Experiments comparing yield, and residual effects on winter wheat, of 1-year clover, rye-grass and clover-rye-grass leys

1. In 1958, leys of late flowering red clover (S. 151) and of Italian rye-grass (S. 22) were undersown in barley. In 1959, yield and N and K uptake by clover, and by rye-grass given 0·0, 0·75 or 1·5 cwt. N/acre, were compared; rye-grass, given 1·5 cwt. N/acre, yielded most dry matter and removed three times as much K, but rather less N than did clover. 2. In 1960, wheat given 0·0, 0·25, 0·5 or 0·75 cwt. N/acre as a top-dressing measured residual effects of the N left by each ley. When no N was given to wheat, most grain and straw was obtained after clover ley and least after rye-grass given no N. The residual N from clover was equivalent to 0·14 cwt. N/acre as a fresh top-dressing; N given to rye-grass left only a small residue. When the wheat had 0·5 or 0·75 cwt. N/acre as a top-dressing, N given to rye-grass in 1959 decreased yield, probably because the rye-grass removed much K, but K uptake at harvest was independent of ley. 3. In 1960, leys of early flowering red clover (Dorset Marl) and of Italian rye-grass (S. 22) and a mixture of the two were under-sown in barley. In 1961, yields and N and K uptakes of clover, and of rye-grass given 0·0, 1·0 or 2·0 cwt. N/acre and of clover-rye-grass given 0·0 or 1·0 cwt. N/acre were compared. Rye-grass given 2·0 cwt. N/acre yielded most dry matter and removed one-third more K than did clover, but clover yielded one-third more N.