控制性分根交替灌水的节水效应

以盆栽玉米为实验材料，通过控制性分根交替灌水试验，证明当土壤含水率为田间持水率的55%~65%时，控制1/2根区交替灌水其用水量减少34.4%~36.8%,而生物产量仅下降6%~12%，水分利用效率、根冠比、气孔阻力明显增加、叶片蒸腾速率明显下降，蒸腾效率提高而光合速率未明显变化；控制1/2根系区域交替灌水比固定1/2区域灌水的用水效率明显提高，根系总量和根冠比增加，根系分布均匀，地上部生物产量增加。初步证明控制性分根交替灌水是一种高效而可行的节水新技术。

The experiment of controlled root-divided alternative irrigation (CRAI) in maize showed that controlled 1/2 root region alternative irrigation in 55 %~65 % of field water capacity is able to save 34.4 %~36.8 % of water use, and the biomass only decrease 6 %~12 %. The efficiency of water use and the root-shoot ratio increase obviously. The transpiration efficiency increases because the photosynthesis is not changed but the stomatal resistance increases and the transpiration rate decreases. The water use efficiency of 1/2 root-divided alternative irrigation is higher than that of 1/2 root-divided fixed irrigation. The weight of dry root and root-shoot ratio increase and the root distributes evenly by alternative irrigation, but the 1/2 root divided fixed irrigation has no this effect. Controlled Roots-Divided Alternative Irrigation is a practicable technology of water saving.