Effect of soil bulk density on inhibition of hydrolysis of surface‐applied granular urea containing phenyl phosphorodiamidate in unsaturated soil
作者:
N. K. Savant,
A. F. James,
G. H. McClellan,
期刊:
Communications in Soil Science and Plant Analysis
(Taylor Available online 1988)
卷期:
Volume 19,
issue 2
页码: 193-204
ISSN:0010-3624
年代: 1988
DOI:10.1080/00103628809367931
出版商: Taylor & Francis Group
关键词: Phenyl phosphorodiamidate;soil bulk density;urea hydrolysis;urease inhibitor
数据来源: Taylor
摘要:
Soil bulk density markedly influences hydrolysis of surface‐applied granular urea that is vulnerable to serious ammonia volatilization losses. In order to decrease the ammonia losses by retarding urea hydrolysis, several chemicals have been tested for their soil urease inhibition properties. Phenyl phosphorodiamidate (PPDA) is a potent soil urease inhibitor. Laboratory studies using soil column incubations were conducted to investigate the effect of soil bulk density on inhibition of hydrolysis of surface‐applied urea granules (=20 mg of urea/granule) containing 1% PPDA in unsaturated soils. The increase in soil bulk density (from 0.69 to 1.50 Mg/m3) markedly increased the rate of hydrolysis of surface‐applied urea granules and significantly decreased the apparent urease inhibition by PPDA present in the granules. These results are attributed to the probable spatial separation of urea and PPDA because of the differences in diffusive transports in unsaturated soils caused in part by differences in their solubilities in water.
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