The response of microbial communities to changes in precipitation can regulate the nutrition cycling of terrestrial ecosystems, but the effect on the structure and interaction of microbial communities and the relationship with environmental factors in arid and semiarid areas are unclear. Here, a field simulation experiment using three precipitation gradients, 50% of normal precipitation (P50), normal precipitation (P100) and 150% of normal precipitation (P150), was carried out in the typical grassland of the Loess Plateau. We applied high-throughput sequencing and network analysis to explore the effect of precipitation changes to soil microbial communities. The results indicated that the structural composition of the microbial community responded to precipitation treatments dramatically. The Top 50 microbials were divided into resource-limited, drought-tolerant and sensitive groups based on their response to altered precipitation. The network of bacteria was more complex and stronger than fungi. Bacterial networks were less stable but more adaptable under drought than fungal. Increasing precipitation promoted the complication and firmness of fungi networks. These findings are crucial for revealing the effects of climate change on soil microbial communities in arid-land and elsewhere and can provide valuable guidance for ecological restoration and response to climate change of the Loess Plateau.

Our study, which was conducted in the desert grassland of Ningxia in China (E 107.285, N 37.763), involved an experiment with five levels of annual precipitation 33% (R33), 66% (R66), 100% (CK), 133% (R133), 166% (R166) and two temperature levels (inside Open-Top Chamber (OTC) and outside OTC). Our objective was to determine how plant, soil bacteria, and fungi diversity respond to climate change. Our study suggested that plant α-diversity in CK and TCK were significantly higher than that of other treatments. Increased precipitation promoted root biomass (RB) growth more than aboveground living biomass (ALB). R166 promoted the biomass of Agropyron mongolicum the most. In the fungi communities, temperature and precipitation interaction promoted α-diversity. In the fungi communities, the combination of increased temperature and natural precipitation (TCK) promoted β-diversity the most, whose distance was determined to be 25,124 according to PCA. In the bacteria communities, β-diversity in CK was significantly higher than in other treatments, and the distance was determined to be 3010 according to PCA. Soil bacteria and fungi α- and β-diversity, and ALB promoted plant diversity the most. The interactive effects of temperature and precipitation on C, N, and P contents of plants were larger than their independent effects.

Knowledge of soil organic carbon (SOC) dynamics underpins accurate estimation of carbon sequestration in fragile ecosystems. However, most studies focus on SOC content in bulk soil while neglecting its distribution within soil aggregate fractions and the associated stabilization mechanisms. In the Mu Us Sandy Land, five vegetation types of the same restoration age were selected: natural grassland (NG), mixed grass–shrubland (GS), pure shrubland (PS), pure woodland (PW), and mixed woodland (MW). SOC stocks in bulk soil and aggregate fractions were quantified, and their key influencing factors were identified. The results showed that vegetation type and soil depth significantly impacted SOC stocks and their distribution among aggregates. Pure woodland exhibited the highest SOC stocks, particularly in macroaggregates and microaggregates. Aggregate stability, nutrient availability, and extracellular enzyme activities jointly regulated SOC accumulation, but their relative importance varied across vegetation types. Aggregate stability and physical protection were the main drivers in GS, PS, and PW, while nutrient availability played a more significant role in MW and NG. In conclusion, these findings emphasize the crucial role of soil aggregate stability and physical protection of macroaggregates and microaggregates in enhancing soil carbon sequestration, providing important theoretical support for optimizing ecological restoration strategies.