Fig. 4. Fluorophore changes in bulk water-extractable C extracts over a 7-d incubation. (I) Wheat straw, Day 0; (II) wheat straw, Day 7; (III) crimson clover, Day 0; (IV) crimson clover, Day 7. Contour interval on all plots = 25 relative intensity units. For a definition of Fluorophores A, B, C, and D, see the Results section.