A model provides information and expertise that growers can use if packaged
as a management tool that is easy to use and increases profitability. Such
tools can be simple, such as a ruler, or complex, such as large-scale deci
sion support software. The latter are difficult to sustain due to the high
costs of support, coupled with a relatively small user-base. Model-based to
ols need to be simple and easy to use in order for growers to use them long
term.