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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1994
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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 |