不同比例有机肥替代化肥对玉米生长及水分利用效率的影响

为了探索黄土高原半干旱区全膜双垄沟播玉米适宜的有机氮替代无机氮水平，于2018—2019年通过大田试验研究了单施化肥(F100M0)、有机肥50%替代(F50M50)、有机肥37.5%替代(F62.5M37.5)、有机肥25%替代(F75M25)以及有机肥12.5%替代(F87.5M12.5)化肥和不施肥(CK)对玉米耗水特性、籽粒产量及水分利用效率的影响。结果表明：两个丰水年，玉米耗水差异主要表现在播种期50~110 cm土层和成熟期10~30 cm土层；与对照相比，F62.5M37.5和F87.5M12.5处理的籽粒产量和生物产量分别较对照增加100.6%、122.0%和132.7%、156.8%，水分利用效率和降水利用效率分别增加了73.1%、165.1%和93.6%、179.8%，水分利用效率和降水利用效率增加的原因主要是F62.5M37.5和F87.5M12.5处理协调了籽粒产量与耗水量之间的关系，使玉米水分利用效率和降水利用效率较对照分别增加。所有处理中，F87.5M12.5处理表现出与单施化肥相当的经济效益。因此，在200 kg·hm^-2施氮水平下，适度降低有机肥替代比例能提高玉米的水分利用效率和经济效益，本研究推荐有机肥替代化肥的水平为12.5%~37.5%。

Effects of different proportions of organic fertilizer substitutes for chemical fertilizer on growth characteristics and water use efficiency of maize

In order to explore appropriate proportions of organic N to inorganic N in the full film double ridge furrow sowing maize in the semi\|arid of Loess Plateau, based on field experiments in 2018 and 2019, the effects of N fertilizer without organic fertilizer (F100M0), 50% substitute of organic fertilizer (F50M50),37.5% substitute of organic fertilizer (F62.5M37.5), 25% substitute of organic fertilizer (F75M25), 12.5% substitute of organic fertilizer (F87.5M12.5) and no fertilizer application(CK)on water consumption characteristics, grain yield and water use efficiency of maize were studied. The results showed that the difference in water consumption of maize in the two wet years was mainly manifested in the soil layer of 50~110 cm at sowing stage and 10~30 cm at maturity stage. In comparison to the CK treatment, the grain yield and biological yield of F62.5M37.5 and F87.5M12.5 treatments were increased by 100.6%, 122.0% and 132.7%, 156.8%, respectively, and the water use efficiency and rainfall use efficiency were increased by 73.1%, 165.1% and 93.6%, 179.8%, respectively. The main reason for the increase of water use efficiency and rainfall use efficiency was that F62.5M37.5 and F87.5M12.5 treatments provided a good balance between grain yield and water consumption, which in turn increased the water use efficiency and rainfall use efficiency of maize when compared with the control. In all treatments, F87.5M12.5 treatment showed comparable economic benefits with F100M0.Therefore, the water use efficiency and economic benefit of maize could be improved by moderately reducing the substitute ratio of organic fertilizer under 200 kg·hm^-2. The recommended proportion of organic fertilizer to substitute chemical fertilizeris12.5%~37.5% based on this study.