Reflectance spectroscopy for the assessment of soil salt content in soils of the Yellow River Delta of China

2008 ◽  
Vol 29 (19) ◽  
pp. 5511-5531 ◽  
Author(s):  
Yongling Weng ◽  
Peng Gong ◽  
Zhiliang Zhu
Keyword(s):  
Yellow River ◽  
Salt Content ◽  
Yellow River Delta ◽  
Reflectance Spectroscopy ◽  
River Delta ◽  
The Yellow River ◽  
The Yellow River Delta ◽  
Soil Salt Content ◽  
Soil Salt

scholarly journals Spatiotemporal Changes of Soil Salinization in the Yellow River Delta of China from 2015 to 2019

2021 ◽  
Vol 13 (2) ◽  
pp. 822
Author(s):  
Lingling Bian ◽  
Juanle Wang ◽  
Jing Liu ◽  
Baomin Han
Keyword(s):  
Vegetation Index ◽  
Yellow River ◽  
Salt Content ◽  
Feature Space ◽  
Yellow River Delta ◽  
Soil Salinization ◽  
River Delta ◽  
The Yellow River ◽  
The Yellow River Delta ◽  
Soil Salt Content

Soil salinization poses a significant challenge for achieving sustainable utilization of land resources, especially in coastal, arid, and semi-arid areas. Timely monitoring of soil salt content and its spatial distribution is conducive to secure efficient agricultural development in these regions. In this study, to address the persistent problem of soil salinization in the Yellow River Delta in China, the feature space method was used to construct multiple feature spaces of surface albedo (Albedo)–modified soil-adjusted vegetation index (MSAVI), salinity index (SI)–Albedo, and SI–normalized difference vegetation index (NDVI), and an optimal inversion model of soil salinity was developed. Based on Landsat 8 Operational Land Imager (OLI) image data and simultaneous field-measured sampling data, an optimal model from 2015 to 2019 was used to obtain the soil salt content in the region at a 30 m resolution. The results show that the proportion of soil salinization in 2015 and 2019 was approximately 76% and 70%, respectively, and overall soil salinization showed a downward trend. The salinization-mitigated areas are primarily distributed in the southwest of the Yellow River Delta, and the aggravated areas are distributed in the northeast and southeast. In general, the spatial variation characteristics show an increasing trend from the southwest to the eastern coastal areas, corresponding to the formation mechanism of salt accumulation in the region. Further, corresponding sustainable development countermeasures and suggestions were proposed for different salinity levels. Meanwhile, this study revealed that the SI–Albedo feature space model is the most suitable for inversion of salinization in coastal areas.

scholarly journals Distribution of soil salt ions aroundTamarix chinensisindividuals in the Yellow River Delta

2016 ◽  
Vol 36 (18) ◽  
Author(s):  
张立华 ZHANG Lihua ◽  
陈沛海 CHEN Peihai ◽  
李健 LI Jian ◽  
陈小兵 CHEN Xiaobing ◽  
冯亚 FENG Ya
Keyword(s):  
Yellow River ◽  
Yellow River Delta ◽  
River Delta ◽  
The Yellow River ◽  
The Yellow River Delta ◽  
Salt Ions ◽  
Soil Salt

scholarly journals Construction and Engineering Application of Salt-Discharging Model for Local Saline-Alkali Soil with Compact Structure in the Yellow River Delta

2020 ◽  
Vol 2020 ◽  
pp. 1-8 ◽  
Author(s):  
Chuanxiao Liu ◽  
Kesheng Li ◽  
Depeng Ma
Keyword(s):  
Yellow River ◽  
Structural Characteristics ◽  
Salt Content ◽  
Yellow River Delta ◽  
River Delta ◽  
The Yellow River ◽  
Compact Structure ◽  
The Yellow River Delta ◽  
Alkali Soil ◽  
Local Saline

