How do montains influence where people farm in the koreas?

Crops can not grow well on rocks and without water. Farming in both North and South Korea is traditionally on the lowlands and focused on rice production which requires large amounts of water. Also the soil is not rich and must be fertilized every year making farming labor intensive. For years they used human waste as fertilizer but this proved damaging to health and limited exports. 

Dhariiet beecher stowe