Soil Carbon And Nitrogen Concentrations Under Different Land Use In The Area Of Wujiang River

Different landuse types have an important impact on the charaeteristics of soil carbon,nitrogen and global climate.In order to understand the characteristics of soil carbon and nitrogen concents in the area of yanxi village of 6 kinds of soil land use(Rapeseedland,Seeding Nursery land,Vegetableland,Soybeanland,Cotton land and Watermelon land),the content of soil organic carbon and nitrogen were analyzed.Through research explores different ways of land use on soil organic carbon, total nitrogen, nitrate nitrogen, ammonium nitrogen, particle composition content and soil physical and chemical properties, in order to improve farmland soil productivity and ecological sustainable development provides the basis. The main conclusions of the research are as follows:1、The impacts of different land use on SOC(1) In the soil layers(0-60cm),the SOC content under different land use decrease with the increase of soil depth,the spatial distribution of soil organic carbon in the vertical general performance in yanxi village:0-20cm soil layer> 20～40 cm soil layer> 40～60cm soil layer.In the soil layer(0～0cm),the order of soil organic carbon content:vegetable land> seeding nursery land> Rapeseed land> Soybean land> cotton land, soil organic carbon content are mainly concentrated in 0-20cm soil layers.In the soil layers (0～60cm),the content of soil organic carbon under vegetable land were between 6.18～25.49g/kg,were in the range of 4.75～22.45g/kg under Seeding nursery land,were in the range of 4.60～16.05g/kg under Soybean land, were in the range of 6.81～21.85g/kg under Seeding nursery landl, were in the range of 1.54～15.61 g/kg under cotton land.(2)There existed highly significant difference amongtotal nitrogen under different land use types.In the soil layer(0～10cm), the content of TN under vegetable land(2.10g/kg) and Seeding nursery land(1.62g/kg) were higher than other land use types. In the soil layer(0-30 cm),the order of total nitrogen were vegetable land> seeding nursery land> soybean land> Rapeseed land> cotton land. In the soil layers(0-30 cm),TN content showed a larger difference uner different land use.Soil SOC and TN contents had similar profile changes, both of them had obvious variances in the vertical distribution profile under different land use types.2、The impacts of different land use on nitrate nitrogen and ammonium nitrogenThe accumulation content of nitrate nitrogen under different land use types in the soil layer (0～40cm)accounted for the soil layer (0-60cm) is respectively:rapeseed land (86%), Seeding nursery land(74%), Vegetable land(75%), Soybean land(87%), cotton land(88%),the accumulated content of nitrate nitrogen under vegetable land in the soil layer(0-40cm)reached to 61.11mg/kg. The nitrate nitrogen content under Vegetable land in the soil layer(0～60cm) was significantly higher than other land use types, mainly because the vegetable crop root system was concentrated in the soil surface,causing the accumulation of nitrate nitrogen content in surface.With soil depth in vertical direction,soil nitrate content under different land use patterns showed a decreasing trend. In general,the order of soil nitrate nitrogen distribution in the vertical profile of performance:0～20cm> 20～40cm> 40～60cm. Ammonium nitrogen is consistent in the vertical distribution of nitrate nitrogen.3、The impacts of different land use on soil partvicle composition contentsoil particle composition content is not same under different land use types. According to the USA’s standard of soil particle composition, divided into three levels: sand (0.05-2mm), silt (0.002～0.05mm) and clay (< 0.002mm). Comparative analysis under different land use types in the same soil layer in accordance with the soil layer 0～10cm,10～20cm,20-30cm,0～40cm,40～50cm,50～60cm.The soil mechanical composition of soil mainly composed of silt, whose contents is more than 50% and sand,clay accounting for small, The content of silt is small in the soil layer(20-30cm), (40～50cm),(50～60cm)under different landuse,the content of silt in the soil layer(0～10cm) under soybean land is higher than other land use types,the content of silt in the soil layer (50～60cm)is higher than other kind of land use types.In the soil layer(30～40cm),the land use pattern of soil particle composition content had little difference.The soil particle composition under same types of land use in different soil layers is not same. In the soil layers (0～60cm),the soil particle content proportion under rapeseed land,seeding nursery land,vegetable land,soybean land,cotton land is shown as:silt> clay> sand, and clay proportion is greater than 50%.According to the various size fractions content under different land uses, Soil mechanical composition were silt loam or clay loam powder.