2.4 Soil organic carbon content and SOC stock
Soil organic carbon in the surface soil varied between 1.85 to 4.23 per cent (Table 4). The forest ecosystems recorded higher organic carbon content 4.23, 2.53 and 2.65 per cent at the surface soils of Chikmagalur, Wayanad and Idukki forests respectively. The reduction in the soil organic carbon content was prominent in the Wayanad coffee plantation in comparison with forest, the values varying from 2.53 to 1.85 per cent.
There was an increase in soil organic carbon stock on conversion from forest to coffee plantation in Wayanad and Idukki, whereas an observable reduction was recorded in Chikmagalur forest on conversion to coffee plantation where it reduced from 14.9 to 12.4 kg m-2(Table 4). Soil organic carbon stock in the surface also recorded a noticeable reduction from 9.1 kg m-2 in the forest ecosystem to 7.3 kg m-2 in the coffee plantation.