Characterization of spatial variability of the relative chlorophyll index in wheat crop

• Autor(a) principal: Pias, Osmar Henrique de Castro
• Data de Publicação: 2014
• Outros Autores: Santi, Antônio Luis, Cherubin, Maurício Roberto, Berghetti, Juliano, Oliveira, Thiago Campos de
• Tipo de documento: Artigo
• Idioma: por
• Título da fonte: Pesquisa Agropecuária Tropical (Online)
• Texto Completo: https://revistas.ufg.br/pat/article/view/29427
• topic: Triticum aestivum L.; precision agriculture; geostatistics.; Triticum aestivum L.; agricultura de precisão; geoestatística.

Site-specific nitrogen application, based on relative chlorophyll index from leaves, may provide many economic and environmental benefits, however, the knowledge on sampling methodologies is still incipient. Thus, this study aimed to evaluate the use of different sampling grids to characterize the spatial variability of relative chlorophyll index of leaves from wheat crop and elaborate thematic maps for site-specific nitrogen application. For determining the relative chlorophyll index, a CFL 1030 chlorophyll meter was used on a regular sampling grid of 10 m x 10 m with 472 sampling points. Based on the initial sampling grid, by using the point elimination method, the simulation was performed in the following sampling grids: 10 m x 20 m; 20 m x 20 m; 20 m x 30 m; 30 m x 30 m; 30 m x 40 m; and 40 m x 40 m. The increase of the sampling grid reduced the diagnostic accuracy of relative chlorophyll index in wheat leaves. As the sampling grid increased, the maps became more general and information on the spatial variability of the relative chlorophyll index were lost. Sampling grids smaller or equal to 20 m x 20 m were effective to detect the spatial variability of the relative chlorophyll index in wheat leaves and enable the elaboration of thematic maps for site-specific nitrogen application.