Three indicators of the utilization of mown and grazed grass used in reference to the production potential of pastures

摘要

In forage systems based on grass, large discrepancies may exist between the production of pastures and what is actually consumed by the animals or harvested as forage. In order to assess the various types of pasture management, the evaluation of grass production has to be dissociated from that grass utilization. Grazing and mowing practices within forage systems can be characterized by the combination of three indicators: the nutritional state; of the pastures (indicating its productivity), the height of grass, and the cumulated temperatures at the moment of utilization (indicating losses). These indicators are generally used at the plot level, but here they serve in a more inclusive manner as diagnostic tools for working out how forage stores are constituted on 4 farms in the Pyrenees. Within a forage system, it was possible to grade the various constraints linked to areas and those linked to the grazing and mowing management. This study shows for instance that the differences in the amount of forage stores per hectare are mainly due to differences in harvest practices: proportion of meadows grazed in spring, heights of grazed grass, mowing dates.