贡嘎山冰川退缩区土壤-植物-微生物功能多样性对磷循环的协同作用

对于植物和土壤微生物来说,磷是重要的生命元素。土壤磷的生物有效性随成土过程发生改变,同时植物和土壤微生物通过调整自身养分利用策略,对土壤磷循环产生影响。基于冰川退缩迹地土壤和植被原生演替序列,探讨了土壤-植物-微生物功能多样性的磷循环协同作用过程,分析了贡嘎山海螺沟冰川退缩区4次冰碛物出露时间(1980、1970、1958、1930年)退缩迹地上发育的土壤物理化学性质、磷形态和酶活性的演化规律。结果表明:①随着植被演替和土壤发育,海螺沟冰川退缩区土壤磷含量及其生物有效性发生明显改变; ②成土作用初期,微生物促进了原生矿物磷的转化,并为早期植被发育提供养分; 随着原生矿物磷释放量的减少,植物养分利用策略经历了由磷回收循环→简单获取→回收循环3个不同阶段; 另外,随着植被演替,微生物更多地参与有机磷活化,提升了植物养分重吸收效率; ③海螺沟冰川退缩区冰碛物磷的快速流失加剧了植物与微生物对磷的竞争。

Synergistic Effects of Soil-plant-microbe Functional Diversity on Phosphorus Cycling in the Glacier Retreat Area of Gongga Mountain,China

Phosphorus is one of the important nutrient elements for plants and soil microbes. The bioavailability of soil phosphorus changes with the soil-forming process, and plants and soil microbes affect soil phosphorus cycling by adjusting their nutrient utilization strategies. The synergistic process of soil-plant-microbe functional diversity development and its impact on phosphorus cycling on the glacier retreat area were studied based on the vegetation primary succession and soil development sequence; plants, soil physicochemical properties, and enzyme activities in the glacier retreat area of Hailuogou, Gongga mountain at four moraine exposure times(1980, 1970, 1958, and 1930)were studied. The results show that ① soil phosphorus content and its bioavailability change obviously in the glacier retreat area of Hailuogou with vegetation succession and soil development. ② At the early stage of soil development, microbes promote the transformation of primary mineral phosphorus and provide nutrients for the early vegetation development; with the amount of phosphorus released from primary mineral decreasing, the plant nutrient use strategy changes at three stages from the phosphorus recycling cycle to simple acquisition, and then to recycling cycle again; with the succession of vegetation, microbes participate more in mineralizing the organic phosphorus and improve the plant reabsorption rate. ③ The rapid loss of moraine phosphorus in the glacier retreat area of Hailuogou intensifies the competition between plants and microbes for phosphorus. Rhizosphere soil phosphorus is significantly enriched at 58 years' site, and plant phosphorus reabsorption rate reaches its peak at late-soil development.