Biocrust impacts on dryland soil water balance: A path towards the whole picture

As a crucial living feature inhabiting the soil-atmosphere boundary, biocrusts play a vital role in liquid water or vapor transport through surface soil and thus have strong effects on soil water regimes. However, it remains unclear how biocrusts affect annual or multi-year soil water budgets through the regulation of evaporation outputs and NRW or infiltration inputs. Thus, we used automated microlysimeters to continually investigate the differences in evaporation and NRW rates between moss-dominated biocrusts and bare soil at 0−5 cm depth for two years. The upper 30 cm of soil moisture (θ) and water storage (W) of bare soil and biocrusts were also monitored. Our results showed that the daily evaporation rate (E) of biocrusts was 17% higher than bare soil. Especially after rainfall events, biocrusts had higher E and larger cumulative evaporation than bare soil. Besides, the daily NRW of biocrusts averaged 15% higher than bare soil over two years. Furthermore, biocrusts increased θ by 1...