Study On Spatiotemporal Variation And Influencing Factors Of Soil Salinization Based On 3S Technolog

Daqing region is a typical salinized soil area in Heilongjiang Province.The salinization degree of soil is becoming more and more serious,which has adverse effects on people’s production and life,agricultural planting development and ecological environment.Using remote sensing technology to analyze the dynamic change of saline soil in time and space scale and to monitor the spatio-temporal change law of saline soil in Daqing area is of great significance for the treatment of saline soil and the protection of ecological environment.Using Landsat8 OLI(Land Imager)remote sensing images in 2021 and 2015 and Landsat5 TM in 2008 and 2001 as data sources,combined with field sampling and measured soil salt content,The correlation between the surface layer(0～10cm),shallow layer(10～20cm)and mixed layer(0～20cm)soil and the remote sensing reflectance was analyzed.Since the remote sensing image did not reflect the deep soil obviously,the deep soil was not studied.The soil salinity inversion model was constructed by using the multiple linear regression model with mathematical transformation of reflectance,and the soil salinity in Daqing from 2001 to 2021 was quantitatively retrieved.Based on this,the influencing factors of soil salinity were analyzed.The following conclusions are drawn:1)There is a positive correlation between remote sensing reflectance and soil salt content,with the highest correlation in the 7th band,followed by the 6th band;After mathematical transformation,the accuracy and stability of the multi-band inversion model are significantly improved.The coefficient of determination of the model is 0.842,and the root mean square error is 0.290.2)The total area of saline soil in the study area increased first and then decreased from 2001 to 2021.From 2001 to 2008,the area of reverse conversion was larger than that of forward conversion.The total area of saline soil increased,but the growth rateslowed down.The total area of saline soil reached a peak of 436311 hm~2 in 2015.From 2015 to 2021,the area of saline soil in all regions decreased rapidly,and the area of positive transformation was greater than that of reverse transformation.3)The influencing factors of soil salinization in the study area are attributed to two major aspects:natural factors and human factors.Natural factors are internal causes,while human factors are external causes,but human activities have a more direct impact on soil salinization in the short term.The effect of human factors on soil has two sides,not only can destroy the natural environment,accelerate the soil salinization process,but also can use amendments to improve the soil environment.