Grain size sorting on tidal sandbanks

A dynamic barcode label system includes label base with a plurality of discrete preprinted barcode character media positioned thereon in side by side relation to form a single barcode indicia sequence. The label base includes a face wall with an elongated window formed therethrough and a rear or backing wall. The barcode character media comprise barcode character strips having a plurality of barcode indicia sets printed thereon and representing a plurality of respective characters. The character strips are slidably adjusted relative to the window to select the characters to be represented by the label. The character strips can be formed as endless barcode character bands supported on a character band support on the rear wall of the label base. In one embodiment of the present invention, the label base is sheet material and the barcode character media are adhesively backed barcode decals, each of which has printed thereon a barcode indicia set representing a single character or symbol. The barcode decals are adhered to the label base in side-by-side relation to form a single barcode indicia sequence.