Study On Soil Salinity Characteristics And Its Salt-driven Actuation Factors In Yutian Oasis

By studying different types land cover soil of Yutian Oasis ,the paper reveal the formation mechanism of saline soil and the law of salinization development, at the same time,reveal its transfer laws.Yutian Oasis Water and Salt migration by the local geographical environment, climatic conditions, hydrological factors, soil parent material, as well as human unreasonable activity, such as the combined effects of an mpact, make the saline soil formation emergence regional differences. Eventually Yutian Oasis saline soil display different characteristics of the salt, and different migration of water and salt.Through our many field investigations, field sampling, laboratory operated by hand, and previous work of groups in our laboratory, and further reveal soil salinization factor of the drive onto the different ecological oasis patches, put forward some reasonable improvement measures for the rational development and provide a basis for the work so as to effectively use of local natural resources.The conclusions of this paper is as follows:1. We take samples in accordance with the different types land cover in Yutian Oasis.Then analyse surface soil salinity status. After comprehensive analysis, we divide Yu Tian oasis soil type into five grades being respectively. Non-saline soil patches mainly distribute in Oasis internal , the main types of land cover is farmland. Slight salinization area mainly distribute in marginal areas of the oasis, the land cover types is mainly low-density grassland. Moderate salinity zone is mainly medium-density grassland which is more closer than the high-density grassland to the oasis internal. Main types of land cover is the dense grass ;or distribute in low-lying land in the oasis, easy to water, often form natural wetland . Re-salinization region dispersedly distribute in the internal oasis, the main types of coverage is high-density grassland. Saline soil areas mainly locatein the vicinity of farmland,where gricultural irrigation water discharge . 2. Oasis exist a more serious internal soil salt accumulation region.Change in salt content on the vertical profile mainly performance the poly salt and mixed salt,also have a small number of desalination. Poly salt mainly distribute saline-alkali land patches and partial high-density grassland. Furthermore in Wetlands, medium-density grassland is also distribute. Their vertical profiles of salinity look similar funnel-shaped things. mixed salt distribute in the farmland and ecotone region between farm and desert region. Salinity of Vertical profile perform central in low-salinity, high salinity in levels.3. Yutian Oasis the various elements of soil salt ions performance Na+ content is the largest;then are SO42- and CL-and HCO3-.All this show that soil suffer most serious hazards of sodium. Variations in the level of various ions are larger difference. This phenomenon is due to micro-topography study area, differences in land use, irrigation system, as well as various factors such as farming methods. Eigenvalue of soil salinity with the conductivity of the soil and TDS,Cl-,K++Na+ is very significant correlation, with HCO3-, SO42-, CO32-, Mg2+ is the more obvious relevance , with pH is partially related . We believe that through a comprehensive analysis the main components of soil salt-ion arer K++Na+, Cl-, SO42-, HCO3-.4. The Yutian oasis local ground water burying depth's change basic condition is: From March, because of the frozen melting function ground water level start to rise fast and the water level is shallowest about mid-April. Afterward the ground water starts to drop, to July what is more to September ground water level fall to deepest, Afterward the water level starts to rise again. The ground water year to year like this moves back and forth . In the experiment process simultaneously we also discovered that soil salinity various characteristic values have certain relevance. The soil main composition type is NaCl ,next is Na2SO4, MgSO4, CaSO4.5. The Yutian oasis soil salinity main body performance is the salt clay. The soil salinified production and the development process, mainly divide into 3 time intervals.They respectively are melting to returning the salty time, the dry season to accumulating the salty time and the winter salinity stabilization period frozen. Melting the frozen time the ground water level is higher than the dry season to accumulating the salty time obviously. These two season soil's salt content change is not very big. Only the soil salinity major constituent carries out redistributing on the vertical direction.6. The Yutian oasis belongs to the extreme dry climate, the local drought index is quite big.And is year to year few rain,is multi-gale sand dust weather, the topography is low-lying ,water resources is extreme scarce. These combined actions are intensifying local unceasingly year by year the salinified recent situation.7. The ground water burying depth, the hardness index and the ground water chemistry type decides the local soil the salinity characteristic value. We obtain finally the conclusion is that the ground water burying depth situation and the soil salinity content become certain reverse connection. The ground water hardness index height becomes certain functional relations with its corresponding soil salinity content size related. And the ground water condition and the soil salt content have the close causally related. We finally determine the changes in soil salinity and groundwater salinity, groundwater level changes in the function.