Soil quality evaluation of different sand-fixing shrub communities in Ulan Buhe Desert

This study examined the chemical properties of soil in six sand-fixing shrub communities in Ulan Buhe Desert, focusing on the 0–150 cm soil layer. Results demonstrated that: (1) Soil organic matter content was significantly higher in all shrub communities than in the control site (BS) (P<0.05). The Nitraria tangutorum Bobrov+Kalidium foliatum (Pall.) Moq. community exhibited the most favorable pH and electrical conductivity. The Ammopiptanthus mongolicus (Maxim. ex Kom.) S. H. Cheng+N. tangutorum community had the highest total nitrogen content, while the highest alkali-hydrolyzed nitrogen content was recorded in the Krascheninnikovia ceratoides (L.) Gueldenst. community. Total potassium levels were highest in the Zygophyllum xanthoxylon (Bunge) Maxim. community. (2) Correlation analysis revealed that pH, conductivity, organic matter, total phosphorus, and available phosphorus were significantly positively correlated with multiple soil quality indicators. (3) The soil quality index (SQI) evaluation identified the N. tangutorum + K. foliatum community as having the highest soil quality, followed by the Haloxylon ammodendron (C. A. Mey.) Bunge+N. tangutorum community and the A. mongolicus + N. tangutorum community, all of which exhibited significantly better soil properties than other communities and the control. These three shrub communities play a critical role in improving soil quality in the Ulan Buhe Desert and have substantial implications for ecological restoration efforts in arid environments.