Summary Soil respiration was measured using the alkali absorption method in a tropical Dalbergia sissoo forest at Kurukshetra. Soil respiration rates showed marked seasonal variations which were attributable to changes in temperature and moisture. The soil respiration rates varied from 90 to 1, 120 mg CO 2 m −2 h −1 , the rates being maximum in rainy season. Positive correlations were observed between CO 2 rates and various abiotic variables (temperature, litter moisture, soil water and rainfall; R 2 = 0.18 to 0.69, P −1 yr −1 ) and carbon output in soil respiration (6, 830 kg C ha −1 yr −1 ) revealed that annual CO 2 -C output was 3.47 times higher than the total input. Loss of carbon in litter decomposition accounted for 86 % of litter production reflecting a meaningful comparison of output and input parameters.