| dc.contributor.advisor | PEARL B. SANCHEZ | |
| dc.contributor.author | JABBAR, S. M. A. | |
| dc.date.accessioned | 2022-04-23T04:24:34Z | |
| dc.date.available | 2022-04-23T04:24:34Z | |
| dc.date.issued | 2006-07 | |
| dc.identifier.uri | http://localhost:8080/xmlui/handle/123456789/556 | |
| dc.description | Nitrogen (N) is the most important nutrient element in rice production
worldwide. More than 90% of the world’s rice is produced and about 60% of the
N fertilizer consumed is used on rice in Asia (Stangel and De Datta, 1985).
Approximately 24% of the increase in Asian rice production from 1965 to 1980
was attributed to fertilizer use, mainly N (Barker et al., 1985). Despite past gains
in rice production, research has demonstrated that industrial N fertilizers
generally are not efficiently utilized by rice, because rice is grown in an
environment that is conducive to N_ losses, i.e., through nitrification,
denitrification, ammonia volatilization, immobilization, runoff, and leaching (De
Datta and Buresh, 1989). Imbalanced use of fertilizers and occurrence of other
macronutrient deficiencies have also given rise to low N-use efficiency in many
rice-based systems (Von Uexkull, 1993). | en_US |
| dc.description.abstract | A field experiment was conducted in the 2005 wet season at the
experimental farm of the International Rice Research Institute (IRRI), Los Banos,
Philippines, to assess differences in grain yield (GY) and nitrogen use efficiency
(NUE) of a range of vadstosines and to determine important varietal traits that
contribute to increase NUE under irrigated and rainfed lowland conditions.
Tested were six upland varieties, five rainfed lowland varieties (including three
traditional varieties), six irrigated varieties, and two hybrid varieties. The
experiment was laid out in a split-plot design with two N treatments (0 and 75 kg
N ha‘') in the main plots and nineteen varieties in the subplots with four
replications. Highly significant differences among the varieties were observed for
GY, harvest index (HI), total plant N uptake (TNU), and internal N use efficiency
(IEN) under both water regimes. Irrigated conditions produced on average 55%
higher GY than rainfed conditions, indicating considerable water stress in the
rainfed treatment. | en_US |
| dc.language.iso | en | en_US |
| dc.publisher | UNIVERSITY OF THE PHILIPPINES LOS BANOS | en_US |
| dc.subject | WATER REGIMES AND NITROGEN LEVELS | en_US |
| dc.subject | Rice Plant Growth and Development | en_US |
| dc.subject | Mineralization and Immobilization | en_US |
| dc.title | NITROGEN USE EFFICIENCY IN SELECTED RICE (Oryza sativa L.) GENOTYPES GROWN UNDER VARYING WATER REGIMES AND NITROGEN LEVELS | en_US |
| dc.type | Thesis | en_US |
