Spatial relationships among cereal yields and selected soil physical andchemical properties

Sandy soils occupy large area in Poland (about 50%) and in the world. This study aimed at determining spatialrelationships of cereal yields and the selected soil physical and chemical properties in three study years (2001−2003) on low productive sandy Podzol soil (Podlasie, Poland). The yields and soil properties in plough and sub-soil layers were determined at 72–150 points. The test crops were: wheat, wheat and barley mixture and oats. Toexplore the spatial relationship between cereal yields and each soil property spatial statistics was used. The bestfitting models were adjusted to empirical semivariance and cross-semivariance, which were used to draw mapsusing kriging. Majority of the soil properties and crop yields exhibited low and medium variability (coefficient ofvariation 5–70%). The effective ranges of the spatial dependence (the distance at which data are autocorrelated)for yields and all soil properties were 24.3–58.5 m and 10.5–373 m, respectively. Nugget to sill ratios showed thatcrop yields and soil properties were strongly spatially dependent except bulk density. Majority of the pairs incross-semivariograms exhibited strong spatial interdependence. The ranges of the spatial dependence variedin plough layer between 54.6 m for yield × pH up to 2433 m for yield × silt content. Corresponding ranges in sub-soil were 24.8 m for crop yield × clay content in 2003 and 1404 m for yield × bulk density. Kriging maps allowedseparating sub-field area with the lowest yield and soil cation exchange capacity, organic carbon content and pH.This area had lighter color on the aerial photograph due to high content of the sand and low content of soil or-ganic carbon. The results will help farmers at identifying sub-field areas for applying localized management prac-tices to improve these soil properties and further spatial studies in larger scale.