以中国贡嘎山由青灰色砂质冰水堆积物发育而成的疏松岩性土壤和德国厄尔士山渍水土壤优先流路径为研究对象,通过野外染色示踪试验和改进的Hedley磷形态提取法,使用优先流染色面积比和优先流程度评价指数定量评价不同类型土壤的优先流程度,通过相关关系分析进一步揭示不同土壤类型中优先流路径对磷形态分布的影响。结果表明:贡嘎山和厄尔士山优先流图片总染色面积比分别为31%和52%,厄尔士山渍水土优先流比贡嘎山疏松岩性土发育较好。贡嘎山疏松岩性土壤优先流发育程度与潜在生物可利用无机磷和有机磷贡献率显著正相关,而即时生物有效无机磷和磷灰石磷与厄尔士山渍水土壤优先流发育程度显著正相关。土壤类型影响优先流路径分布和土壤磷形态分布,从而影响土壤磷赋存状况和下游水质安全。

With the development of earth's critical zone, the crucial hydropedological problems are needed to be solved. The quantitative expression of preferential flow and soil structure and stratification, water flow in situ and solute transport is the key research to the earth's critical zone. Phosphorus loss from soils and water flow has been a vital water quality issue because of the critical role that phosphorus plays in eutrophication. Preferential flow pathways (PFPs) are one of main factors that affect subsurface phosphorus transport, which are the direct connections between soil surface and groundwater. The phosphorus fractions of two types of soil, Regosols from Gongga Mountain and Stagnosol from Ore Mountain, were investigated by using the modified Hedley sequential phosphorus extraction method. Regosols in Gongga Mountain was developed by the moraine colonization by plants in the relatively mild and humid climate. PFPs were identified by the dye tracer experiments using brilliant blue FCF. The tracer-infiltration patterns were parameterized by dye coverage ratio (D_c) and evaluation index of PFPs (C_v). The impact of PFPs on the distribution of phosphorus fractions was evaluated by the Pearson correlations and T-test. The results indicated that dye coverages of Regosols from Gongga Mountain and Stagnosol from Ore Mountain were 31% and 52%, respectively. The degree of preferential flow in Ore Mountain Stagnosol soil was tended to be larger than that in Regosols soil from Gongga Mountain; PFPs in Gongga Mountain were important contributors to the potential bioavailable inorganic phosphorus (PBPi) and organic phosphorus load, while PFPs in Ore Mountain were important contributors to the readily bioavailable inorganic phosphorus (RBPi). In conclusion, the results showed that soil types could affect both the infiltration patterns of PFPs and the transfer process of phosphorus fractions.