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Comparison of urease inhibitor N‐(n‐butyl) thiophosphoric triamide and oxidized charcoal for conserving urea‐N in soil
Author(s) -
Guimarães Gelton G. F.,
Mulvaney Richard L.,
Khan Saeed A.,
Cantarutti Reinaldo B.,
Silva Antônio M.
Publication year - 2016
Publication title -
journal of plant nutrition and soil science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.644
H-Index - 87
eISSN - 1522-2624
pISSN - 1436-8730
DOI - 10.1002/jpln.201500622
Subject(s) - chemistry , urea , ammonia volatilization from urea , urease , volatilisation , fertilizer , incubation , hydrolysis , nuclear chemistry , environmental chemistry , charcoal , nitrogen , cation exchange capacity , inorganic chemistry , soil water , organic chemistry , biochemistry , ecology , biology
Charcoal‐based amendments have a potential use in controlling NH 3 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 15 N‐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 15 N recovery as volatilized NH 3 , mineral N (as exchangeable NH $ _4^+ $ , NO $ _3^ - $ , and NO $ _2^ - $ ), and immobilized organic N. The OCh amendment reduced NH 3 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 NH 3 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.