Data/hora: 09/06/2024 09:24:02

Provedor de dados: | Scientia Agricola
País: | Brazil
Título: | Estimating foliar nitrogen in Eucalyptus using vegetation indexes
Autores: | Oliveira,Luiz Felipe Ramalho de; Oliveira,Marcio Leles Romarco de; Gomes,Francisco Sérgio; Santana,Reynaldo Campos.
Data: | 2017-04-01
Ano: | 2017
Palavras-chave: | Leaf nitrogen concentration; Non-destructive analyses; Spectrometer; Spectral reflectance; Leaf reflectance.
Resumo: | ABSTRACT Nitrogen (N) has commonly been applied in Eucalyptus stands in Brazil and it has a direct relation with biomass production and chlorophyll content. Foliar N concentrations are used to diagnose soil and plant fertility levels and to develop N fertilizer application rates. Normally, foliar N is obtained using destructive methods, but indirect analyses using Vegetation Indexes (VIs) may be possible. The aim of this work was to evaluate VIs to estimate foliar N concentration in three Eucalyptus clones. Lower crown leaves of three clonal Eucalyptus plantations (25 months old) were classified into five color patterns using the Munsell Plant Tissue Color Chart. For each color, N concentration was determined by the Kjeldahl method and foliar reflectance was measured using a CI-710 Miniature Leaf Spectrometer. Foliar reflectance data were used to obtain the VIs and the VIs were used to estimate N concentrations. In the visible region, the relationship between N concentration and reflectance percentage was negative. The highest correlations between VIs and N concentrations were obtained by the Inflection Point Position (IPP, r = 0.97), Normalized Difference Red-Edge (reNDVI, r = 0.97) and Modified Red-Edge Normalized Difference Vegetation Index (mNDI, r = 0.97). Vegetation indexes on the red edge region provided the most accurate estimates of foliar N concentration. The reNDVI index provided the best N concentration estimates in leaves of different colors of Eucalyptus urophylla × grandis and Eucalyptus urophylla × urophylla (R2 = 0.97 and RMSE = 0.91 g kg−1).
Tipo: | Info:eu-repo/semantics/article
Idioma: | Inglês
Identificador: | http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162017000200142
Editor: | São Paulo - Escola Superior de Agricultura "Luiz de Queiroz"
Relação: | 10.1590/1678-992x-2015-0477
Formato: | text/html
Fonte: | Scientia Agricola  v.74 n.2 2017
Fonte: | info:eu-repo/semantics/openAccess