Mix legumes and grasses to improve the soil fertility, and the nutritional value of the feed. It also improves the yields of the potatoes that you plant next. If you are not able to irrigate, plant the fodder at the beginning of the rains. The mix should include plants that are only cut once as well as other, permanent pasture plants that can be cut several times a year. After every cut, fertilize with ash or composted manure.