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.