Abstract: We investigated ammonia-oxidizing bacteria (AOB) community under different types of sand-fixing plantation, including Artemisia halodendron, Hedysarum fruticosum, Salix gordejevii, Pinus sylvestris var.mongolica, Populus simonii, and Caragana microphylla. The composition, abundance, community structure and potential nitrification were measured using the clone library analysis of amoA gene, fluorescent quantitative PCR, terminal restriction fragment length polymorphism technique and the shakenslurry procedure, respectively. The results showed that Nitrosospira cluster 3a was the most dominant group in AOB community, followed by cluster 6. The average abundance of Nitrosospira cluster 3a and cluster 6 varied significantly among different sand-fixing plantations. The highest abundances of Nitrosospira cluster 3a as well as AOB were detected in C. microphyllaplantation. The concentrations of total nitrogen, soil organic matter, and available potassium were the main factors shaping AOB community structure. There was significant difference of potential nitrification rate among sand-fixing plantations, with C. microphyllahaving the highest potential nitrification rate. Potential nitrification rate had a significantly positive correlation with AOB abundance and soil total nitrogen concentration. Our results suggested that artificial sandfixing plantation type had no effects on AOB community composition and structure, but affected the relative abundances of dominant groups, AOB abundance, and the potential nitrification rate. The AOB abundance and the relative abundance of Nitrosospira cluster 3a could be used as indicators of the recovery of AOB. The restoration of AOB community was the best in the C. microphyllaplantation among all plantation types tested.

Key words: adaptation perception, Ganan Plateau., climate change, farmer, risk perception, adaptation intention