Assessment of maize yield-increasing potential and optimum N level under mulched drip irrigation in the Northeast of China

Abstract

A field experiment under film mulched drip irrigation was conducted for two consecutive years (2014.5–2015.10) in the Northeast Plain of China (NEC), in order to quantify the maize yield-increasing potential and optimum nitrogen (N) level. The results showed that mulched drip irrigation significantly promoted the environmental factors, maize growth and production in the NEC (p≤0.05). Compared with the traditional rain-fed management, the total soil water storage (SWS) at ridge significantly increased by 80mm and the topsoil accumulative temperature (TC) increased by 353°C under mulched drip irrigation. Compared with non-mulched surface drip irrigation, the total SWS and TC also increased by 9mm and 245–314°C under mulched drip irrigation. The increased TC was the main reason for the promotion of crop development in the early stage, and it prolonged the duration from tasseling stage (VT) to physiological maturity (R6) and increased the yield. Furthermore, the soil total N at the root zone and N uptake also increased under mulched drip irrigation, about 0.28g/kg and 28.41kg/hm2 higher than local management, respectively, which could be regarded as the second reason for the yield-increase. The third main reason for the increase in yield was that more net radiation was intercepted by maize under mulched drip irrigation. Compared with local maize cultivation, the maize yield increased by 10%-29%, and water use efficiency (WUE) increased by 10%-31% and nitrogen use efficiency (NUE) increased by 57%-84% at 230kg/hm2N under mulched drip irrigation. There was no significant yield-increasing (p >0.05) with N changed from 230kg/hm2 to 330kg/hm2. Therefore, N of 230kg/hm2 was recommended for mulched drip-irrigated maize and an increase of more than 10% of yield and WUE was validated by mulched drip irrigation experiments in the NEC.