The effects of weather and nutrition on the yield of hay from Palace Leas meadow hay plots, at Cockle Park Experimental Farm, over the period from 1897 to 1980

The yield of hay on the Palace Leas meadow hay plots has increased significantly with time on the higher yielding plots but has remained constant on the lower yielding plots. Yield on the higher yielding plots shows a relatively low fluctuation from year to year, and yields of plots treated with farmyard manure show high intercorrelations with each other, but lower correlations with the other plots. Yield is influenced by weather, but even the most successful climatic parameter– maximum soil moisture deficit—only accounts for 30% of the year on year variation in yield. There are highly significant autocorrelations between yields within each of the farmyard manure, treated plots indicating cyclic effects with periods of up to 6 years, but these are not related to the cyclic patterns of manure application.