Late-season nitrogen applications improve grain yield and fertilizer-use efficiency of dry direct-seeded rice in the tropics
•We evaluated late-season N application (LSNA) in tropical dry direct-seeded rice.•N recovery increased with an increasing proportion of N input at later stages.•LSNA increased the percentage of filled grains and harvest index.•LSNA increased yield by 6% in the dry season and 7% in the wet season. E...
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Published in | Field crops research Vol. 233; pp. 114 - 120 |
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Main Authors | , , , , , |
Format | Journal Article |
Language | English |
Published |
Elsevier B.V
01.03.2019
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Subjects | |
Online Access | Get full text |
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Summary: | •We evaluated late-season N application (LSNA) in tropical dry direct-seeded rice.•N recovery increased with an increasing proportion of N input at later stages.•LSNA increased the percentage of filled grains and harvest index.•LSNA increased yield by 6% in the dry season and 7% in the wet season.
Efficient nitrogen (N) management plays an important role in rice cultivation. Previous studies in the tropics mainly focused on split-N applications before panicle initiation in transplanted rice. In this study, we examined the effects of top-dressing at panicle initiation and flowering of dry direct-seeded rice on yield and fertilizer-use efficiency in field experiments at the International Rice Research Institute, the Philippines, in the dry and wet seasons. Two high-yielding indica cultivars (Rc222 and Rc282) were drill-seeded under four split-N application regimes and a control with no supplemental N. The timing of the split-N applications significantly affected grain yield, even though the total N input was unchanged. The late-season N application at heading increased yield by 6% (0.49 t ha−1) in the dry season and 7% (0.49 t ha−1) in the wet season. The N recovery efficiency also increased with an increasing proportion of N applied at later growth stages. The yield advantage of the late-season N application over the early-season N application (seeding to panicle initiation) may be attributable to delayed senescence (maintenance of more and greener leaves toward maturity), higher canopy photoassimilation, greater grain-filling, and a higher harvest index. Our results underline the importance of late-season N application in dry direct-seeded rice under favorable lowland conditions in the tropics. The optimal split-N regimes during the vegetative stage may depend on the season or temperature regime, so this subject requires additional investigation. |
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ISSN: | 0378-4290 1872-6852 |
DOI: | 10.1016/j.fcr.2019.01.010 |