The correct answer is D. Shifting cultivation.
Crop diversification, use of fertilizer, and making check dams are all practices that can help to reduce soil erosion. Crop diversification helps to prevent soil from becoming compacted, and the use of fertilizer helps to improve soil health. Making check dams helps to slow down the flow of water, which can reduce the amount of soil that is eroded.
Shifting cultivation, on the other hand, is a practice that can actually increase soil erosion. This is because it involves clearing a piece of land for cultivation, then abandoning it and moving on to a new piece of land after a few years. This process leaves the land exposed to the elements, which can lead to soil erosion.
In conclusion, the correct answer is D. Shifting cultivation.