Page 165 - Ilmu Tanah

152 The Chemistry and Fertility of Soils under Tropical Weeds

The change in the availability of Mn in Tri Mulya is similar to those of Cu, Zn,
and Fe; higher in the primary forest and the secondary forest than those in the
coffee plantation and cultivated land both in topsoil and subsoil (Fig. 8.11). The
change are also well-correlated with Organic C (r = 0.725), with Total N (r = 0.748),
and soil CEC (r = 0.627). In Bukit Ringgis and Tri Mulya, the availability of Mn was
higher in the coffee plantation and/or the cultivated land. It is probable that in
these locations the released Mn was immobilized stronger on the soil solids and
hence more difficult to leach.

300

250

Mn (mg kg -1 ) 200
150

100

50

0
Primary Secondary Coffee Cultivated
Forest Forest Plantation Land
Topsoil Subsoil

Fig. 8.11. The changes in soil available Mn in different land-use systems of
Tri Mulya, West Lampung, Indonesia (Redrawn from Salam, 1999).

In general, the effects of land-use conversion from forest to coffee plantation
and cultivated land shows similar pattern on the availability of heavy metal
micronutrient including Cu, Zn, Fe, and Mn. Their availabilities are higher in the
forests that those in the coffee plantation and the cultivated land. The availabilities
are well-correlated with the changes in several soil properties like organic C,

Abdul Kadir Salam and Nanik Sriyani – 2019