Abstract: Significant changes in the Brazilian sugarcane agricultural sector have been observed in recent years, with the rapid expansion of planted areas, mainly in the western part of the country. In addition to the enlargement of boundaries and the installation of new industrial units, sugarcane expansion demands the development of new technologies to facilitate better use of the production areas, increase the yield and quality of the sugarcane, and reduce production costs. For that, the adoption of precision agriculture may be an important tool in the management of sugarcane production, which is based on the understanding of the relationship between soil attributes and sugarcane quality. Therein, the objective of this work was to study the Pearson correlation between chemical soil attributes and sugarcane quality parameters based on soil physical zones and to verify the spatial-temporal variability of the quality attributes over time. The work was carried out in an area of 10 ha located in Araras, São Paulo, Brazil, from November 2008 to July 2011. Sugarcane quality (Brix, pol, and fiber) was measured in samples collected within a grid of 30 × 30 m (total of 117 sample points) just before harvesting. The soil samples were collected immediately after harvesting in the same grid points. The chemical soil attributes analyzed were macronutrients and micronutrients, and the soil physical attribute was soil texture. The correlations obtained between the sugarcane quality parameters and soil chemical attributes varied from weak (Zn0–0.2: −0.36; Ca0.2–0.5: −0.30 with fiber and soil organic matter 0–0.2: −0.36 with pol) in sandy loam zone at the first year to strong correlations (P0–0.2: 0.77; Ca0–0.2: 0.67 with fiber) in sand clay loam zones at the second year. They also revealed major negative soil property correlations (P, Ca, Mg, sum of base, cation exchange capacity, base saturation) with sugar concentration and positive correlations with fiber. There were no clear patterns of the temporal stability of the quality parameters, which suggests that studies that include more crop cycles are needed.
1School of Agriculture Engineering, University of Campinas (UNICAMP), Campinas, São Paulo, Brazil. Dr. Paulo Sérgio Graziano Magalhães is corresponding author.
2Brazilian Bioethanol Science and Technology Laboratory, CTBE, Campinas, São Paulo, Brazil.
3School of Agronomy ESALQ, São Paulo State University (USP), Piracicaba, São Paulo, Brazil.
Address for correspondence: Dr. Paulo Sérgio Graziano Magalhães, School of Agriculture Engineering, University of Campinas (UNICAMP), Campinas, São Paulo, Brazil. E-mail: firstname.lastname@example.org
Financial Disclosures/Conflicts of Interest: This project was funded by FAPESP (State of São Paulo Research Foundation), FINEP (Brazilian Agency of Innovation), and CNPq (National Research Council), which supported the scholarship of the first author.
Received October 5, 2012.
Accepted for publication March 8, 2013.