Above soil plant litterfall

When litter falls from the leaves (or sometimes stems or grain) of a plant, C_{Leaf→SurfaceLitter} or N_{Leaf→SurfaceLitter}, it first enters a microbial-inactive pool on soil surface, C_{LitterSurface} and N_{LitterSurface}. After that it continues into the litter pool(s), C_Litter1(2) and N_Litter1(2), and the humus pool, C_Humus and N_Humus, at continuous rates:

                                              (6.1)

                                             (6.2)

where l_l1 is a parameter. Similarly the parameters l_l2 and l_h in the corresponding equation gives the flows to the second litter pool (if selected) and the humus pools.