INFLUENCE OF NITROGEN AND PHOSPHORUS FERTILIZERS ON 2,4-D DEGRADATIONIN SOIL

Mineralization of C-14-2,4-D in soil amended with a nitrogen fertilize r (NH4NO3) was markedly reduced and progressively decreased with N app lication rate. On the other hand, 2,4-D mineralization in soil was gen erally not affected by the addition of a phosphorus (P) fertilizer [Ca (H2PO4)(2)]. Addition of both N and P fertilizers to soil, 2,4-D miner alization either further reduced or was not affected. Even though NH4N O3 may increase overall soil microbial activity, especially nitrificat ion activity, as a result of catabolite repression, it may inhibit 2,4 -D degradation.