地膜玉米免耕轮作小麦的减水减氮效应

Effects of reducing water and nitrogen supplies in rotated wheat with previous plastic mulched maize

  • 摘要: 针对长期连作作物生产力低下等突出问题,研究前茬地膜覆盖作物免耕留膜,轮作后茬作物的生产效应,对于优化栽培模式,建立甘肃河西绿洲灌区作物生产的节本增效技术具有重要意义。2016-2017年,通过田间定位试验,研究了前茬地膜覆盖玉米茬口两种耕作方式(免耕留膜,NT;传统耕作,CT)、两种灌水水平(传统灌水,2400 m3·hm-2,I2;传统灌水减量20%,1920 m3·hm-2,I1)和3个施氮水平(传统施氮,225 kg·hm-2,N3;传统施氮减量20%,180 kg·hm-2,N2;传统施氮减量40%,135 kg·hm-2,N1)对轮作小麦产量、光能与灌溉水利用及经济效益的影响,以期为优化试区小麦的栽培技术提供理论依据。研究结果表明,前茬玉米免耕留膜较传统耕作小麦全生育期总叶日积提高21.6%~26.1%(P < 0.05),特别是小麦灌浆至成熟期提高41.3%~45.2%(P < 0.05),具有延缓衰老的作用。小麦灌浆至成熟期,免耕留膜集成减量20%水氮供应(NTI1N2)处理比传统耕作和水氮供应(CTI2N3)提高叶日积34.8%~50.7%。免耕留膜较传统耕作提高籽粒产量、光能利用率和灌溉水利用效率分别为10.1%~10.4%、5.6%~12.3%和10.1%~10.3%(P < 0.05);NTI1N2较CTI2N3处理小麦增产15.2%~22.0%、光能利用率提高8.1%~18.5%、灌溉水利用效率提高44.0%~52.5%(P < 0.05)。免耕留膜结合减量水氮供应可降低生产成本,提高纯收益和产投比,NTI1N2较CTI2N3处理纯收益和产投比分别提高22.9%~23.9%和34.8%~35.1%,单方水效益提高53.6%~68.9%(P < 0.05)。因此,前茬地膜覆盖玉米免耕留膜配套减量20%灌水(1920 m3·hm-2)与施氮(180 kg·hm-2)可作为甘肃河西绿洲灌区发展节本增效小麦生产的关键技术。

     

    Abstract: To combat low crop productivity in long-term continuous cropping systems, it is necessary to study the effects of no-tillage and continued mulched plastic to optimize cultivation and establish cost-saving and benefits-increasing technology in Hexi irrigated areas in Gansu Province. A field experiment was conducted in northwestern irrigated areas in 2016-2017 to evaluate the yield, light energy, irrigation water utilization, and economic benefits of all combinations of two tillage practices, two irrigation levels, and three nitrogen application levels on wheat. The two tillage practices included no-tillage and continued mulched plastic in previous maize (NT) and conventional tillage in previous maize after removing the mulched plastic from soil (CT). The two levels of irrigation included the local conventional irrigation amount, 2400 m3·hm-2 (high: I2), and the local conventional irrigation amount reduced by 20%, 1920 m3·hm-2 (low: I1). The three levels of nitrogen application included the local conventional nitrogen amount, 225 kg·hm-2 (high: N3), the local conventional nitrogen amount reduced by 20%, 180 kg·hm-2 (medium: N2), and the local conventional nitrogen amount reduced by 40%, 135 kg·hm-2 (low: N1). The results showed that NT increased the leaf area duration (LAD) of wheat across all growth stages by 21.6% to 26.1%, and the LAD remained high from the wheat filling to the maturity stage, increasing by 41.3% to 45.2% (P < 0.05), compared with CT, and delaying senescence. A 20% reduction in irrigation and N application combined with NT (NTI1N2) resulted in a greater LAD (by 34.8% to 50.7%) from the wheat filling to the maturity stage than CT with conventional high levels of irrigation and nitrogen (CTI2N3). NT increased wheat grain yield, light use efficiency, and irrigation water use efficiency by 10.1% to 10.4%, 5.6% to 12.3%, and 10.1% to 10.3% (P < 0.05) compared with CT, respectively. The grain yield, light use efficiency, and irrigation water use efficiency were significantly increased by 15.2% to 22.0%, 8.1% to 18.5%, and 44.0% to 52.5% with NTI1N2 compared with CTI2N3, respectively. NT integrated with reduced irrigation and nitrogen application reduced the production cost and improved the net return and input-output ratio. The NTI1N2 treatment increased the net return and input-output ratio by 22.9% to 23.9% and 34.8% to 35.1%, respectively. In addition, the benefit per cubic meter of water increased by 53.6% to 68.9% with NTI1N2 compared with CTI2N3 treatment. These results suggest that no-tillage and continued mulched plastic in previous maize with low irrigation (1920 m3·hm-2) and medium nitrogen (180 kg·hm-2) can reduce costs and increase the benefits of wheat production in Hexi irrigated areas in Gansu Province.

     

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