How to handle data entered as ranges or greater than X

In several draft datasets, data for field slope or planting depth were entered as ranges, while soil depths or depth to water table might be expressed as greater than a reference depth. The current template and tools only accept numeric values.
One option would be to allow such data to be entered either as single values or strings (e.g. '3 - 4') and then parse the data in the QC tool.