When it comes to needing soil testing and determining what varieties of forages will best meet your needs, there is no better source of information than your Cooperative Extension Service agricultural professional in your county. To determine fertilizer application, you will need to soil test your pasture. Most soil tests are conducted fairly quickly at state-level soil testing labs; many are associated with the land-grant university in your state. Insofar as variety of winter annual to plant, you will most likely find three or four popular choices depending on your locale and what is best suited for your growing area; it may be rye grass, wheat, or other winter annual. Many area suppliers of seed also provide a ''winter mix'' that contains a variety of cool-season annuals, as the different grasses have small differences in their optimum time of growth in the year. On most farms, the decision to overseed pays off economically and esthetically and assists with soil conservation in heavy use, erodable areas. Check with your local Cooperative Extension professional as soon as you can.