Study On Characteristics Of Regional Ecological Geology In Qaidam Basin,Qinghai Province

The Characteristics of Regional Ecological Geology were conducted in Qaidam Basin,Qinghai Province.Studies on edaphic characteristics and their relationships with plant distributions in Tuanjie salt marshes,are presented in this paper.The distribution model of plants from sandy gravel Gobi to dry salt lake was established.Combined with the literature data,this thesis analyzed the characteristics and existing problems of regional land use,and put forward some suggestions of development salt lake agriculture in this area.The result showed that the communities were dominated by plants with strong saline-alkaline tolerance,such as Tamarix,Lycium ruthenicum,Phragmites australis,and Apocynum venetum.The salts strongly migrated to the surface in the vertical direction;however,the surface layer of the soil had a variable salt content,which fluctuated from the edge of the gravel Gobi in the northern Kunlun Mountains to the salt flats of the playa.The salt composition mainly consisted of NaCl in the surface crust and mainly Ca2+,Cland SO42-in the subsurface layer.The type of vegetation at the study site could be divided into two categories:halophytes,which form salt-tolerant vegetation communities,and hygrophytes,which exhibit weak salt tolerance.The halophytes were influenced by Na+,Cl-,and the salt content.The soil of these vegetation communities had higher salt and Na+contents and lower Ca2+and K+contents.The hygrophytes were mainly controlled by the Ca2+/Na+and K+/Na+ratios.In these communities,the soil salt and the Na+contents were low,and the soil Ca2+content was high.In the study area,with the content of salt,Na+,Cl-,SO42-increase,the vegetation decrease.However,with the content of total C,total N,K+,Ca2+,Mg2+increase,the vegetation increase.According to the above results,a vegetation distribution model of saline lakes on an inland plateau was established.The vegetation changes from sandy gravel Gobi to dry salt lake is:Psammophytes,salt tolerance vegetation community,weak salt tolerance vegetation community,salt tolerance vegetation community,non-vegetation cover.And the soil types are:saline sandy desert soil,meadow solonchak,saline meadow soil,desert salt.In Qaidam basin,the saline land were the main land type.The accumulated temperature and heat energy this area were abundant.Furthermore,saline water,brackish water and plant resources were very rich.In Qaidam Basin,the proportion of agricultural land was 0.17%and a large number of agricultural land has not developed.So,the abandoned area was much.Grassland area accounted for 46.64%,but its application was limited by the altitude,climate,traffic and other conditions.The proportion of the forest was 2.87%,but the forest has been damaged seriously.Although saline land area accounts for 11.68%,it’s hardly used at present.In a word,the resources are abundant in Qaidam Basin,and has great potential for developing.We suggest that agricultural demonstration district should be set up in this area,and salt lake ecological agriculture should be developed.Meanwhile,the study of halophytes should be strengthened,and saline land resources should be developed and utilized rationally.