Page 71 - Ilmu Tanah

58 The Chemistry and Fertility of Soils under Tropical Weeds

Martin, 1984; Nasution, 1986; Tate III, 1987; Park et al., 1992; Sakai and Tadano,
1993; Joner et al., 1995; Joner and Jakobsen, 1995; Dharmakeerti and Thenabadu,
1996; Vinotha et al., 2000; Supriatin et al., 2007). Some of these enzymes live in
soils for several days, and some may live for several weeks or months, depending
on their forms and susceptibility to decomposition by protease – enzymes that
accelerate the decomposition of enzyme proteins.

Table 4.3. The effects of vegetation on some soil chemical properties of
coffee plantations in West Lampung Indonesia* (after Salam, 2014).

Available P
Organic C Total N
-1
pH -1 -1 (mg kg )
(g kg ) (g kg )
1997 1999 1997 1999 1997 1999 1997 1999

A. No Vegetation (Control)
Topsoil 4.00 3.49 23.1 21.1 1.80 1.50 6.05 2.78

Subsoil 3.87 4.27 11.7 7.8 0.90 1.10 4.67 3.48

B. Grass (Paspalum conjugatum)
Topsoil 4.94 3.87 30.5 29.2 1.30 2.70 4.67 3.52

Subsoil 4.66 4.89 26.1 26.9 2.00 1.90 4.67 3.11

C. Natural Vegetation
Topsoil 4.58 3.97 12.4 26.7 1.30 2.40 5.36 3.52
Subsoil 4.47 4.56 11.4 20.6 1.10 1,40 4.67 2.81

*Adapted from Salam et al. (2001)

Deforestation may greatly affect the soil enzymatic activities. In general the
activities of soil enzymes were reported to be lower in the degraded land-uses like
cultivated lands and higher in coffee plantation and the highest were in secondary

Abdul Kadir Salam and Nanik Sriyani – 2019