Data/hora: 09/06/2024 03:58:59

Provedor de dados: | Scientia Agricola
País: | Brazil
Título: | Optimum size in grid soil sampling for variable rate application in site-specific management
Autores: | Nanni,Marcos Rafael; Povh,Fabrício Pinheiro; Demattê,José Alexandre Melo; Oliveira,Roney Berti de; Chicati,Marcelo Luiz; Cezar,Everson.
Data: | 2011-06-01
Ano: | 2011
Palavras-chave: | Soil attributes; Grid sampling; Kriging; Cross-validation; Kappa statistic.
Resumo: | The importance of understanding spatial variability of soils is connected to crop management planning. This understanding makes it possible to treat soil not as a uniform, but a variable entity, and it enables site-specific management to increase production efficiency, which is the target of precision agriculture. Questions remain as the optimum soil sampling interval needed to make site-specific fertilizer recommendations in Brazil. The objectives of this study were: i) to evaluate the spatial variability of the main attributes that influence fertilization recommendations, using georeferenced soil samples arranged in grid patterns of different resolutions; ii) to compare the spatial maps generated with those obtained with the standard sampling of 1 sample ha-1, in order to verify the appropriateness of the spatial resolution. The attributes evaluated were phosphorus (P), potassium (K), organic matter (OM), base saturation (V%) and clay. Soil samples were collected in a 100 × 100 m georeferenced grid. Thinning was performed in order to create a grid with one sample every 2.07, 2.88, 3.75 and 7.20 ha. Geostatistical techniques, such as semivariogram and interpolation using kriging, were used to analyze the attributes at the different grid resolutions. This analysis was performed with the Vesper software package. The maps created by this method were compared using the kappa statistics. Additionally, correlation graphs were drawn by plotting the observed values against the estimated values using cross-validation. P, K and V%, a finer sampling resolution than the one using 1 sample ha-1 is required, while for OM and clay coarser resolutions of one sample every two and three hectares, respectively, may be acceptable.
Tipo: | Info:eu-repo/semantics/article
Idioma: | Inglês
Identificador: | http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162011000300017
Editor: | São Paulo - Escola Superior de Agricultura "Luiz de Queiroz"
Relação: | 10.1590/S0103-90162011000300017
Formato: | text/html
Fonte: | Scientia Agricola  v.68 n.3 2011
Fonte: | info:eu-repo/semantics/openAccess