the term k, which would probably be called a constant, but is not, must be determined experimentally for each material . It would not apply above a certain moisture content which would be the dividing point between combiend and the free moisture. Sines there is an overlapping between thee, no exact points exists. Furthermore, the value will very/ owing to weather aond soil conditiond under which the product was grown, the variety, its treatment between harvest in the time drying is started, etc.