Structural characteristics of local saline-alkali soil in the Yellow River Delta were studied by microscopic test methods of liquid nitrogen vacuum freeze-drying machine, fully automatic mercury intrusion porosimetry, X-ray diffractometer, and high- and low-vacuum scanning electron microscope. Permeability of the saline-alkali soil belongs to two grades of micropermeable water and extremely micropermeable water. Average volume ratio of pores with diameters no more than 2 μm is 86.25%; therefore, the saline-alkali soil may mainly consist of micropores and ultramicropores. Most void ratios of the soil are not beyond 0.5, and its dry densities are all greater than 1.6 g/cm3. Because average proportion of the clay minerals is only 12.24%, they are obviously not the main reason for poor permeability of the local saline-alkali soil. Based on the structural characteristics of compact structure and slightly developed fracture, mechanisms of surface runoff, and water-salt migration of the local saline-alkali soil, a salt-discharging engineering model mainly with surface runoff was established considering auxiliary infiltration and without interflow. Salt content distribution of the local saline-alkali soil is studied experimentally, by which relationship between salt content and conductivity has been fitted as y = 2.74x. The relationships between depth and salt content in the saline-alkali soil region present that the depth of salt-discharging engineering as open ditch should be beyond 60 cm. From the relationships between precipitation and salt content, the effectiveness of engineering measure shown in the salt-discharging model has been verified immediately or indirectly, and the engineering salt-discharging model may be suitable for managing saline-alkali soil in the Yellow River Delta.

Effects of reclamation on net ecosystem CO2 exchange in wetland in the Yellow River Delta, China

2013 ◽  
Vol 37 (6) ◽  
pp. 503-516 ◽  
Author(s):  
Li-Qiong YANG ◽  
Guang-Xuan HAN ◽  
Jun-Bao YU ◽  
Li-Xin WU ◽  
Min ZHU ◽  
...  
Keyword(s):  
Yellow River ◽  
Yellow River Delta ◽  
Co2 Exchange ◽  
River Delta ◽  
The Yellow River ◽  
Net Ecosystem Co2 Exchange ◽  
The Yellow River Delta

scholarly journals Impacts of Consolidation Time on the Critical Hydraulic Gradient of Newly Deposited Silty Seabed in the Yellow River Delta

2021 ◽  
Vol 9 (3) ◽  
pp. 270
Author(s):  
Meiyun Tang ◽  
Yonggang Jia ◽  
Shaotong Zhang ◽  
Chenxi Wang ◽  
Hanlu Liu
Keyword(s):  
Yellow River ◽  
Yellow River Delta ◽  
Hydraulic Gradient ◽  
River Delta ◽  
Theoretical Formula ◽  
The Yellow River ◽  
The Yellow River Delta ◽  
Critical Hydraulic Gradient ◽  
Seepage Flows ◽  
The Yrd

The silty seabed in the Yellow River Delta (YRD) is exposed to deposition, liquefaction, and reconsolidation repeatedly, during which seepage flows are crucial to the seabed strength. In extreme cases, seepage flows could cause seepage failure (SF) in the seabed, endangering the offshore structures. A critical condition exists for the occurrence of SF, i.e., the critical hydraulic gradient (icr). Compared with cohesionless sands, the icr of cohesive sediments is more complex, and no universal evaluation theory is available yet. The present work first improved a self-designed annular flume to avoid SF along the sidewall, then simulated the SF process of the seabed with different consolidation times in order to explore the icr of newly deposited silty seabed in the YRD. It is found that the theoretical formula for icr of cohesionless soil grossly underestimated the icr of cohesive soil. The icr range of silty seabed in the YRD was 8–16, which was significantly affected by the cohesion and was inversely proportional to the seabed fluidization degree. SF could “pump” the sediments vertically from the interior of the seabed with a contribution to sediment resuspension of up to 93.2–96.8%. The higher the consolidation degree, the smaller the contribution will be.

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