开发高效蓄水保墒技术提高水资源利用效率，是发展现代化节水农业的主要途径之一。微生物保水肥料应用是实现土壤蓄水保墒一个重要手段。目前微生物保水肥料的研究侧重于发酵工艺开发和施用后生物学生长指标测定，缺乏土壤保水机理的探索。本项目基于土柱和蒸渗仪模拟实验，研究土壤施用微生物固体发酵生产的γ-多聚谷氨酸(γ-PGA)微生物有机肥后，对土壤γ-PGA合成菌株和谷氨酸合成菌株行为动态、γ-PGA的稳定性、微生物生态学的影响及变化规律；分析土壤团聚体的形成和孔隙属性变化原因；监测土壤表层结皮、导水率、水分特征曲线、水分有效性等物理学属性变化；测定田间地表径流、深层渗漏、土壤保蓄、土壤蒸发、植物蒸腾等指标变化，阐述基于γ-PGA土壤行为动态、土壤微生物生态学、土壤物理学以及田间水分运移规律的γ-PGA微生物有机肥土壤保水机理，为微生物保水有机肥在提高降水利用率和农业灌溉节水中的应用提供理论和实践基础。

The development of water-retaining technology to improve water use efficiency is one of the main ways for the development of modern water-saving agriculture. Application of water-retaining bioorganic fertilizer is an important means for soil water retainment. Researches of the water-retaining bioorganic fertilizer, at present, are more focused on the fermentation process and plant growth after the fertilizer application, and lacked the exploration of the soil water-retaining mechanism. Based on the soil column and lysimeter experiment, this project wishes to study the soil water-retaining mechanism of γ-poly glutamic acid (γ-PGA) bioorganic fertilizer which produced by solid fermentation with microbial. After the soil applied with γ-PGA bioorganic fertilizer, the project will study the dynamic of bacteria synthesizing γ-PGA or glutamic acid in the soil, γ-PGA stability, variation of microbial ecology, mechanisms of the formation of soil aggregates and the change of soil pore properties, the effect of soil surface crust, hydraulic conductivity, soil characteristic curve, water availability and water availability, as well as determination of surface runoff, deep percolation, soil water retention, soil evaporation, plant transpiration for the field water movement. The project will provide theoretical and practical basis for the application of γ-PGA bioorganic fertilizer in increasing use efficiency of rainfall and water-saving agricultural irrigation.