Graze Anatomy

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THE GOOD EARTH

All these benefits-more humane livestock farming, healthier humans, fewer floods, a richer and more natural landscape-are powerful arguments for a return to perennial pasture. But then there is the greatest potential benefit of all: a massive reduction of carbon emissions.

Soil is a mix of minerals from the earth's crust, a bit of living matter, and dead and decayed plant mass. Pure prairie builds this matter: the richest of virgin soils in the Midwest once ran to 10 feet deep and were about 10 percent organic. What's left of those soils now typically contains less than half that amount of organic matter. But perennial pastures can restore the original richness of the soil in a decade or so.

The heart of all organic matter-about half the total-is carbon, the very stuff of global warming. When we speak of farming's carbon footprint, we generally calculate such things as internal combustion in tractors, transportation, and processing. But this ignores the fact that row-crop farming releases into the atmosphere carbon that has been stored in the soil. Researchers have found that tillage releases not only carbon dioxide but also nitrous oxide and methane (both global warming gases) by triggering the decay and erosion of topsoil. Without exception, all of the tillage systems examined in a recent study published in Science contributed to global warming, and the worst offenders were conventionally farmed corn, soybeans, and wheat. Fields of perennial crops in the same study pulled both methane and carbon dioxide from the atmosphere and stashed them in the soil. There is even some evidence that perennial grasslands are often better at sequestering carbon than forests are.

The Rodale Institute has tracked the amount of carbon sequestered by organic farming for nearly 30 years. Working with the Pennsylvania Department of Environmental Protection, it has found that such practices have an effect similar to that of perennial pasture in storing carbon in the soil in the form of organic matter. In 2008, researchers with the project concluded that converting all of the nation's cropland to organic agriculture would suck up enough carbon to offset
25 percent of our total fossil fuel emissions. In other words, we would have a continent-wide carbon sink. If that projection is right, such a shift would yield a net reduction of emissions greater than the Obama administration's target for 2020 and put us well on the way to meeting the target for 2050. True, these numbers are for organic farming, but perennial pastures arguably store even more carbon because of their deeper roots, and they almost eliminate the fossil fuel energy that organic farming uses for tillage.

There are good reasons to approach such landscape-level calculations with caution, however, simply because quantifying carbon sequestration is difficult. There are just too many variables. For instance, Randall Jackson, an ecosystem scientist at the University of Wisconsin at Madison who specializes in the study of pasture systems, says evidence suggests that rising global temperatures are already stimulating microbial activity in soils, which in turn may be increasing decay and adding to the release of global warming gases. But even a skeptic like Jackson is confident that conversion of industrial corn and soybean fields to permanent pastures would head us in the right direction. Simply put, conventional cornfields are a carbon source; pastures are more likely to be a sink. If we can get our beef and milk from a sink instead of a source, we probably ought to do it.Combining pasture and organic crop farming may further enrich the soil and improve the bottom line. While many of the producers from whom Churchill buys stock are pure grass farmers who have sold their tractors and converted all of their land to managed pastures, many are not. And Francis Thicke's operation is not pure grass but rather an organic dairy. He also grows some grain and sells it.

I talked about this with Fred Kirschenmann, whom I first met in the late 1990s at his 3,500-acre organic farm in North Dakota, an operation he took over in 1976 after getting his Ph.D. in religion. He told me then that try as he might, he could not make organic farming pay without livestock. By bringing cattle into the mix, he gained the manure, controlled weeds through grazing, decreased tillage and energy use, and found a use for low-market-value crops such as grass and alfalfa, which can help build soil and stop erosion. These crops were also once regarded as critical to prudent crop rotation. But on conventional farms, nutrients lost to depletion and erosion are simply replaced by chemical fertilizer.

Kirschenmann still runs his farm, but he also serves as a distinguished fellow at Iowa State University's Leopold Center for Sustainable Agriculture. He told me last year that his earlier assertion about livestock has been strongly borne out. Studies throughout the Midwest have shown sharp increases in profitability when livestock is factored in-not just beef and dairy cattle but free-range chickens, hogs, goats, and sheep. Permanent pasture, in other words, is not an all-or-nothing proposition. The important point is to bring back the grass, and that can be done with full-scale grass-fed dairy and beef operations or by introducing a little bit of pasture here and there on organic or even conventional farms. This flexibility means that the benefits of pasture can evolve incrementally.

The presence and diversity of livestock on grass farms make the whole business a lot more interesting and plain pleasant, says Richard Cates, who teaches the operation of grass systems at the University of Wisconsin at Madison and is himself a grass farmer. He sees interest in his classes rapidly building among farm-raised students who are looking to become free-range people. And that is really the last of the many benefits of grass farming: it may stem the flight of the brightest and best young people from the small farm towns of the Midwest.

True, not every farmer can do it. Grass farming is more intellectually demanding than conventional farming. It deals in complexity and in the end is more an art than a science. But Cates and others believe that's one of its appealing features.

And while it may be complex on the level of an individual farm, the idea seems simple and eminently doable when compared with the vast array of costly technologies on the table for reducing our energy use and combating global warming. To be sure, enlightened federal farm policy could go a long way toward encouraging a shift to grass. Our current system of subsidies encourages industrial agriculture, which is to say that our nation's worst environmental problem is taxpayer funded. What is most impressive, though, is that the solution is a bootstrap operation; it is developing in spite of bad policy. The driver is the market pull, and it is gaining strength. Everyone I spoke to for this story agreed that demand for grass-fed products is well ahead of supply. Todd Churchill says the market could easily support 10 times the number of grass farmers now in business. We tend to associate exponential growth with environmental harm, but in this case it would be good news, an economic solution designed by nature's economy and scaled up by market demand.