The Chinese were the first to learn the process of making strong iron plows, also very helpful when it came time to harvest their crops. They learned that they could pour melted iron into molds-and make anything else a lot stronger than it was before. The iron plows were used to push dirt away from the row that was being plowed so soil wouldn't pile up in front of the plow. With ironwork, the people of the Han Dynasty could even innovate their own invention. By making the wheelbarrow stronger, it would make it more durable to hold more crops.