河套灌区不同膜下滴灌方式对玉米拔节期光合日变化的影响

Effects of Different Drip Irrigation and Plastic Mulching on Photosynthetic Characteristics and Yield of Maize in Hetao Irrigation District

玉米是河套灌区第二大粮食作物,研究当地节水灌溉耕作方式下玉米光合生理特征,对提高水分限制条件和土壤盐渍化严重的河套灌区发展玉米膜下滴灌高效节水灌溉技术具有现实意义。在河套灌区通过大田试验,设置全膜平作、半膜平作处理,每种处理均进行高、中、低水滴灌量共6种膜下滴灌方式组合,研究了其对拔节期玉米光合特性、叶绿素荧光参数的影响。结果表明:河套灌区高水和中水滴灌量覆盖全膜条件下,玉米产量分别达到14 432.1 kg/hm2和15 472.0 kg/hm^2显著高于同等滴灌量的半膜覆盖处理,增幅达10.3%~27.5%。不同覆膜相同滴灌量处理之间净光合速率Pn、蒸腾速率Tr、胞间CO_2浓度、气孔导度Gs日变化均差异显著(P<0.05),相同覆膜条件下,低水与中水、高水处理的净光合速率Pn、蒸腾速率Tr、胞间CO_2浓度、气孔导度Gs日变化均值差异显著(P<0.05),中水与高水无显著差异(P>0.05),说明拔节期灌溉中水滴灌量即可提高玉米净光合速率。相同覆膜条件下,中水和高水增加了Fv/Fm,PSII反应中心原初光能转化效率提高,提高了实际光化学效率ФPSII,有利提高玉米叶肉细胞光合作用能力。

It is of great significance to study the photosynthetic characteristics of food crops of maize in key growth period. Developing high-efficiency water saving agriculture, applying and promoting water-saving irrigation techniques are significant measures to promote realistic use of agricultural water re-sources, enhance agricultural water resources use efficiency and realize agricultural sustainable devel-opment. Field experiment was conducted to study the effects of drip irrigation under mulch in different cropping patterns on photosynthesis characteristics, chlorophyll fluorescence characters and yield for-mation of maize. The results showed that the yields of high drip irrigation and middle drip irrigation with whole film covering are 14 432. 1 kg/hm2 and 15 472. 0 kg/hm2 , by increasing up to 10. 3% ~27. 5%, significantly above the same amount of drip irrigation with half film covering. Between differ-ent film mulching and same irrigation treatment, the diurnal changes of net photosynthetic rate, tran-spiration rate, intercellular CO2 concentration and stomatal conductance are significant difference （ P〈0. 05 ） . There is no significant difference between the treatments with high drip irrigation and middle drip irrigation （ P〉0. 05 ） . The net photosynthetic rate of maize could be increased by middle drip ir-rigation at jointing stage. Under the same film mulching condition, the Fv/Fm andФPSII are increas-ing by high drip irrigation and middle drip irrigation. It is in convenient for facilitating the ability of photosynthesis in mesophyll cells.