水氮互作对冷凉区域稻田氮素特征的影响

Effects of Water and Nitrogen Interaction on Nitrogen Characteristics of Rice Field in Cold Region

[目的]研究寒地稻田不同水肥管理模式下的土壤供氮特征,为筛选环境友好型寒地稻作灌溉施肥模式提供支撑。[方法]在大田试验条件下,设置间歇灌溉、淹灌2种水分管理模式及4个供氮水平(0,75,105,135kg/hm^2),以龙庆稻2号为材料,研究水肥互作模式对水稻产量、土壤供氮特征及氮素利用率的影响。[结果]灌溉模式和供氮水平对水稻产量、地上部氮素积累量、水稻氮素利用率均有显著(p<0.05)或极显著影响(p<0.01)。间歇灌溉模式下,增加氮肥施用量有利于提高单位面积水稻有效穗数、籽粒产量、生物产量、籽粒氮素累积量,均以施氮105kg/hm^2处理最高;水肥互作对氮素利用率影响明显,水稻的氮肥利用率在21.4%~59.1%;氮肥生理利用率、氮肥农学效率及氮肥偏生产力均随着施氮量的提高而降低,施氮量75kg/hm^2处理的氮素吸收利用各项指标均高于其他处理。相关分析表明,水肥因素是影响氮素积累及氮素吸收利用效率的重要因子。[结论]综合考虑水稻产量及氮素利用率的矛盾,间歇灌溉配合适宜减氮模式应予以高度重视。

[Objective] The soil nitrogen characteristics under different water management pattern on cold paddy were studied to provide support for selection of irrigation and fertilization pattern of environment friendly cold rice.[Methods] An in situ field experiment was conducted to investigate the effects of water and nitrogen interaction on rice yields, soil nitrogen supply and nitrogen utilization using materials Longqing rice No.2. The experiment had two water management patterns （intermittent irrigation and flood irrigation）, each pattern had four nitrogen levels（0, 75, 105, 135 kg/hm2）.[Results] Rice yield, amount of accumulated nitrogen of aerial part and nitrogen use efficiency of rice were obviously affected by water management pattern and nitrogen supply level. Under intermittent irrigation pattern, indices of effective panicles per unit area, grain yield, biological yield and grain nitrogen accumulation amount were all improved when nitrogen level increased. All these indicators performed best in nitrogen level of 105 kg/hm2. Nitrogen use efficiency was obviously affected by water and nitrogen interaction. The rice nitrogen utilization efficiency ranged from 21.4% to 59.1%. The nitrogen physiological utilization efficiency, nitrogen agronomic efficiency and nitrogen partial productivity were all decreased with the increase of nitrogen application. When nitrogen application level was 75 kg/hm2, the above three indicators of nitrogen uptake were higher than those of other treatment. Correlation analysis showed that the factors of water and fertilizer were the most important influence factors of nitrogen accumulation and nitrogen uptake efficiency.[Conclusion] Considering the contradiction between rice yield and nitrogen utilization efficiency, we should pay more attention to the pattern of intermittent irrigation plus appropriate nitrogen application.