China's agricultural/plowing technology didn't recover to the pre-Mongolian-conquest level until the 1800s. Possibly because China's population fell 40-50% duri

China's agricultural/plowing technology didn't recover to the pre-Mongolian-conquest level until the 1800s. Possibly because China's population fell 40-50% during the conquest and subsequent Mongol rule, which must have destroyed a lot of knowledge.