Response of Soil Microbial Diversity to Long-term Enclosure in Degraded Patches of Alpine Meadow in the Source Zone of the Yellow River

Abstract

The soil pH, water content, nutrients, and microbial community composition and diversity among one-year term (E1), short-term (E4), and long-term (E10) enclosures were analyzed for understanding the response of soil bacterial and fungal communities to long-term enclosure in degraded patches of alpine meadow in the source zone of the Yellow River, through determining the soil physicochemical properties and microbial diversity using high-throughput sequencing technology. The results showed that the E1 enclosure significantly decreased soil pH, whereas long-term and short-term enclosures increased soil pH. The long-term enclosure could significantly increase soil water content and total nitrogen content, and the short-term enclosure could significantly increase available phosphorus content. The long-term enclosure could significantly increase the bacterial Proteobacteria. The short-term enclosure could significantly increase the abundance of the bacteria Acidobacteriota. However, the abundance of the fungus Basidiomycota decreased in both long-term and short-term enclosures. With the extension of enclosure years, the Chao1 index and Shannon diversity index of bacteria showed an increasing trend, but there was no significant difference between long-term and short-term enclosures. The Chao1 index of fungi gradually increased, and the Shannon diversity index first increased and then decreased, but there was no significant difference between long-term and short-term enclosures. Redundancy analysis indicated that enclosure altered microbial community composition and structure mainly by changing soil pH and water content. Therefore, the E4 short-term enclosure could significantly improve the soil physicochemical properties and microbial diversity at the degraded patches of alpine meadow. The long-term enclosure is not necessary and will lead to the waste of grassland resources, reduction in biodiversity, and restriction of wildlife activities.