Compost, Manure and Sewage Sludge Applied to a Crop Rotation

The disposal of organic wastes specially from urban origin is a very serious problem. The recycling through agriculture is certainly one of the best solutions but it means a thorough control of the composition and doses applied, as well as the response of the crops, in production and quality. In this paper we deal with compost of solid urban residues, sewage sludge, and cow manure as a known reference, on a crop rotation of barley, rape seed, wheat and sorghum. The experience is planned on the basis of N crop needs, considering that manure and compost mineralize 60% the first year and 40% the second after their application, while sewage sludge does it 75% and 25%. Crop composition has not shown any significant difference between treatments, and a rather high production increase comparing with the testimony plot.