Soil Physicochemical Properties And Quatity Evaluation Of Different Land In Permafrost Regions,Daxing'an Mountation

Permafrost plays an important role in the habitat.Permafrost degradation brings serious problems of marshes,forest degradation,land desertification.The permafrost is widely distributed in Daxing'an Mountains,has become one of the hot areas of permafrost research in China.With the global warming,soil carbon and nitrogen content of different land patterns will change,therefore,we selected the marshes,arable land and woollands in permafrost regions of Daxing'an Mountains as the research objects,analyzing the change regularity of soil carbon,nitrogen contents and soil quality evaluation of different land.The variation of soil carbon,nitrogen and other nutrient elements in different land patterns was studie and soil quality evaluation.To explore the differences of carbon and nitrogen distribution and soil quality evaluation under different land patterns and soil quality evaluation,it provides basic data for the ecological environment protection in this area.(1)Soil carbon and correlations under different land patterns the contents of total carbon,soil organic carbon,dissolved organic carbon in marshes,arable land and woollands types decreased with the depth of the soil profile,and the carbon content in the change trend of soil 0-10 cm was basically the same as that of soil 10-20 cm and soil 20-30 cm.The carbon content of soil in three different landorder size of the total carbon and dissolved organic carbon content is marshes> Pinus sylvestris var.mongolica > Larix gmelinii > arable land,the total carbon content of marshes was significantly different from that of arable land,Larix gmelinii(P<0.05).The soil dissolved organic carbon content of marshes was significantly different from that of woollands,arable land(P<0.05).the dissolved organic carbon content of Larix gmelinii and arable land was significantly different from that of marshes(P<0.05).In the DOC/SOC,low proportion of marshes and arable land,and water solubility and stability are relatively poor.(2)The change of total nitrogen,ammonium nitrogen,nitrate nitrogen and total mineral nitrogen in the vertical direction of three different land is consistent with that of carbon content.In the vertical direction,the order of total nitrogen,ammonium nitrogen content under different land patterns is that,marshes> Pinus sylvestris var.mongolica >Larix gmelinii>arable land;he order of nitrate nitrogen,total mineral nitrogen content under different land patterns is that,marshes> Larix gmelinii > Pinus sylvestris var.mongolica >arable land.The total nitrogen,ammonium nitrogen,nitrate nitrogen,total mineral nitrogen content of the marsh was significantly different from that of the other two land patterns(P<0.05).The total nitrogen content of arable land was significantly different from that of forest land(P<0.05).Through the carbon nitrogen ratio,Larix gmelinii is more conducive to the accumulation of organic matter.(3)In the vertical direction,soil total phosphorus,available phosphorus,pH in different land patterns decreased with the increase of soil depth.The order of total phosphorus,available phosphorus content under different land patterns is that marshes> Pinus sylvestris var.mongolica >Larix gmelinii>arable land,The order of p H: arable land> Larix gmelinii> Pinus sylvestris var.mongolica > marshes.The total phosphorus content of the marsh was significantly different from that of other lands(P<0.05).The total phosphorus content of the arable land was significantly different from Pinus sylvestris var.mongolica(P<0.05).The available phosphorus in marsh is significantly higher than other land methods(P<0.05).The pH value of arable land is significantly higher than that of other land(P<0.05),and the relationship between marshes and woodland is significant(P<0.05).The phosphorus supply level of marshes,Larix gmelinii soil is higher than that of Pinus sylvestris var.mongolica,arable land.(4)The size of the soil quality index is: Pinus sylvestris var.mongolica >Larix gmelinii> marshes> arable land.There was little difference in soil quality index among different land types,the overall quality is relatively high,it indicates that the soil is in a reasonable range of use.