus leaching. It also reveals other information relevant for policymaking because it summarizes how to create more sustainably-managed soils. For example, if green manure can effectively help to decrease the phosphorus leaching and enhance the phosphorus availability for a succeeding crop, planting green manure needs to be further promoted as a good agricultural practice.