长期有机物循环对红壤稻田土壤磷吸附和解吸特性的影响

 【目的】为揭示土壤磷素肥力的变化机制，对16年长期不同施肥模式处理后红壤稻田0～20 cm和20～40 cm土层的土壤磷吸附-解吸特性进行了研究。【方法】将4种施肥处理土样置于恒温摇床中连续振荡培养，定期测定不同处理土壤磷的各种吸附参数、累积解吸量和解吸率。【结果】长期不同施肥模式处理显著改变了土壤磷的吸附—解吸特性，其中对0～20 cm土壤的影响尤为突出。长期有机物循环利用显著降低了0～20 cm土壤磷吸附亲和力常数（k）、最大吸附量（Q）和吸附缓冲容量（MBC），同时也明显提高了该层土壤磷的累积解吸量和累积解吸率;与不施化肥基础上的有机物循环利用相比，NPK化肥配施基础上的有机物循环利用在降低0～20 cm土层土壤磷吸附参数和提高该层土壤磷累积解吸量与累积解吸率方面的效果更为突出。长期NPK化肥配施与不施肥处理相比，对土壤磷吸附—解吸特性的影响不大。【结论】化肥与有机肥长期配施能显著降低红壤稻田耕层土壤对磷的吸附性，促进土壤磷的解吸，有效提高土壤磷素肥力水平。有机物循环利用对土壤磷吸附－解吸特性的影响并不会增加磷素对水环境的污染风险。

Effects of Organic Nutrient Recycling on Phosphorus Adsorption-Desorption Characteristics in a Reddish Paddy Rice System

【Objective】 For revealing the mechanism of soil P fertility changes, the influences of different patterns of long-term fertilizer application for 16 years on phosphorus adsorption-desorption characteristics at the layers of 0-20 cm and 20-40 cm were studied in a reddish paddy rice field. 【Method】 Soil samples collected from the long-term experimental field were incubated in a constant temperature cabinet and parameters of soil P adsorption, rate of soil P desorption and amount of accumulative P desorption were then determined. 【Result】 The characteristics of soil P adsorption-desorption were changed remarkably under different patterns of long term fertilizer application, especially at 0-20 cm of soil layer. The affinity constant (k) of soil P adsorption, the maximal P adsorption (Q) and the buffering capacity of P adsorption (MBC) were declined significantly at the layer of 0-20 cm by the employment of long term organic nutrient recycling, and meanwhile, the amount and rate of accumulative soil P desorption were increased significantly in this soil layer. Organic nutrient recycling combined with chemical fertilizer application was more effect in declining soil P adsorption parameters and increasing the amount and rate of accumulative P desorption at 0-20 cm compared with that of organic nutrient recycling alone. There was no significant difference between treatments of NPK fertilizer application and the control without tertilize application on soil phosphorus adsorption-desorption characteristics. 【Conclusion】 Combination of NPK fertilizer and organic nutrient recycling could significantly decrease soil phosphorus adsorption and enhance P desorption of the plough layer, and hence increase soil P fertility in the reddish paddy rice field. The effects of organic nutrient recycling on soil P adsorption-desorption would not increase the risk of P pollution of water environment.