Soil and yield variability is a common problem in Florida citrus production; however, only limited progress has been made in charactering and identifying major yield-limiting properties. This study characterized the variability in soil chemical and biological properties. To achieve this, a citrus grove was divided into five productivity zones based on tree canopy volume (0-1.84, 1.84-3.67, 3.67-5.51, 5.51-7.34, and 7.34-9.18 m³ m-1 row for very poor, poor, medium, good, and very good, respectively) using geographic information system software. Six random soil samples were collected from each productivity zone at four depths (0-15, 15-30, 30-45, and 45-60 cm) to analyze various soil properties. Soil organic matter, Mehlich I extractable 13, K, Ca, and Mg, and oxalate-extractable Fe and AI varied greatly along the productivity gradient, and their differences among zones were most prominent in the lower soil depths. These soil properties had a common pattern of spatial distribution (range 150-200 m) that matched the variation in fruit yield. The results of discriminant function and partial least squares regression analyses revealed that the productivity within the grove differed in the O- to 60-cm soil depth, signifying that greater root zone depths could better explain the differential productivity of citrus groves than the 0- to 15-cm layer, which is the depth used presently for fertilizer recommendations. Collectively, our results suggest that soil sampling depths for citrus should be 0 to 60 cm and sampling should be done based on the variogram range of easily measured soil properties. [ABSTRACT FROM AUTHOR]