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An in situ incubation technique to measure the contribution of organic nitrogen to potatoes

2004Journal article Open access
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dc.contributor.authorRodrigues, M.A.
dc.date.accessioned2010-03-08T10:51:57Z
dc.date.available2010-03-08T10:51:57Z
dc.date.issued2004
dc.description.abstractThe quantification of sidedress N rate from in-season information on crop N nutritional status is extremely important in order to use only the necessary amount of nutrient to achieve maximum yields without significant N losses from soil. During three consecutive years (1996, 1997 and 1998) field N fertilizer experiments with irrigated potato (Solanum tuberosum L., cv. Désirée) were conducted in Bragança (NE Portugal). Eight preplant treatments (0, 50, 100, 200 and 300 kg urea-N/ha and poultry manure, farmyard manure and municipal solid waste in rates equivalent to 100 kg organic-N/ha) were arranged as main plots and five sidedress N rates (0, 25, 50, 100 and 200 kg urea-N/ha) included as subplots. Petiole nitrate concentration, determined by a laboratory method (PNLab, g NO3-N kg−1, dry weight basis) and by the portable RQflex reflectometer (PNRQflex, mg NO3 kg−1, from fresh tissues), and leaf N content (LeafN, g kg−1, dry weight basis) were used as N nutritional indices. From the five sidedress N rates applied over each of the preplant treatments, critical sidedress N rates were estimated for several different crop N nutritional status. This was achieved by establishing exponential asymptotic curves between sidedress N rates and tuber yields and solving the equations for 95% of maximum tuber yield. In a second step, multiple regression equations were established between the estimated critical sidedress N rates (SNrate, kg N/ha), as dependent variable, and each crop N nutritional indices (PNLab, PNRQflex or LeafN) and days after emergence (DAE). The equations obtained are: SNrate = 182.7 − 4.146 × PNLab −1.87 × DAE SNrate = 161.0 − 0.013 × PNRQflex −1.34 × DAE SNrate = 562.2 − 8.416 × LeafN −3.59 × DAE These equations provide quantitative sidedress N rates for any level of crop N nutritional indices and sampling dates from 10 to 48 days after emergence.pt
dc.identifier.citationAgronomie. Agriculture & Environment,ISSN 24: 249-256pt
dc.identifier.doi10.1051/agro:2004022
dc.identifier.issn1161-0301
dc.identifier.urihttp://hdl.handle.net/10198/2202
dc.language.isoengpt
dc.publisherElsevierpt
dc.subjectSolanum tuberosumpt
dc.subjectCrop N managementpt
dc.subjectDecision support systempt
dc.subjectPlant analysispt
dc.subjectTissue testingpt
dc.titleAn in situ incubation technique to measure the contribution of organic nitrogen to potatoespt
dc.typejournal article
dspace.entity.typePublication
oaire.citation.endPage88pt
oaire.citation.issue23(1)pt
oaire.citation.startPage79pt
oaire.citation.titleEuropean Journal of Agronomypt
person.familyNameRodrigues
person.givenNameManuel
person.identifier.ciencia-id371D-DF0D-8D68
person.identifier.orcid0000-0002-5367-1129
person.identifier.ridO-1721-2016
person.identifier.scopus-author-id35270106800
rcaap.rightsopenAccesspt
rcaap.typearticlept
relation.isAuthorOfPublication43621353-fa11-4559-9b24-27eba5ad3de0
relation.isAuthorOfPublication.latestForDiscovery43621353-fa11-4559-9b24-27eba5ad3de0

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