Integration of information on climate, soil and cultivar to increase water productivity of maize in semi-arid eco-regions of Ethiopia

Abstract

Climate related risks highly influence crop performance and thus water productivity in different eco-regions of Ethiopia. In view of its low rainfall and short growing period, the semi-arid eco-regions like the Central Rift Valley of Ethiopia (CRV) are the most affected. A study was conducted in Bofa, CRV to utilize climate information in guiding cropping and water management decisions. Tercile probability was computed to characterize rainy seasons into best (April), expected (May) and worst case (June) planting scenarios. Three independent experiments were designed to fit planting scenarios. In each set, one improved and one local maize cultivars (best: BH660 and Bolonde; medium: A511 and Limat; worst: Melkassa-1 and Shaye) were combined with three tillage practices: Modified-Moldboard Plow (MMP), Wing-Plow (WP) and local Maresha. Rainwater productivity and grain yield were compared. The results illustrate differences among planting scenarios and suggesting early planting decision is a possible practice in semi-arid CRV when soil water conserving tillage is integrated to escape climate associated risks. BH660 shows higher water productivity (9.46 kgmm-1 of rainfall) under 2*MMP tillage than late plantings in experimental years. About 84 % of the variability in grain yield (BH660), 88% (Bolondie), 76% (A-511) and 70% (Limat) can be explained by the available soil water in crop root zone at planting. Hence, integration of climate information, tillage practices and cultivar choice enabled not only successful aversion of climate related risks for long duration maize but also increased yield and rain water productivity in semi-arid areas. Furthermore, tailored rainfall forecast can help in selection of planting scenarios, tillage practices and crop cultivars in advance and further increase probability of success.

Keywords: Climate risk, tercile probability, tillage, planting scenario