高密度栽培条件下灌水量对河西灌区玉米群体质量及水分利用效率的影响

提高种植密度是玉米产量持续增长的重要措施，探讨高密度栽培下的合理灌溉定额对保障玉米高产及水资源可持续利用具有重要意义。2023年4 — 10月在河西灌区张掖节水农业试验站开展田间试验，研究高密度栽培条件下不同灌水量(270.0、390.0、510.0、630.0 mm)对玉米群体质量、产量和水分利用效率的影响。结果表明，随着灌水量的增加，玉米的干物质量、产量呈增加趋势，高灌水量(630.0 mm)下的干物质量和产量均最高，中等灌水量(510.0 mm)下干物质量、产量分别高达32 013.36、16 000.31 kg/hm2，仅比高灌水量处理分别低2.89%、3.13%，而在390.0、270.0 mm灌水量下显著降低。各处理的光合势、生长速率随生育进程的推进先增加后降低，其中吐丝期后20 d达到最大，且随灌水量增加而增大；吐丝期后20 d至灌浆中期，510.0、390.0 mm灌水量下的光合势下降幅度为0.38%、2.40%，生长速率下降幅度为26.16%、30.19%，均低于高灌水量处理和低灌水量(270.0 mm)处理。玉米水分利用效率随灌水量、耗水量增加先上升后下降，390.0、510.0 mm灌水量处理下水分利用效率分别为26.21、25.14 kg/(hm2·mm)，差异不显著；而产量最高的高灌水量处理及耗水量最低的低灌水量处理仅为22.77、23.98 kg/(hm2·mm)，均低于390.0、510.0 mm灌水量处理。综合考虑玉米产量与水分利用效率等指标，在种植密度为11.70万株/hm2 条件下，510.0 mm为玉米生育期适宜灌水量，可实现增产节水目标。

Effects of Irrigation Volume on the Quality of Maize Population and Water Use Efficiency Under High-density Cultivation in Hexi Irrigation Area

Increasing planting density is a crucial measure for the sustained growth of maize yield. Exploring reasonable irrigation quotas under high-density cultivation is significant for ensuring high maize yields and sustainable water resource utilization. From April to October 2023, field experiments were conducted at the Zhangye Water-saving Agriculture Experimental Station in the Hexi Irrigation District to study the effects of different irrigation capacities(270.0, 390.0, 510.0, 630.0 mm) on the quality of the maize population, yield, and water use efficiency under high-density cultivation conditions. Results showed that as irrigation volume increased, both dry matter and yield of maize tended to increase. The highest dry matter and yield were observed under high irrigation(630.0 mm), with medium irrigation(510.0 mm) achieving dry matter and yield of 32 013.36 and 16 000.31 kg/ha, respectively, only 2.89% and 3.13% lower than those of high irrigation, while data were significantly decreased under 390.0 and 270.0 mm irrigation. The photosynthetic potential and growth rate of each treatment increased and then decreased as the growth progressed, peaking 20 days after silking, and increased with irrigation volume; from 20 days post-silking to the middle of grain filling, the decline in photosynthetic potential was 0.38% and 2.40% under 510.0 and 390.0 mm irrigation, respectively, with growth rate declines of 26.16% and 30.19%, both lower than those under high and low irrigation(270.0 mm). Water use efficiency of maize first increased and then decreased with rising irrigation and water consumption, with 26.21 and 25.14 kg/(ha·mm) under 390.0 and 510.0 mm irrigation, respectively, no significant differences were detected, whereas the highest yield under high irrigation and the lowest water consumption under low irrigation were only 22.77 and 23.98 kg/(ha·mm), respectively which were significantly lower than those under 390.0 and 510.0 mm irrigation. Considering both maize yield and water use efficiency, an irrigation volume of 510.0 mm during the growth period is suitable under a planting density of 117 000 plants/ha, achieving goals of increasing yield and saving water.