Response of total belowground soil biota in Alhagi sparsifolia monoculture at different soil vertical profiles in desert ecosystem

The soil organisms are extremely important for the land-based ecosystem. There is a growing interest in studying the variety and composition of the entire underground soil organism community at a large ecological scale. Soil organisms show different patterns in relation to soil physiochemical properties (SPPs) in various ecosystems. However, there is limited knowledge regarding their response to soil vertical profiles (SVPs) in monoculture of Alhagi sparsifolia, which is the primary shrub in the deserts of China, and is well-known for its contributions to sand dune stabilization, traditional Chinese medicine, and forage. Here, we investigated the population dynamics of soil bacteria, fungi, archaea, protists and metazoa across six different SVPs ranging from 0 to 100 cm in monoculture of A. sparsifolia, in its natural desert ecosystem. Our findings indicate that the soil biota communities displayed a declining pattern in the alpha diversity of bacteria, protists, and metazoa with an increase in soil depth. However, the opposite trend was observed for fungi and archaea. The beta diversity of soil biota was significantly affected by SVPs, particularly for metazoa, fungi and protists as revealed by Non-Metric Dimensional Scaling. The most prevalent soil bacterial, fungal, archaeal, protist, and metazoa classes were Actinobacteria, Sordariomycetes, Nitrososphaeria, Filosa-Sarcomonadea, and Nematoda, respectively. The correlation among vertical distribution of the most abundant biotic communities and variations in SPPs exhibited that the variations in total carbon (TC) and total nitrogen (TN) had the most significant influence on bacterial changes, while available potassium (AK) had an impact on fungi. Archaea were affected by TC and pH, protists by the C/NRatio and TP, and metazoa by TN, AK, and soil water capacity (SWC). Collectively, our findings provide a new perspective on the vertical distribution and distinct response patterns of soil biota in A. sparsifolia monoculture under natural desert ecosystem of China.

Automated summary

The response patterns of soil biota in the vertical distribution of Alhagi sparsifolia monoculture in the natural desert ecosystem of China vary among different microbial groups. Bacteria, protists, and metazoa showed a decreasing alpha diversity pattern with increasing soil depth, while fungi and archaea exhibited an opposite trend. Soil physiochemical properties significantly influenced the vertical distribution of soil biota, with different microbial groups responding to different properties.