SOIL PHYSICOCHEMICAL PROPERTIES IN DIFFERENT STAND AGES AND SOIL DEPTHS OF Acacia Mangium PLANTATION

Abstract

Soil physicochemical properties are essential to support tree stand growth and vital for the optimum wood biomass production in forest plantation management. This study aims to determine the soil physical and chemical properties in different stand ages and soil depths of an A. mangium plantation. Data were collected from the Daiken Sarawak Sdn Bhd forest plantation area. Soil profiles were established in five stand ages of 3.7, 5.8, 8.5, 10.8 and 12.7 years old, and an unplanted area is used as a reference. Soil samples were collected from depths of 0–20, 20–40, 40–60, 60–100 cm from each of the stand ages and the reference site. The soil organic matter (SOM) and total carbon increased with the increase in stand ages. The soil texture was sandy clay loam soil. The soil is extremely acidic. The SOM, total carbon, pH and total nitrogen decreased with soil depths. Soil in the reference site had the highest pH, SOM percentage, total carbon and total nitrogen. Among the stand ages, the oldest stand age had the highest amount of total soil nitrogen. The cation exchange capacity was the highest in the intermediate stand ages. The soil properties in 10.8- and 12.7-year-old stand were closely comparable to that of the reference site.