Respirasi Tanah sebagai Indikator Kepulihan Lahan Pascatambang Batubara di Sumatera Selatan

Abstract

Soil respiration has been widely studied in relation to soil health and carbon sequestration. Respiration measurements are better performed in the field, either with in-situ static or dynamic systems. This study evaluated the recovery of coal post-mining land in Tanjung Enim, South Sumatra, which is reflected from the ground surface indicators and soil respiration. Observations were carried out at PT Bukit Asam location represented by Muara Tiga Besar (MTB). Secondary forest was also used as a reference. The area had been revegetated generally with sengon, bamboo and acacia in 2000 (North MTB), while planting in 2005, 2006 and 2007 only with acacia interspersed with eucalyptus (South MTB). Soil samples were taken with a number of brass rings and then divided into 0-2, 2-5 and 5-10 cm depth. Respiration with inverted box technique used a solution of 0.5 M KOH. Revegetation increased significantly the organic carbon content from 0.96% to 1.96%, although still lower than organic carbon of the forest soil with the average of 2.81%. There was also a similar pattern found for total N and available P. It is evident that soil enrichment occurs in the 0-2 cm layer. In situ soil respiration showed no consistent increase with age of revegetation with values ranging from 670 to 767 mg CO2/m2 per hour, while the forest soil reaches 789 mg CO2/m2 per hour. Based on these facts we conclude that soil respiration can not be used as the sole indicator of recovery in coal post-mining land, thus needs to be combined with other variables.