Abstract: An improved rotary soil probe is provided with a frame pivotally mounted on the rear of a truck or vehicle for movement about a horizontal axis between raised and lowered positions. A rotatable wheel is pivotally mounted to the frame for movement about an upwardly angled axis between an extended use position and a folded transport position. The wheel includes probes extending radially outwardly from the perimeter of the wheel. The probes are adapted to receive soil samples as the wheel is rolled along the ground. Plunger assemblies automatically discharge the soil samples on each rotation of the wheel so that the samples can be continuously collected, without the need to stop to clean out the soil samples.