Separating nitrogen fertilizer and irrigation water application in an alternating furrow irrigation system for maize production

The efficient use of water and nitrogen represents a primary concern to agricultural production in Northwest China. A 2-year field experiment was conducted to assess the separation of nitrogen (N) fertilizer and irrigation water with alternating furrow irrigation (SNWAFI) in a maize (Zea mays L.) production system. Irrigation water use efficiency and nitrogen use efficiency with SNWAFI were generally greater than with conventional irrigation and fertilization (CIF). Response surfaces indicated that maximum maize yields were obtained with 238 kg urea-N ha−1 and 106 mm irrigation water in 2008 and 244 kg urea-N ha−1 and 95 mm of irrigation water in 2009. When the predicted yields were highest (6,384 and 6,549 kg ha−1), water use efficiency, N uptake, and N use efficiency were greater with SNWAFI than CIF. Conversely, soil NO3–N change during maize growing season decreased with SNWAFI compared CIF. With SNWAFI, optimizing irrigation water and N fertilizer rates can maximize yield, save irrigation water, and reduce N leaching.