Yield and Nitrogen Use Efficiency of Rainfed Maize Response to Splitting and Nitrogen Rates in Kashmir, Pakistan

Abstract

Efficient use of N for maize ( Zea mays L.) production is an important management strategy for increasing crop yield and improving N use efficiency (NUE). A 2‐yr (2007 and 2008) field experiment was conducted to evaluate the effect of timing and rate of N application on growth and yield, N uptake, and NUE of rainfed maize. The experiment was a randomized complete block design with split‐plot arrangement using three replications. Treatments consisted two application timings—full dose of N at planting or a split application, with half at sowing and half at V6 stage—and seven N rates of 30, 60, 90, 120, 150, 180, and 210 kg N ha −1 and a control. Results indicated that N fertilization increased straw yield by 34 and 27% and grain yield by 88 and 80% in 2007 and 2008, respectively, over the control. The maximum grain was recorded for 180 kg N ha −1 . Splitting N did not show a significant effect in 2007 but displayed a significant increase in both straw and grain yield (6%) over full N application in 2008. The maximum N uptake ranged between 122 and 139 kg N ha −1 and required 180 kg N ha −1 (except split application in 2007). Splitting of N significantly increased N uptake by 6 and 13% (2007 and 2008, respectively). The maximum NUE was observed between 68 and 70% at 90 kg N ha −1 and there was a general trend of decreasing NUE with increasing N rates. Splitting N increased NUE by 14% (2008). Results of this experiment showed that application of 180 kg N ha −1 in split applications is a successful and sustainable management strategy for maize production in rainfed mountainous ecosystems.