Spatial variability of the yield and physical properties of orange (Citros sinensis [L.] Osbeck cv. Monte Parnaso) fruits

Abstract

Precision agriculture (PA) is used as a tool in the citrus industry and aims to increase production reduce costs and search for answers to explain the spatial variability of yield. The aim of this study was to model the spatial variability of yield and physical properties of fruits of orange trees in relation to the geographic quadrant where the fruits are on the trees. The experiment was carried out in a 1 ha commercial orchard of orange trees cv. Monte Parnaso. A GPS receiver and a total station were used to georeference the experimental area and the position of each sampled tree in the area, as well as the location of the geographic quadrant where the fruits sampled were on the trees. Twelve fruits were collected from each of the 13 sampled trees, resulting 39 fruits per quadrant, totalling 156 fruits each crop-year (2011 and 2012). Yield was estimated after the harvest (kg.quadrant -1 ). Physical analyses were performed for each fruit, measuring the following physical properties: equatorial diameter, total mass and juice yield. We conducted analysis of descriptive statistics and spatial variability in the data through techniques related to geostatistics. The results showed the highest spatial variability between the quarters for the juice yield and yield, and the verified juice yield was within the acceptable standard by regulatory bodies.