What is the significance of popularizing iron farm tools and farming?

Changed the past slash-and-burn farming, greatly improved productivity, and entered the intensive cultivation period; China was a country dominated by agriculture in ancient times. The use of iron plows, Niu Geng and iron farm tools changed the slash-and-burn farming with low productivity and environmental damage in the past, greatly improved productivity and production efficiency, thus promoting the improvement of production relations, and the landlord class began to rise.