Bivariate spatial statistics applied to precipitation and off-season corn yield in the state of Paraná, Brazil

ABSTRACT

The state of Paraná is one of the largest corn producers in Brazil, cultivating in two growing seasons. This study evaluated bivariate correlations between precipitation and the second-crop corn yield between the first 10 days of April and the first 10 days of October using spatial statistics. The spatial analysis of yield was evaluated using geostatistical models and validated by cross-validation. Spatial analysis was performed using the local indicator of spatial association and a cross-semivariogram, and the co-dispersion coefficient was used to validate the correlation between variables. Cross-validation identified the exponential model as the best fit, indicating a spatial dependence of 317.26 km. Spatial associations between municipalities were significant throughout the state of Paraná, Brazil. The cross-semivariogram allowed fitting the wave, spherical, Gaussian, and exponential models, with a spatial correlation of 37.04 to 570.38 km between the precipitations and yield. Moreover, the co-dispersion coefficient validated the correlation between the two variables for all 10-day periods.

KEYWORDS:

• cross-variogram
• geostatistics
• co-dispersion

Editor A. Castellarin; Associate Editor N. Malamos

Editor A. Castellarin; Associate Editor N. Malamos

Acknowledgements

We thank the Western Paraná State University (UNIOESTE), the Coordination for the Improvement of Higher Education Personnel – Brazil (CAPES) (Finance Code 001), the National Council for Scientific and Technological Development (CNPq) for their assistance, the National Water Agency (ANA) and the National Supply Company (CONAB) for providing the database, and the Spatial Statistics Laboratory (LEE/UNIOESTE).

Disclosure statement

No potential conflict of interest was reported by the authors.