Papers

Assessment of spatial variability of soil attributes as a basis for the adoption of precision agriculture in sugarcane plantation

Author: José Eduardo Corá, A. V. Araujo, Gener Tadeu Pereira e J. M. G. Beraldo

Keywords: soil management, geostatistics, kriging, soil clay.

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Summary

The spatial variability of physical and chemical attributes of Latosols (Oxisols) cultivated with sugarcane was assessed. The study was carried out in a 90 ha area in the surroundings of Jaboticabal, São Paulo State, Brazil (21 o 15 ’ S and 48 o 18 ’ W). A 50 m regular grid was projected onto the experimental area. Soil samples were obtained at each 50 m grid point (421 points) from the 0 to 0.20 m and from the 0.60–0.80 m soil layers. Organic matter, pH, P, K+, Ca2+, Mg2+, H + Al, CEC, soil clay content, and V% values of each sample were determined. The data set was submitted to descriptive statistics, geostatistics, and kriging analyses. The range of the spatial dependence for the soil attributes, was lower in the 0.60–0.80 m than in the 0–0.20 m layer. Results showed a higher discontinuity in the spatial variability of soil attributes in the 0.60–0.80 m layer of Oxisols indicating that, in disagreement to the currently established concept, this soil class does not present homogeneity of soil attributes. Soil management altered the spatial dependence of soil chemical attributes in the surface, reducing the spatial variability structure in comparison to the deeper soil layer. The assessment of the spatial variability of soil chemical attributes and soil clay content in the top and the subsurface layers allowed the identification of homogeneous site-specific management zones which permit the adoption of precision agriculture for sugarcane.