不同固沙植被恢复模式对土壤理化性质、酶活性和草本植物多样性的影响OA

The aim of this study was to investigate the effects of different types of sand-fixing vegetation restoration on soil physico-chemical properties,soil enzyme activities,and herbaceous plant diversity.The control was bare mobile sand dunes(CK)and the four types of sand-fixing vegetation were Psammochloa villosa(SB),Caragana korshinskii(N),Corethrodendron scoparium(H),and a mixture of C.korshinskii and C.scoparium(NH).The results show that:1)Compared with mobile sand dunes,the shrub sand-fixing modes(N,H,NH)increased the contents of soil organic carbon(SOC),total nitrogen(TN),and available phosphorus(AP).The treatments were ranked,from highest AP content in soil to lowest,as follows:N>H>SB>NH>CK,with the AP content in C.korshinskii(N)plots(8.73 mg·kg⁻¹)being 45.5%higher than that in CK.The five treatments were ranked,from highest TN content in soil to lowest,as follows:H>N>NH>SB>CK,with the TN content in C.scoparium(H)plots(0.20 g·kg⁻¹)being 263%higher than that in CK.Meanwhile,the highest values of SOC content(1.51 g·kg⁻¹)and carbon-to-nitrogen ratio(C/N,25.13)were in the mixed(NH)plots,and were 55.5%and 42.8%higher than their corresponding values in CK.2)The highest activities of soil β-glucosidase and alkaline phosphatase were in the C.korshinskii(N)plots,and they were significantly higher(by 73.7%and 1315.1%,respectively)than their corresponding values in CK.The treatments were ranked,from highest activity of β-1,4-N-acetylglucosaminidase in soil to lowest,as follows:SB>NH>CK>H>N,with the highest activity in the P.villosa(SB)plots.The soil β-glucosidase activity was significantly correlated with pH,TN,and nitrogen-to-phosphorus ratio(N/P),while β-1,4-N-acetylglucosaminidase activity was significantly positively correlated with soil pH.3)The Pielou evenness index of vegetation was significantly lower in the P.villosa(SB)plots than in the shrub sand-fixing plots.The Simpson's dominance index and Pielou evenness index of vegetation were significantly negatively correlated with soil β-1,4-N-acetylglucosaminidase activity.Moreover,this enzyme(R²=0.66,P=0.003)and the carbon-to-phosphorus ratio(R²=0.41,P=0.01)were identified as key factors affecting herbaceous plant diversity.In summary,different types of sand-fixing vegetation affected the diversity of herbaceous plants by regulating the carbon-to-phosphorus ratio and β-1,4-N-acetylglucosaminidase activity in soil.Among the different vegetation modes,the mixed mode and C.korshinskii played important roles in maintaining the carbon-nitrogen balance and improving the content of available phosphorus,respectively.The findings of this study provide a scientific basis for optimizing sand-fixing vegetation and for promoting the sustainability of desertification control projects.