Rotate Crops different crops take different nutrients from the soil. They also have different pests and diseases. These can build up if you plant the same crop again and again. To reduce pests and diseases and to keep your soil healthy, rotate your crops. This is where you plant a crop from a different family (note that tobacco, tomatoes are in the same family as potatoes).
After your potato crop, plant maize. Then plant cabbages, then beans. After beans you can return to potatoes. You will have healthier soil and a better crop. Beans and peas are legumes. They are very good for your soil as they add Nitrogen.