Adaptation of Sorghum (Sorghum bicolor L. Moench) Crop Yield to Climate Change in Eastern Dryland of Sudan

Abstract

Dryland sorghum (Sorghum bicolor L. Moench) crop production in semiarid areas of eastern Sudan is vulnerable to climate change through the direct impacts of sporadic and highly varied rainfall accompanied by high temperature conditions. Continuous practice of conventional tillage (WLD) in clay soil using wild-level disc harrow over more than 70 years had created a hard subsurface layer that prevents both adequate storage of water and deep penetration of crop roots. Thus, sorghum crop experiences frequent water stress periods during its life cycle due to unreliable water source (rainfall) and deteriorated reservoir (soil). Investigating the capability of conservation tillage (CT) practices and in-situ water harvesting (ISWH) techniques to achieve sustainable and adaptable sorghum yield is the main objective of this study. The behavior of sorghum grain yield (GY), water use efficiency (WUE), water use (ET), and soil water status at sowing and at harvest (SWS and SWH, respectively) were the main parameters that explored under CT and ISWH: WLD, as a control treatment, no-till (ZT-M) and contour chisel plowing (CCP-M), both with residue mulching, as CT practices, and contour ridge-furrow (CRF-M), and contour tied-ridging (CTR-M CT), both with residue mulching, as ISWH techniques. The research was carried out at a Pilot Farm of University of Gadarif, Twawa area, during three consecutive rainy seasons (2011-2013). The experiment was set-up using a randomized complete block design (RCBD) with four replications. Mean GY (Kg.ha ’) and WUE (Kg.ha ’. mm ’) in response to CT and ISWH treatments were about 1895 and 5.0, 2184 and 6.2, 2198 and 6.0, 1945 and 5.2, and 2357 and 6.5, under WLD, CFR-M, CCP-M, ZT-M, and CTR-M, respectively. GY under CTR-M were generally higher than the mean GY either in wet (12%) or in dry (18%) rainy season. At sowing and harvest time, moisture in the soil profiles under CTR-M treatment is more than WLD, CCP-M, ZT-M, and CTR-M treatments by 3-15% and 9-28%, respectively. Treatments CTR-M, CFR-M, and CCP-M showed adaptation potential to climate change in drought- prone dryland in eastern Sudan.