For example, we know how plants use solar energy, moisture and carbon dioxide in photosynthesis and there is a great deal of information on how and why different plants react differently to various environmental conditions. Similarly, we know how a particular nutrient influences growth, reproduction and lactation in an animal. The challenge is to assimilate this information into a form that the rancher and farmer can make use of in the context of total ranch management. Modern computer technology has given us the means to do this because of the ability of the computer to assimilate enormous matrices of information very rapidly. Therefore, separate parameter sets containing the coefficients used in the equations are required for each plant species.
Pastures can consist of one or more species.
Within each species, the biomass is divided into live, standing dead and litter material, and further split into digestibility classes. If radiation data are not available, they can be computed from sunshine hours or from temperature and the coordinates of latitude and longitude. Some pastures consist of a number of populations of different species or cultivars. Phenology is modeled by following each species through a number of stages. After vernalization, the plant enters the vegetative stage.