Characteristics of Ultisols differing in wildfire history in South Sumatra, Indonesia

Abstract

In spite of the significant increase in the frequency and extent of fire occurrence in Indonesia recently, little information is available about the immediate, short-term, and long-term effects of fire on soils. To investigate the effects of wildfires on the dynamics of T-C, T-N, available P, pH, exchangeable bases, and cation exchange capacity (CEC) of Ultisols from South Sumatra Indonesia, surface soils of an unburnt 9-year old Acacia mangium plantation and of A. mangium plantations burnt in 1995, 1997, 1998, and 2000 were sampled in triplicate consecutively from December 1998 until December 2000. The values of T-C, T-N, available P, pH, and exchangeable bases significantly increased immediately after the fire while the levels of Al saturation and CEC significantly decreased. Soil nutrients were still accumulated 1 year after the fire but by the end of the second year, they were depleted and returned to the pre-fire levels. Although fallowing aggraded the burnt sites, the nutrient levels in the burnt sites were still lower than those in the unburnt sites. In addition, the residual effects of fire on the soil nutrient levels were still evident 5 years after the fire.