Study On The Magnetic Characteristics Of The Different Landuse Soil

Urbanization in arid in China is co-adaptation process between regional development and eco-system because the oasis cities are the center of human activities and have the most sensitive man-earth relationship.The urbanization rate of arid area reached 43.5% in the year of 2011,which was in the middle stage of urbanization.With the speeding up increasingly of the process of urbanization,increasing continuously of the population and extending of urban land,these phenomenon have negative effect on the urban soil quality.In this paper,choosing different land-use types of topsoil in the Urumqi city and Urumqi city.The basic datas were geted by some experiment methodes.The magnetic parameters were measured by magnetic methodes,using the dry sieve method to measure the content of soil particle size,measuring the content of soil organic matter(SOM)by loss on ignition method,and making use of the colorimetry to measure the content of soil ammonium nitrogen(AN),soil available kalium(AK)and soil available phosphorus(AP).The analysis of main contents include three parts in this paper.The first part,the soil magnetic properties in different land-use types were analyzed.The second part,analyzing the the soil magnetic properties in different soil particle size and discussing the relationship between soil magnetic and soil particle size.The third part,analyzing the relationship between the soil magnetic properties and soil nutrients in different land-use types.Based on the analysis and discussion,the main conclusions are as follows:(1)Soil magnetic properties in different land-use typesAccording to the mean value of low frequency mass susceptibility(?lf)in different land use types,the order is transportation land > commercial land > green land > public facility land > non-construction land > residential land.The mean value of ?lf in transportation land,public facilities and business land is higher than others land.The study were showed that the ferrous magnetic mineral content of low coercivity has a positive effect on the value of ?lf.As for the particle size of soil magnetic minerals in different land-use types,which dominated by the multi-domain(MD)magnetic minerals and contained a small amount of single-domain(SP)and stable single-domain(SSD)magnetic minerals.(2)Soil magnetic properties in different soil particle sizeIn the same land-use types,with the decrease of particle size,the content of magnetic parameters ?lf,saturated isothermal remanence(SIRM)and soft remanence(SoftIRM)are gradually increasing.As for soft remanence(HIRM),except for the non-construction land,this rule is not obviously in HIRM.And ?fd(frequency magnetic susceptibility)decreases with the decrease of particle size.In the same particle size,the content of ?lf,SIRM and SoftIRM in construction land are higher than others,while the ?fd is converse.(3)The relationship between soil magnetic and nutrient ?lf is positively correlated with available potassium(AK),and the available potassium and low-frequency in the middle and non-construction land of the transportation land are related to the relationship between soil magnetic properties and nutrient.?lf,SIRM and SoftIRM have a positive correlation, reflecting the ferrous minerals and available potassium produced by the minerals have a certain relationship.There was a positive correlation between the total soil samples ?fd and SOM,which regular was founded in the green land and the non-construction land.Therefore,?fd were considered as the proxy index of SOM.