川西北高寒草甸土壤微生物功能多样性对磷(P)添加的响应

研究高寒草甸添加不同磷(P)肥梯度对土壤养分状况与土壤微生物的影响,探明土壤养分变化和微生物功能多样性的差异及其互作关系。采用常规实验室分析和Biolog-ECO生态板法,研究了0 g m~(-2)(CK),10 g m~(-2)(P10),20 g m~(-2)(P20),30 g m~(-2)(P30)4个施P肥水平下土壤养分及土壤微生物功能多样性的变化规律。结果表明:P肥显著增加高寒草甸的速效养分、全磷和全钾的含量,但对有机质、全氮和pH无显著影响。AWCD值在表层(0~10 cm)无显著变化,但深层(10~20 cm)则为P20>P30>P10>CK。土壤微生物多样性在表层随施肥量增加而降低,而深层随施肥量增加而升高。主成分分析表明,氨基酸类、胺类、酯类是土壤微生物利用的主要碳源类型,其中在表层糖类和酯类随施肥量增加而降低,而深层碳源利用均在P20处理下显著提高。冗余分析表明,土壤速效氮、速效磷和速效钾含量是影响高寒草甸土壤微生物功能多样性和代谢活性的主要因子。因此,在退化高寒草甸适量添加P肥有利于生态系统的恢复重建。

Responses of Soil Microbial Functional Diversity to Phosphorus Addition in an Alpine Meadow on Northwestern Plateau of Sichuan Province

This paper was to study the effects of different phosphorus (P) addition rates on soil nutrients,microbial functional diversity and their relationship in alpine meadow in Northwestern Plateau of Sichuan Province.To explore the soil microbial changing characteristics after different P addition rates of 0 g m-2 (CK),10 g m-2 (P10),20 g m-2 (P20),30 g m-2 (P30),we examined soil nutrients and microbial functional diversity using conventional laboratory analysis and the Biolog-ECO microplate method.Our results showed that the P addition significantly increased soil available nutrients,total P and potassium contents,but had no significant effects on soil organic matter,total nitrogen and pH.Average well color development (AWCD) value had no significant changes in surface soil layer (0-10 cm),but it decreased following the order of P20 ＞ P30 ＞ P10 ＞ CK in deep soil layer (10-20 cm).Soil microbial diversity increased with the reducing in fertilization gradient in surface soil layer and the opposite trend was found in deep soil layer.Principal component analysis (PCA) showed that amino acids,amines and esters were the main carbon sources for maintaining soil microbial community.Carbohydrates and Esters reduced with the increase in fertilization gradient in surface soil layer,and carbon utilization significantly increased in deep soil layer soil of P20 treatment.Redundancy analysis (RDA) indicated that soil nutrients and microbial diversity was closely linked,and available potassium and pH were the main factors influencing the metabolic rate of soil microbial community and microbial functional diversity in alpine meadow.These results indicated that using P fertilizer was benefit to the rehabilitation of degraded grassland.