Effect of grassland degradation on soil quality and soil biotic community in a semi-arid temperate steppe

Zhengwen Wang,Qi Li,Siwei Jiang,Xu Han,Xiaofang Du,Yingbin Li,Yuhui Li

doi:10.1186/s13717-020-00256-3

Abstract

Grasslands provide a number of ecosystem services for human society. Degradation of grasslands results in the loss of biodiversity and leads to the deterioration of ecosystem functions. In order to accurately assess the influence of grassland degradation on belowground ecosystems, we conducted experiments on a temperate steppe with different levels of degradation and investigated the influence of degradation on soil quality and soil biotic communities. Our results showed that grassland degradation significantly decreased soil quality, with lower values of soil quality index (SQI) observed in the degraded grassland than the meadow steppe and the grassland from the forest-steppe ecotone. Changes in the SQI along the grassland degradation gradient were positively correlated with soil carbon stock and the aboveground biomass, and negatively correlated with the root shoot ratio. Nematode trophic diversity and the ratio of fungal to bacterial PLFA were lower in the degraded grassland than the grassland from the forest-steppe ecotone. The dissimilarities in soil microbial and nematode community composition increased with the changes in soil quality index. Our results indicate that soil quality index based on the minimum data sets could effectively assess the influence of grassland degradation on soil biodiversity and ecosystem function. In order to effectively restore degraded grasslands, the key contributors to the soil quality, such as soil carbon, should be taken on priority basis for revitalizing the soil biodiversity and ecosystem function.

Highlights

Grasslands are the largest terrestrial ecosystems on earth and it covers about 40% of the earth’s surface, providing a large number of ecosystem services to human society (Hu et al 2016; Lyu et al 2020)
Effect of grassland degradation on soil quality index Grassland degradation significantly influenced plant biomass (Table 1), with lower aboveground biomass observed in the degraded grassland (DG) than that in meadow steppe (MG) and the grassland from foreststeppe ecotone (TG), but the root biomass did not differ among three grassland types (Table 1)
The root shoot ratio was higher in DG than that in Meadow steppe (MG) and The grassland from the forest-steppe ecotone (TG)

Summary

Introduction

Grasslands are the largest terrestrial ecosystems on earth and it covers about 40% of the earth’s surface, providing a large number of ecosystem services to human society (Hu et al 2016; Lyu et al 2020). Grasslands in China account for 11.8% of the global grassland area and play important roles in livestock production and environmental conservation (Dong et al 2012; Ren et al 2008). One-third of grasslands in China have shown varying degrees of degradation due to the increased human interference (such as overgrazing) and climate change (Chen et al 2014; Qi et al 2012). Grassland degradation causes the loss of biodiversity and leads to ecosystem function degradation (Gang et al 2014; Lyu et al 2020; Raiesi and Salek-Gilani 2020). Elucidating the mechanisms that influence grassland degradation on the changes in soil quality and biotic communities is important so as to develop effective solutions to restore the degraded grassland ecosystems (Lal 2015; Raiesi and Salek-Gilani 2020)

Methods

Results

Discussion

Conclusion