YIELDS OF MILLET BETWEEN SHELTERBELTS IN SEMIARID NORTHERN NIGERIA, WITH A TRADITIONAL AND A SCIENTIFIC METHOD OF DETERMINING SOWING DATE, AND AT 2 LEVELS OF ORGANIC MANURING

Eucalyptus camaldulensis shelterbelts positively influenced yields of millet planted close to the belts. Only smaller distances between shel terbelts than used in semi-arid Nigeria, certainly less than 100 m, ca n fully exploit crop protection from advected hot dry air. Yields in t wo years with completely different rainfall regimes, for a traditional determination of sowing date, based on the Ramadan, were statisticall y significantly less (20-40%) than those for a scientific method of de termining sowing date, based on Kowal's method. Assistance in on-farm application of proper sowing dates is needed. Millet grown outside the influence of the belts yielded about 50% less when including both met hods of determining the onset of the growing season. Soil moisture ava ilability early in the season and its influence on growth, tillering, and grain filling most of all determined yield differences between plo ts. Substantial yield differences as function of distance from the bel ts could be explained by soil moisture at sowing and the effects of ho t dry turbulent air generated by the belts on crop growth conditions. Compared to the best organic manuring that farmers could afford, half that amount gave yield losses near 35% in both years, suggesting that manuring is not yet optimum.