There are few studies to verify the benefits of VRF management
based on soil testing and rice growth diagnosis to produce
uniform
high quality rice at the farm scale. Recent research conducted
in other countries (Angus et al. 1990; Dobermann et al.
2002;
Wang et al. 2001; Wopereis et al. 1999) has demonstrated
limitations
of the current approach of fixed-rate, fixed-time fertilizer
recommendations for large areas. This approach does not
take
into account the existence of large variability in soil nutrient
supply and crop response to nutrients among, or even within,
farms.
The specific objectives of this research were to quantify
the
reduction in the variability of rice yield and yield components,
and improvements in rice quality in experiments conducted
on 60 individual (45 VRF and 15 FPM) fields.