2.2 Soil reaction, exchangeable bases, extractable acidity, CEC and base saturation
Surface soils of coffee plantation ecosystem recorded a pH of 6.10, 6.20 and 5.01 at Chikmagalur, Wayanad and Idukki respectively (Table 2). Coffee soils recorded relatively higher pH and exchangeable Ca and Mg than forest soils in all the profiles. Whereas, in Idukki, the soil reaction at the surface is not varying significantly between both systems (4.94 and 5.01) and only a slight decline in acidity in the coffee plantation ecosystem is observed. Total exchangeable bases of 3.42, 2.86 and 1.45 cmol (+) kg-1 of soil were recorded in coffee plantations and 2.41, 2.19 and 0.70 cmol (+) kg-1 of soil in forests of Chikmagalur, Wayanad and Idukki respectively. The coffee soils in its deeper layers recorded higher exchangeable Ca of 2.31, 1.70 and 1.08 cmol (+) kg-1 of soil in Chikmagalur, Wayanad and Idukki respectively (Table 2). BaCl2-TEA extractable acidity was higher in the forest soils and it was evident in the surface soils of Chikmagalur and Wayanad forest (20.20 and 12.20 respectively). Cation Exchange capacity (CEC) was noticeably higher in Chikmagalur and Idukki coffee plantations (98.06 and 30.12 cmol (+) kg-1respectively) than forest soils.