Potato farming is usually done in the sandy soil. This type of soil contain very less or minimal organic matter and this cannot hold the water. On the contrary, farmers use chemical Organic Manure more than required for the potato crop which gets dissolved into the water and go far below the roots.
This means high cost of farming or waste of money. Potato crop require nutrients for a long period of time but the farmers puts most of the Organic Manure during preparation of the farm which may not be available after some time. Potato is a crop with roots and for this the soil must be loamy and soft so that the potato tubers become big, shiny and of similar size.