Desertification is considered one of the major ecological and environmental threats, along with climate change, resource depletion, and land management in semi-arid agro-pastoral transitional zone of Inner Mongolia, China. Land degradation caused by decreased precipitation, land use shifts from sandy grasslands to irrigated croplands (mostly maize), and high intensity livestock grazing, resulted in a serial of environmental problem (e.g. underground water table reduction) and massive farming material pollution (e.g. maize straw and livestock dung). Sustainable restoration amendments have been highly appealed to combat desertification under current water-limit condition. We used microbial cultivation technique to screen efficient cellulose decomposers (NMCel) and nitrogen-fixing bacteria (NMAzo) from the matrix of sandy soils and cattle dung. Maize straw and cattle dung were smashed and mixed to produce microbial organic compound (MOC). NMCel dilution was used to accelerate the fermentation rate of MOC, while NMAzo was acclimated to increase MOC fertility. A field experiment was conducted to test the effects of the optimized MOC to sandy land restoration.
This study focused on the use of microbial organic compound amendments as a mean to help restore degraded grassland. The optimized MOC was significantly efficient in rehabilitating bare sand dunes and accelerating biological soil crust formation. The MOC had a potential advantage for increasing water holding capacity, wind erosion resistibility and soil fertility. Results showed that the optimized utilization of MOC in sand dunes enhanced surface soil organic carbon by 43%-64% and total nitrogen by 38%-51%; improved vegetation coverage from 6% to 26% and soil crust thickness from 0 to 2-5 cm; enhanced soil water hold capacity by 24%-47%, and wind erosion resistance ability by 5.4-8.6 times compared with natural restoration. This technique provides an effective and ecological method that aims to accelerate successful restoration from bare sand dunes to shrub-grass-crust integrated ecosystem in the semiarid agro-pastoral transitional area.