부산대학교 도서관

Charcoal-based amendments have a potential use in controlling NH3 volatilization from urea fertilization, owing to a high cation-exchange capacity (CEC) that enhances the retention of NH $ _4^+ $. An incubation study was conducted to evaluate the potential of oxidized charcoal (OCh) for controlling soil transformations of urea-N, in comparison to urease inhibition by N-(n-butyl) thiophosphoric triamide (NBPT). Four soils, ranging widely in texture and CEC, were incubated aerobically for 0, 1, 3, 7, and 14 d after application of 15N-labeled urea with or without OCh (150 g kg−1 fertilizer) or NBPT (0.5 g kg−1 fertilizer), and analyses were performed to determine residual urea and 15N recovery as volatilized NH3, mineral N (as exchangeable NH $ _4^+ $, NO $ _3^ - $, and NO $ _2^ - $), and immobilized organic N. The OCh amendment reduced NH3 volatilization by up to 12% but had no effect on urea hydrolysis, NH $ _4^+ $ and NO $ _3^ - $ concentrations, NO $ _2^ - $ accumulation, or immobilization. In contrast, the use of NBPT to inhibit urea hydrolysis was markedly effective for moderating the accumulation of NH $ _4^+ $, which reduced immobilization and also controlled NH3 toxicity to nitrifying microorganisms that otherwise caused the accumulation of NO $ _2^ - $ instead of NO $ _3^ - $. Oxidized charcoal is not a viable alternative to NBPT for increasing the efficiency of urea fertilization. [ABSTRACT FROM AUTHOR]