Page 48 - Ilmu Tanah
P. 48
The Chemistry and Fertility of Soils under Tropical Weeds 35
Chapter 3
The Important Facts about Tropical
Weeds
3.1 The Concept of Weeds
3.2 Weeds as Pioneer Vegetation
3.3 General Effects of Tropical Weeds on the Soil Environment
3.4 Methods of Weed Control
Key Questions
H
uman life has never been free from the presence of weeds that directly or
indirectly disturb the human activities. The most important direct negative
effects of weeds may include the decrease in the quantity and quality of
crop products that may cause direct negative effects on the farmer’s economy.
Some other negative effects are the presence of weed allelopathy that may poison
the main crops, the difficulties in manual and mechanical crop harvesting, the role
of weeds as hosts of plant pests and diseases, as well as the decrease in land values
due to weed infestation (Sembodo, 2010). Weeds may also disturb lands for
conservation and recreation, lower land esthetics, decrease the environmental
quality, and disturb the animal, human, and wildlife health and existence.
Abdul Kadir Salam and Nanik Sriyani – 2019