POTENTIAL IMPACTS OF CLIMATE CHANGE ON PATTERNS OF PRODUCTION AND THE ROLE OF DRAINAGE IN GRASSLAND

Grass production can be predicted using a simple model whose inputs include daily meteorological variables. Changes in both daily temperature and the soil water balance can be expected as a consequence of anthropogenic increases in the CO2 content of the atmosphere. Possible consequences of such changes for grass production are then predicted using the model. These indicate that, for the UK, patterns of grass production could be shifted significantly. Greater grass growth in the spring would follow from the increase in temperature, particularly on drained land where growth is not constrained by, waterlogging. However, grass growth would be depressed by the mid-season soil moisture deficit, and this again is more marked on drained land. It is concluded that, under a changed climate, the drainage of grassland to enable early season access to the land, together with sound management to optimize output, will be even more important than at present.