Nucleic acids are rapidly degraded in soil releasing purine and pyrimidine bases and orthophosphate (Pi). This study was carried out to assess the effects of 14 trace elements, 12 herbicides, and two fungicides on dephosphorylation of yeast ribonucleic acid (RNA) and deoxyribonucleic acid (DNA) added to soils (Xerollic Calciorthids and Typic Haploxeralfs). The cumulative amount of Pi released from nucleic acids increased linearly with time of incubation (up to 72 h), decreased with profile depth, and was highly influenced by soil pH. When trace elements were applied and compared by using 2.5 mmol kg−1 of soil, the average inhibition in dephosphorylation of RNA and DNA in two soils ranged from 17% with Co(II) to 52% with Cu(II). The most effective inhibitors of nucleic acid dephosphorylation were Ag(I), Cu(I), Cd(II), Cu(II), Mn(II), Ni(II), and Pb(II) (avg inhibition ≥ 35%). Other elements that inhibited dephosphorylation of RNA and DNA added to soils included Ba(II), Co(II), Hg(II), Zn(II), Ti(IV), V(IV), and W(VI). When the pesticides were compared by using 5 mg of active ingredient kg−1 of soil, the average inhibition in nucleic acid dephosphorylation ranged from 14% with butylate to 39% with chloramben. The most effective inhibitors (> 25%) were atrazine, naptalam, chloramben, dicamba, trifluralin, and maneb. Other pesticides that inhibited RNA and DNA dephosphorylation in soils included cyanazine, 2,4-D, dinitroamine, EPTC plus R-25788, alachlor, paraquat, butylate, and captan.