No-till farming has been around since the 1960s, when it was developed to reduce erosion of valuable topsoil from cropland. Since then, the realization of the method's other benefits--reduced need for irrigation, less labor for farmers, increased soil quality--has encouraged its adoption across the U.S. and around the world. In recent years, however, interest in no-till has risen due to its greenhouse gas benefits, which have farmers seeing another kind of green: cash.

No-till farming, as its name indicates, does away with the mechanical churning of the soil between crops. Rather than being plowed under, agricultural wastes are left on top of the soil, where they decompose more slowly. The intact soil suffers far less erosion, retaining more nutrients. In addition, it holds water more effectively and, with minimal compaction by heavy equipment, is well-aerated. Less tillage of soil reduces labor, fuel, and machinery costs for farmers.

However, special equipment to perform no-till farming is expensive, and in the transition from conventional tillage to no-till, farmers often experience reduced yields. Without tillage to eliminate weeds, no-till farmers apply more pesticides and herbicides and are likely to rely on genetically modified plants, which bring along their own environmental concerns. If fertilizer is applied, additional measures must be taken to inject it into the soil; otherwise, manure spread on top of a no-till field creates polluting runoff into waterways.

Progress in Battling Erosion

Rates of erosion in the U.S. have greatly declined in recent years, according to the U.S. Department of Agriculture. The agency attributes the decline to its encouragement of conservation tillage, which includes no-till farming, and to the Conservation Reserve Program, which retires plots of highly-erodible cropland.

Still, the rate of erosion is unsustainable. According to a 2006 study, the U.S. is losing soil to erosion 10 times faster than it can be naturally replenished. Erosion from cropland contributes to algal blooms in coastal waters, which are creating dead zones in the Gulf of Mexico and other bodies of water. For every pound of food on the grocery store shelf, it's estimated that two to seven pounds of topsoil were lost.

For erosion reduction and other environmental benefits, no-till farming has spread rapidly around the world. About 18 percent of U.S. cropland and 30 percent of Canadian cropland is no-till. South American countries have widely adopted the no-till method; by the end of 2004 half of Brazil's farmland was no-till. In one of the driest Australian states, no-till farming makes up 92 percent of the farmed acreage.

Growth of No-till Cropland in Brazil, 1975-2003

Source: EarthTrends, 2008 using data from FAO, 2004.

A New Incentive

Environmental concerns have driven farmers around the world to switch to no-till farming. But, with the 2003 opening of North America's first voluntary carbon market, the Chicago Climate Exchange (CCX), farmers in Canada and the U.S. have a new incentive to switch--they get paid to do it.

Under the terms of the CCX, no-till farming counts as a carbon offset. Contracts for these offsets are traded in a sort of carbon stock market, where they are purchased by corporations, governments, and other organizations. Though voluntary, the offsets are legally binding and subject to independent verification. The compensation farmers receive fluctuates, but one Wisconsin farmer estimates he annually earns an extra dollar or two per acre for a practice many farmers are already doing anyway. Only farms across the U.S. and Canada are eligible for CCX. However, it's possible that the international climate treaty that replaces the Kyoto Protocol in 2012 will offer carbon credits for no-till farming in other countries.

Even so, proponents recognize that no-till farming is merely a stopgap for the time being and not the final solution to reforming the carbon footprint of agriculture. But for now, many farmers are happy to comply with a method that makes ecological sense and pays too.

Top photo by Bizzy Girl via Flickr

RELATED LINKS:

Chicago Climate Exchange

Seattle Post-Intelligencer, 1/22/08: "The Lowdown on Topsoil: It's disappearing"

Earthtrends

Livestock Sector Drives Increasing Water Pollution

World Map of Areas Affected by Water Erosion

Agriculture and Food Searchable Database

November 2007 Monthly Update: The Multiple Dimensions of Water Scarcity