Sampling grids used to characterise the spatial variability of pH, Ca, Mg and V% in Oxisols

Abstract

-Knowledge of spatial variability is an important factor to be considered in planning a program of soil sampling and crop management under precision agriculture (PA). In this context, the aim of this work was to evaluate the efficiency of the dimensions of sampling grids used in the state of Rio Grande do Sul (RS), Brazil to characterise the spatial variability of the attributes pH water , base saturation (V%), calcium (Ca) and magnesium (Mg) levels. The study was carried out on 30 agricultural sites located in the northern region of RS, having soils classified as Oxisols and managed using the tools of PA. The dimensions of the grids under study were: 100 x 100 m (10 areas), 142 x 142 m (10 areas) and 173 x 173 m (10 areas). Soil was collected at a depth of 0.00 to 0.10 m. The data for pH water , V%, Ca and Mg were subjected to exploratory statistical analysis and to geostatistical analysis by means of semivariograms. The areas showed high Ca (>4.0 cmol c dm -3) and Mg (>1.0 cmol c dm -3 ) levels and localised problems of soil acidity (pH water <5.5 or V<65%), justifying the carrying out of liming at specific sites. For the geostatistical procedures, the sample grids used at the sites of the Oxisols managed under PA in RS are not efficient in capturing the scales of spatial variability of the attributes pH water , V%, Ca and Mg, which could compromise the accuracy of corrective prescriptions for specific sites.

Variabilidade espacial da produtividade de milho irrigado e sua correlação com variáveis explicativas de planta

“…(CAMBARDELLA et al, 1994). Esses valores de alcance são semelhantes aos anteriormente reportados para atributos da fertilidade em Latossolos do estado do Rio Grande do Sul (CHERUBIN et al, 2014a;CHERUBIN et al, 2014b). Com isso, sugere-se que, para caracterizar a variabilidade espacial de plantas dominadas (PD), faz-se necessário um número de amostras por área semelhante ao utilizado para a caracterização da fertilidade do solo.…”

Sample planning for quantifying and mapping magnetic susceptibility, clay content, and base saturation using auxiliary information

“…This result indicates that the use of secondary information may soften the effects of reduced sampling density. The ideal sampling density for soil properties is the focus of several studies due to its key role for planning and, especially, enabling the local variability characterization of soil properties for different purposes (Kerry et al, 2010;Bilgili et al, 2011;Nanni et al, 2011;Montanari et al, 2012;Cherubin et al, 2014;Siqueira et al, 2014).…”

Impact of the industrialization on soil surrounding Sirgitti industrial area in Bilaspur

“…Bioremediation can also occur by sulphate reducing bacteria like Albizia procera and Terminalia arjuna. Desulfovibrio desulfuricans converts sulphate into hydrogen sulphate which reacts with heavy metals such as zinc, iron and manganese to form insoluble metal sulphites [44][45][46][47][48][49]. Most of the above microbe assisted remediation is carried out by ex-situ.…”