Enzymatic activity of different sequence of biocrusts and loess soils in Incheh Borun region.

Soil enzyme activity is an indicator of microbial community and functions that reflects changes in soil biological properties, soil organic matter dynamic and nutrient cycling. Therefore, this study was conducted to investigate the enzyme activity in different sequences of biocrusts and loess soils in the semi-arid region of Incheh Borun, Golestan province, Iran. The Incheh Borun region has the highest abundance of biological crusts on loess plateau. Biocrusts were identified based on morphological characteristics. Enzyme activity was measured (cellulase, chitinase, α-glucosidase, β–glucosidase, acid phosphomonoestrase, arylsulfatase, β-xylosidase, butyrate esterase and leucine aminopeptidase) in the presence of cyanobacteria, lichen and moss crusts and their absence (i.e., the physical crust) as affected by three treatments (crust, soil and soil + crust) and three replications at a depth of 0- 2 cm. The results showed that the presence of biocrusts compared to physical crust in the surface parts (0 to 2 cm depth) improved the activity of enzymes in all three treatments. The highest enzyme content was related to the β-glucosidase enzyme in the lichen biocrust, and the lowest content was observed in the β-xylosidase enzyme in the physical crust. The lichen crust (Diploschistes diacapsis (Ach.) Lumbsch) had the greatest enzyme activity compared to other crusts. This species can fix he carbon of atmosphere by photosynthesis and increasing soil stability better than the other biocrusts. The most enzyme activity in the presence of biological crusts indicates a more active biological diversity or microbial population compared to the physical crusts. This can improve soil quality.