Nothing is more thrilling to a farmer than planting a seed and standing back to see what happens. Every year about 2.1 million U.S. farmers do just that.

Some plant thousands of acres; others plant a patch of land the size of a small backyard. Still others take former industrial sites in places such as Detroit and Philadelphia and convert them into urban farms.

They are all participating in a 12,000-year-old ritual that has allowed humans to escape the role of hunter-gatherer and create a society where big ideas can be pursued. Once crops could be grown efficiently and animals could be domesticated for milk and meat, humans were free to think beyond their next meal.

Today, farming is done across the globe. In China, farmers have cultivated rice for more than 7,500 years. In Bolivia, another ancient crop, quinoa, attracts extraordinarily high prices among so-called foodies in the U.S. In Brazil, ranchers raise beef cattle similar to those first brought to South America from India.

Agriculture is important everywhere, but nowhere is it more important than in the United States. It was agriculture that helped a handful of colonies blossom into a booming economic powerhouse and world leader. Last year, U.S. farmers raised more than $400 billion in crops and livestock on slightly more than 900 million acres.

U.S. farmers feed their fellow Americans — and much of the world. U.S. wheat, for example, can be found in noodles sold by a Tokyo street vendor, in flat bread baked in a stone oven in Algiers or in a steamed bun sold in a Jakarta restaurant.

Other crops and products fill the shelves of shops and stores around the world, helping to feed 7 billion people.

Who is the American farmer? Though statistics tell us that the average age is about 58 and the average farm is a little more than 400 acres, no farmer is typical. Just as every family is different, so too is every farmer. Some families have farming in their blood; they have tilled the land for generations. Others are new to it. Starting small, they add equal parts of inspiration and perspiration in an effort to grow new life and a livelihood from the land.

Ours is a society that reveres high technology. Smart phones, electric cars and all manner of computer-enhanced gizmos are seen as the wave of the future.

Yet, without agriculture, without food and fiber, none of that would exist. Before there could be iPhones, there had to be plows and tractors and combines.

National Ag Day is March 18. It is a day to talk about how food is produced, and about the integral role farming and ranching play in society.

And it is a celebration of the most important industry in the world.