Water balance and migration for maize in an oasis farmland of northwest China

Water balance and migration characteristics are vital to the establishment of an efficient irrigation management system. Based on the observed data including microclimate and growing parameters of maize from 2009 to 2012, actual evapotranspiration during the growth period was estimated by a combination of the FAO-56 crop coefficient approach and the Penman-Monteith model; the changes in soil water storage were estimated through the monitored water content at different depths from 0 to 3 m; the water content monitoring zone was divided into three sub-zones according to the water-balance characteristics of different soil layers and water monitoring data. On these bases, in combination of water-balance model, three aspects were analyzed: water-balance characteristics at different growth stages; water-balance characteristics in the three different sub-zones; and water-migration characteristics of ten sunny days following irrigation. These analyses revealed severe deep leakage under present irrigation management, which could be remedied by limiting one-time irrigation practices and increasing irrigation frequency. Additionally, some practical suggestions are provided for different growing stages.