Distribution of Organic Matter and Alo+1/2Feo Contents in Soils Using Principal Component and Multiple Regression Analysis in Jeju Island

The contents of soil organic matter (SOM) and Alo+1/2Feo in soils are important criteria for the classification of new Andisols in Soil Taxonomy system. There are many soil types in Jeju Island with various soil forming environments. This paper was conducted to estimate the contents of soil organic matter and the content of ammonium oxalate extracted Al and Fe (Alo+1/2Feo) using various environmental variables and to make soil property maps using a statistical analyses. The soil samples were collected from 321 locations and analyzed to measure the contents of SOM and Alo+1/2Feo. It was analyzed the relationships among them and various environmental variables such as temperature, precipitation, net primary product, radiation, evapotranspiration, altitude, soil forming energy, topographic wetness index, elevation, difference surrounded area, and distances from the shore and the peak. We can exclude multi-collinearity among environmental variables with principal component analysis and reduce all the variables to 3 principal components. The contents of SOM and Alo+1/2Feo were estimated by multiple regression models and maps of them were made using the models.