不同产量水平下夏玉米光合及耗水特性研究

【目的】通过控制施肥量来模拟夏玉米不同产量水平,了解不同产量下夏玉米光合及耗水特性变化,为田间用水管理、区域农业高效用水发展战略的制定提供理论依据。【方法】设置4个产量水平分别为9 000 kg/hm~2(C0),9 750 kg/hm~2(C5),10 500 kg/hm~2(C10),11 250 kg/hm~2(C15),以不施肥为对照(CK),研究不同产量下夏玉米穗位叶光合性能、叶绿素荧光及耗水量和水分利用效率变化。【结果】夏玉米拔节期、花前和花后的株高、叶面积指数、净光合速率、气孔导度和蒸腾速率均随目标产量的提高而增加,花前胞间CO2摩尔分数随产量的提高而增加,C15处理株高、叶面积指数、净光合速率、气孔导度、蒸腾速率和胞间CO2摩尔分数分别较CK平均增加25.5%、39.1%、42.1%、97.9%、79.8%、32.0%;夏玉米拔节期、花前和花后SPAD随目标产量提高,C15处理SPAD较CK平均增加17.9%,qP、ETR、Y(Ⅱ)在不同光照强度下为CKC0处理>C5处理>C10处理>C15处理;耗水量和水分利用效率随产量的提高而增加,土壤体积含水率降低,C15处理耗水量和水分利用效率较CK分别提高15.2%、14.1%,土壤体积含水率较C0处理降低11.0%。【结论】夏玉米较高的叶面积指数、生物量和耗水量是形成高产的重要原因,其中后期干物质的合成是产量形成的主要原因,因此应加强夏玉米生育后期田间用水管理。

Study on Photosynthesis and Water Consumption Characteristics of Summer Maize under Different Yield Levels

【Objective】In this experiment, the yield of summer maize was controlled by controlling the amount of fertilization, and then the changes of photosynthesis and water consumption characteristics of summer maize under different yields were studied, which provided a theoretical basis for the development of field water management and regional agriculture efficient water development strategy.【Method】Four yield levels, including 9 000 kg/hm~2(C0),9 750 kg/hm~2(C5),10 500 kg/hm~2(C10),11 250 kg/hm~2(C15), with no fertilization(CK) as control,were set to study the changes of photosynthetic performance, chlorophyll fluorescence, water consumption and water use efficiency of summer maize under different yields.【Result】At the summer maize jointing stage, before and after flowering, plant height, leaf area index, net photosynthetic rate, stomatal conductance and transpiration rate increased with the increase of target yield, the intercellular CO2 concentration increased with the increase of yield, and plant height, leaf area index, net photosynthetic rate, stomatal conductance, transpiration rate and intercellular CO2 concentration of C15 treatment increased by 25.5%, 39.1%, 42.1%, 97.9%, 79.8%, 32.0% respectively, compared with CK. The relative content of chlorophyll in summer maize jointing stage, pre-flowering and post-flowering increased with target yield, the relative content of chlorophyll in C15 treatment increased by17.9% compared with CK. qP, ETR, Y(II) results showed the order CKC0>C5>C10>C15. Water consumption and water use efficiency increase with increasing yield, soil volume and water content decrease, the water consumption and water use efficiency of C15 treatment increased by 15.2% and 14.1%, respectively compared with CK, and the soil volumetric water content decreased by 11.0% compared with C0.【Conclusion】Higher leaf area index, biomass and water consumption of summer maize are the main reasons for high yield, and the main reason for yield formation is the synthesis of dry matter in later stage, therefore, the field water management in the late stage of summer maize growth should be strengthened.