Page 53 - Ilmu Tanah Book

40 The Chemistry and Fertility of Soils under Tropical Weeds

A B

C D

Fig. 3.2 Selected tropical broad-leaf weeds of Indonesia
(A - Mimosa invisa Mart. Ex Colla, B - Mikania micrantha Kunth., C - Chromolaena odorata
(L.) King & Robins, and D - Centella asiatica (L.) Urb.).

Ecologically, weeds are considered important component of an ecosystem.
Their existence is a part of plant community succession. Upon disturbance on an
ecosystem caused by a particular anthropogenic or natural phenomenon like
agriculture, forest clearing, forest fires, or drought, plant community may
encounter succession, called as secondary succession, controlled by climate and
soil fertility (Radosevich et al., 1997). Similar composition of forest vegetation may
arise after a series of vegetation changes through the processes of forest recovery.
However, a radical changes caused by natural disasters may emerge a physical
spaces in the new ecosystem for plant colonization. This space is usually fastly
occupied by pioneer plants like weeds. Weeds may dominate the spaces for years
or hundreds of years. This normal process of colonization may seriously affect the
existence of more economical plants.

Abdul Kadir Salam and Nanik Sriyani – 2019