Worksheet(s) in the FABLE Calculator:
⇒ 5_feas_livestock
⇒ 6_feas_crops
Any discrepancy between targeted and feasible pasture area and/or cropland area needs to be channeled back through the causality chain up to the consumption level (cf. Figure 2). Livestock is the first sector that should be adjusted. The targeted pasture area (cf. Pasture) is first multiplied with the pasture adjustment ratio. This affects the ruminant herd number (cf. Herd) which is recomputed as the feasible pasture area times the ruminant density. The feed demand for all crops and processed products from crops (cf. Feed) is first multiplied by the cropland adjustment ratio. Then, the new feed demand based on feasible ruminant herd number is computed using feed requirements. The feasible feed demand is the minimum value between the new feed demand based on adjusted herd and the adjusted feed demand based on cropland adjustment ratio. The feasible herd is finally computed as the feasible feed divided by the feed requirement. Exports and final human consumption of livestock products are proportionally reduced to the reduction of the feasible herd compared to the targeted herd.
For crops, targeted harvested area for all the crops (cf. Crops) is multiplied by the cropland adjustment factor (i.e. harvested area by crop is reduced proportionally to the total cropland reduction). Feasible production is computed as the feasible harvested area by crop times the productivity per hectare. Feasible feed is taken from the previous step and imports are fixed. Feasible final human demand, feasible exports, and feasible processed demand are adjusted to compensate for the remaining crop production reduction so that market balance is ensured. Note: if the scenario Fixed trade is selected, exports are not adjusted proportionally to the production reduction resulting from the land constraint: the reduction is distributed between feed demand and final human consumption only.