EFFECT OF THE SYSTEM OF RICE INTENSIFICATION (SRI) ON ...

Rainfed rice in Cambodia is often grown with water levels ranging from 0 to 25 cm and in some
situations after e.g. floods even more (Javier, 1997). During some periods of the cropping season
for rainfed rice the soil might not be covered with water and aerobic conditions will be present due
to little or no rainfall (Javier, 1997).
Characteristic for rainfed lowland rice systems is typically that the possibility of drainage is often
non-existing or only present to a small extent (Greenland, 1997) and the dependence on
precipitation is enormous (Wade et al., 1999). Some of the main problems concerning rice yields
from lowland rainfed rice systems are the time of rainfall, the amount of rainwater and low soil
fertility (Pheav et al., 2005). As a consequence of the dependence on rainfall, water shortage is
common (Seng et al., 1999). If the rainfall during the growing season is less than needed, this can
lead to poor growth even if a given area receives enough precipitation throughout the year (Tsubo et
al., 2007). As it is impossible to control the water level in the field for lowland rainfed rice
systems, the rice crop will experience periods with total flooding and anaerobic conditions and
other periods with drought which will have major influences on the availability of nutrients (Wade
et al., 1998). Rice plants grown in this rice system are often tall (as submergence comes and goes
very unpredictable) and have limited root growth and might not be able to take up enough water
during drought periods (Wade et al., 1999). Due to the very changing water table weeds, insects
and diseases are as well a major problem (Wade et al., 1999).
5.3 SRI in Cambodia
SRI was introduced to Cambodia in 2000 through various NGO based projects (Anthofer, 2004)
and by 2003 approximately 10.000 farmers practised SRI and in 2004 50.000 farmers practised SRI
(Surridge, 2004). This number increased to 60.000 farmers in 2006 and in 2007 the number was
approximately 80.000 farmers out of approximately 1.8 million rice farmers in Cambodia (Koma,
2007). As a result of this development the Cambodian government has now adopted the SRI
methodology in their National Development Plan for 2006 to 2010 (Koma, 2007). CEDAC has
been one of the leading agencies spreading and providing extension for SRI throughout Cambodia.
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