Classification, vegetation dynamics and forage production of permanent pastures in Lorraine

Abstract

Forecasting the forage production of permanent pastures is of agronomical and environmental interest for various reasons : planning the provision of cattle feed, estimation of the financial consequences of technical decisions, and prediction of the effects of non-polluting techniques on the loss of produc tion. For this purpose, it is necessary to determine the effects of edaphic, climatic and technical factors on permanent pastures. The paper describes the vegetation dynamics in Lorraine (north-eastern France) based on a study of the qualitative (species composition) and the quantitative (percentage of species in the biomass) botanical composition, and on a survey of the management of 720 permanent pastures. Two major factors influence botanical composition : the water regime and the level of intensification. For each type of water regime in Lorraine, the effect of intensification on the percentage of grasses, legumes and other species is described. The consequences of these variations for forage production are analysed for a subsample of pastures where yields were measured over eight years.The feasibility of a quantitative model designed to predict forage production at a regional scale is then examined. Two major problems are foreseen : the large data requirement, and the great variability of the vegetation of permanent pastures.