Overview to Four Volumes: Sustainable Agriculture and Food xxxixtotal pesticide use has indeed increased in the course of IPM introduction. These
are mainly in zero-tillage and conservation agriculture systems, where reduced till-
age creates substantial benefits for soil health and reduces off-site pollution and
flooding costs. These systems usually require an increased use of herbicides for
weed control (de Freitas, 1999), although there are some examples of organic
zero-tillage systems (Petersen et al, 2000). Over 60 per cent of the projects are in
category D where pesticide use declines and yields increase. While pesticide reduc-
tion is to be expected, as farmers substitute pesticides by information, yield
increases induced by IPM are a more complex issue. It is likely, for example, that
farmers who receive good quality field training will not only improve their pest
management skills but also become more efficient in other agronomic practices
such as water, soil and nutrient management. They can also invest some of the cash
saved from pesticides in other inputs such as higher quality seeds and inorganic
fertilizers.
Effects on Carbon Balances
The 1997 Kyoto Protocol to the UN Framework Convention on Climate Change
established an international policy context for the reduction of carbon emissions
Note: Data from 80 crop combinations, 62 projects, 26 countries.
Figure 4 Association between pesticide use and crop yields