Maize yields where the nitrogen source was sulphur-coated urea combined with ordinary urea were significantly greater than those where an equivalent amount of ordinary urea was applied at identical times. Urea blended with neem cake was less effective.

K. P. Prabhakaran Nair y P. B. Sharma: Eficacia comparada de la urea normal y revestida y urea tratada con inhibidores de la nitrificación como fuente de nitrógeno para el maiz

At Pantnagar, India, linear response in maize to nitrogen application was observed up to 150 kg. of N/ha. with some of the most promising hybrids and composites released by the All India Co-ordinated Maize Improvement Programme. Increase in grain yield, and total nitrogen accumulation in grain, were substantially more in Ganga 2 than in the local cultivar or the composites, at higher rates of N application. In absolute terms, the local cultivar accumulated more nitrogen in its grain, but the relative amounts declined at higher rates of N application. Among the yield components influencing ultimate grain yield, barrenness exerted a negative influence on grain yield through the number of cobs per plot. Among cob characters, such as thousand grain weight and number of grains per cob, the former exerted a substantial influence on grain yield.

Field experiments conducted over 2 years to evaluate the merits of fractional application of N to hybrid maize unequivocally established its utility in circumventing leaching losses and consequently boosting grain yield. Combinations of fractional application need to be phased to minimize leaching losses and also to correspond to crop needs. Fractional application improved yields even in years when the incident rainfall was evenly distributed.

Groundnut (Arachis hypogaea) has very great economic importance in Cameroon. In pot experiments, groundnut yields on highly acidified but limed soil were 50% greater than those on unlimed soil. These results demonstrate that severely acidified soils of the western highlands of Cameroon should be limed at moderate rates to sustain crop productivity.

Ten wheat and six barley genotypes were tested for their response to soil salinity regimes varying from 0 to 16 mmhos cm−1. Barley showed remarkable resistance to salt stress, linked to its capability to resist efflux of potassium ions from the plant system. Both crops showed substantial yield reductions at 12 mmhos cm−1, but barley still outyielded wheat by over 50%. There were significant interactions between salinity levels and genotypes in wheat but not in barley.The wheat variety Sonalika showed poor salt tolerance. The implications of these findings in breeding salt-tolerant varieties are discussed.