Agriculture experts have a message for farmers worldwide: Take care of your soil, and your soil will take care of you. By using the techniques of “conservation agriculture”, they say farmers can save their land and save money, at the same time.

This is becoming more important as the world’s population grows. More people means more food needs to be grown to feed them.

Most modern agriculture looks like long rows of green crops covering large areas of land. They have neat rows of single kinds of plants with uncovered soil in between.

Trey Hill’s farm in the U.S. state of Maryland does not look anything like that. Instead, there are green plants mixed in with what is left from other plants. Together they cover the soil.

"If you don't like your fields to look like a mess -- It has to kind-of grow on you. Yet, I have a lot of other owners and peers that are, like, 'Wow, what you're doing is really exciting.'"

So, what is farmer Hill doing that is different? He is going against farming practices that are thousands of years old.

Most farmers around the world till their fields. That means they turn over and break up the soil before every planting. In modern times they use mechanical equipment to do the work.

In addition to tilling their fields, most farmers leave the soil bare, or uncovered, in the off-season. That is when they are not growing a crop. And many plant the same crop year after year.

All three of these methods can wear out the soil, however.

So some experts are backing the so-called conservation agriculture used by farmers like Hill.

David Montgomery is a professor of Earth and Space Sciences at the University of Washington in Seattle. His newest book is called Growing a Revolution. He spoke to VOA by Skype.

"These principles of conservation agriculture flip all three of those ideas on their head. So, it's a completely different philosophy to not till, to always have the ground covered with either a commercial crop or a cover crop, and to grow a much more diverse rotation."

Farmer Hill plants his crops into what is left of the crop before -- without tilling the soil.

In the off-season he covers his fields with different crops. They hold onto the soil, and prevent erosion, when water and wind remove soil.

The cover crop is not meant to be harvested. Instead, it feeds the soil. University of Maryland soil scientist Ray Weil says these fields will do better in times of extreme dryness.

"This kind of cover, whether it's standing or down here, is going to drastically increase the amount of rain that soaks into the soil."

And, Hill says, this kind of farming is more profitable. Less tilling means using less fuel for his farm equipment. He buys less fertilizer -- which are substances added to the soil -- because his cover crops feed the soil.

Hill, however, is not an organic farmer. He kills his cover crops with chemicals.

But Weil says healthy soils do not have to be organic.

"These soils are full of life. And I bet you could go into even a certified organic field, if it's been tilled, you'll never find these things crawling around."

Of course, this is not a perfect solution. Hill says some of these methods create new problems for him.

"Actually, this field was planted twice because slugs ate the beans the first time. Obviously, not very cost-effective. Seed's expensive. Planter's expensive. Diesel's expensive. So, it cost us a lot of money to learn. But we view it all as a learning process."

Experts are working to help farmers in the developing world, as climate change and rising populations increasingly challenge the world's food growers.