Monitoring soil salt content using HJ-1A hyperspectral data: A case study of coastal areas in Rudong County, Eastern China

Abstract

Hyperspectral data are an important source for monitoring soil salt content on a large scale. However, in previous studies, barriers such as interference due to the presence of vegetation restricted the precision of mapping soil salt content. This study tested a new method for predicting soil salt content with improved precision by using Chinese hyperspectral data, HuanJing-Hyper Spectral Imager (HJ-HSI), in the coastal area of Rudong County, Eastern China. The vegetation-covered area and coastal bare flat area were distinguished by using the normalized differential vegetation index at the band length of 705 nm (NDVI 705). The soil salt content of each area was predicted by various algorithms. A Normal Soil Salt Content Response Index (NSSRI) was constructed from continuum-removed reflectance (CR-reflectance) at wavelengths of 908.95 nm and 687.41 nm to predict the soil salt content in the coastal bare flat area (NDVI 705 < 0.2). The soil adjusted salinity index (SAVI) was applied to predict the soil salt content in the vegetation-covered area (NDVI 705 ≥ 0.2). The results demonstrate that 1) the new method significantly improves the accuracy of soil salt content mapping (R 2 = 0.6396, RMSE = 0.3591), and 2) HJ-HSI data can be used to map soil salt content precisely and are suitable for monitoring soil salt content on a large scale.

Carbon Footprint and Driving Forces of Saline Agriculture in Coastally Reclaimed Areas of Eastern China: A Survey of Four Staple Crops

“…The study area has a subtropical monsoon climate with an annual total rainfall of around 1250 mm. The annual mean temperature is about 14 • C. Saline and alluvial soils are the main soil types [27]. The study area is a coastally reclaimed zone with a 45-year history ( Figure 1).…”

Ecological Security and Ecosystem Services in Response to Land Use Change in the Coastal Area of Jiangsu, China

“…Ninety percent of the entire coastline along the Jiangsu coast is tidal flat [54]. Research shows that the coastal tidal flat is currently expanding seaward at a rate of ±20 cm per year [55][56][57]. The study area, which is about 0.38 million ha, including part of the Yellow Sea and South Yellow Sea Radial Sand Ridges, is located in the central part of the coastal zone of Jiangsu Province (Figure 2).…”

“…The study area contains four administrative units: Sheyang, Dafeng, Dongtai and Rudong. The climate is classified as subtropical monsoon with an average annual temperatures of 14 • C, annual precipitation of 1000 mm and annual sunshine of 2238.9 h [55].…”

Influence of Fractional Differential on Correlation Coefficient between EC1:5 and Reflectance Spectra of Saline Soil

“…Hyperspectral Data for Estimation of Soil Salinity. Soil salinization is occurring at a progressively rapid rate in the world [1], which brings severe social, economic, and ecological consequences in fragile arid and semiarid area. Thus, identifying, monitoring, and mapping soil salinity are badly needed for sustainable agricultural management in the areas which are facing the salinization problem [2].…”