Introduction:
Agriculture is the cultivation of plants and the rearing of animals for food, fiber, medicinal plants, and other products used to sustain and enhance human life. It is one of the oldest and most essential human activities, dating back thousands of years. Agriculture began along river valleys due to the benefits provided by the fertile soil, water availability, and the ease of transportation. Over time, the definition of agriculture has expanded to include various practices and technologies that enhance productivity and sustainability.

Early Agriculture in River Valleys:
- The earliest evidence of agriculture can be traced back to around 10,000 years ago in the Fertile Crescent region, which includes the present-day countries of Iraq, Syria, and parts of Turkey and Iran.
- The river valleys of Tigris and Euphrates in Mesopotamia, Indus in the Indian subcontinent, Nile in Egypt, and Huang He (Yellow River) in China were some of the key regions where agriculture began.
- The fertile soil and regular flooding of these rivers provided the necessary nutrients for crop cultivation.
- Early agricultural practices involved the domestication of plants and animals, including the cultivation of wheat, barley, rice, and the rearing of livestock such as sheep, goats, and cattle.
- The development of irrigation systems, such as canals and dikes, helped farmers control water supply and manage flooding.

Wider Definition of Agriculture:
- Agriculture has evolved significantly over time and now encompasses a broader range of practices and technologies.
- It includes not only crop cultivation and animal rearing but also various aspects of agricultural science, such as plant breeding, soil management, pest control, and agricultural machinery.
- Modern agriculture utilizes advanced technologies like genetic engineering, precision farming, hydroponics, and organic farming practices.
- Sustainable agriculture, which focuses on environmental stewardship, economic viability, and social responsibility, is gaining importance worldwide.
- Agroforestry, aquaculture, horticulture, and agribusiness are some other areas included in the wider definition of agriculture.

NCERT Solutions - Agriculture:
NCERT Solutions is a series of books that provide comprehensive and detailed explanations of various subjects, including agriculture. These solutions are designed to assist students in understanding the concepts and solving problems related to agriculture. They cover topics such as crop production, farm management, agricultural practices, agricultural economics, and more. The NCERT Solutions - Agriculture helps students develop a strong foundation in the subject and prepares them for higher education and future careers in agriculture and related fields.