The utilization of different levels of protein, supplied mainly as soybean meal, was examined by a feeding experiment with sheep. Measurements of the concentrations of N-containing rumen metabolites and of blood urea showed that protein degradation in the rumen and removal of urea by the kidneys were limited when highly increased amounts of protein were ingested.

Increases in nitrate have been found in eight out of ten soils irradiated over the range 0·25–2·5 Mrad, with maximum accumulation between 0·25–0·75 Mrad. Oxidation of ammonium added to normal soils was poor at low pH, and showed a highly significant correlation with nitrate produced after 0·25 Mrad. It is suggested that radiation-released ammonium is less limiting to nitrate formation than the original population or activity of nitrifying organisms, which are favoured by alkaline conditions.