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Conservation Tillage

Tillage methods

Conservation tillage (top) vs.
standard cultivation.

When people hear "air pollution," they usually think of automobiles or factories. Much of this pollution, however, comes from a surprising source - farming.

Standard cultivation techniques, practiced on more than nine million acres in the Central Valley, rely on intensive soil disturbance and diesel-burning machinery. The California Air Resources Board identifies land preparation as a major source of air pollution in the Central Valley.

The San Joaquin Valley Air Pollution Control District estimates that crop cultivation and harvest contribute nearly twice the amount of particulate matter each day than all other sources combined. Tractors that run on diesel also release potentially harmful nitrogen oxides into the air which react chemically to form ozone pollution.

As a result of poor air quality, San Joaquin Valley residents - especially children and the elderly - suffer from a myriad of related health problems. At least 10% of the population is afflicted with chronic breathing disorders. Fresno County, the leading agricultural region in the nation, also has the highest Asthma mortality rate.

Clearing the Air

An effective and relatively simple solution to reduce farming's impact on air quality is a cultivation practice called "conservation tillage."

It involves leaving crop stubble (such as corn stalks) on the surface of the soil and planting a new crop right on top. Unlike conventional tillage, the remaining crop residue protects the soil from erosion and prevents wind from blowing it into the air. Statewide, implementing conservation tillage could cut dust pollution from agricultural sources by more well over 50% compared to standard cultivation methods.

Conservation tillage also eliminates the number of tractor passes farmers are required to make to prepare their fields for planting. This translates into noteworthy fuel, labor and maintenance costs - all without harming crop yields. In total, savings have been estimated between $40 and $75 per acre per year. The longer term practice of conservation tillage also results in a build up of organic material which improves the soil's ability to retain water, as well as soil quality that comes from sequestering carbon dioxide - a potent greenhouse gas –released in standard tillage operations.

For more information about the benefits of conservation tillage and to try it on your farm, contact Ladi Asgill, Sustainable Conservation Senior Project Manager, at (209) 576-7729 or lasgill@suscon.org.