Evaluation of the quantitative use of a cone penetrometer considering differences between models and between operators

Abstract

To promote the quantitative use of cone penetrometers, we analyzed patterns in the variation and distribution of penetration resistance data that were caused by differences in models and operators. Because of differences in the mechanism of pressure detection between models, the values of penetration resistance tend to be model-dependent around the boundary area above and below the plow pan. This prompted us to carry out data comparison between models. Nine operators surveyed 60 points each over the entire area of an 0.31-hectare field. The operators were two men and two women in their 40s, a man and two women in their 50s, and two women in their 60s. When weak women or elderly persons penetrated from the plow layer to the plow pan with the cone tip of the cone penetrometer more slowly than strong men, it appeared that the penetration resistance data around the boundary area above the plow pan could be collected more accurately. We conclude that the data necessary for creating three-dimensional distribution maps of soil hardness can be collected if the range of up to 3000 kPa of penetration resistance and 45 cm depth can be measured using a cone penetrometer, making it suitable as a machine setting.