Grain yield losses in relation to rainfall regimes in maize growing areas of Kenya
1996
Onyango, J.W(Kenya Agricultural Research Institute, Nairobi (Kenya). National Agricultural Research Laboratories) | Chege, A.G(Kenya Agricultural Research Institute, Nairobi (Kenya). National Agricultural Research Laboratories)
This paper investigates the causes of maize yield losses in relation to planting time and ensuing rainfall received up to physiological maturity. Data was obtained from fertilizer experiments carried out between 1986 and 1994 in 69 Fertilizer Use Recommendation Project (FURP) trial sites in the high and medium rainfall areas of Kenya. Longterm rainfall data by 1985 was obtained from the Kenya Meteorological Department and used to determine climatic planting dates from these sites. Using the cropping seasons between 1986 and 1991, early and late planting dates from two years with relatively large differences in yields were determined. The difference in number of days between the two planting dates and the equivalent yield losses were compiled and compared. Three categories of yield losses were distinctly recognized. These were those which lost yields due to excess rains, the prevailing climatic disturbance in October, and late planting. These three categories affected 31.3%, 20% and 31.3% respectively. Another 20% of the sites were eliminated from the analysis due to disparities of data. Regression analysis between rainfall deficiencies and daily grain yield losses in the third category was significant at the 0.05 level. To raise national maize production, early planting is recommended for the first and third categories, while moisture conservation practices or irrigation is recommended for the second.
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