The invention concerns agricultural apparatus (12,13,14). The apparatus (12,13,14) collects earth and deposits loose/destoned soil as it moves across the ground, and comprises a sensor arrangement (36) to determine the depth of the deposited soil. The invention also relates to a method of separating earth into soil and larger objects, depositing the soil, and determining the depth of soil deposited. Records of the soil depth in one or more particular locations may also be saved for use or reference in subsequent operations.