Effect of biological soil crusts on microbial activity in soils of the Tengger Desert (China)

- Biocrusts significantly increased soil microbial activity parameters.
- Severe trampling of biocrusts markedly affected soil microbial activity parameters.
- Moss crusts increased soil microbial activity more than cyanobacteria-lichen crusts.
- The sand dune restoration age was correlated with soil microbial activities.
- Soil microbial activity parameters beneath biocrusts varied with soil depth and season.

Soil microbes, as an important biological component of soils, have a function in the formation of soils and soil-remediation processes. This paper aims to analyze effects of biocrusts on soil microbial activities in desert ecosystems. Two sets of samples were collected under biocrusts in April, July, October, 2013, and January, 2014, in natural and revegetated areas of the Tengger Desert. The results showed that biocrusts significantly improved soil physicochemical properties, basal respiration and the quantity of soil alkaline phosphatase, protease, and cellulose, and decreased qCO2 in vegetated areas. Impact of biocrusts on soil microbial activities also varied, depending on the successional stage of crusts and the restoration age. Soil basal respiration and enzyme activity were obviously higher, but qCO2 were significantly lower in moss-dominated crusts than those dominated by cyanobacteria-lichen. Soil basal respiration and enzyme activity positively correlated with the restoration age, but qCO2 negatively correlated with the restoration age. Soil basal respiration and enzyme activity were the highest in summer, followed by autumn, and the lowest in spring and winter; whereas, qCO2 displayed an opposite trend. The study suggests that biocrusts have the ability to improve soil quality and promote soil recovery in vegetated areas of the Tengger Desert.