Spatial statistical measures of crop temperature variability using infrared thermography in radiant heated greenhouse crops

ABSTRACTCrop surface temperature under a radiant heated greenhouse was measured using a portableinfrared thermometer. Plants were arranged so that each plant occupied a grid cell of 30cm x 30cm(ift x ift). Data collected were analyzed for their spatial distribution. Geostatistical software was usedto characterize the spatial variability of the plant surface temperature. The shape of the empirical semi-variogram suggested that a spherical model was best fitted to the empirical semi.variogram. This model indicated that the nugget effect was estimated at 1.2, the sill at 3.3 and the range at 1.65 m.This model was used in block kriging to estimate plant surface temperature for unsampled locations.Keywords: Infrared, Thermometry, Geostatistics, Kriging, Spatial Variability.1. INTRODUCTION 1.1 Geostatistical conceptsMeasurements of physical entities or biological properties in space and time cannot be considered as independent samples. Properties at locations near to each other tend to have values more