Analysis of maize yield responses to climate in the arid and semi arid lands of lower eastern Kenya

Abstract

Climate is key determinant of crop yields under rain fed conditions in Kenya’s dry lands as well as other parts of the country. Climate variability and change has had adverse effect on maize yields and food supply in ASALs. The objective of the study was to analyze the response of maize yields to changing climate in the arid and semi arid districts of lower Eastern Kenya. This study was based on the desire to understand the impact of climate variability/change on maize yields with an aim to provide strategies for adaption. Longitudinal survey and evaluation research designs were used in the study. Purposive and cluster sampling techniques were employed to select the study samples. The study utilized maize and climate time series datasets of lower eastern Kenya’s four ASALs districts covering the thirty year period of 1979-2009. Both primary and secondary datasets were utilized. Primary data was collected by the use of questionnaires, key informant interviews and focus group discussions. Secondary data for maize yields was collected from the Ministry of Agriculture which were analyzed by use of INSTAT and SPSS statistical packages. Climate data were collected from KMD and KEFRI and analyzed to determine trends and patterns over the period. Responses of maize yields to climate were sought through Z-scores, tend analysis and descriptive. The findings revealed that there has been wide variability in climate in lower eastern Kenya. From climate variability analysis, the results show adverse effects on maize production and thus food security. The results indicated that there is enormous negative impact of climate on maize yields in the four ASAL districts of lower Eastern Kenya. Trend analysis revealed that maize yields are alarmingly declining at high levels in Machakos district (22.5 Kg/acre pa) followed by Kitui (12.0 Kg/acre pa), Mwingi (7.3 Kgs/acre pa) and lastly Makueni 8.7 Kg/acre pa). The maize yields Z-values were predominately negative in the period 1994-2008. Rainfall trend analysis revealed that four of the six weather stations were declining at alarming rate (0.6-15.5 mm pa). Evidently there was upward warming of annual and seasonal temperature at rate of 0.03 0C pa. These findings are startling but are crucial in planning appropriate adaptation mechanisms by government, researchers and other development workers in lower Eastern Kenya in support of enhancing resilience of maize production and food security. They will also be used by farmers to monitor climate risks and forecast maize production under rain-fed conditions in lower Eastern Kenya’s dry lands.