摘 要：探究N、P、K不同配比施肥对玉米产量的影响和不同氮水平下土壤无机氮的变化特征，为当地推荐合适施肥量提供依据。对“3414”田间试验各处理玉米产量和不同氮水平（N0 = 0、N1 = 93.75、N2 = 187.5、N3 = 281.25 kg·hm-2）下土壤无机氮的测定。结果发现，施氮对玉米产量的影响达到差异显著水平，施磷钾肥对玉米产量的影响差异不显著。随着施氮量升高，玉米产量先升高后稳定，通过方差分析确定当地最佳推荐施氮量变化范围为N1 ~ N3（93.75 kg·hm-2 ~ 281.25 kg·hm-2）之间。施氮可以提高1 m土壤中铵态氮和硝态氮的积累量。铵态氮易被固定，拔节期以后，土壤中铵态氮积累较为稳定。硝态氮在土壤中变异较大，尤其在高施氮量（281.25 kg·hm-2）时，1 m土体中硝态氮积累量显著增加。无机氮总量与施氮量显著相关，当施氮量为N3（281.25 kg·hm-2）时，大大增加了中期（抽雄期）氮素损失风险，故确定安全施氮量处于N2 ~ N3（187.5 kg·hm-2 ~ 281.25 kg·hm-2）之间。基于提高产量、减少氮素损失的生产目标，207.27 kg·hm-2的施氮量为当地经济安全施氮量。
英文摘要:
Abstract: The objective of this study is to investigate the nitrogen, phosphorus and potassium fertilizers’ rates and ratio on the corn yield and the corresponding soil nitrogen characteristics during the growing season in order to recommend the appropriate fertilizers’ rates for corn. The experiment was designed as “3414” with three factors and four levels for each factor, being 14 treatments in total and four replications. The results showed that the effect of nitrogen rate on the corn yield was highly significant, while the effect of neither phosphorus fertilizer nor potassium fertilizer on the corn yield was significant. Corn yield increased with nitrogen rate at first until a stable state. The results of ANOVA showed that the recommended optimal N rate ranged from 93.75 to 281.25 kg ha-1. Application of nitrogen increased the accumulations of both NO3-N and NH4-N in 1 m deep soil profile. NH4-N is readily to be fixed and its soil accumulation is relatively stable after the stem extension of corn. NO3-N varied greatly and accumulated significantly in the 1 m soil profile at higher N rate (281.25 kg·ha-1). Total inorganic nitrogen is highly correlated to the N rates. Nitrogen loss risk after the middle growing stage (tasseling) highly increased when the N rate was set at 281.25 kg·ha-1 and the environmental safe nitrogen rate ranged from N2 to N3 （187.5 kg·ha-1 ~ 281.25 kg·ha-1）. Based on the aim of the increase in corn yield and reduction in nitrogen loss, the nitrogen rate of 207.27 kg ha-1 was set as the economical and safe nitrogen rate for the local region.
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