February 25, 2008 | General

Climate Change Connections: Vote For Soils in '08

BioCycle February 2008, Vol. 49, No. 2, p. 20
Sally Brown

I watched the clip of Hillary Clinton’s emotional moment in New Hampshire and really felt for her (at least up until the point where she started with I’m right and they’re wrong). She’s under a lot of stress at the moment and I understand how all those demands can really get to you. She is trying to be a presidential candidate, senator, wife, mother, lawyer and so on. I get that way and I am just trying to juggle the demands of the job and the family (a kid who still requires transportation and a dog who thinks that three miles is just a warm up). There is just so much I can be to however many people before I get exhausted.
What this is leading up to is how our soil feels. Now grant you, as a soil scientist I am well aware that soil consists of the mineral fraction, organic fraction and pore space, and none of those components is really what one would call emotional or even sentient. And so, perhaps a better way to think of this is what is the health of our soils and what are we asking from them?
Soil was not something that I thought much about for the first 30 or so years of my life. Now, I love soil, but I would venture to guess that most people don’t spend a lot of time thinking about it. On a very basic level, soil is essential to our survival. Even before I knew about soils I knew that I loved to eat. And all of the food that we eat is grown in the soil (red and yellow peppers in the winter not withstanding). Some historians have argued that civilizations – meaning the artists, writers and thinker components of our societies – are made possible only by excess food. If a society does not grow sufficient food to create a surplus, there aren’t any artists, writers and thinkers. There are only subsistence farmers.
People also have argued that when soils fail to support the productive demands placed on them by societies, the societies themselves collapse. A classic example is the cradle of civilization that is now called Iraq. Another example closer to home is the Great Dust Bowl that forced the migration of thousands to California. Books have been written about this. Collapse by Jared Diamond is one. Dirt by David Montgomery is another.
So what is going on with soils these days? The “Green Revolution” is one thing. Here the introduction of synthetic fertilizers, large-scale machinery for agriculture, the ability to cost-effectively pump groundwater for irrigation and improved seed cultivars have enabled our soils to produce significantly more food and feed many more people than had been thought possible. Biofuels are a more recent “demand” on soils. With biofuels, we’re also asking the soil to grow our gas. In the U.S., this is primarily in the form of corn-based ethanol with biodiesel coming in a distant second. However, we’re just starting to understand how this type of production can reduce the tilth of the soil.
High prices of corn, as a result of the demand for its use as fuel as well as for food, have resulted in corn cultivation on land that had been taken out of production – land too sensitive to grow this industrial crop. Corn has very high fertilizer and water demands. It is like the Barry Bonds of agronomy. Nebraska was one of the states that lost a lot of population in the 1930s. As the soil blew away (Dustbowl), so did the people. In Nebraska rainfall is often insufficient, so water is being pumped from below. The National Academy of Sciences recently issued a report on the potential damage that the corn growing frenzy will have on our water resources.
Soil scientists are raising alarms as well. A recent study showed that organic carbon concentrations in soils fertilized with synthetic nitrogen (N) are actually lower than those either not fertilized at all or fertilized with organic sources of N. We’ve already recognized that conventional tillage effectively destroys soil structure and mineralizes well over half of a soil’s organic matter. But we are also depleting our groundwater resources and destroying our soil’s tilth.
Tilth is a way to express the health or level of stress on the soil, since it relates directly to how much organic matter is in the soil. More organic matter, better tilth. Carbon, the backbone of soil organic matter, is the key to improved soil structure, soil water holding capacity, the ability of soils to let water infiltrate and a healthy soil microbial community, among other things. The carbon in soils provides the single largest storage bank of carbon on earth, more than the plants, more than in the ocean.
This means that if we take care of our soils, they may not win the New Hampshire primary but they will continue to be able to feed us and potentially even fuel us if we’re smart about it. In addition to this, soils have the potential to remove a great deal of the carbon that we’ve pumped into the atmosphere. Rattan Lal, president of the Soils Science Society of America, said that 300 million tons per year of carbon could go into soils in the U.S. with proper tillage and management practices. In other words, if treated well, the soils may also save us from drowning (rising sea levels are predicted with global warming).
So are we treating our soils well? Yes and no. In Italy, compost application for soils is required and subsidized by the government. The U.S. (and South America) have the largest percent of farmland in no till agriculture of any of the continents. This is great. Organic farming in the U.S. (which advocates practices like the use of organic fertilizers that are high in organic matter) is growing, but still represents a very small portion of total acreage.
On the other hand, corn is the current bonanza crop in the U.S. Corn production using conventional agronomic practices is not sustainable, doesn’t use organic amendments or limit water use to slow depletion of aquifers. Salinity and desertification are growing threats. Soil is something that we need to pay special attention to. Here the stakes are even higher than for the 2008 election, and that is saying a lot.
Sally Brown – Research Associate Professor at the University of Washington in Seattle – is a member of BioCycle’s Editorial Board, and will be authoring this regular column on the connections of composting, organics recycling and renewable energy to climate change. E-mail Dr. Brown at

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