Residual effects of calcium sulphate on the yield and composition of a grass-clover association

Abstract

Gypsum at rates of 0, 25, 50 and 100 and 200 lb per acre was applied to a grass-legume association, and the effects on the yields of dry matter, nitrogen and sulphur were followed for four seasons. Pronounced residual effects were noted and had not completely disappeared by the last harvest. Underground transference of nitrogen from clover to grass over the four years was about equal to the nitrogen harvested in the clover. Of the sulphur applied, 80, 80, 50 and 30 per cent were recovered from the 25, 50, 100 and 200 lb rates of gypsum respectively. Eight to twelve pounds of nitrogen were fixed for each pound of sulphur recovered.