Long‐term effects of vegetational restoration on soil microbial communities on the Loess Plateau of China

Abstract

Soil microbial communities are important indicators for evaluating the effectiveness of vegetational restoration. The ability of soil microbial communities to recover under six types of restoration was examined using Biolog, phospholipid fatty acid (PLFA), and denaturing gradient gel electrophoresis (DGGE). Soil samples were collected from eroded loessial soils that had been restored for 30 years on the Loess Plateau with natural grass, black locust, korshinsk peashrub, Chinese pine, and mixed forest of Chinese pine-indigo and black locust-indigo. Part of sloped farmland that had not been restored represented pre-restoration conditions. An 80-year-old forest of Chinese arborvitae represented the end point of restoration. Soils that were originally farmed but have been under restoration treatments for the past 30 years had significantly higher average well-color development, total PLFAs, bacterial PLFAs, fungal PLFAs, and Shannon indices of catabolic diversity, structural diversity, and bacterial phylogenetic diversity. These indicators, though, were lower than those for the native forest. Principal component analysis significantly separated the sloped farmland, Chinese arborvitae, and the six types of restoration. Redundancy analysis indicated that pH, total organic carbon, total nitrogen, available nitrogen, and available phosphorus were the most important environment factors in affecting soil functional diversity, and C/N ratio and available nutrients were the main properties in determining microbial community structure. Vegetational restoration substantially increased microbial biomass and microbial physiological activity, and shifted microbial community structure, but the community structures and compositions did not recover to the status of the natural forest during the early stage (<30 years) of vegetational restoration.

Changes in the Soil Bacterial Community in a Chronosequence of Temperate Walnut-Based Intercropping Systems

“…Guo [28] found a higher abundance of Firmicutes and lower abundance of Proteobacteria and Actinobacteria in cropland than in the restoration site, which is in accordance with our result. However, the higher frequency of Firmicutes in the studied site was in sharp contrast to the relatively lower abundance reported in other studies [29][30][31]; this is mainly due to the high abundance of Bacillus. Firmicutes, typically Bacillus and its derived genera, are a group of aerobic endospore-forming bacteria abundant in soils [36].…”

“…Diversified plant species and the resultant rhizosphere chemistry and litter quality could affect the soil microbial community [28]. Some previous studies in the same region found that microbial diversity increased with afforestation [29][30][31], and the microbial diversity associated with the aboveground vegetation. Zhang [32] observed that soil bacterial diversity decreased at the early stage of restoration on farmland along with the aboveground vegetation decrease.…”

Over twenty years farmland reforestation decreases fungal diversity of soils, but stimulates the return of ectomycorrhizal fungal communities

“…Although relatively similar in richness, the community composition of total fungi and major functional guilds (ECM and SAP) in SF were still divergent from those in PF after 20 years of reforestation. These findings support our second hypothesis, and agree with Xiao et al (2016) who showed that soil microbial communities do not fully recover 30 years after the reforestation of farmland in Shanxi China. In contrast, based on fungal sporocarp data, Oria-de-Rueda et al (2010) showed that abandoned farmland dominantly reforested with Pinus spp.…”

A comparison of the effects of natural vegetation regrowth with a plantation scheme on soil structure in a geological hazard‐prone region

“…Other studies have demonstrated that microaggregates are rich in small pores with diameters of <0.2 μm, and small pores are thought to be effective in preventing internal organic carbon decomposition by bacteria. Small pore structures are also stable and difficult to destroy (Xiao, Liu, Zhang, & Xue, ). Simultaneously, plant root systems can act as ecosystem engineers to reduce water‐induced soil erosion by sequestering more SOM into soil, thereby improving its hydrological properties (Eldridge, ).…”