ABSTRACT
The experiment was conducted using automatic rain shelter to study the effect of precisely controlled water quota of alternate subsurface drip irrigation (ASDI) on spring maize yield and water use efficiency (WUE). The results showed that jointing to heading stage and heading to hilling stage were the key stages of water requirement for spring maize under ASDI. In particular, both the water consumption percentage and diurnal water consumption in these two stages were higher than in other stages and were more sensitive to water deficit stress. The water demand in these two stages should be prioritized if irrigation was limited. Maize yield generally increased with the increasing irrigation quota. When the irrigation quota below 2764.5 m3·hm-2, the yield increased rapidly with the increasing irrigation quota. The yield increase then slowed down after the irrigation quota reached 2764.5 m3·hm-2. The maximum of maize yield of 12109.0 kg·hm-2 was obtained at the irrigation quota of 3357.1 m3·hm-2. Compared to fixed subsurface drip irrigation (FSDI), under the same irrigation quota, the yield, WUE and irrigation water use efficiency (IWUE) of spring maize in ASDI treatment were improved by 5.4%, 1.4% and 5.6%, respectively. Compared to FSDI, the maize yield in ASDI decreased by 1.8%, but its WUE and IWUE increased by 11.0% and 22.7% when the irrigation quota decreased by 20%. The optimal irrigation quota of ASDI for spring maize in the study area was1600.4-3357.1 m3·hm-2 by taking into account of yield and WUE.
