Exploring Crop Yield Benefits of Integrated Water and Nutrient Management Technologies in the Desert Margins of Africa: Experiences from Semi-arid Zimbabwe

Abstract

The benefits of integrating locally adaptable water and nutrient management technologies were explored in semi-arid Zimbabwe. On-farm maize-based experiments were set up on six farmers’ fields in Ward 5, Shurugwi. Three tillage systems, namely post-emergence tied ridging (PETR), rip and potholing (RPH) and conventional mouldboard ploughing (CMP) were integrated to three nutrient management regimes, i.e. a control with no fertility amelioration, pit-stored cattle manure band applied at 10 t/ha and the latter with an additional top dressing of ammonium nitrate (34.5% N) at 100 kg/ha. On each site the treatments were set up as a completely randomized split-plot block design replicated three times with tillage (water management) as the main treatment and fertility as the sub-treatment. CMP mimicked the farmer’s common land preparation practice, while PETR and RPH systems represented the improved water harvesting tillage techniques. Results revealed significant nutrient management effects right from the first season giving 3-year means of 1298, 1977 and 2490 kg/ha for the control, manure and manure plus fertilizer treatments, respectively. On the other hand, water harvesting tillage effects were insignificant initially (2003/2004) but had beneficial effects in subsequent seasons (2004/2005 and 2005/2006) with 3-year grain yield means of 1624, 2032 and 2108 kg/ha for CMP, PETR and RPH, respectively. Maximum yield benefits from integrating PETR and RPH with manure + AN fertility ameliorants amounted to 218 and 261%, respectively, compared to CMP with no fertility amendment. The results, therefore, showed increased benefits when in situ water harvesting tillage techniques are integrated with appropriate nutrient ameliorants giving realizable food security benefits to the farmer.KeywordsCrop yieldIn situ water harvestingNutrient managementTillageWater