Evolution à long terme d'une lande de montagne pâturée par des bovins ou des chevaux. II. Production fourragère

Abstract

The evolution of the plant biomasses, primary production and soil of a disused hill moor was examined during 12 years after introduction of new management. Horses are more efficient than cattle for the elimination of herbaceous or ligneous masses. As a result, the forage offered is more abundant but of lower quality in the case of cattle. The final production is 2.5 t DM/ha/year by horses versus 3.5 by cattle. The soil organic matter evolves best under the areas closely-grazed and stamped by horses. Horses cause local transfers and exhaustions in K, whereas cattle make the K-fertility uniform. According to the animals, the results as a whole, show opposite evolutions of botanical composition and production. The uniform restitution of animal manure due to cattle is necessary for the maintenance or improvement of productivity ; the elimination of biomasses in excess due to horses is sufficient for botanical improvement. This raises the question of which of the 2 criteria has to te favored in order to maintain mountain grasslands.