Evaluating N management strategies for hybrid maize in Southeast Asia

Abstract Increasing yields on existing farmland is the only option to meet the rising demand for maize without resorting to land use change. Maize yields in Southeast Asia are typically less than their potential because of sub-optimal fertilizer management, particularly nitrogen. We evaluated a range of N-fertilizer treatments on irrigated maize grown on medium-textured soils in Indonesia and Vietnam during the dry seasons of 2008–2009. The treatments included split applications with rates adjusted according to leaf color. We found no advantage in more than two splits in terms of yield or agronomic efficiency. Adjusting applications according to leaf color gave 0.80 t ha −1 more grain than fixed rates and US$ 182 ha −1 higher profit. N-use was highly efficient in the range of 30–65 kg kg −1  N.