Influence of phosphorus application on methane emission and production in flooded paddy soils

Abstract

In a field study, phosphorus applied as single superphosphate (SSP) distinctly inhibited CH₄ emission from a flooded field plot planted to rice. In subsequent laboratory studies, application of P at 50 and 100 μg g^-1 dry soil as K₂HPO₄ stimulated CH₄ production in a P-deficient soil, while there was no such stimulation in P-normal alluvial soil. CH₄ production in soils depended on the source of P applied as evidenced by stimulation with K₂HPO₄ or Jordan rock phosphate, while Mussorie rock phosphate and SSP were inhibitory. The results indicate that the S content of the P sources determines the extent of stimulation or inhibition of CH₄ production. Moreover, supplementary addition of K₂SO₄, even with K₂HPO₄, mimicked the inhibitory effect of SSP on CH₄ production. In practice, use of SSP in rice cultivation, in addition to supplying P to the growing crop, could mitigate CH₄ production and emission through its S content.