黄土高原氮磷肥水平对旱作冬小麦产量与氮素利用的影响

    Effect of nitrogen and phosphorus fertilization rate on yield and nitrogen utilization of winter wheat in dryland of Loess Plateau

    • 摘要: 为了探求氮磷肥合理和高效利用的科学依据,以黄土高原中南部的旱地农田生态系统长期定位试验为基础,选取了不同施氮和施磷水平,探讨了不同降水年份,氮磷肥用量对作物产量、氮素吸收和利用等相关指标的影响。结果表明,平水年份施氮水平在0~45?kg/hm2和干旱年份在0~90?kg/hm2范围内作物产量和收获指数均随施氮水平的增加迅速提高,超过这个范围后则差异较小;施磷水平在0~45?kg/hm2之间产量增幅较大,干旱年份施磷量反而降低了收获指数;吸氮量随氮磷用量变化与产量有相似趋势;不同降水年份施氮水平对氮素收获指数均无显著影响,而施磷水平在干旱年份对氮素收获指数没有显著影响,平水年份则随施磷水平增加而有所提高;平水年份氮素利用效率随施氮水平的增加呈降低趋势,而干旱年份施氮水平对冬小麦氮素利用效率没有显著影响,施磷则在不同降水年份均比不施磷肥的处理提高了冬小麦的氮素利用效率,但较高的施磷水平之间差别较小。冬小麦产量和吸氮量之间有显著相关关系,干旱年份更接近二次曲线,氮素利用效率随吸氮量增加呈直线下降趋势。旱作农田氮磷配施及采用适中的氮磷肥用量可以促进作物对氮素的吸收,同时得到较高的氮素利用效率,从而使冬小麦获得较高的产量和较强抵御干旱的能力。

       

      Abstract: Based on long term positioned fertilization experiment of rainfed farmland ecosystem in the Middle and South Loess Plateau, effect of nitrogen rate and phosphorus rate on crop yield, nitrogen absorption and utilization in two precipitation-type years were researched by selecting ten treatments. Crop yield increased rapidly with increasing nitrogen in the range of 0-45 kg/hm2 during average year and 0-90 kg/hm2 during dry year, while there were little difference out of this range. In the range of 0-45 kg/hm2 crop yield could be improved rapidly but phosphorus application reduced harvesting index in dry year. Nitrogen absorptions by crop had a similar tendency with yields while nitrogen and phosphorus application changing. Nitrogen harvesting indexes under different nitrogen rates had no significant difference in both precipitation years, but increased with increasing phosphorus rates in dry year and had no significant difference in average year. Nitrogen utilization efficiency (NUE) decreased with increasing nitrogen rates in average year while there was no significant difference in dry year among nitrogen rate treatments. Phosphorus application improved NUE while little difference to higher phosphorus rate treatments. Yield had a significant relationship with nitrogen absorption which was expressed to quadratic curve and hence NUE decreased with nitrogen absorption to linear curve in dry year. Nitrogen and phosphorus application combined with temperate rate were important for ensuring higher nitrogen absorption and NUE , at the same time, higher yield could be obtained and preventing drought ability of winter wheat could be stronger for in dryland on the Loess Plateau.

       

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