Results of an experiment at Rothamsted testing farmyard manure and N, P and K fertilizers on five arable crops and permanent grass III. Yields 1961–1965

Abstract

SUMMARYAn experiment begun in 1956 and using a five-course rotation of barley, grass-clover ley, potatoes, wheat and kale and a block of permanent grass was continued.N decreased yields of the rotation ley, slightly increased yields of potatoes (after the ley), but greatly increased yields of wheat, barley and kale and permanent grass. P increased the yields of all arable crops, of kale dramatically, but not of permanent grass. K greatly increased yields of wheat and the rotation ley and even more of potatoes, but it increased yields of barley, kale and permanent grass little.F.Y.M. increased the yields of all crops; potatoes responded most. Applying fertilizers with the F.Y.M. diminished its effects, but except for wheat and barley grain a combination of the two produced the largest yields.Mean yields from all combinations of N, P and K were a little smaller between 1961 and 1965 than between 1956 and 1960, and the yields were maintained best by applying F.Y.M. and fertilizers together. Responses to N and to K were similar in both rotations, but responses to P became larger with time.