The correct answer is option 3: fallowing. Fallowing is a practice where a piece of land is left uncultivated for a certain period of time to restore its fertility. This is done by allowing natural processes to occur, such as the breakdown of organic matter, the replenishment of nutrients, and the improvement of soil structure. During fallowing, the land is not used for cultivation and is usually left with vegetation to protect the soil from erosion and enhance the accumulation of organic matter. This practice helps to improve the nutrient content and moisture retention capacity of the soil, making it more suitable for crop cultivation in subsequent seasons. Fallowing is an effective and sustainable method to restore the fertility of the soil over time.