Analysis of pentad rainfall for agricultural purposes in Kenya

Abstract

During some phenological stages of crop development J water stress of even short duration would significantly influence yields. The study of variability of rainfall during the sensitive stages of the crop is of great importance. It is because of this sensitiveness of crop to water stress of short duration that pentad rainfall was chosen for this study. The object of the present work is to study distribution and variability of pentad rainfall for 100 stations with records of more than twenty years, spread allover Kenya in order to use the knowledge in land use planning for crops. For that purpose the following statistical properties of pentad rainfall were examined at each of the 100 stations ,, and for each of the 73 pentads in a year; mean, standard deviation coefficient of skewness, coefficient of kurtosis and the probabilities of pentad rainfall exceeding 25, SO, 75, 100, 125 and 150 per cent of the mean pentad rainfall It was observed that coefficient of variation, coefficients of skewness and coefficients of were higher in dry pentad and in semi-arid and arid regions and lower in wet regions. Thus it was evident from the results of coefficients of skewness and,coefficients of kurtosis that pentad rainfall was different from "normal"