A pot experiment was conducted to evaluate the relative agronomic
effectiveness (RAE%) of a Syrian phosphate rock when it is added alone and as
mixture with elemental sulfur with three different ratios (PR:S) (2:1) (5:1) (8:1)
and compared with tr
iple superphosphate. The main results of this study
showed that Ain Layloun phosphate rock was not effective for direct use by
Rye grass when used alone, but it became effective when mixed with elemental
sulfur. The relative agronomic effectiveness was varied following mixing ratios,
it was 50%, 76% and 87% in (8:1), (5:1) and (2:1) (PR:S) mixing ratios
respectively. This is due to the increase of available soil phosphorus content
which is related to the increase of phosphate rock solubility due to decrease of
pH derived from oxidation of sulfur by Thiobacillus spp.
