USING THE GEOINFORMATICS TECHNOLOGY FOR SOIL DEGRADATION ASSESSMENT IN UPPER LAMCHIENGKRAI WATERSHED, NAKHON RATCHASIMA, THAILAND

摘要

Soil erosion and soil salinity are major environmental problems in Thailand that cause extreme damage to cultivation and environmental sustainability. In addition, soil erosion leads to depletion of organic matter (OM) in soil. Soil erosion, salinity and OM depletion are significant indicators for soil degradation assessment. The aims of this study were (1) to classify LULC, (2) to assess soil loss and its severity, (3) to assess soil salinity and its severity, (4) to assess soil OM and its depletion, and (5) to assess soil degradation and its severity. In this study, LULC classification using CART classifier, soil erosion with RMMF model, soil salinity and depletion of OM with linear and non-linear regression analysis were first separately analyzed and their results then were combined to evaluate soil degradation using multiplication method. As results, an optimum CART model provided an overall accuracy of 87.50 and Kappa hat coefficient of 80.10%. In the experiment, an average erosion rate was 3.37 ton/ha/year. The most dominant soil erosion severity class was very slightly eroded, and it covered area of 437.70 km2. In addition, soil salinity severity class was very low and it covered area of 415.55 km~2. Soil biological degradation class was moderate and it covered area of 296.05 km2. According to soil degradation assessment using multiplicative method without and with severity classification, the most dominant soil degradation class was very low and they covered area of 443.00 sq. km and 462.53 sq. km of the total study area, respectively. Both soil degradation severity classification provided similar result with common severities classes about 442.82 sq. km of the total study area. In conclusion, it appears that geoinformatics technology can be efficiently used as tools for assessing soil loss, soil salinity, and soil organic matter depletion and their severities for soil degradation evaluation.