HERBICIDES in Asian rice - IRRI books - International Rice ...

Social price assumptions of 25-50% of the market wage are unreasonable for the
Asian rice economy as a whole, but they may be quite reasonable for regions where
employment opportunities for rural unskilled labor are limited. In the Philippines, the
social price of labor is probably greater than 25% of the market wage, although the
economy has been growing slowly and real wages have remained stagnant for several
decades (Table 2). Field surveys of employment opportunities for unskilled workers
on Java suggest that the opportunity cost of labor is close to the market wage (Naylor
1991). However, the older women who do much of the weeding in the Java rice
economy may have a lower opportunity cost, and the social value of their labor could
fall significantly if the economy turns down (Naylor 1994b). For Asia as a whole, this
means the assumption that herbicide use will be profitable to farmers both privately
and socially (in terms of reduced drudgery) rests heavily on the continuation of strong
economic growth and structural transformation throughout the region.
In reviewing the equity implications of herbicide use, it is important to balance
the potential negative impact of labor displacement against the positive effects of
lower rice prices in the market which could result from reduced input costs. Sixty
percent of Asia’s labor force is still employed in agriculture (IRRI 1995), and the
proportion of poor households employed primarily in agriculture is even higher. Agricultural
production in general, and rice production in particular, thus plays a large
role in the level and distribution of rural income in Asia. Many of the households that
are employed in the rice sector, however, are actually net consumers of rice. In very
poor regions, households spend 80% or more of their total budgets on food, and up to
35% of their budgets directly on rice and other cereals. This means that production
technologies that lower the price of rice can have a positive impact on the real income
of poor households.
An empirical analysis of the effects of herbicide use on rice prices and income
distribution has yet to be done for the less developed countries of Asia. Japan, where
rice herbicides have been used for decades, in principle could serve as a model for
such a study. In practice, however, production subsidies and price supports would
distort the results (due to national price and trade policies, market prices of rice in
Japan have been up to ten times the world price). Given the relative newness of herbicide
use in many other rice-producing regions of Asia, the verdict on herbicide-rice
price interactions and their effects on income distribution is not yet in.
Ecological and health risks
In addition to the potential displacement of unskilled workers, the costs of herbicide
use include potential ecological and health damage that is not valued in the market.
Current research indicates that most herbicides are less toxic and persistent than the
majority of insecticides used in Asian rice production (Pingali 1992, Antle and Pingali
1994). But all pesticides are toxic to some degree, and it is often their misuse, particularly
in the handling of the chemicals, that is the main source of problems. In addition,
with widespread herbicide use, large concentrations of herbicides could accu-
Herbicide use in Asian rice production 11