The correct answer is: a) Jhum cultivation.
Jhum cultivation, also known as shifting cultivation or slash-and-burn agriculture, is a traditional agricultural practice in which farmers clear a piece of land by cutting down trees and burning the vegetation. The ashes from the fire provide nutrients to the soil, and the farmers plant crops in the cleared area. After a few years, the soil becomes depleted of nutrients and the farmers move on to clear a new piece of land. This practice can lead to soil erosion and loss of fertility.
Mulching is a soil conservation practice that involves covering the soil with a layer of organic material, such as leaves, straw, or compost. Mulch helps to protect the soil from erosion, retain moisture, and suppress weeds. It also helps to improve soil fertility by adding organic matter and nutrients.
Crop rotation is a system of farming in which different types of crops are grown in the same field in a planned sequence. This helps to prevent the build-up of pests and diseases, and it also helps to improve soil fertility.
Terrace farming is a system of farming that involves building terraces on hillsides. This helps to reduce soil erosion and makes it possible to grow crops on land that would otherwise be unsuitable for agriculture.
In conclusion, jhum cultivation is the agricultural practice that leads to soil erosion and loss of fertility. Mulching, crop rotation, and terrace farming are all practices that help to conserve soil and improve soil fertility.