Penetrometer measurements for screening soil physical variability

Abstract

Spatial variability of soil physical conditions can easily be assessed by means of a penetrometer. This is demonstrated at a reforestation site near Hannover on a Podzol-Cambisol (FAO). Reafforestation was performed after deep ploughing to a depth of 80–100 cm. Penetration resistance was measured as kg cm −2 with a dial penetrometer. The data showed recompaction after deep ploughing. Furthermore, it became evident that measuring penetration resistance is a simple and inexpensive way to obtain a preliminary impression of the area to be examined. Based on these results, locations with minimum, maximum and average values can be chosen for further investigations, depending on the aim of the investigation. For screening purposes it is not important whether penetration resistance is expressed in physical units or other values, such as the number of blows per unit depth with a falling-weight penetrometer. In these circumstances the low specificity of penetration resistance is not a disadvantage, but enables any change in soil physical conditions to be detected.