模拟控制性分根交替滴灌对玉米的节水效应

Effect of simulated controlled roots-divided alternate drip irrigation in maize on water use efficiency

以盆栽玉米为试材,模拟田间控制性分根交替滴灌(ControlledRoot-dividedalternativeDripIrrigation,简称CRDADI)供水方式对夏玉米净光合速率、气孔导度、蒸腾速率、水分利用效率及其根冠比的影响。结果表明,控制1/2根区交替滴灌(ADI1)比常规滴灌(CK)节水25%而生物量仅下降9%,水分利用效率和根冠比均明显增加,气孔导度和蒸腾速率下降明显而净光合速率变化很小,蒸腾效率明显提高;控制1/2根区固定滴灌(FDI2)水分利用效率虽然是CK的1.2倍,但生物量仅为CK的60.1%,ADI1的66.0%,严重影响了玉米的正常生长;控制1/2根区交替滴灌(ADI)比控制1/2根区固定滴灌(FDI)的根冠比、根干质量和根条数增加且根系分布均匀,地上部分生物量增加。表明控制性分根交替滴灌(ADI)能在不牺牲作物光合产物积累的前提下提高玉米的水分利用效率。

Effects of simulated roots-divided alternate drip irrigation on the photosynthetic rates, stomatal conductance, transpiration rate, water use efficiency (WUE) and the root-shoot ratio of summer maize are studied with controlled alternate drip irrigation for half part of root zone (ADI), controlled fixed drip irrigation for half part of root zone (FDI) and conventional drip irrigation for whole root zone (CK) through potted experiment. The results showed the water saving effect of ADI was higher 25% than that of CK, but the biomass decreased only by 9% and the WUE and the root-shoot ratio increased obviously compared with CK. The stomatal con-ductance and the transpiration rate of ADI also reduced clearly, but the photosynthetic rate changed little, which caused the transpira-tion efficiency increase evidently. The WUE of FDI2 was higher than that of CK, but the biomass was only 60.1% of CK,66.0% of ADI1, which affected the normal growth of maize badly. The root-shoot ratio、the dry weight and the number of roots of ADI were higher than those of FDI and the roots distributed evenly, the dry matter mass of above-ground part increased. It suggested that ADI could improve the water use efficiency without sacrificing the accumulation of biomass.