Nitrogen Efficiency of Urea Amended With Inhibitors and Cations Applied to Rice

Urea, the major source of nitrogen (N), is subjected to extensive gaseous N losses to the atmosphere. Ammonia (NH3)volatilisation and denitrification losses are important mechanisms for N losses from urea and are causes of poor fertilizer use efficiency by lowland rice. The study was undertaken...

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Main Author:	Shah, Shree Chandra
Format:	Thesis
Language:	English English
Published:	1994
Subjects:	Rice - Fertilizers Urea as fertilizers Nitrogen excretion
Online Access:	http://psasir.upm.edu.my/id/eprint/10339/1/FP_1994_1_A.pdf
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id	my-upm-ir.10339
record_format	uketd_dc
spelling	my-upm-ir.103392011-09-07T01:42:20Z Nitrogen Efficiency of Urea Amended With Inhibitors and Cations Applied to Rice 1994 Shah, Shree Chandra Urea, the major source of nitrogen (N), is subjected to extensive gaseous N losses to the atmosphere. Ammonia (NH3)volatilisation and denitrification losses are important mechanisms for N losses from urea and are causes of poor fertilizer use efficiency by lowland rice. The study was undertaken in a series of five experiments to evaluate means of increasing the efficiency of urea-N under flooded rice soil conditions. A laboratory incubation experiment of different rice soils was conducted to study the kinetics and transformations of urea in flooded soils. A greenhouse experiment was carried out on marine and riverine alluvial soils to evaluate urea-N efficiency in direct-seeded (DS) rice and transplanted (TP) rice under similar N management practices using lSN-Iabelled urea. Two greenhouse and one field studies were conducted to evaluate the effectiveness of inhibitors and cations on marine and riverine alluvial rice soils on the efficiency of urea-N using 15N recovery techniques. Urea hydrolysis followed the first-order kinetics and rate constants ranged from -0.032 to -0.076 ha-1 A lag phase existed in flooded soil conditions and it varied from 6 to 15 hours. The half-life of urea ranged from 12 to 26 hours. Urea conversion to NH4 -tN was initially rapid with about three-fourths being converted within 48 hours of incubation and total conversion completed within 108 hours. Rice - Fertilizers Urea as fertilizers Nitrogen excretion 1994 Thesis http://psasir.upm.edu.my/id/eprint/10339/ http://psasir.upm.edu.my/id/eprint/10339/1/FP_1994_1_A.pdf application/pdf en public phd doctoral Universiti Pertanian Malaysia Rice - Fertilizers Urea as fertilizers Nitrogen excretion Faculty of Agriculture English
institution	Universiti Putra Malaysia
collection	PSAS Institutional Repository
language	English English
topic	Rice - Fertilizers Urea as fertilizers Nitrogen excretion
spellingShingle	Rice - Fertilizers Urea as fertilizers Nitrogen excretion Shah, Shree Chandra Nitrogen Efficiency of Urea Amended With Inhibitors and Cations Applied to Rice
description	Urea, the major source of nitrogen (N), is subjected to extensive gaseous N losses to the atmosphere. Ammonia (NH3)volatilisation and denitrification losses are important mechanisms for N losses from urea and are causes of poor fertilizer use efficiency by lowland rice. The study was undertaken in a series of five experiments to evaluate means of increasing the efficiency of urea-N under flooded rice soil conditions. A laboratory incubation experiment of different rice soils was conducted to study the kinetics and transformations of urea in flooded soils. A greenhouse experiment was carried out on marine and riverine alluvial soils to evaluate urea-N efficiency in direct-seeded (DS) rice and transplanted (TP) rice under similar N management practices using lSN-Iabelled urea. Two greenhouse and one field studies were conducted to evaluate the effectiveness of inhibitors and cations on marine and riverine alluvial rice soils on the efficiency of urea-N using 15N recovery techniques. Urea hydrolysis followed the first-order kinetics and rate constants ranged from -0.032 to -0.076 ha-1 A lag phase existed in flooded soil conditions and it varied from 6 to 15 hours. The half-life of urea ranged from 12 to 26 hours. Urea conversion to NH4 -tN was initially rapid with about three-fourths being converted within 48 hours of incubation and total conversion completed within 108 hours.
format	Thesis
qualification_name	Doctor of Philosophy (PhD.)
qualification_level	Doctorate
author	Shah, Shree Chandra
author_facet	Shah, Shree Chandra
author_sort	Shah, Shree Chandra
title	Nitrogen Efficiency of Urea Amended With Inhibitors and Cations Applied to Rice
title_short	Nitrogen Efficiency of Urea Amended With Inhibitors and Cations Applied to Rice
title_full	Nitrogen Efficiency of Urea Amended With Inhibitors and Cations Applied to Rice
title_fullStr	Nitrogen Efficiency of Urea Amended With Inhibitors and Cations Applied to Rice
title_full_unstemmed	Nitrogen Efficiency of Urea Amended With Inhibitors and Cations Applied to Rice
title_sort	nitrogen efficiency of urea amended with inhibitors and cations applied to rice
granting_institution	Universiti Pertanian Malaysia
granting_department	Faculty of Agriculture
publishDate	1994
url	http://psasir.upm.edu.my/id/eprint/10339/1/FP_1994_1_A.pdf
_version_	1747811100084142080

Nitrogen Efficiency of Urea Amended With Inhibitors and Cations Applied to Rice

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