Geostatistics to determine spatial variability of soil chemical properties using different preparation systems

• Autor(a) principal: de Carvalho, José Ruy Porto
• Data de Publicação: 2002
• Outros Autores: da Silveira, Pedro Marques, Vieira, Sidney Rosa
• Tipo de documento: Artigo
• Idioma: por
• Título da fonte: Pesquisa Agropecuária Brasileira (Online)
• Texto Completo: https://seer.sct.embrapa.br/index.php/pab/article/view/6449
• topic: soil pH; soil preparation; cropping systems; analytical methods; pH do solo; preparo do solo; sistema de cultivo; métodos de análise

Spatial variability of pH, Ca, Mg, P and K under three soil preparation systems (moldboard plough, harrow disc and no-tillage) was studied using geostatistical concepts in clayey Oxisol, in Santo Antônio de Goiás, GO, Brazil, at Embrapa-Centro Nacional de Pesquisa de Arroz e Feijão, for five consecutive years (1992-1996). Within a total of 30 combinations among soil chemical properties, soil depth and preparation system, 14 presented pure nugget effect, indicating absence of spatial dependence. Directional semivariograms revealed strong and moderate spatial dependence in the direction of Y. Experiments conducted for a long time and cultural practice conducted in a single direction tend to change the spatial structure of the soil properties. The anisotropy direction was more associated with harrow disc as a system of soil preparation and the strongest spatial dependence was verified for pH at 5-20 cm soil depth. These results suggest that sample location to estimate the values of the soil chemical properties should take field operations into account and should be carefully selected. Samples should be taken in other directions, so that a more realistic representation of the sampled area could be obtained.