Effect of straight and spiral sugar beet extraction paths and lift acceleration on soil tare and relative soil adherence

Abstract

The soil tare, i.e. the relative amount of soil adhering to sugarbeet after harvest, should be reduced to lower the increasing costs of soil disposal and to prevent negative effects on the environment. The soil loosening effects of nine methods of lifting by extraction and one reference treatment were studied by evaluating the net soil tare (on a clean beet basis) and the relative soil adherence at the stage between lifting and cleaning of beets produced on marine clay loam soils in the Netherlands in 1994 and 1995. In the reference treatment, the beets were dug out carefully. The extraction treatments used were vertical (no spiral), large pitch spiral and small pitch spiral lifting paths at slow, moderate and quick accelerations. The net soil tare was lowest for the quick, small pitch spiral motion: respectively 14% in 1994 and 6% in 1995 for comparable beet properties and normal soil moisture conditions. The relative soil adherence increased significantly with decreasing soil tare. This phenomenon was attributed to the original in situ soil adherence: some soil close to the surface of the beet is reinforced by rootlets or is located in surface niches and adheres strongly to the beet. As soil loading during extraction was non-compressive for all extraction treatments, it is unlikely that the extraction treatments induced the strong soil adherence at low soil tare.