IMPACTS OF TIN MINING ON SOIL PROPERTIES

Abstract

The study funded by Kasetsart University Research and Development Institute (KURDI) and International Foundation for Sciences (IFS) was aimed to determine soil dynamics as the results of tin mining. The study site was in Phangnga province, about 900 km South of Bangkok. Sixty-three soil samples were collected from the top 20 cm of 7 age classes after mining (1, 3, 5, 7, 10, 15, and 20 years), 3 zones (gravel, sand, and massive) in each age class. The results showed that tin mining affected both physical and chemical characteristics of soil. Soil texture in general was considered as sandy loam having sand particle more than 60%, especially during the first 10 years after mining. Soil pH was as low as 4.3 which could be ranked into extreme acidity and very strong acidity levels leading to very low and low availability of all macronutrients concerned including CEC. However, clay particles and nutrient contents tended to increase with increasing ages after mining. Based on topographic feature, the land left over after tin mining in southern Thailand could be divided to 3 zones. It was found that there were between-zone significant differences in most soil properties involved in all ape classes, Strictly speaking, area occupied by sand was found to be the poorest zone from chemical standpoints of view. Gravel and massive zones could provide higher amounts of plant nutrients resulting to greater productivity of aboveground biomass. These findings suggested that amelioration of tin-mined lands was strongly required, since natural development was a time consumption.