ABSTRACT
Soil, water, vegetation, and production systems constitute the most important natural resources in an agroecosystem. In the rainfed production systems, the importance of water shortage and associated stress cannot be overemphasized especially in the semiarid tropical (SAT) regions (Pathak et al., 2009; Passioura and Angus 2010; Rockström et al., 2010; Sahrawat et al., 2010a; Sharma et al., 2010). However, apart from water shortage, soil infertility is also the issue for crop production and productivity enhancement in much of the SAT regions of the world (El-Swaify et al., 1985; Black 1993; Zougmore et al., 2003; Sahrawat et al., 2007, 2010a; Bationo et al., 2008; Singh 2008; Twomlow et al., 2008a; Bekunda et al., 2010).
