绿洲灌区不同密度玉米群体的耗水特性研究

针对水资源不足严重制约绿洲灌区玉米生产,密植对玉米耗水特性影响研究薄弱,以及生产实践中缺乏调控种植密度以同步提高产量和水分利用效率的理论依据等问题,2012—2015年,以先玉335为参试品种,在相同施肥、灌水制度下,设75 000株hm–2(低,D1)、87 000株hm–2(中,D2)、99 000株hm–2(高,D3)3个密度水平,探讨密度对玉米耗水的时间动态、耗水结构以及利用效率的影响,以期为优化密植增产节水技术提供理论依据。结果表明,随密度增大,玉米全生育期总耗水量(ET)增大,大喇叭口期至吐丝期是耗水量增大的主要时期,高、中密度处理与低密度处理相比,全生育期总耗水量4年平均分别高22.8%、14.4%,大喇叭口期至吐丝期平均分别高28.4%、18.2%,其他生育时期不同处理的耗水量差异不显著。增加密度可降低玉米的无效耗水,提高水分利用率,高、中密度处理较低密度处理全生育期的棵间蒸发量(E)4年平均分别减少56.5 mm、27.6 mm,密植降低棵间蒸发量的主要时期在拔节至灌浆期,其中大喇叭口期至吐丝期的日均棵间蒸发量分别减少0.51 mm、0.27 mm;高、中密度与低密度处理相比,全生育期的E/ET分别降低15.8%、6.2%,其中拔节至大喇叭口期减小幅度最大,分别为22.1%、10.7%。与低密度处理相比,高、中密度处理的籽粒产量分别提高了17.9%、14.8%,但高、中密度处理间的产量差异不显著;高、中、低密度处理的水分利用效率(WUE)分别为18.2、19.3和16.8 kg hm–2 mm–1,中密度处理的WUE显著高于低密度处理;与低密度处理相比,高、中密度处理4年平均灌溉水利用效率(IWUE)分别提高了34.5%、19.6%。本研究说明,在传统供水覆膜条件下,进一步增加种植密度是干旱绿洲灌区提高玉米产量和灌溉水利用效率的可行措施。

Effect of Planting Density on Water Consumption Characteristics of Maize in Oasis Irrigation Area

In oasis irrigation agricultural region, water resources deficit is one of the most serious constraints for crop production. However, the insufficient academic support for how compact planting affecting crop water consumption has led to a great short slab on increasing yield and water use efficiency (WUE) simultaneously through the regulation of plant density in practices. Under the same fertilization and irrigation level, a field experiment was carried out in 2012-2015 in order to investigate the water consumption characteristics, yield and water use efficiency of maize under different density levels (D1, 75 000 plants ha^-1, low; D2, 87 000 plants ha^-1, medium; and D3, 99 000 plants ha^-1, high). Withincreasing planting density the total water consumption (ET) increased in whole growth stage, but had no significant changes from sowing to jointing stage and from filling to full ripe stage. The total ET in high and medium density treatments significantly increased by 22.8% and 14.4% on average of four years, while by 28.4% and 18.2% on average of four years mainly in big trumpet to silking stage, respectively, compared with low density treatment. Similarly, increasing planting density could reduce invalid water consumption and increase water use efficiency, the high and medium density treatments reduced evaporation (E) in whole growth stage, by 56.5 mm and 27.6 mm, significantly decreased average daily evaporation from jointing to filling, and even greatly from big trumpet to silking stage, with the decreased values of 0.51 mm and 0.27 mm, respectively, compared with low density treatment. For E/ET, it was decreased with planting density increases, and the E/ET under high and medium density was reduced by 34.5% and 18.8%, respectively, especially from jointing to big trumpet, which decreased by 22.1% and 10.7%, respectively. On average, the grain yield under high and medium density was 17.9% and 14.8% greater than that under low density, but the difference was not significant. The water use efficiency (WUE) under high, medium and low density was 18.2, 19.3, and 16.8 kg ha^-1 mm^-1, respectively. While, the irrigation water use efficiency (IWUE) under high and medium density was increased by 34.5% and 19.6%, respectively, compared with low density. Therefore, further increasing planting density is favorable to improve grain yield and IWUE under the condition of traditional water supplement and film mulching in Oasis irrigation region.