Mapping the Soil Texture in the Heihe River Basin Based on Fuzzy Logic and Data Fusion

Abstract

Abstract:Mapping soil texture in a river basin is critically important for eco-hydrological studies and water resource management at the watershed scale. However, due to the scarcity of in situ observation of soil texture, it is very difficult to map the soil texture in high resolution using traditional methods. Here, we used an integrated method based on fuzzy logic theory and data fusion to map the soil texture in the Heihe River basin in an arid region of Northwest China, by combining in situ soil texture measurement data, environmental factors, a previous soil texture map, and other thematic maps. Considering the different landscape characteristics over the whole Heihe River basin, different mapping schemes have been used to extract the soil texture in the upstream, middle, and downstream areas of the Heihe River basin, respectively. The validation results indicate that the soil texture map achieved an accuracy of 69% for test data from the midstream area of the Heihe River basin, which represents a much higher accuracy than that of another existing soil map in the Heihe River basin. In addition, compared with the time-consuming and expensive traditional soil mapping method, this new method could ensure greater efficiency and a better representation of the explicitly spatial distribution of soil texture and can, therefore, satisfy the requirements of regional modeling.

A Comparison of Markov Chain Random Field and Ordinary Kriging Methods for Calculating Soil Texture in a Mountainous Watershed, Northwest China

“…These two coarse maps show seven soil texture types in the study area: loam, loamy sand, sandy clay loam, sandy loam, silt, silt loam, and silty clay loam [8,15]. Silt loam is the main soil texture type in the upstream area of the Heihe River Watershed.…”

“…Gao et al [15] developed a soil texture map for the watershed, which is based on the soil classification by the Chinese occurrence taxonomy or diagnosis taxonomy classification criteria with 53 sampling points for the entire Heihe River Watershed. Lu et al [8] used fuzzy logic and data fusion to generate a soil texture map from 220 samples, for the entire Heihe River watershed with most of the samples for the upstream region taken from the valley area. To date, no detailed digital soil texture mapping for the entire Heihe River Watershed has been conducted [8].…”

“…Lu et al [8] used fuzzy logic and data fusion to generate a soil texture map from 220 samples, for the entire Heihe River watershed with most of the samples for the upstream region taken from the valley area. To date, no detailed digital soil texture mapping for the entire Heihe River Watershed has been conducted [8].…”

“…Soil maps available for this watershed include the global soil texture map (1:1,000,000 scale) [46] and the 1:1,000,000 soil map of China [47,48]. Recently, two more soil texture maps have become available, for the study area [8,15]. Gao et al [15] developed a soil texture map for the watershed, which is based on the soil classification by the Chinese occurrence taxonomy or diagnosis taxonomy classification criteria with 53 sampling points for the entire Heihe River Watershed.…”

“…It also influences the physical, chemical, biological, and hydrological processes of watersheds [3][4][5]. Therefore, it is essential to accurately map the spatial distribution of different soil texture types at the watershed scale for eco-hydrological studies and water resource management [1,[6][7][8][9][10].…”