| Desert oasis in arid zone of northwest China transition zone,the main vegetation landscape pattern as the patch shape,vegetation structure is simple,the influence of climate and water in arid areas,vegetation to resist outside interference ability is weak,but its role for windbreak and sand-fixation,therefore,in this paper the dynamic changes of the desert oasis vegetation pattern transition zone plaques and its soil hydrological properties as the research object,The 3S technology was used to analyze the vegetation landscape pattern of the study area in 2010,2015 and 2020.At the same time,the characteristics of soil moisture evapotranspiration,soil moisture content and soil moisture infiltration in 2010,2015 and 2020 in the study area were studied by using MODS satellite remote sensing images and measured observation data.The relationship between vegetation pattern and soil moisture evapotranspiration,soil moisture content and soil moisture steady infiltration rate were analyzed by using grey relational degree method.The main research results are as follows:(1)The landscape with higher landscape dominance in 2010 was the landscape with higher vegetation cover,the landscape with higher vegetation cover in 2015,and the landscape with higher vegetation cover in 2020;The landscape fragmentation degree of medium vegetation cover and low vegetation cover is relatively serious,while the landscape fragmentation degree of high vegetation cover is the lowest.(2)At the landscape level,the vegetation landscape patches are mainly small patches.From 2010 to 2020,the landscape with higher vegetation coverage has the largest average patch area in 2020,with an average patch area of 7.68hm2.The characteristics of the landscape in the study area are as follows: high heterogeneity,serious fragmentation,easy to produce edge effect and high neighborhood degree of landscape type.(3)From 2010 to 2020,vegetation landscape type shift change process,mainly for the degradation process,landscape transfer area is the vegetation landscape in the smallest,the largest for high vegetation landscape,notes the vegetation landscape is relatively s Tab,with high stability of the vegetation landscape is relatively weak,easily influenced by external conditions.(4)In 2020,the soil water content in the study area increased with the increase of soil depth.After the rainy season,the soil water content was higher than that before the rainy season due to the rainwater supply.The nugget coefficient showed that the soil moisture content of the 10?60cm,80?100cm and 40?120cm layers before and after the rainy season was mainly autocorrelated with variation,while the soil moisture content of the other layers was mainly random variation.Variation A indicated that there was no short-distance variation of the soil moisture content before and after the rainy season in 2020.(5)The soil water infiltration rate of the three kinds of sand fixed vegetation in the study area changed greatly in the first 10 min,and tended to be s Tab after 10 min.The soil water infiltration rate of different plants showed that the soil water infiltration rate of different plants was >,and the soil water infiltration rate of different plants showed a continuous decreasing trend with the increase of soil depth.(6)During the observation period,the maximum variation coefficient of soil moisture evapotranspiration was for H.ammodendron vegetation in 2019,while the minimum variation was for H.ammodendron vegetation in 2020.The soil moisture evapotranspiration during the observation period all showed moderate variation.(7)Correlation showed that air temperature,land surface temperature,10 cm soil temperature,total net radiation and total soil heat flux were significantly positively correlated with soil moisture evapotranspiration in the study area,while relative humidity and water pressure were significantly negatively correlated with soil moisture content.Principal component analysis showed that total net radiation had the largest weight ratio.Moreover,the annual distribution of soil moisture evapotranspiration in the study area showed a unimodal distribution trend that increased first and then decreased,and the evapotranspiration mainly concentrated between May and October.The seasonal characteristics of soil moisture evapotranspiration in the study area were > in summer,> in autumn,> in spring,and > in winter,which was consistent with the seasonal variation characteristics of soil moisture evapotranspiration in the arid area.(8)The grey correlation degree showed that the vegetation coverage under the average patch shape index(SHAPE?MN),largest patch index(LPI)and spread in parallel index(IJI)on soil water evaporation and soil moisture,soil moisture content the influence degree of the steady infiltration rate is the largest,the most influence on soil hydrological processes in the study area. |
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