As this chapter shows, the rapid increase in agricultural pesticide use poses
particular challenges for mountainous areas, for two main reasons. First, the increase
in intensity of pesticide use has been particularly rapid in mountainous areas, where
until recently pesticides were not used at all. This fast rate of increase, combined with
limited knowledge among farmers about their correct use and health risks, has
created a particularly hazardous situation. Second, high levels of pesticide application on steep slopes, together with high and intense rainfall and the presence of welldeveloped preferential flow pathways, has resulted in a large share of pesticide
residues being transported from their site of application to adjacent environmental
compartments. Due to the hydrological connection between highland and lowland
areas, pesticide residues can spread to a larger area and affect many people.
This chapter addresses both the socio-economic and biophysical dimension of
pesticide use, particularly in terms of the impacts and environmental exposure of
using such pesticides in relation to upland agriculture. The objectives of this chapter
are to quantify the increasing intensity of pesticide use, to give explanations as to why
this is happening, to study the impact of pesticides on the environment and to discuss
possibilities for reducing exposure and increasing the efficiency of pesticide use.
The chapter is based on detailed information gained from studies carried out in
two case study areas in Thailand and Vietnam, those introduced in more detail in
Chap. 1 of this book. First, the Mae Sa area in the northern uplands of Thailand
represents a watershed with rapidly intensifying land use, as the area has an
intensive horticultural production system in which farmers grow high-value
vegetables, fruit and flowers. Farmers here have easy access to nearby urban
markets and use inputs intensively. Second, Chieng Khoi in the north-western
uplands of Vietnam represents an area with lower levels of market access, and
where farmers cultivate rice for subsistence in the valleys, while on hillsides they
mainly grow maize and cassava as cash crops. Traditionally farmers practiced
shifting cultivation in this area, but fallow periods have shortened and most sloping
fields are now cultivated year-on-year.
The chapter is organized as follows. Section 4.2 places the increased use of
pesticides in the mountainous areas of Thailand and Vietnam in the context of general
pesticide use trends in these countries. Section 4.3 summarizes the situation in terms
of pesticide use in the mountainous areas of Thailand and Vietnam, after which
Sect. 4.4 gives an account of the eco-toxicological risk and environmental exposure
created by such use. Section 4.5 discusses the policy options for rationalizing
pesticide use in mountainous areas, after which conclusions are offered in Sect. 4.6.
4.2 General Trends in Relation to Intensified Pesticide
Use in Thailand and Vietnam
The problems of pesticide use in the mountainous areas of Thailand and Vietnam
should be seen within the general context of rapidly intensifying levels of pesticide
use across the fast growing economies of Southeast Asia, including Indonesia,
4 Agricultural Pesticide Use in Mountainous Areas of Thailand and Vietnam. . .
151
particular challenges for mountainous areas, for two main reasons. First, the increase
in intensity of pesticide use has been particularly rapid in mountainous areas, where
until recently pesticides were not used at all. This fast rate of increase, combined with
limited knowledge among farmers about their correct use and health risks, has
created a particularly hazardous situation. Second, high levels of pesticide application on steep slopes, together with high and intense rainfall and the presence of welldeveloped preferential flow pathways, has resulted in a large share of pesticide
residues being transported from their site of application to adjacent environmental
compartments. Due to the hydrological connection between highland and lowland
areas, pesticide residues can spread to a larger area and affect many people.
This chapter addresses both the socio-economic and biophysical dimension of
pesticide use, particularly in terms of the impacts and environmental exposure of
using such pesticides in relation to upland agriculture. The objectives of this chapter
are to quantify the increasing intensity of pesticide use, to give explanations as to why
this is happening, to study the impact of pesticides on the environment and to discuss
possibilities for reducing exposure and increasing the efficiency of pesticide use.
The chapter is based on detailed information gained from studies carried out in
two case study areas in Thailand and Vietnam, those introduced in more detail in
Chap. 1 of this book. First, the Mae Sa area in the northern uplands of Thailand
represents a watershed with rapidly intensifying land use, as the area has an
intensive horticultural production system in which farmers grow high-value
vegetables, fruit and flowers. Farmers here have easy access to nearby urban
markets and use inputs intensively. Second, Chieng Khoi in the north-western
uplands of Vietnam represents an area with lower levels of market access, and
where farmers cultivate rice for subsistence in the valleys, while on hillsides they
mainly grow maize and cassava as cash crops. Traditionally farmers practiced
shifting cultivation in this area, but fallow periods have shortened and most sloping
fields are now cultivated year-on-year.
The chapter is organized as follows. Section 4.2 places the increased use of
pesticides in the mountainous areas of Thailand and Vietnam in the context of general
pesticide use trends in these countries. Section 4.3 summarizes the situation in terms
of pesticide use in the mountainous areas of Thailand and Vietnam, after which
Sect. 4.4 gives an account of the eco-toxicological risk and environmental exposure
created by such use. Section 4.5 discusses the policy options for rationalizing
pesticide use in mountainous areas, after which conclusions are offered in Sect. 4.6.
4.2 General Trends in Relation to Intensified Pesticide
Use in Thailand and Vietnam
The problems of pesticide use in the mountainous areas of Thailand and Vietnam
should be seen within the general context of rapidly intensifying levels of pesticide
use across the fast growing economies of Southeast Asia, including Indonesia,
4 Agricultural Pesticide Use in Mountainous Areas of Thailand and Vietnam. . .
151