砂田砾石覆盖对土壤大孔隙特征及其土壤水文过程的影响研究进展

Research Progress on Influence of Mulching Gravel and Sand on Soil Macropore Characteristics and Soil Hydrological Process of Gravel-Sand Mulch Field

砂田是利用砾石覆盖地表的典型节水范例,砾石覆盖对土壤大孔隙的半径、数量、连通性和密度都有重要影响。大孔隙的研究方法可分为直接观测法和间接描述法,并讨论其适用性和局限性。因为大孔隙及优先流的成因复杂,应将大量的野外实验和室内实验相结合,同时改进观测方法。土壤大孔隙研究的最终目的是调控它,为减少地下水污染、控制养分和水分的流失提供一条新途径。砾石覆盖土壤能增加大孔隙并促进降水入渗,加快壤中流的发生,减少径流和抑制蒸发,改变了土壤水文循环过程,土壤水文生态功能也随之改变。并指出了砾石覆盖下土壤优先流研究中存在的问题和今后应该加强的研究领域。

Gravel-sand mulch field is a typical case of mulching gravel on land surface to retain water. Gravel- sand mulch field, as a kind of method to prevent drought, can reduce evaporation by artificially laying gravel to form a dry soil layer on soil surface. Soil macropore is the pore offering path for preferential flow. Mulching gravel has important influence on radii, quantity, connectivity and density of soil macropore. The study methods could be divided into two types, direct measurement and indirect description, and the suitability and limitation of the two methods were discussed. Because of the complexity of soil macropore and preferential flow formation cause, the experiments in laboratory should be combined with field trial, and observation techniques should be improved. The final aim of soil macropore research was to reduce groundwater contamination, control the loss of nutrient and water by regulating soil macropore. Mulching gravel can enhance soil macropore and thus facilitate precipitation infiltration and interflow and decrease runoff and evaporation. In that soil hydrological cycle process, its functions were changed respectively. In addition, some existent questions and research field of soil macropore were suggested for the future research