John Havlin: Soil Scientist

If soils do indeed achieve the higher profile they so desperately need, John L. Havlin will be one of the people to thank. The professor at North Carolina State University is past president of the Soil Science Society of America, and a dedicated campaigner whose work is helping to establish the House of Representatives Soils Caucus and a $4 million Smithsonian educational exhibit on the subject, opening in 2008. The goal is to help the national museum’s six million visitors a year “understand how soil is intricately linked to the health of humanity, the environment and the planet.”

It’s often said that the Native Americans had a special relationship with the Earth. Do you think we need to rekindle a relationship with the earth, meaning the soil beneath our feet?

There’s no question that people today do not understand the importance and value of soil and other natural resources to their very existence. Yes, it needs to be rekindled. People need to understand that if we didn’t have that thin layer of material on the Earth’s surface we couldn’t exist on this planet. And when I say it’s a thin layer, let me use this example from our grade: If you take an apple, the thickness of the skin of the fruit is approximately the soil on the Earth’s surface. And if you slice that apple in sections 32 times, one of those small sections is the amount of land that we produce food on.

Is part of the problem the fact that so few Americans make a living from agriculture?

Absolutely. We have less than two million farmers, people on the land, according to USDA statistics. In 1900, farmers were 70 to 80 percent of the population.

In the 1960s we had what was called the green revolution, which increased agricultural productivity. And I think people assume that this cycle will continue endlessly, that by using fertilizers and pesticides we can continue to increase farm yields. But when does soil depletion cause that to change?

Technology has been and is being developed that will enable adequate food production without degrading the soil. Obviously, you can go back in history and see many, many examples of failed civilizations and many failures in this country due to soil degradation. A civilization cannot sustain itself without productive soil. But what folks don’t understand is that we have made huge strides in this country in technologies to enhance the productive capacities of our soils.

What are some of those advances?

We know now that you can’t leave the soil surface bare in environments that are highly erodable. For example, we have a program in the U.S. that pays farmers to take land out of production and put it back into grass. It really has protected soils in the Great Plains, predominantly, from wind erosion. It also provided resources to take highly erodable lands out of areas that are influenced by water erosion. Our experiments throughout the Great Plains show that soils are becoming more productive under those circumstances. The practice of soil tillage leaves crop residues on the surface and can increase productivity.

Is it fairly widespread, the use of covers like that?

It’s increasing nationally at fairly decent rates. For instance, in North Carolina in the 1950s and 1960s, the soil was fully tilled before planting. But now we have no-till, which means that soil is not disturbed in the planting and production of a crop. And now in North Carolina, depending on where you are, 30 to 50 percent of the producers are using these methods.

Another big trend obviously is toward organic agriculture. And certainly this should have multiple soil benefits.

There’s no question that if organic agriculture incorporates those kinds of technologies in which soils are not disturbed, and are protected from erosive losses of the valuable organic matter, then productivity will be enhanced.

Are you optimistic in the long run that we will preserve our soil health in some of the richest farmland in the world?

Only if we educate our young people so that they understand where food comes from, how it’s produced and why soils have to be protected. One issue is degradation of soils, but the other is land use. Many cities were originally established in areas with very high soil productivity. Chicago, for example, was developed because there was a large body of water, and some of the most productive soils on the planet. But Cook County no longer has anything to do with agriculture. And the surrounding counties have been zoned out of farmland, too. And that’s the real challenge: we have to figure out a way to have an additional three billion people and still maintain our most productive lands for the purpose of growing food. If we continue to build parking lots and shopping malls on our most productive soils, we’re eventually not going to be able to be the agricultural exporter that the U.S. has been in the last century.

Paul Gleason contributed research to this interview.