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dc.contributor.authorGweyi-Onyango, J.
dc.contributor.authorNtinyari, W.
dc.contributor.authorEgesa, A.O.
dc.contributor.authorMose, R.
dc.contributor.authorNjinju, S.
dc.contributor.authorGiweta, M.
dc.contributor.authorMasso, C.
dc.date.accessioned2021-07-16T12:37:18Z
dc.date.available2021-07-16T12:37:18Z
dc.date.issued2021-06-25
dc.identifier.citationGweyi-Onyango, J.P., Ntinyari, W., Egesa, A.O., Mose, R., Njinju, S., Giweta, M. & Masso, C. (2021). Differences in seasons and rice varieties provide opportunities for improving Nitrogen Use Efficiency and management in irrigated rice in Kenya. Environmental Research Letters,16(7): 075003, 1-16.
dc.identifier.issn1748-9326
dc.identifier.urihttps://hdl.handle.net/20.500.12478/7182
dc.description.abstractApart from nitrogen (N) rates, N use efficiency (NUE) (yield N/total input N) is affected by seasons, crop developmental stages, and varieties. Knowledge of how these factors affect NUE in rice production in Kenya is limited. Therefore, field experiments were conducted with 'low rates' of N (simulating farmers' practices) of 0, 26, 52 and 78 kg N ha−1 with five varieties (MWUR1, MWUR4, IRAT109, NERICA4 and NERICA10) and higher rates of N (125, 175, and 225 kg N ha−1) simulating researchers' doses with two lowland varieties (Basmati 370 and BW 196) and IR 72. Another experiment on NUE responses to sites, N rates and dose (split or full dose) was undertaken with the IR97 variety. With the 'low rate', yields increased with incremental N rates up to 52 Kg N ha−1 and declined (during cold periods, for some varieties). In this scenario, the N agronomic efficiencies (AEN) declined with increasing N but depended on sites and seasons. However, most AEN values were above 100, implying nutrient mining. In most cases (except at the Mwea site), the N utilization efficiency (NUtE) ranged from 16 to 22kg kg−1 and were not significantly affected by sources and methods of N application. In all cases, an increase in N elicited declining trends in NUtE. Moreover, N uptake efficiency ranged between 22 and 90kg kg−1 without significant variation among varieties. For the 'high N rates', high biomass yield resulted in higher grain yields in BW 196 and IR 72 but yield declined beyond 75 kg ha−1 N rates due to poor grain filling, particularly when a cold period coincided with booting and grain filling. We conclude that N rates, doses and rice varieties are key determinants of AEN and NUtE in contrasting rice growing seasons in Kenya. Cropping seasons and rice varieties are therefore potential key determinants of sustainable rice productivity and improved NUE in rice-based systems in the studied regions of Kenya.
dc.description.sponsorshipAgricultural & Livestock Research Organization
dc.description.sponsorshipKenyatta University
dc.description.sponsorshipInternational Nitrogen Management Systems
dc.format.extent1-16
dc.language.isoen
dc.subjectSeed filling
dc.subjectTemperature
dc.subjectNitrogen
dc.subjectUse efficiency
dc.subjectNutrient
dc.subjectMining
dc.subjectPolicies
dc.subjectKenya
dc.titleDifferences in seasons and rice varieties provide opportunities for improving nitrogen use efficiency and management in irrigated rice in Kenya
dc.typeJournal Article
cg.contributor.crpRice
cg.contributor.affiliationKenyatta University
cg.contributor.affiliationInternational Institute of Tropical Agriculture
cg.contributor.affiliationJames Finlay Kenya
cg.contributor.affiliationKenya Agricultural & Livestock Research Organization
cg.coverage.regionAfrica
cg.coverage.regionEast Africa
cg.coverage.countryKenya
cg.coverage.hubCentral Africa Hub
cg.researchthemeNatural Resource Management
cg.identifier.bibtexciteidGWEYIONYANGO:2021
cg.isijournalISI Journal
cg.authorship.typesCGIAR and developing country institute
cg.iitasubjectAflatoxin
cg.iitasubjectAgronomy
cg.iitasubjectNatural Resource Management
cg.journalEnvironmental Research Letters
cg.notesOpen Access Journal
cg.accessibilitystatusOpen Access
cg.reviewstatusPeer Review
cg.usagerightslicenseCreative Commons Attribution 4.0 (CC BY 0.0)
cg.targetaudienceScientists
cg.identifier.doihttps://dx.doi.org/10.1088/1748-9326/ac03dd
cg.iitaauthor.identifierCargele Masso: 0000-0002-3980-6832
cg.futureupdate.requiredNo
cg.identifier.issue7: 075003
cg.identifier.volume16


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