Measurement and characterization of macropores by using AUTOCAD and automatic image analysis

Macropores (with equivalent diameters greater than 1600 μm) were quantified under no-till and conventional tillage practices by using AUTOCAD and automatic image analysis. To quantify macropores, undisturbed soil blocks (50 by 50 cm) were impregnated with plaster of paris slurry. After the plaster of paris set, soil layers were taken out in 5 cm increments to a total depth of 60 cm. At each soil plane pictures were taken by a 35 mm camera and macropores were traced on transparent acetate sheets; (...)