Insight into the influence of sand-stabilizing shrubs on soil enzyme activity in a temperate desert

- Sand-stabilizing shrubs can obviously increase soil enzyme activities.
- Soil enzyme activities under C. korshinskii were higher than those under A. ordosica.
- Soil enzyme activities varied with soil depth and shrub positions.
- Clear seasonal fluctuation in activities of C and N cycle enzymes was evident.

Shrubs can induce spatial heterogeneity of soil nutrition and play a crucial role in dune stabilization in arid and semi-arid ecosystems. Soil enzyme activity can be used to investigate soil nutrient cycling, which further indicates soil recovery after sand stabilization. However, information regarding the effects of different shrubs on soil enzyme activity is scarce. To reveal and compare soil enzyme activities of two dominating sand-stabilizing shrubs, namely, Caragana korshinskii Kom. and Artemisia ordosica, we evaluated various hydrolase and oxidase enzymes involved in the carbon cycle (polyphenol oxidase, cellulose, and β-glucosidase) and nitrogen cycle (nitrate reductase and urease) at the shrub base (ASB), beneath the midcanopy (BMC), and in bare intershrub spaces (BIS). The results indicated that the sand-stabilizing shrubs improved soil nutrition and enzyme activity compared with bare soil. The effects varied with shrub type and position. Soil enzyme activities were greater in C. korshinskii than those in A. ordosica, and maximum enzyme activity was found at ASB, followed by BMC and BIS. All enzyme activities, except polyphenol oxidase, were higher at 0-5 cm depth. The enzyme activities exhibited similar seasonal patterns during the growing season, with relatively higher values in the summer rainy season than in the other seasons because of soil moisture and shrub growth. The results of this study suggest that sand-stabilizing shrubs, especially C. korshinskii, can increase soil nutrition and improve soil properties, thus playing a vital role in soil recovery in degraded areas of desert ecosystems.