IMAGE-ANALYSIS OF THE MACROPOROSITY OF AN ORCHARD SOIL

In order to study the macroporosity of a soil of an apple orchard, image analysis was applied to soil samples impregnated with a polyester resin. The method is based on local thresholding which allows macropores and soil matrix to be distinguished. Three parameters were used for pore identification: size, shape and orientation. The porosity analysis of 5 levels in the soil allowed differences to be distinguished which were not found with physical measurements. Changes in pore characteristics were clearly distinguishable on histograms of the soil profile. Consequences of the penetration of roots and water in the soil have been discussed. Size, shape and orientation of pores could be used to predict the agronomic behaviour of the soil.