If the small farm is to be a permanent source of food for its owners, it must be managed in a sound fashion that provides a constant source of nutrients, fuel, construction materials, etc. without damage to the land or its productive capacity. Forage crops are important to the small farm as one element of the production system because they can utilize lands that are not easily used for other crops, they can grow rapidly and often can be produced continuously, they serve as principal sources of feed for a number of different kind of animals, and thus indirectly as sources of meat, milk, and eggs. They are inexpensive crops to grow and usually easy to produce. Furthermore, grasses are useful in preventing erosion, and legumes can increase the nitrogen available in the soil for other crops.