水氮管理模式与磷钾肥配施对杂交水稻冈优725养分吸收的影响

【目的】研究水氮管理模式与磷钾肥配施对水稻养分吸收的影响，为水稻水肥高效利用提供依据。【方法】以杂交稻冈优725为材料，通过“淹水灌溉+氮肥优化运筹（W1N1）”、“控制性交替灌溉+氮肥优化运筹（W2N1）”、“旱种+氮肥优化运筹（W3N2）”3种水氮管理模式及不同的磷钾肥配施处理，分析对水稻氮、磷、钾吸收特点的影响，并探讨各养分间及其与产量、生理特性指标间的关系。【结果】水氮管理模式和磷钾肥配施对水稻氮、磷、钾素的吸收、生理特性及产量均存在显著的影响；W2N1管理模式与磷、钾肥施用量均为90 kg?hm-2的配施（P90K90处理）组合能促进抽穗及成熟期各养分的累积，提高剑叶光合速率（Pn）、超氧化物歧化酶（SOD）活性及根系活力，延缓剑叶丙二醛（MDA）增幅，为本试验稳产、高效最佳的水肥运筹模式；而配施肥量过重（P90K180处理）时水肥调控优势减弱，增产不显著，会导致肥料利用效率、产投效益降低。旱种相对于淹灌下的水氮优化管理模式与P90K180配施组合，会导致肥料利用效率降低，但能提高稻谷增产幅度，为生产中水资源不足的情况下参考。相关分析表明，水肥调控下稻株抽穗及成熟期氮、磷、钾累积间及与产量间均存在显著正相关（r=0.644*—0.939**）；且抽穗及成熟期各养分累积量和产量与结实期各阶段剑叶Pn、SOD活性及根系活力均存在正相关性（r=0.545—0.902**），与剑叶MDA含量呈显著或极显著负相关（r=-0.612*—-0.879**），尤其以抽穗后1—7 d相关性最高。【结论】本试验条件下，W2N1-P90K90为最优的水肥调控模式，在一定程度上调节结实期稻株生理代谢活性，提高养分累积量及稻谷产量，W1N1模式与P90K90配施为宜，而W3N2模式下可适当提高钾肥配施量以P90K180配施为宜。

Effects of Water-Nitrogen Management Patterns and Combined Application of Phosphorus and Potassium Fertilizers on Nutrient Absorption of Hybrid Rice Gangyou 725

【Objective】In order to provide a scientific basis for high water-fertilizer use efficiency of rice, an experiment was conducted to study the effects of water-nitrogen management patterns and combined application of phosphorus potassium fertilizers on nutrient absorption and physiological characteristics of hybrid rice.【Method】Hybrid rice variety Gangyou 725 was used to investigate the effects of three water-nitrogen management patterns (submerged irrigation and optimized nitrogen (N) application, W1N1; controlled alternate irrigation and optimized N application, W2N1; and dry cultivation and optimized N application, W3N2) and different phosphorus (P)-potassium (K) combined applications on absorption of N, P, and K in rice, analyze their physiological characteristics, and study on correlations of N, P, and K absorption characteristics and its relationship with physiological index and grain yield. 【Result】The results showed that different water-nitrogen management patterns and P-K fertilizer combined application significantly affected N, P and K absorption, physiological characteristics and grain yield. W2N1 and suitable P90K90 combined application (P and K application rates both at 90 kg?hm-2) enhanced N, P, and K absorption at heading and maturity stages, increased the photosynthetic rate, superoxide (SOD) in flag leaves and bleeding intensity during grain filling, and activated malondialdehyde (MDA) in flag leaves, being the best model in this paper referred as the water-fertilizer regulating management model. Combined application of P90K180 resulted in superiority decrease of water-fertilizer regulating, yield increase not significant, and lowering the fertilizer use efficiency and the ratio of output to input. Compared with W1N1, W3N2 and suitable P90K180 had compensated for yield outputs. Correlation analysis indicated that there existed significantly positive correlations (r=0.644*-0.939**) between the amounts of N, P, and K, and between each of them and yield under different water-fertilizer regulation, and the amounts of different nutrients at heading and maturing stages and grain yield had a positive correlation with Pn, SOD in flag leaves, and root vigor (r=0.545-0.902**), and a high significant negative correlation with MDA in flag leaves (r=-0.612*--0.879**) at different growth stages at heading stage, with different correlation coefficients at different growth stages. According to the conditions above, it was important for delaying the leaf senescence, keeping root vigor, and increasing yield that the amounts of N, P, and K at heading stage and physiological metabolism of rice during 1-7 d after heading stage.【Conclusion】The results suggest rice plant growth could be improved and high grain yield and high fertilizer use efficiency could be achieved through integrating and optimizing water-fertilizer regulating techniques in rice production. W2N1 and suitable P90K90 combined application was considered to be optimum under the experimental conditions, optimum phosphorus (P)-potassium (K) combined application amount was P90K90 for W1N1, and P90K180 for W3N2.