Influence of nitrogen and phosphorus fertilizers on 2,4-d degradation in soil

Mineralization of C-14-2,4-D in soil amended with a nitrogen fertilizer (NH4NO3) was markedly reduced and progressively decreased with N application rate. On the other hand, 2,4-D mineralization in soil was generally 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 mineralization either further reduced or was not affected. Even though NH4NO3 may increase overall soil microbial activity, especially nitrification activity, as a result of catabolite repression, it may inhibit 2,4-D degradation.