Characteristics of nutrient uptake and utilization of super hybrid rice under different fertilizer application rates

Chinese. 【目的】探索超级杂交稻对氮、磷、钾养分的吸收利用规律。【方法】于2004年和2005年，选用超级杂交稻品种准两优527和两优293为供试材料，在湖南省5个不同水稻种植生态区进行田间小区试验，研究在农民实际平均施肥量及分别减少和增加25%施肥量条件下，超级杂交稻抽穗期和成熟期植株体内的氮、磷、钾养分含量和吸收积累规律。【结果】无论在抽穗期，还是成熟期，不同施肥水平条件下水稻植株体内氮、磷、钾养分的含量均无显著差异，其在不同地点间的变化幅度低于相应的水稻产量和养分吸收量；养分吸收量差异主要由单位面积干物质生产量不同所引起。在不同施肥水平下，随着产量升高，氮、磷、钾收获指数呈上升趋势，但生产单位稻谷所需养分量呈下降趋势。在产量最高的桂东点，其植株体内氮、磷、钾养分含量和积累量均处于中等水平。【结论】采用多次施肥，不同施肥水平（135～225 kg N・ha. 1、29.7～49.5kg P・ha. 1、112.1～186.8 kg K・ha. 1）对超级杂交稻株体内的氮、磷、钾养分吸收积累影响不明显；随着产量的提高，超级杂交稻对氮、磷、钾养分的吸收利用率也可提高，从而实现高产与养分高效利用的协调统一。

English. [Objective] Characteristics of nitrogen （N）, phosphors （P） and potassium （K） uptake and their utilization of super hybrid rice were studied. [Method] Field experiments with super hybrid rice Zhunliangyou 527 and Liangyou 293 were conducted in five locations of Hunan province in 2004 and 2005. Fertilizer application rates were designed as the treatments of low rate （135 kg N・ha. 1, 29.7 kg P・ha. 1, 112.1 kg K・ha. 1）, medium rate （180 kg N・ha. 1, 39.6 kg P・ha. 1, 149.4 kg K・ha. 1） and high rate （ 225 kg N・ha. 1, 49.5 kg P.ha-1, 186.8 kg K・ha. 1） by using randomized complete block design with 4 replications. Aboveground plants were sampled to measure the dry matter weight, NPK content, NPK uptake rate, NPK harvest index and nutrient use efficiency at heading and maturity stage. [ Result ] No significant differences of plant NPK content at heading and maturity stage were found between two tested varieties and among 3 fertilizer application rates. And the variation range of plant NPK content among 5 locations was relatively smaller than that of the actual yield as well as the NPK uptake rate. The differences of plant NPK uptake rates among the locations were mainly due to the differences of the dry matter production. With the increase of the actual yield, the harvest index of NPK showed an increased tendency and the requirements for NPK nutrients to produce 1 000 kg grain yield showed a declined tendency. The highest actual yield was recorded in Guidong site but the plant NPK nutrient content and their uptake rates were at the medium level among 5 locations. [ Conclusion ] There was no significant differences in plant NPK content and uptake rate for super hybrid rice in the range of fertilizer application rates of 135-225 kg N・ha. 1, 29.7- 49.5 kg P・ha. 1, 112.1-186.8 kg K・ha. 1. With the increase of actual yield of super hybrid rice, the uptake and use efficiency of fertilizer NPK nutrients increased. Therefore, the high use efficiency of fertilizer nutrients was associated with the high yield performance of super hybrid rice.