The results of the analysis of 50 soil
samples from rubber plantation in South of
Thailand showes that most of soil samples
contained organic matter, total nitrogen and
exchangeable Ca higher than critical value'
On the other hand, exchangeable K and
exchangeable Mg were lower than critical
Table 2. Criteria for soil data interpretation (8)
value (12). However, the criteria of chemical
properties of soil for growing rubber tree is
quite different, depending on the source.
Another
criteria of rubber growing soil other
than Rubber Research lnstitute was summarized
in Table