Characteristics of Aeolian Soil Wind Erodibility and the Quantifying Model in the Ulanbuh DesertCN
Abstract：Soil wind erodibility refers to the sensitive degree of soil particles to wind erosion,which is affected by the intrinsic properties of soil particles.The dynamic factors and revision of localization are not taken into account in the existing quantitative indicators of wind erosion erodibility.Therefore,the Aeolian soil in the Ulanbuh desert was taken as the research object in this study.The method of field soil sample collection,indoor physical and chemical properties analysis,wind tunnel experiments and mathematical statistics combined with mathematical model construction were used to analyze the intrinsic attributes,i.e.the differentiation law of erodibility factors,of Aeolian soil in Ulanbuh desert,and to reveal the ecological process of the changes of erodibility factors.The strongest correlation factor was taken as the quantitative index of wind erosion erodibility by analyzing the correlation relationship between the normalized factors,such as threshold velocity,average amount of wind erosion,cumulative amount of wind erosion and maximum amount of wind erosion,and soil erodibility factors.The correction modules of wind erosion erodibility equation in the process of dry-wet alternation and freeze-thaw cycles were established respectively.And the quantitative models of the Aeolian soil in Ulanbuh desert were established,finally.The main results and conclusions were as follows.(1)Dune fluidity had significant effect(P<0.05)on the organic matters,the content of calcium carbonate and the particle size distribution of the Aeolian soil in Ulanbuh Desert.The Organic matters and the content of calcium carbonate increased significantly(P<0.05)with the decrease of dune fluidity.Dune·position had no significant effect(P>0.05)on the organic matters and the content of calcium carbonate in Aeolian soil,but had significant effect(P<0.05)on the content of fine sand and medium sand.(2)Dry-wet alternation and freeze-thaw cycle were the main factors affecting the erodibility of Aeolian soil.The erodibility of Aeolian soil during freeze-thaw cycles weas significantly higher(P<0.05)than that during wet-dry cycles.(3)The normalized cumulative amount of wind erosion had the most significant correlation relationship with soil erodibility factors such as the organic matters,the content of calcium carbonate content and the particle size distribution characteristics,which could be used as a quantitative index of wind erosion erodibility of the Aeolian soil.(4)The multiple regression equation between erodibility of the Aeolian soil and erodibility factors under dry-wet alternation and freeze-thaw cycles had high reliability(R2>0.60,NSE>0.80)and small error(NRMSE<0.20,| AVE |<0.05).It could be used as a quantitative model of the Aeolian soil erodibility in the Ulanbuh desert,and could provide some theory basis for monitoring and prediction of wind erosion in northern China.In this study,the quantitative indicators of wind erosion erodibility in the Ulanbuh desert area were selected,and the dynamic change mechanism of wind erosion was fully considered.The optimization and localization of wind erosion erodibility model were realized.