As all crop models do, STICS characterises the plant subsystem by its shoot biomass and leaf area index. Once calculated, the shoot biomass is partitioned into the various organs and feedback occurs between this partitioning and shoot growth for indeter-minate plants. In STICS, indeterminate denotes species for which there is significant trophic competition between vegetative and harvested organs. This definition differs from the botanical one, and species like rapeseed or pea are considered as determi-nate in STICS. This is because the assumption of independence between vegetative and reproductive growth is acceptable, though these two developmental scales can overlap. Meanwhile, species like sugarbeet are regarded as indeterminate because the growing tuber greatly influences shoot growth. The harvested organs (grains, fruits or tuber) are the only ones characterized in terms of number (see § 8). The present chapter touches on various interrelated processes that are covered in other chapters. See figure 4.1 to see how the paragraphs of this chapter relate to other chapters.