PRODUCTIVITY OF PLANTS AND SOIL CHANGES IN AGROFORESTRY SYSTEM: A CASE STUDY ON LAND AFTER TIN MINING

Abstract

The reforestation experiment was conducted on tin mine tailings at Takua Pa district, Phangnga province. Eucaluptus camaldulensis was used for silvicultural plots, while pineapple and cassava were for agronomic plots. The mean annual stem biomass increment (MABT) of E. camaldulensis was only 0.13 ton ha yr without treatment. The biomass production rate of E. camaldulensis was improved by mulching treatment (MABT = 0.9 ton ha yr ") and clayey soil dressing with fertilization (MABT = 3.7 ton ha yr). Organic matter application like compost and mulching seemed to be the most promising method to improved the deteriorated soil in the study site. Increase in pHw, OM, T-N, Av.N, Av.P, Ex.K and Ex.B were observed, while no remarkable change was observed in the others (EC, Ex. Ca, Ex. Mg, Ex. Na) during the five years of study. The crop cultivation trails revealed that the intensive care, including mulching treatment, could increase the yield of cassava and pineapple to the commercial level both in traditional system and in agroforestry system.