Maize root development and grain production as affected by soil and water management on a sandy soil in a semi-arid region of southern Mozambique

Average yield of maize (Zea mays L.) in Mozambique is low, mainly due to low use of inputs in agriculture, high seasonal rainfall variability and inadequate soil preparation. A study conducted in two summer crop seasons (November-March 2012/2013 and 2013/2014) examined the impact of three tillage methods (hand hoeing, strip tillage and conventional tillage), two fertiliser levels (0 and 40% N) and two water supply regimes (rainfed and irrigated) on maize root development and grain yield on a sandy soil in a semi-arid region of Mozambique. Tillage had a major effect on soil penetration resistance, but little effect on root growth and limited effect on yield. Thus, there appears to be little need for loosening on this soil. There was also no interaction between tillage and the other experimental factors, meaning that tillage system can be chosen irrespective of fertiliser and water supply. Irrigation had the largest impact on root and shoot growth and crop yield, increasing yield in season 2 from 670 to 4780kg ha(-1).There was a very strong interaction between fertiliser and water supply, with no yield increase for fertiliser in the rainfed treatment, while combined with irrigation it increased yield by 1590kg ha(-1) in season 1 and 1840kg ha(-1) in season 2. Thus, for the conditions studied here, it was rational to add fertiliser only in combination with irrigation and not in a rainfed system.