黄土旱塬几种农田水分管理模式下春玉米氮素吸收及分配的差异

【目的】以高原沟壑区典型代表性土壤黑垆土为供试土壤,以紧凑型玉米品种先玉335为供试作物,根据目标产量,在高密栽培及优化施氮量和施氮时期基础上,研究4种农田水分管理模式下春玉米氮素吸收、分配及转移规律,以期为黄土高原南部半干旱区春玉米高产高效栽培提供依据。【方法】田间试验以补充灌溉、雨养、地膜覆盖和秸秆覆盖等为农田水分管理模式,通过在玉米苗期、大喇叭口期、抽雄吐丝期、灌浆期、蜡熟期和生理成熟期等关键生育时期采集地上部植株样品,研究春玉米各生育时期不同器官氮素累积、分配和转移规律与产量及水分养分效率的关系。【结果】随生育阶段推进,春玉米生长速度加快,氮素吸收累积逐渐增加,进入生殖阶段后,各器官氮素分配随生长中心转移而发生变化。不同农田水分管理模式明显影响春玉米氮素累积、分配及转移,在各个测定时期,补充灌溉处理氮素累积量均高于其它3个处理,地膜覆盖处理在玉米成熟期氮素累积量仅次于补充灌溉处理,成熟期雨养和覆秸秆处理氮素累积量相对较低。在补充灌溉条件下,各器官氮素向籽粒转移量最多,完熟期籽粒氮素累积量最大,为235.5kg·hm-2,其次是覆膜处理为225.3kg·hm-2,二者差异不显著;秸秆覆盖处理籽粒氮素累积量与雨养处理差异也不显著,但补充灌溉处理和地膜覆盖处理显著高于雨养和秸秆覆盖处理,与产量及氮素利用效率高低具有一致性。【结论】有利于提高产量及水分利用效率的农田水分管理模式可提高氮素吸收及籽粒氮素累积。从玉米氮素累积、分配及与产量和水分养分效率关系看,补充灌溉和地膜覆盖为本试验条件下的较优农田水分管理模式,从节约水资源及充分利用天然降雨角度考虑,应首选地膜覆盖管理模式。

Nitrogen Absorption and Allocation of Spring Maize on Dryland of Loess Plateau in Different Farmland Water Management Patterns

【Objective】 A field experiment was carried out on typical Hap-Ustic Isohumisol soil on dry highland of loess plateau to study the absorption and translocation of nitrogen in different farmland water management patterns under the same N fertilizer rate, therefore, the result would have good application values in guiding high yield cultivation of maize. 【Method】 Four field water management practices, including supplementary irrigation, rain-fed, corn straw mulching and plastic film mulching, were adopted in spring maize Xianyu 335. The amount and proportion of N from different management practices at 6 growing stages (seedling, jointing, tasseling, blister, dough and maturity) were measured. 【Result】 The experimental results showed that with the growing stage increasing, N absorption increased. After tasseling stage, with the center of growth changing the absorption quantity of organs absorbing N was changed. In every growing stage the N amount in supplementary irrigation treatment was higher than other three treatments, followed by plastic film mulching treatment, rain-fed treatment and corn straw mulching treatment. In supplementary irrigation treatment, the amount of organs N translocation was 235.5 kg?hm-2, higher than other three treatments, followed by 225.3 kg?hm-2 in plastic film mulching treatment; straw mulching treatment was higher than rain-fed treatment, but the difference was not significant. Supplementary irrigation treatment and plastic film mulching treatment were significantly higher than other two treatments. 【Conclusion】 Under the conditions of this experiment, in dry highland of loess plateau area, different farmland water management patterns had significantly effects on spring maize nitrogen absorption, distribution and translocation. The management patterns which can increase the yield, the water utilization efficiency and the nitrogen utilization efficiency can also increase the N absorption and the grain N content. Supplementary irrigation treatment and plastic film mulching treatment were better treatments in this experiment. As for the comprehensive water saving and rainfall use efficiency, the recommended management practice should be the plastic film mulching treatment based on the results of this experiment.