Study On Saline Changes And Landscape Ecological Effects In The Downstream Oasis Of Kaidou River Based On RS And GIS

In recent years, with the rapid development of social economy, populationincrease, the scale of the reclaimed land, the area of land use of major change in theway, and caused ecological environment effect also has a corresponding change. Theland use is considered to be able to show the human activities from landscape istypical of the process. This research area-Kaidu River Basin in southern Xinjiangdownstream oasis, with area in hydrological environment dry climate, and thedevelopment of oasis irrigation agriculture, making the oasis salinization, and furtherdeterioration secondary salinization phenomenon, this already on the local and theadditional living environment evolution and sustainable development is influenced.Through field investigation of study area, combining with the current situationand history of local oasis data, collected with abundant data and the maps material,and GPS point information and field landscape photo library, this paper study areafor extracting landscape information provides a good data base. Through thelandscape transfer matrix, center of gravity model and landscape index in the studyarea landscape pattern as the natural factors and analyzed the influence of the socialeconomy, the land use change constantly, and become an important factors affect theregion ecological effect. The river downstream oasis, the current resources andecological environment research hot spot problems, namely, the change of land useand its regional scale ecological effect for research. The results show that:（1） In the remote sensing and geographic information system to support3period（19902000and2009） remote sensing image classification processing, the land usetypes are divided into farmland, forest land, water, wetland and other type.Salinization is divided into the degree of salinization, light salinization, severesalinization three types.In the years1990²000, the area of cultivated land change trend, the area of16.9008km²growth a year, mainly turn a direction is woodland,13.873%conversion ratio, forest land, gently in saline, other to reduce trend, the forest landarea of1.2306km²reduce annual, mainly turn out for cultivated land and otherdirection,37.405%to22.34%. Light to reduce annual average saline area of19.08km². Other34.08km². Main turn a direction is farmland, the proportion is6.147%.Wetland reduced on average every year the area of6.66km². Annual averageincrease water area of25.006km². Severe saline this10years to increase the area of2.616km²between each year.In the years2000²009, rapid growth trend of cultivated land area, the annualaverage increase area is60.47km², its main by forest land and the other is to, turn tothe total area of754.442km²for. Forest land area of23.22km²reduce annualaverage, the reduction of the former period than many. Wetland annual average increase the area of5.52km², ten years after the wetland area of growth trend.Gently in a year on average meander to reduce the area of0.54km², no major change.Other area of16.55km²reduce annual, severe saline to reduce the trend, reduceannual for2.053km². Every year on average water area of26.22km²reduce.1990²00920years of cultivated land area of big increase, especially after aperiod of time, increased to773.729km². Proportion of forest land by7.514%in1990to4.966%in2009, the total by244.468km², the forest land transferred out ofthe cultivated land and other direction is, area of371.752km², respectively, and586.729km², is the largest land type reducing area. Wetland area and water area ofgeneral growth trend, reduced on average every year the area of0.57km². Water turninto the area of the wetland and other, the face of22.294km²and add25.553km².Light saline to20years to reduce trend during each year, the area of9.81km²reduced on average. Severe saline to whole change is now decreasing trend growth.Other area still decreasing trend, every year reduced on average area of25.32km².（2） the area, each layer of soil salinization type mainlychloride-sulfate-resistant saline soil is given priority to, second sulfuric acid salinesoil. Other type saline soil proportion is very small. The surface of the soil sample foran average0.867%salt content, belong to severe salinization of soil.10-30cm and30to50cm deep soil layer of salt content at an average of0.506%and0.56%,respectively, all belong to a moderate soil salinization.0-50cm deep soil layer of saltcontent at an average0.644%, belong to severe soil salinization, show that salt hascertain table sex together. Different sampling in depth, Ca²⁺, Mg²⁺,SO₄^2-,HCO₃^-,Cl^-,Na⁺, K⁺and other major soilion content has: surface>10-30cm>30to50cm characteristic; Through each layer of soil characteristics and the averagevalue of a digits in comparison, salt and is the distribution of ions are skewness.（3） This paper in the study area type level and the level of patches landscapechanges of landscape structure are compared and analyzed.In1990²009years between three processes, research area landscape shapeindex types are a significant change. From type level on look, cultivated land, gentlyin saline, other, wetlands, forest land, water, severe saline to index is small, simpleshape.Look from patches type, shape index is still the largest cultivated land were51.785, the whole landscape as a proportion of the big, complicated structure,deviated from the square degree high, irregular shape. Other and wetlands are16.406,9.892average patch fractal dimension and1990difference. Simple structure,concentrated, together with strong sex. With the expansion of the cultivated land area,the interference of ecological landscape of human level increased.1990²009from the whole landscape patches density decreased; The biggestpatches index, the contrast between the near distance, patches of growing spent. The shape of patch complicated, landscape fragmentation degree is higher. The landscapehas no obvious advantages types and various patches in the landscape type evenlydistributed. The contrast between the near distance measure is the space of thelandscape pattern, general index, reflecting the similar patches of distance betweentypes apart, distribution are scattered. The center of gravity of the landscape with awhole migration trend of the east, the artificial oases and expand are closely related,at the same time, the center of the indications oasis migration direction.