Effect of six triorganotin(IV) compounds on nitrification and ammonification in soil

Abstract

AbstractThe effects of six triorganotin(IV) compounds and of Thiram on nitrification and ammonification in soil were investigated. Low concentrations of up to 50 μg g−1 of the triorganotin(IV) compounds enhanced nitrate‐nitrogen (NO3−‐N) production in soil. Except for diphenylbutyltin bromide, which inhibited nitrification at 250 μg g−1, the other triorganotin(IV) compounds were inhibitory at concentrations of 100 μg g−1 to less than 250 μg g−1. At 10 μg g−1, only triphenyltin acetate was less inhibitory towards nitrification compared with Thiram. At 250 μg g−1, Thiram exerted a strongly persistent inhibitory effect towards nitrification. The NO3−‐N level recorded 28 days after application was only 0.10 μg g−1 soil. With the triorganotin compounds NO3−‐N levels of 7.05–12.06 μg g−1 soil were recorded 28 days following their application. The deleterious effects of the triorganotin(IV) compounds were less persistent and recovery of nitrification was evident seven days after application. Low concentrations of Thiram and triorganotin(IV) compounds inhibited ammonification, whereas higher concentrations enhanced ammonification. Complete inhibition of ammonification was attained 21–28 days after application of Thiram at 50 μg g−1. On the other hand, with the triorganotin(IV) compounds, except for diphenylbutyltin bromide at 10–50 μg g−1, ammonification persisted at all concentrations 28 days after application.