Land Allocation
Land allocation comprises Initial land-cover, Land-Cover Model and Livestock Production Systems
Livestock Production Systems, description Figure: Scheme showing the distribution of livestock production over mixed and landless systems and pastoral ones, the calculation of the number of animals from the milk production per animal for diary cattle, and carcass weight and off-take rate for beef cattle, sheep and goats, feed conversion efficiency, composition of feed, and finally total feed crop, residue consumption and area of grassland via the grazing intensity. IMAGE 2.4 includes a model for describing pastoral and mixed/landless (industrial) livestock production systems. This is needed because most of the increase in ruminant meat and milk production has been achieved by increasing the production in mixed and landless production systems, and much less so in pastoral systems. These systems have different characteristics. Pastoral systems rely mainly on grazing by ruminants, whereas mixed/landless systems have integrated crop and livestock production in which animal diets consist of a mix of several feedstuffs. Landless ruminant production systems are included in mixed + landless systems because they have the same inter-relations (food crops, fodder, manure, etc.) with crop and grass production systems as livestock production in mixed systems do. Mixed and landless systems were assumed to occur in mosaics with arable land, while grid cells with pastoral systems have less arable land. This is to ensure that the production of crops for feeding animals and possibilities for disposal of animal waste as manure, required in mixed and landless systems, are available nearby. The fraction of arable land in cells with mixed and landless production systems varies from one world region to another. The remainder of all grassland, including low-productive grassland, was assigned to the pastoral systems. Pastoral systems are used generally in areas with low population density and away from intensive crop production areas. In these mixed/landless systems the by-products of one activity (crop by-products, crop residues, and manure) serve as inputs for another. The two broad production systems serve as a basis for allocating fertilizer and animal manure application in the Nutrient Management Model. For details about the production systems we refer to Bouwman et al. (2005) and Bouwman et al. (2006).
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