施磷对下辽河平原稻田土壤溶液可溶性磷动态变化的影响

Effects of Fertilization on the Changes of Dissolved Phosphorus Contents in Paddy Soil Solution in Lower Reach of Liaohe River Plain

试验研究不同磷肥施用量(0、50、250kgPhm-2),下辽河平原潜育性水稻土在水稻生长期间田面水和不同深度(30、60和90cm)土层渗滤液中可溶性磷(DP)浓度随时间的动态变化。研究结果表明,各施磷处理田面水和30cm处渗滤液DP浓度施磷后立即达到峰值,随后迅速下降并趋于稳定,且浓度随施肥量的增加而增加,均高于水体富营养化发生的阈值0.02mgL-1;各处理60cm和90cm处渗滤液中DP浓度一直稳定在0.01mgL-1左右,各处理间差异均不显著;各施磷处理土壤不同深度渗滤液中DP浓度均表现为60cm以上自上向下逐渐降低,60cm以下没有显著差异。

A field plot experiment with three P application rates（0,50 and 250kg P hm^-2）was conducted on paddy soil in Lower Reach of Liahe River Plain in 2007 to monitor the concentration of dissolved phosphorus （DP） in leachate at different depth. Results indicated that the concentration of DP in the surface water and leaching of 30 cm depth was the highest among all the samples, and it was increasing with the application rates of P fertilizer. The concentration declined subsequently as the time passed. All concentrations were higher than 0.02 mg L^-1, which suggests that the leaching could contribute to water eutrophication. The concentration of DP in leachate of control and fertilized treatments had no disciplinary difference and stabilized at about 0.01-0.02mg L^-1 below 60 cm soil layer. The concentration of DP in leachate of topsoil were significantly higher than subsoil upon 60cm soil lay at the initial stage, while had no difference at 60-90 soil layer.