Effects of Artemisia ordosica on fine-scale spatial distribution of soil C, N and P and physical-chemical properties in the Mu Us Desert, China

Purpose Vegetation restoration is an effective measure for improving the function of soil ecosystems and promoting the biogeochemical cycling of carbon (C), total nitrogen (TN) and total phosphorus (TP). Here, we aimed to quantify the fine-scale (pedon scale) spatial distribution of soil C, N, P and soil physical-chemical properties in the Mu Us Desert ecosystems. Methods We systematically evaluated the effects of A. ordosica on fine-scale (pedon scale) spatial distribution of C, TN, TP, soil-available nutrients, and liable organic carbon (LOC) and their stoichiometric characteristics in the semiarid Mu Us Desert in the 0-100-cm soil profiles at various distances from the plant. Results and discussion The results demonstrated that soil organic carbon (SOC), TN and LOC were decreased with increasing distance from the plant and soil depth. SOC stocks at 20 cm were 16.98% higher than those at 120 cm from the plant. SOC stocks at 20, 60 and 120 cm from the plant were increased by 71.62%, 58.14% and 46.72% compared with shifting sandy land (S-land), respectively. Microbial biomass carbon (MBC) and readily oxidised organic carbon (ROOC) were significantly affected by different soil layers and distances and their interaction (p < 0.05), whereas dissolved organic carbon (DOC) was affected by the soil layers. TN and soil-available nutrients in the surface layer and at closer distances to the plant were higher than those in the sublayer and S-land. The ratio of C:N:P was generally decreased with different distances from the plant and different soil layers. The ratios of soil C:N, C:P and N:P were significantly different at different soil layers, whereas the ratios of soil C:P and N:P were significantly different at different distances from the plant (p < 0.05). Soil C:P ratio was positively correlated with soil C:N and N:P ratios (p < 0.001). N and P contents in leaves were higher than those in roots, branches and litter, but C contents in leaves were lower than those in other plant tissues and litter (p < 0.01). N:P ratio in leaves (13.94) showed that there was a shortage of N and P in the Mu Us Desert ecosystems. Conclusions We concluded that A. ordosica could enhance the accumulation of SOC, LOC and N on a fine scale and improve mineral-nutrient availability in semiarid deserts and, as a result, the function of soil ecosystems could be improved. Moreover, the limitation of N and P can be alleviated by adding additional N and P.

Automated summary

Vegetation restoration is crucial for improving soil ecosystem functions and enhancing the cycling of carbon, nitrogen, and phosphorus. In this study, the fine-scale spatial distribution of soil properties in the Mu Us Desert ecosystems was quantified, showing that A. ordosica can enhance soil carbon accumulation and nutrient availability at a fine scale.