Distribuição espacial das características físicas e químicas do solo de cerrado utilizando Krigagem indicativa

Abstract

Precision agriculture becomes increasingly used, because knowledge of the variations in productivity characteristics that interfere with base maps for spatial and temporal variability leads to informed decision-making and accuracy. This study evaluated the probabilistic uncertainty of the spatial variability of the physical and chemical soil using geostatistics by kriging. Data were collected on the characteristics of a field managed under no-tillage, where 124 were geocoded points in a mesh of 60 x 60m. At each point of the data were collected Penetration Resistance (PR), undisturbed sample for determination of bulk density, and soil samples for the determination of physical and chemical attributes of the soil. The evaluation of crop yield was performed at the time of harvest, where all the plants in 1m ² next to each sampling point were collected and evaluated for productivity. The original data were submitted to descriptive statistics in order to understand and summarize each variable, soon after, to characterize the spatial and probabilistic uncertainty of the results was used by geostatistical indicator kriging technique, transforming and categorizing data binary code (0 or 1), where: the values were below or equal to the cutoff were coded in one (1) and which are above, at zero (0). reference values for cutoffs. The best semivariogram model was determined by the highest coefficient of determination (R ²) and lower Sum of Square Waste (SQR) semivariance experimental data, prevailing models and Gaussian spherical. To the points where it was proven to the spatial dependence was constructed contour maps, using the technique of kriging. The physical / chemical (RP 0.15 m, 0.40 m RP, K, P, Mg, SB) spatial dependence, while (pH, Ca, Al, Zn, Acid Potential, MO, CTC and productivity) do not showed spatial variability, ie behavior exhibited pure nugget effect (EPP) and were explained by descriptive statistics The discussion of spatial uncertainty of the results generated by kriging technique, subsidized based on the natural variability of the physical and chemical attributes, one decision making to correct chemical and / or mechanical intervention in troubled areas substantiated by the probability of occurrence of each attribute under consideration