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

In a field study, phosphorus applied as single superphosphate (SSP) distinctly inhibited CH(4) emission from a flooded field plot planted to rice. In subsequent laboratory studies, application of P at 50 and 100 mu g g(-1) dry soil as K(2)HPO(4) stimulated CH(4) production in a P-deficient soil, while there was no such stimulation in P-normal alluvial soil. CH(4) production in soils depended on the source of P applied as evidenced by stimulation with K(2)HPO(4) 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 CH(4) production. Moreover, supplementary addition of K(2)SO(4), even with K(2)HPO(4), mimicked the inhibitory effect of SSP on CH(4) production. In practice, use of SSP in rice cultivation, in addition to supplying P to the growing crop, could mitigate CH(4) production and emission through its S content. (C) 1997 Published by Elsevier Science Ltd. All rights reserved.