There is significant evidence that (1) SRI increases rice
yields in regions other than Madagascar; and (2) SRI
increases rice yields on low-fertility soils and has no effect
on yields in moderate- to high-fertility soils. The results of
this meta-data analysis should be considered as preliminary
and replicated field trials with detailed soil fertility data are
needed to improve our confidence in the yield differences
between SRI and conventional rice production systems. The
biological and chemical mechanisms that lead to increased
rice yields on these low-fertility soils remain to be
elucidated. Although the scientific debate over SRI
continues, more than a million farmers around the world
have now adopted the system35. We suggest that the
minimum data set to be provided by future field studies
comparing the SRI versus conventional system should
include data on soil fertility class, texture, pH, macronutrient
availability, fertilizer use and standard deviation of
the mean yield value