The impacts of weather on sugarcane production in the mumias sugar zone of western Kenya

Abstract

This study sought to understand the existing trend in selected weather variables and investigate the effect of these variables on annual yield of sugarcane in the Mumias sugarcane growing region of Western Kenya. The weather-yield relations were investigated using two sugarcane varieties CO 421 and CO 945 under same growing conditions at Mumias Sugar Company nucleus estate in Mumias district. Two weather datasets were used; one comprising of daily rainfall, temperature and radiation data from 1981 to 2008 and another comprising of 40-year mean monthly data from 1968 to 2008 of the same variables. The yield data set comprised of yields at field level for the period between 1984 and 2008. Trend analysis for both the weather and yield data was done using the Mann-Kendall and Sen Statistics. The influence of different weather-related variables on sugarcane yield was investigated using correlation and regression analysis. Analysis of the trends in the observed weather records indicated an increase in the mean monthly minimum temperature during all the months of the year with the magnitude of change ranging between 0.05°C and 0.08°C per year. The records also showed an increasing trend in the mean monthly maximum temperatures which was significant during the months of July and August with a magnitude of O.03°C for both months. Rainfall records did not indicate any significant trends. Trend analysis of the yield data showed a general decreasing trend in the yields in both the varieties, with variety CO 421 showing a slower decline than CO 945. Analysis on the interaction of the selected weather variables on sugarcane yields in the two varieties showed that CO 945 was more sensitive to weather variables than CO 421.