Sustainable soil management: long term field experiments (VELDBODEM)

We investigate if soil quality and disease pressure on arable land can be positively influenced by the soil improving practices 1) compost application and/or 2) non-inverse soil tillage. We evaluate the effect of these practices on field trial plots that are fertilized with the maximum allowed dose cattle slurry dose or the maximum allowed pig slurry dose. We also investigate if the organic carbon content of the soil can be increased within the legal constraints of the fertilization laws using slurry and the application of good agricultural practices (cover crops, straw incorporation) and, if not, if this goal can be reached with an extra dose of compost without increasing N leaching.

ILVO started the long term field experiment in spring 2010. The trial has a 4-year rotation with maize, potato, summer cereal and a vegetable, with cover crops during winter periods. We compare field trial plots that do and do not receive compost application on top of slurry. We investigate field trial plots that are conventionally tilled (ploughing) and non-inversely tilled field trial plots. We monitor nutrient balances, physical and biological soil quality and disease suppression (including plant parasitic nematodes and disease inducing fungi). The potato crop is inoculated with the bacterial disease Dickeya to evaluate the natural disease suppressiveness of the soil. Two ILVO research groups (Crop Husbandry & Environment and Crop Protection) work together for this trial.

Legislation limits the use of fertilizers and crop protection products. An optimal soil quality that allows for good nutrient use efficiency, increased organic carbon content, optimal aeration and water retention, and a diverse soil life is indispensable for profitable cropping. A healthy soil suppresses diseases and can assure plant production in the long run. Good agricultural practices are needed to reach such a good soil quality. This field trial is used for the EU FP7 projects Catch-C and Fertiplus.