Soil fertility can be conserved and renewed by crop rotation and cover crops. Crop rotation involves changing the crop planted in a particular field each growing season, which helps to prevent depletion of soil nutrients and build up of soil-borne pests and diseases. Cover crops are crops that are grown specifically to protect and enrich the soil rather than for harvest. They help to reduce soil erosion, add organic matter to the soil, and fix nitrogen from the atmosphere, which can improve soil fertility. Together, these practices help to maintain and improve soil fertility over time, which is important for sustainable agriculture.