Browsing by Author "Allan, Alexander Young"

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    The influence of agronomic factors on maize yields in western Kenya with special reference to time of planting
    (University of Dar es Salaam, 1971) Allan, Alexander Young
    Maize is Kenya’s staple food and most important crop. About one million hectares are grown, and estimated average yields are 12.5 quintals per hectare. Over 90% is planted by small famers for subsistence, and only their surplus is sold. Under 20% of Kenya receives adequate rainfall for maize; this area is mostly at higher altitudes in Central and Western Kenya. A though the Portuguese probably brought maize to the Coast in the 16th century, it did not spread inland until much later in some areas it arrived within living memory maize research in Western Kenya is centred at Kitale, 1 °N , 35°E, altitude 1 ,890m .The mean temperature is 1s.5°c , with moderate diurnal but negligible seasonal variations. Annual rainfall averages 1 , 140m.m ., occurring from late March to November. Before 1 964 maize agronomy research was rather uncoordinated, studying mainly fertilizers, varieties and spacing’s. Objective information was lacking on the relative importances of agronomic factors, and on their interactions. Without this knowledge there was little understanding of why yields were low, or how to improve them. Part 1 of this thesis was designed to obtain this information. A large factorial trial was laid down at 3 sites around Kitale in 1966, and again 1967. Six agronomic factors, in a 2^6 confounded design, were included, each at either a high level representing current good practices, or a low level representing current good practices, or a low level representing a defined level of bad practices. The mean yield was 51.5 g/ha. Overal1, high levels out yielded low by the following margins, (q/ha.):­ Early planting, 10.3; high population, 6.6; hybrid, 8.6; clean weeding , 5.3; phosphate,0.99 nitrogen, 3.2. Several important interactions considerably modified the main effects, especially the response to fertilizers. From these results, it was deduced that:- 1 ) farmers' yields are low because of poor husbandry, especially late planting; 2) output could be increased fourfold by adopting better practices and hybrid seed; 3 ) at current low yield levels, lack of fertilizer is not a major limitation; 4)fertilizer applied to poor maize is unprofitable, but cultural improvements make fertilizer profitable. Next the cost/benefit ratios were calculated, to assess the profitability of various treatments.