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Increased salinity and groundwater levels lead to degradation of the Robinia pseudoacacia forest in the Yellow River Delta

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Journal of Forestry Research 2022年第4期33卷 1233-1245页

作者： Chaoxia Lu Chen Zhao Jing Liu Kailun Li Baoshan Wang Min Chen Shandong Provincial Key Laboratory of Plant Stress Research College of Life ScienceShandong Normal UniversityJi’nan 250014People’s Republic of China Shandong Provincial Key Laboratory of Crop Genetic Improvement Ecology and PhysiologyShandong Academy of Agricultural SciencesJi’nan 250100People’s Republic of China

Forest degradation is a worldwide problem,although its causes vary due to geographical and climatic differences and man-made *** recent years,the Robinia pseudoacacia forest in the Yellow River Delta has suffered severe *** causative mechanisms were investigated in the field over two years,and the results show that increased forest degradation was reflected by increased tree mortality,high leaf and soil sodium salt levels and groundwater *** tree diameters decreased,and leaf chlorophyll and soil microbial contents *** discriminate analysis(RDA)showed that degradation of the forest was correlated positively with soil salt content,but negatively with groundwater *** analysis showed that 0.79%–0.95%soil salt content and above 1.20 m groundwater depth caused the death of *** trees due to localized anthropogenic economic activities,such as rice farming,that disrupted the original water–salt *** are recommended to prevent further degradation and restore degraded forests.

关键词： Forest degradation Groundwater depth Robinia pseudoacacia forest soil salt content The Yellow River Delta

A Spectral Index for Estimating soil Salinity in the Yellow River Delta Region of China Using EO-1 Hyperion Data

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Pedosphere 2010年第3期20卷 378-388页

作者： WENG Yong-Ling GONG Peng ZHU Zhi-Liang Department of Surveying and Mapping Engineering College of Transportation Southeast University Nanjing 210096(China) State Key Laboratory of Remote Sensing Science Institute of Remote Sensing Applications of the Chinese Academy ofSciences and Beijing Normal University Beijing 100101 (China) Department of Environment Science Policy and Management University of California Berkeley CA 94720 (USA) EROS Data Center U.S. Geological Survey Sioux Falls SD 57198 (USA)

soil salinization is one of the most common land degradation processes. In this study, spectral measurements of saline soil samples collected from the Yellow River Delta region of China were conducted in laboratory and hyperspectral data were acquired from an EO-1 Hyperion sensor to quantitatively map soil salinity in the region. A soil salinity spectral index (SSI) was constructed from continuum-removed reflectance (CR-reflectance) at 2052 and 2203 nm, to analyze the spectral absorption features of the salt-affected soils. There existed a strong correlation (r = 0.91) between the SSI and soil salt content (SSC). Then, a model for estimation of SSC with SSI was established using univariate regression and validation of the model yielded a root mean square error (RMSE) of 0.986 and an R2 of 0.873. The model was applied to a Hyperion reflectance image on a pixel-by-pixel basis and the resulting quantitative salinity map was validated successfully with RMSE = 1.921 and R2 = 0.627. These suggested that the satellite hyperspectral data had the potential for predicting SSC in a large area.

关键词： hyperspectral reflectance soil salt content spectral absorption features

Estimating soil Salinity in the Yellow River Delta, Eastern China——An Integrated Approach Using Spectral and Terrain Indices with the Generalized Additive Model

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Pedosphere 2016年第5期26卷 626-635页

作者： SONG Chuangye REN Hongxu HUANG Chong State Key Laboratory of Vegetation and Environmental Change Institute of Botany Chinese Academy of Sciences Key Laboratory of Plant Resources Institute of Botany Chinese Academy of Sciences Institute of Geographical Sciences and Natural Resources Chinese Academy of Sciences

soil salinity is one of the most severe environmental problems worldwide. It is necessary to develop a soil-salinity-estimation model to project the spatial distribution of soil salinity. The aims of this study were to use remote sensed images and digital elevation model(DEM) to develop quantitative models for estimating soil salinity and to investigate the influence of vegetation on soil salinity estimation. Digital bands of Landsat Thematic Mapper(TM) images, vegetation indices, and terrain indices were selected as predictive variables for the estimation. The generalized additive model(GAM) was used to analyze the quantitative relationship between soil salt content, spectral properties, and terrain indices. Akaike's information criterion(AIC) was used to select relevant predictive variables for fitted GAMs. A correlation analysis and root mean square error between predicted and observed soil salt contents were used to validate the fitted GAMs. A high ratio of explained deviance suggests that an integrated approach using spectral and terrain indices with GAM was practical and efficient for estimating soil salinity. The performance of the fitted GAMs varied with changes in vegetation *** in sparsely vegetated areas was estimated better than in densely vegetated areas. Visible red and near-infrared bands, and the second and third components of the tasseled cap transformation were the most important spectral variables for the estimation. Variable combinations in the fitted GAMs and their contribution varied with changes in vegetation cover. The contribution of terrain indices was smaller than that of spectral indices, possibly due to the low spatial resolution of DEM. This research may provide some beneficial references for regional soil salinity estimation.

关键词： Akaike's information criterion digital elevation model Landsat TM image soil salt content terrain in indices vegetation cover

Growth characteristics of Suaeda salsa under different soil salinity gradients in controlled experiments

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International Journal of Agricultural and Biological Engineering 2021年第5期14卷 142-148页

作者： Fei Zhang Yun Chen Jie Yuan Ligang Ma Changjiang Liu Key Laboratory of Wisdom City and Environment Modeling of Resources and Environmental Science College Urumqi 830046China Key Laboratory of Oasis Ecology Xinjiang UniversityUrumqi 830046China Engineering research center of Central Asia Geoinformation Development and Utilization National Administration of SurveyingMapping and GeoinformationUrumqi 830002China Commonwealth Scientific and Industrial Research Organization Land and Water CanberraACT 2601Australia

Xinjiang is the province with the largest saline-alkali land in *** growth of halophytes will be stressed when their salt content reaches the *** this study,the pot experiments were conducted and Suaeda salsa,a typical halophyte,was selected as the object to explore the relationship between growth characteristics and salt content under different soil salinity *** gradients were set according to the maximum soil salinity in the current years of Ebinur Lake Wetland National Nature Reserve(ELWNNR).They were classified using the following threshold values:≤2 g/kg(Control Group),10 g/kg,20 g/kg,30 g/kg,and 40 g/*** original spectrum,trilateral position and growth characteristics were used as indexes for *** the increase of soil salt content,the red edge shift occurs first,followed by the blue edge *** position of yellow edge,green peak and blue edge were not sensitive to the change of soil *** indicates that the red edge is the best indicator for evaluating plant *** with the Control Group,when the salt content is less than 10 g/kg,the growth status of plant seems not significantly ***,plant growth begins to be stressed when the salt content increases to 20 g/kg,which is a turning point for plant *** increase of soil salt content can inhibit chlorophyll synthesis and plant *** begin to die when the salt content reaches 40 g/***,40 g/kg could be regarded as the critical point of salt content which inhibits plant *** study also shows that the relationship between plant-height change rate and soil salt content is the most significant,indicating that the plant-height change rate is significantly impacted by soil salt content.

关键词： Suaeda salsa soil salt content gradient spectral growth characteristics