15 septembre 1996
auteur
Lorsque le pâturage est le principal mode d'utilisation des fourrages semés, les éleveurs souhaitent que l'on améliore la prise alimentaire de l'animal, en quantité et en qualité, et que la prairie supporte mieux la présence des troupeaux. Ailleurs (zones herbagères, montagnes humides, zones de parcours), les prairies semées sont surtout utilisées pour constituer des stocks ; on cherchera à améliorer leur facilité d'implantation, la répartition de la production, la pérennité, la plasticité d'utilisation, ainsi que l'aptitude au séchage, la valeur alimentaire et l'état sanitaire du fourrage. Enfin, pour mieux respecter l'environnement, le fourrage devra être moins riche en matières azotées, et la prairie devra contribuer à mieux gérer les flux d'azote de l'exploitation, mieux valoriser les apports de fertilisants et pouvoir pousser en conditions limitantes.
The various constraints endured by agriculture in general re not without effect on what animal farmers expect from their leys. The latter are very apt to respond to the various situations, present and future, corresponding to these expectations, be it through genetic improvement, or through adequate methods of management, of harvest, or of conservation. The diversity of use of leys on the French metropolitan territory is shown, and a certain number of expectations are discussed. On a large part of the territory, sown forage plants are mainly grazed, and the aim is to improve, quantitatively and qualitatively, the intake by the animal and to give the pastures the ability to bear the weight of the herds present on them. Elsewhere, in regions with natural grasslands, with humid upland pastures and with rough grazings, the leys are used for the production of stored feeds. Desired improvements are mainly in the fields of ease of establishment, of seasonal distribution of yield, of aptitude to be dried, and of persistency. Feeding value and sanitary state are also essential. The pastures must also have a certain plasticity of use, in other words be apt to endure short or medium term changes in management. Lastly, the environment becomes a major concern, and the pastures are directly involved. A reduction in crude protein content of the forage, an aptitude of forage plants to utilize efficiently fertilizer inputs and to grow under limiting conditions will be desirable goals. Pastures should also make possible a better management of the flow of nitrogen at the farm level.
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