Respirasi tanah pada lantai hutan mangium

Emission of CO2 from forest floor can be studied as an indicator of soil microorganism activity, root activity and supply of CO2 to atmosphere. Soil respiration on mangium (A ca c ia mangium) plantation was very important to be studied, because litterfall decomposition rate was low: The study of soil respiration on mangium forest floor was carried out from August 1995 to January 1996 in Gadjah Mada University Education Forest, Wanagama I Yogyakarta. Soil respiration was calculated monthly by alkali absorption method at three location namely denuded area, 5 yr-old and 10 yr-old mangium plantation. Emission of CO2 from soil horizon decreased with increasing plantation age. Soil respiration and soil microorganism activity from organic horizon were relatively lower than from mineral horizon. Carbon dioxide emission from soil horizon at denuded area were 43.6 t/ha/yr, at 5 yr-old mangium plantation were 36.2 t/ha/yr and at 10 yr-old mangium plantation were 24.4 t/ha/yr. Emission of CO2 from organic horizon at 5 and 10 year-old mangium plantation were 9.6 and 13.8 t/ha/yr. respectively. Total CO2 emission from forest floor at denuded area were 43.6 t/ha/ yr, at 5 yr-old mangium plantation were 45.8 t/ha/yr and at 10 yr-old mangium plantation were 38.2 t/ha/yr. The CO2 emission from mangium forest floor was lower compared to emission from other vegetation cover in tropical area, but twice compared to emission from temperate forest. Keywords: respiration, mangiu