Abstract: Based on the GIS data, statistical yearbook data, and the idea of “classifying indices first and weighting each index then”, by adopting Kruskal-Wallis (χ²) test to confirm index weight, and in combining with RS/GIS software, this paper evaluated the ecoenvironmental quality of Huidong County, Guangdong Province of South China, aimed to approach the construction method of eco-environmental quality assessment index system and the method of confirming weight, and to establish an easily transplanted eco-environmental quality assessment model at county, town, and raster scales. The assessment at county scale showed that the overall eco-environmental quality of Huidong County was good, with the eco-environmental quality index (EQI) being 3.6. The assessment at town scale showed that Gaotan Town had the best eco-environmental quality (EQI=4.26), while Port Management Committee had the worst one (EQI=2.64). The assessment at raster scale showed that the eco-environmental quality of the economically developed region in southwest coast of Huidong County was fair or poor, with an area accounting for 21% or 23% of total area, respectively, while that of the economically undeveloped region in northeast mountains of Huidong County was good, with an area accounting for 56% of the total.

Key words: biochar, red soil, nitrate nitrogen, vertical transport, CXTFIT 2.0.