Extensive data from productivity enhancement studies in Africa and Asia demonstrate the enormous potential to enhance green water-use efficiency as well as increase the availability of green water (Wani Pathak and Tam, 2002, Wani, Pathak and Jangawad, 2003, Wani, Joshi and Raju, 2008, Wani, Sreedevi and Marimuthu, 2009b, Wani, and Rockstrom, 2011c, Rockstrom, Hatibu and Oweis, 2007, Barron and Keys, 2011). Of the 1 338 million poor people worldwide, most live in the developing countries of Asia and Africa in dryland/rain-fed areas (Rockstrom, etal., The reliance on rainfed agriculture varies regionally. In sub-Saharan Africa, more than 95 percent of the farmed land is rain fed, with almost 90 percent in Latin America, 60 percent in South Asia, 65 percent in East Asia, and 75 percent in the Near East and North Africa (FAOSTAT, 2010). A large proportion of the global expansion of cropland areas since 1900 has occurred in rain-fed regions.