INTEGRATIVE EVALUATION OF REHABILITATIVE EFFECTS OF <em>ACACIA</em> <em>AURICULIFORMIS</em> ON DEGRADED SOIL

Abstract

DOI, R. & RANAMUKHAARACHCHI, S. L. 2007. Integrative evaluation of rehabilitative effects of Acacia
auriculiformis on degraded soil. Multivariate soil profiling was applied to determine the rehabilitative effects of 17- and 18-year-old Acacia auriculiformis plantation plots on a degraded land in Thailand. Soils were sampled from the A. auriculiformis plantation plots, a dry evergreen forest (the original vegetative type) and bare ground (the most degraded vegetation) in Sakaerat, Thailand. The soils were profiled by (1) physico-chemical measurements; (2) antibiotic disc diffusion method for soil bacterial community; and (3) long bean growth measurements. Soil dehydrogenase activity, as a soil microbial activity indicator, was also measured. No variables showed differences between soils of the dry evergreen forest and the plantation. Most of the physico-chemical and long bean variables showed clear differences between the bare ground soil and soils of the dry evergreen forest and the A. auriculiformis plantation. The bacterial variables showed less distinctive differences between the soils profiled. The land degradation was explained in terms of deteriorated soil physico-chemical conditions and crippled biotic functions. The principal components and discriminant analyses of the data sets for the methods and for all the variables indicated that the A. auriculiformis plantation soil had been restoring its original soil conditions, including abiotic properties and biotic functions. For rehabilitating degraded lands in the Thai savanna region, it would be practical and effective to plant A. auriculiformis.