No-Till Farming Could Help Reduce Climate Change

According to a Purdue University study, no-till farming not only helps prevent erosion and retain soil nutrients, but may also combat climate change. Purdue researchers say they’ve found that fields which were not plowed in between plantings released 57% less nitrogen oxide than fields farmed using conventional plowing methods. Though much less important than the carbon dioxide released from burning fossil fuels, nitrogen oxide is a significant greenhouse gas that contributes to climate change. The gas is far less abundant than carbon dioxide, but traps 310 times as much heat on a molecule per molecule basis and can remain in the atmosphere for 120 years.

Farmland is the biggest source of nitrogen oxide emissions in the United States, although power plants and automobile tailpipes are also important sources. Nitrogen atoms are a valuable and natural component of the soil, and various nitrogen compounds are essential for providing plants with nutrients. However plowing fields used for farming stirs up the soil and allows nitrogen atoms to recombine and form the gas nitrogen oxide. By minimizing the degree to which soil is disturbed, no-till farming methods prevent this from happening.

Industrial farming practices are especially likely to contribute to climate change, because they rely on large inputs of nitrogen fertilizers to keep the soil productive. This increases the amount of nitrogen available to turn into gas compounds. The Purdue researchers also found that fields emit fewer greenhouse gases if nitrogen fertilizer is injected underneath the soil rather than left on the ground’s surface. Fertilizer exposed to the air is much more likely to break down into nitrogen oxide. In fact a no-till field where fertilizer is left on the soil’s surface can still have a larger climate change impact than a plowed field where the fertilizer is injected underground. The fertilizer in question may be one of the synthetic compounds used on industrial farms, or organic manure which also contains nitrogen.

It is worth noting that any practice which reduces nitrogen oxide emissions from farmland will also help improve soil fertility. That’s because nitrogen is such a valuable soil nutrient, the loss of which inhibits growth of crops. In general new findings about the contribution of farming practices to climate change confirm what was known already: practices that disturb the soil as little as possible and reduce reliance on large amounts of chemical fertilizers tend to be better for the planet as well as maximizing land productivity.

Though it will not solve climate change on its own, widespread adoption of no-till farming in the US and elsewhere could make a very real dent in global greenhouse emissions, buying precious time as countries make the shift from a fossil fuel economy to one powered by clean energy. No-till farming and responsible fertilization practices both have an essential part to play in reducing the agricultural sector’s hefty carbon footprint.

Photo credit: Daniel X. O'Neil