L'élevage bovin indispensable à la pérennité des grandes cultures ? Tentative de réponse dans le territoire du Parc naturel des Plaines de l'Escaut

Abstract

Cattle breeding, adopted in the Neolithic for the production of milk/meat and the supply of natural fertilisers for the soil by cattle manure, is however abandoned in favour of field crops. This specialization and intensification of agricultural production threatens the state of our soils. Several parameters are evaluated to objectively assess the state of soil fertility. This work focuses on the total organic carbon of the soil as well as the various essential nutrients (organic nitrogen, phosphorus and potassium). Total organic carbon is essential for many key soil functions. It thus determines the quality and fertility of a soil. The factors influencing its dynamics are numerous but this work focuses on the effects of the contribution of organic matter to the soil in the form of cattle manure. Grasslands also play a critical role in sequestering total organic carbon. The Natural Park of Scheldt Plains, located on the silty, sandy-silty and Campine Hennuyère agricultural regions, is seeing large-scale crops spread to the detriment of cattle farms. This territory presents general deficiencies in the different nutrients studied within the two study groups (farms with and without cattle) applying livestock effluents on their agricultural soils. However, deficiencies are accentuated in the agricultural land of farms without cattle. These nutrient deficiencies appear to decrease with increasing amounts of manure applied. However, despite the use of organic and/or mineral fertilizers, the state of soil fertility seems difficult to maintain. Grazed grassland soils have higher total organic carbon and organic nitrogen levels than cropland but deficiencies remain.