What was one of the primary results Chinese civilizations settling in river valleys?

The Chinese civilizations that settled in river valleys, particularly along the Yellow River and Yangtze River, developed advanced agricultural techniques that enabled them to produce abundant crops. These techniques included:

- Irrigation systems: The Chinese built extensive irrigation systems to channel water from rivers and streams to their fields, ensuring a reliable water supply for their crops.

- Crop rotation: Chinese farmers practiced crop rotation, alternating different crops in the same field to maintain soil fertility and prevent pests and diseases.

- Fertilizers: Chinese farmers used various types of fertilizers, including manure, compost, and green manure, to improve soil fertility and increase crop yields.

- Seed selection: Chinese farmers carefully selected and bred seeds to improve the quality and yield of their crops.

These advanced agricultural techniques allowed Chinese civilizations to produce large surpluses of food, which supported their growing populations and enabled them to develop complex societies and advanced civilizations.