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

9.5.1. Seeds and varieties
The amount of seeds used for SRI versus traditional growing was very significant: farmers only
used 0.02 kg seeds m -2 compared to their traditional fields where they used 0.63 kg seeds m -2
respectively. The seeds are not directly sown in the fields but in small nurseries where after the rice
seedlings are transplanted. These results are in accordance with SRI practices in other countries.
Menete et al. (2008) used 0.1 kg of seed per m 2 for trials in Mozambique and Satyanarayana et al.
(2007) report that SRI farmers in India are able to reduce the seeding rates (20% of conventional
use) with app. 0.0005 kg to 0.001 kg m -2 . Anthofer (2004) reports that Cambodian SRI farmers
were able to reduce seeding rates from 90 kg ha -1 30 kg ha -2 by converting to SRI corresponding to
0.009 kg ha -1 to 0.003 kg ha -1 respectively.
Most of the identified rice varieties used by farmers were traditional – 36 different (see Appendix
E) with only few being modern introduced varieties such as IR varieties. The farmers use in average
four different varieties, often mixed within the same field. Farmers use the same varieties for both
SRI and their traditional fields. Koma (2002) states that local varieties perform very well with SRI
practices and even though modern cultivars give higher yields, consumers still prefer local varieties
hence market prices are higher. Local varieties have probably adapted to the lowland rainfed
conditions which according to Wade et al. (1999) are very alike in all lowland rainfed rice systems
and often are tall as submergence comes and goes very unpredictable. Prasad (2006) evaluates that
SRI can be seen as a variety independent system which does not seek higher yields from growing
different varieties. Kabir & Uphoff (2007) did however find from SRI FFS in Myanmar that most
popular non SRI methods included selecting better genetic material and higher quality seeds which
resulted in 18% and 28% increase in yield respectively (performed with SRI).
The green revolution only introduced new varieties for dry season production in Cambodia and only
few varieties for the wet season (Koma, 2008) meaning few varieties for the rainfed systems. The
green revolution had a great impact on irrigated areas with good soil with fertilizer responsive
varieties but in indigenous systems trials have often tried to replace and not complement the
farming systems which were not successful (Greenland, 1997). However with future breeding on
rainfed rice the possibility of varieties performing well with rainfed conditions might prove very
efficient with SRI practice.
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