Biological soil crusts (BSCs), composed of cyanobacteria, microfuge, lichens and mosses with soil particles, cover the first millimeters of topsoil and are ubiquitous cover types in desert ecosystems.  

The existence of BSCs could change surface soil characteristics, such as increasing C and N stocks and changing soil texture as well as aggregate stability, which contribute to enhancement in soil stability and improvement in soil fertility. Therefore, the application of BSCs has become one of the effective biological measures to prevent desertification in recent years. 

However, current studies discussed the role of BSCs in infiltration process and the influences of BSCs on rainfall infiltrative depth, but the results are far from conclusive. 

Recently, scientists from the Northwest Institute of Eco-Environment and Resources (NIEER) of the Chinese Academy of Sciences investigated the effect of BSCs on soil moisture dynamics under different rainfall conditions in the Tengger Desert. 

Using ECH₂O moisture sensors, they monitored the soil moisture under soil of moss-dominated, soil with algae-dominated BSCs, and dune sand, respectively. They found that the influence of BSCs on infiltration amount was dependent on rainfall regime and soil depth. 

The result showed that BSCs significantly increased surface infiltration and soil moisture, but had a negative effect on deep soil moisture recharge, which may be disadvantageous to the deep rooted vegetation dynamics. Besides, it also indicated that more developed moss crust had higher water holding capacity than less developed algae crust, and thus exhibiting a higher rainfall infiltration. 

Furthermore, the effect of BSCs on infiltration varied with rainfall and antecedent soil condition. BSCs significantly affected the infiltration in small and medium rainfall events and had no effect in large rainfall event. Antecedent soil condition had a promoting effect in deep infiltration. 

The objectives of this study are to investigate the role of BSCs on rainfall infiltration in different natural rainfall events and to quantify the soil moisture dynamics and soil water availability under BSCs and sand. 

The study entitled "The effect of biological soil crusts on soil moisture dynamics under different rainfall conditions in the Tengger Desert, China" was published in Hydrological Processes.