The Impacts of Vegetation Types and Soil Properties on Soil Microbial Activity and Metabolic Diversity in Subtropical Forests

Danbo Pang,Genzhu Wang,Jinxing Zhou,Xiuqin Wu,Jianhua Cao,Long Wan,Yuguo Liu

doi:10.3390/f10060497

Abstract

Microbial functional diversity is significantly associated with both nutrient cycling and organic matter decomposition. However, how different forests as well as the soil parent materials influence the soil microbial carbon metabolism remains poorly understood. In this study, a natural secondary forest and a Pinus yunnanensis plantation, with similar climatic conditions under contrasting parent materials (clasolite in the non-karst areas and limestone in the karst areas) in Yunnan Province, China, were investigated. The soil microbial carbon metabolism diversity was assessed by the Biolog® ECO-plates. During the dry season, the soil microbial communities used carbon substrate in secondary forest and Pinus yunnanensis plantation, showing no significant difference, both in non-karst and karst areas. The microbial communities in the non-karst area were more efficient in utilizing carbon substrates than those in the karst area with the same vegetation types, resulting in the higher accumulation of organic carbon in the karst area. The six categories of most frequently utilized carbon substrates were carbohydrates, carboxylic acids, and amino acids in both the non-karst and the karst areas. The soil basal respiration of the secondary forest was higher than that of the Pinus yunnanensis plantation, both in the non-karst and the karst areas. In addition, the driving factors of the soil microbial community functional diversity in the non-karst and karst areas are different. Our findings suggest that soil microbial functional diversity is governed by vegetation types as well as by soil properties in subtropical forests. Moreover, calcareous soil holds a higher proportion of recalcitrant organic carbon, which is difficult to utilize by microorganisms.

Highlights

Soil microorganisms directly participate in important ecological processes and respond rapidly to environmental changes; they have been identified as the most active part of soils [1]
The soil basal respiration of the secondary forest was higher than that of the Pinus yunnanensis secondary forest and Pinus yunnanensis plantation showed no significant difference in the karst area plantation, both in the non-karst and the karst areas (Figure 3a)
Our findings indicate that during the dry season in subtropical forests, drought or drying might induce soil water stress and reduce the substrate availability for microbes, resulting in no significant difference in the soil microbial functional diversity among different vegetation types

Summary

Introduction

Soil microorganisms directly participate in important ecological processes and respond rapidly to environmental changes; they have been identified as the most active part of soils [1]. The composition, structure, diversity, and activity of the microbial community play an important role in Forests 2019, 10, 497; doi:10.3390/f10060497 www.mdpi.com/journal/forests. Microbial functional diversity is significantly associated with nutrient cycling, organic matter decomposition, soil aggregation, and soil productivity [4,5,6]. As the principal drivers of the soil organic matter decomposition and turnover, soil microorganisms play a significant role in the global carbon cycling [7]. The microbial community composition and function are central for soil functioning and forest productivity [8]. How different forests and soil parent materials influence the soil microbial community in karst ecosystems remains poorly understood

Methods

Findings

Discussion

Conclusion