To address soil salinization’s significant impact on human production and livelihood in arid regions,especially in high-salinity areas like salt lake regions,this study used multi-source remote sensing data to extrac...To address soil salinization’s significant impact on human production and livelihood in arid regions,especially in high-salinity areas like salt lake regions,this study used multi-source remote sensing data to extract 52 surface factors.Combined with measured soil salinity data,correlation analysis,multicollinearity testing,and projection importance analysis identified eight dominant factors.Subsequently,four machine learning algorithms were applied for modeling,and the optimal models were selected to study the spatiotemporal variation of soil salinization.The results indicate that the average soil salt content in the study area was 20.74%in 2020.LST(land surface temperature)can effectively identify areas with high salinity,such as saline-alkali land and salt flats.Among inversion models,the GBDT(gradient boosting decision trees)model demonstrated the highest predictive ability and minimal errors.The optimal inversion results revealed that soil salinization distribution was influenced by topographic elevation,distance from Qarhan Salt Lake,and river network density.Over the past 21 years,there was significant fluctuation in soil salinity observed in the concentrated area of grassland within the groundwater overflow zone,indicating strong variation in salinization.This fluctuation correlates with changes in groundwater levels in the groundwater overflow zone,which are influenced by temperature variations that determine the amount of snow and ice meltwater,and the precipitation in the upstream area.This study enhances understanding of soil salinization and its drivers in extremely arid salt lake regions.展开更多
Winter irrigation is a crucial measure for preventing farmland salinity in arid inland regions.However,given the relatively complex process of salt leaching under the influence of freezing and thawing,present salinity...Winter irrigation is a crucial measure for preventing farmland salinity in arid inland regions.However,given the relatively complex process of salt leaching under the influence of freezing and thawing,present salinity management has led to soil quality deterioration in the irrigation areas in Northwest China.To better understand this process,a field experiment was conducted in Huangyang Town,Wuwei City,Gansu Province,China to simulate the evolution of soil profile salinity and alkalinity in a typical oasis farmland under 3-year regular barley planting,using a local prevailing water-salt management mode of drip irrigation for the growing period and winter irrigation for the fallow period.This study investigated the impact of freezing on salt leaching by comparing the soil profile water,heat,and salt movements under different winter irrigation quotas.Compared to no winter irrigation,a reduction in the winter irrigation quota from the standard one to a halved one led to a transition from a sink of 11.05% by salt leaching to a source of 13.75% by salt addition.This means that overwintering soil freezing,especially in oases with deep groundwater tables,can worsen root zone salinization caused by a deficit winter irrigation,through freezing-induced root zone soil water and salt return.Furthermore,dry saline soil dominated by sulfate is at the risk of soil alkalization when freezing-induced oversaturation of solute concentration leads to significant salt precipitation.These findings are crucial for understanding the mechanisms behind the increasing secondary salinization caused by unsustainable winter irrigation in oasis irrigation areas.展开更多
基金The Second Tibetan Plateau Scientific Expedition and Research Program,No.2019QZKK0805-02The Innovation Team Foundation of Qinghai Office of Science and Technology,No.2022-ZJ-903+2 种基金The Comprehensive Development and Utilization of Salt Lake Resources,No.2023ZXKYA05100The Special Research Assistant of Chinese Academy of Sciences(Han Jinjun)The Kunlun Talented People of Qinghai Province,High-end Innovation and Entrepreneurship Talents,2023(Han Jinjun)。
文摘To address soil salinization’s significant impact on human production and livelihood in arid regions,especially in high-salinity areas like salt lake regions,this study used multi-source remote sensing data to extract 52 surface factors.Combined with measured soil salinity data,correlation analysis,multicollinearity testing,and projection importance analysis identified eight dominant factors.Subsequently,four machine learning algorithms were applied for modeling,and the optimal models were selected to study the spatiotemporal variation of soil salinization.The results indicate that the average soil salt content in the study area was 20.74%in 2020.LST(land surface temperature)can effectively identify areas with high salinity,such as saline-alkali land and salt flats.Among inversion models,the GBDT(gradient boosting decision trees)model demonstrated the highest predictive ability and minimal errors.The optimal inversion results revealed that soil salinization distribution was influenced by topographic elevation,distance from Qarhan Salt Lake,and river network density.Over the past 21 years,there was significant fluctuation in soil salinity observed in the concentrated area of grassland within the groundwater overflow zone,indicating strong variation in salinization.This fluctuation correlates with changes in groundwater levels in the groundwater overflow zone,which are influenced by temperature variations that determine the amount of snow and ice meltwater,and the precipitation in the upstream area.This study enhances understanding of soil salinization and its drivers in extremely arid salt lake regions.
基金supported by the Strategic Priority Research Program of Chinese Academy of Sciences(No.XDA24040203)the Inner Mongolia Key R&D Program,China(No.NMKJXM202107)+1 种基金the Key R&D Program of Gansu Province of China(No.21CX6QA026)the Natural Science Foundation of Gansu Province of China(No.20JR5RA074)。
文摘Winter irrigation is a crucial measure for preventing farmland salinity in arid inland regions.However,given the relatively complex process of salt leaching under the influence of freezing and thawing,present salinity management has led to soil quality deterioration in the irrigation areas in Northwest China.To better understand this process,a field experiment was conducted in Huangyang Town,Wuwei City,Gansu Province,China to simulate the evolution of soil profile salinity and alkalinity in a typical oasis farmland under 3-year regular barley planting,using a local prevailing water-salt management mode of drip irrigation for the growing period and winter irrigation for the fallow period.This study investigated the impact of freezing on salt leaching by comparing the soil profile water,heat,and salt movements under different winter irrigation quotas.Compared to no winter irrigation,a reduction in the winter irrigation quota from the standard one to a halved one led to a transition from a sink of 11.05% by salt leaching to a source of 13.75% by salt addition.This means that overwintering soil freezing,especially in oases with deep groundwater tables,can worsen root zone salinization caused by a deficit winter irrigation,through freezing-induced root zone soil water and salt return.Furthermore,dry saline soil dominated by sulfate is at the risk of soil alkalization when freezing-induced oversaturation of solute concentration leads to significant salt precipitation.These findings are crucial for understanding the mechanisms behind the increasing secondary salinization caused by unsustainable winter irrigation in oasis irrigation areas.
