Green manuring for barley at Woburn

Abstract

SummaryThree short-term experiments on green-manuring are described. In the first, trefoil (T) and ryegrass given fertilizer N (RN) increased the yield of a following barley crop grown without fertilizer N by 500–900 kg/ha, but did not affect yield of barley given N. In the second, T and RN increased yield by 1400 kg/ha whether or not fertilizer N was given to the barley. Ryegrass without fertilizer N (R) had smaller effects in both experiments. The third experiment (with different treatments) suggested that the effect of trefoil was caused by the greenstuff turned in, not by any physical or microbiological change in the soil.