Spatial variability of soil chemical attributes and productivity and the chemical and physical properties of oranges

Abstract

The purpose of this study was to analyze the spatial variability of soil properties and productivity and the chemical and physical properties of oranges (Monte Parnaso variety) in their geographical quadrants. This experiment was conducted in a commercial orange orchard in the municipality of Nova Laranjeiras in the State of Paraná, Brazil. A GPS receiver and a total station were used to measure the spatial location of the fruit and to determine which quadrant they were located in. In this experiment, 13 trees were studied. Twelve fruits were evaluated in each geographical quadrant, and 156 fruits were considered. After harvest, the productivity was expressed as kg per quadrant (kg quadrant-1). Next, physical tests (equatorial diameter (EqD), total fruit mass (TFM), juice yield (JY)) and chemical tests (total soluble solids (TSS), total titrable acidity (TTA), the TSS/TTA ratio, and the ascorbic acid (AA) content) were conducted in the laboratory. In addition, the data were subjected to analysis by descriptive statistics and geostatistics to determine the spatial variability of the physical and chemical properties of the oranges, the variations of the soil properties and the correlations between the following parameters: the pH properties of the fruit and Zn; TFM and K; EqD and K, and C and TSS. The orchard varies spatially, especially regarding the EqD, TFM, JcP, TSS and AA for the quadrants with the highest values (the Northwest, Southeast, Northeast, Southwest and Southeast, respectively). The soil potassium and zinc contents were strongly correlated with the physical and chemical properties of the orange fruits.