中国主要土壤有效磷演变及其与磷平衡的响应关系

Changes in Olsen Phosphorus Concentration and Its Response to Phosphorus Balance in the Main Types of Soil in China

【目的】明确土壤有效磷的演变规律及其与磷平衡(土壤磷输入减去磷输出)的响应关系,为指导磷肥施用以及管理有效磷水平提供依据。【方法】选取21个农业部国家耕地质量长期监测点,分析常规施肥条件下中国主要5种类型土壤上有效磷的演变规律与土壤磷素的平衡状况,得到单位磷平衡的有效磷变化量(即有效磷效率),同时对土壤的有效磷效率与土壤性质(pH、有机质、全氮和碱解氮)进行相关性分析。【结果】21个土壤监测点中有2个点的磷素出现耗竭,19个点的磷素出现累积,累积磷盈亏在-290—4 919 kg·hm-2。在监测时间内,有14个监测点的有效磷随年份显著上升,2个监测点显著下降,其余持平。21个监测点的有效磷年均上升0.74mg·kg-1。81%的土壤监测点有效磷与磷平衡呈显著的正相关关系,土壤每累积100 kg P·hm-2,褐土有效磷平均增加1.12 mg·kg-1,变异系数为25%;黑土有效磷增加3.76 mg·kg-1,水稻土有效磷平均增加5.01 mg·kg-1,变异系数为52%;紫色土有效磷平均增加2.34 mg·kg-1,变异系数为68%;灌淤土有效磷增加0.47 mg·kg-1。有效磷效率与土壤pH呈显著的直线负相关关系(r=0.65,P<0.01),与土壤有机质(r=0.62,P<0.01)、全氮(r=0.52,P<0.01)和碱解氮(r=0.63,P<0.01)呈显著的直线正相关关系。【结论】中国主要类型土壤的有效磷效率有一定差异,范围在0.47—10.76 mg·kg-1,有效磷效率均值在不同土类之间为水稻土>黑土>紫色土>褐土>灌淤土,且土壤pH、有机质、全氮、碱解氮与土壤有效磷效率呈显著的直线相关关系。

【Objective】The objective of this study is to clarify the changes in available phosphorus（P） and its response to P balance（P input minus P output）, and to provide a scientific basis for rational fertilization.【Method】Twenty-one monitoring sites of the main five types of soil in China with long-term conventional fertilization were chosen to explore the relationships of change of available P and P balance, available P efficiency（available P efficiency refers to the change of available P by the unit of accumulated P budget） and soil properties（pH, soil organic matter, total nitrogen and alkaline-hydrolyzable nitrogen）.【Result】The P was exhausted at two monitoring sites, and accumulated at nineteen sites. The P balance in different sites ranged from-290-4 919 kg·hm-2 under conventional fertilization. Soil available P increased at 14 monitoring sites, and decreased at 2 sites. Available P increased significantly by 0.74 mg·kg-1 each year at 21 monitoring sites. Among all the sites, 81% have a significant positive correlation between changes of available P and soil P balance. Available P increased by 1.12, 3.76, 5.01, 2.34, and 0.47 mg·kg-1 with an average surplus of 100 kg P·hm-2 under fluvo-aquic soil, black soil, paddy soil, purplish soil and irrigation-silted soil. And the coefficient of variation was 25%, 52% and 68% under fluvo-aquic soil, paddy soil and purplish soil. Available P efficiency in the conventional fertilization soil was significantly correlated with the soil pH（r=0.65, P0.01）, soil organic matter content（r=0.62, P0.01）, total nitrogen（r=0.52, P0.01） and alkaline-hydrolyzable nitrogen（r=0.63, P0.01）.【Conclusion】The available P efficiency of different soil types ranged from 0.47-10.76 mg·kg-1. The overall trend in available P efficiency across all soil types was paddy soilblack soilpurplish soilfluvo-aquic soilirrigation-silted soil. The available P efficiency in the conventional fertilization soil was significantly correlated with the soil pH, soil organic matter, total nitrogen, and alkaline-hydrolyzable nitrogen.