Quantcast

How Carbon Farming Can Reverse Climate Change

Climate

Are there agricultural practices that might offer more potential than the ones commonly discussed in the “carbon farming” conversation? In a companion post, I wrote about what the science tells us about cover cropping and reduced tillage, two practices getting a lot of attention in what I’ve called the “carbon farming” rage. Here I want to address some more agroecological practices, those that incorporate ecological principles and what is known from field research about their ability to add carbon to the soil.

Cattle graze here on a ranch in the Sand Hill region of North Central Nebraska. Grasslands cover a large percentage of the planet and research demonstrates greater potential with improved management (such as compost additions and plant composition) to increase soil carbon.

What Do We Know About Soil Carbon Potential Beyond the Basic Conservation Practices?

There is less research on the relationship of agroecological practices, such as crop rotations, agroforestry and improved grazing-based systems, with soil carbon—but what is known is very positive. A synthesis paper of global field studies found that crops in rotation plus cover crops increased total soil carbon by 8.5 percent. Some estimates have suggested that when land is shifted from use for growing agricultural crops to pasture for livestock, carbon increases significantly (by 19 percent, according to one study synthesizing several research sites). The same analysis found that returning some cropland to forest could lead to even larger soil carbon gains (up to 53 percent).

On grazing lands, which cover around 25 percent of lands globally, changes to management (for example, compost additions or improved grazing practices such as fertilizer additions or the use of native plant communities) can increase soil carbon such that small changes make a big difference when scaled up. Further, on the option of integrating of trees into agricultural lands, scientists have estimated the potential of agroforestry systems to increase soil carbon to be approximately 95 times greater than the conservation practices of no-till, cover crops and crop rotations (as estimated by one analysis that looked at many studies in the tropics).

This is quite impressive untapped potential, particularly when considering that many of these ecological practices receive a fraction of public research dollars. Of course, some of these practices require taking a small amount of land out of production, but if done strategically on low yielding unprofitable sections of a field, such diversification practices could offer a “win-win” in the form of cost savings for producers and environmental benefit for all.

An alfalfa crop next to a plowed bare soil at a research farm near Iowa State University. Alfalfa is a forage crop that puts down roots for multiple seasons, leading to a greater potential for soil carbon increase relative to bare soil or annual crops. Photo credit: Aaron Price

Even With Complexities in the Science, Carbon Farming Deserves the Attention

Carbon farming is a topic of growing interest for both the research and policy communities. The science is complex. Researchers in the fields of ecology, agronomy, forestry, soil science and biogeochemistry, among others, dedicate entire careers toward this area. It can take a lot of soil sampling to detect changes, which is expensive and potentially difficult. Soils are highly variable from one location to another. The initial carbon content of soil heavily influences how much carbon can be increased.

It is important to note that there are other emissions linked to agricultural management decisions, so any net change in the carbon sink is just one piece of the overall greenhouse gas emissions picture. One example of this from my own work is that cover crops may lead to small increases in nitrous oxide emissions, depending upon management.

Finally, something else I found in my research was that the warmer temperatures resulting from climate change may drive increased carbon decomposition—all the more reason to get started sooner rather than later growing the soil carbon sink.

It is important to conclude explicitly that not all carbon farming practices are equal. Many equate to working around the edges rather than systemically changing our design of agricultural systems and landscapes. As I’ve discussed here and in a companion post, the current science indicates that the approaches offering the greatest opportunities to increase soil carbon are those which increase the amount of crops covering the soil in both space and time (which would increase the total carbon input to the soil “budget”) and/or incorporate multiple carbon farming principles. If the agriculture sector is going to get serious about soils as a sink for carbon (and agriculture as a net sink of greenhouse gas emissions), more comprehensive research, combined with appropriate policy and economic incentives, will be necessary.

Andrea Basche is a Kendall Science Fellow in the Union of Concerned Scientists food and environment program.

YOU MIGHT ALSO LIKE

Why Buying Local Flowers Is Just as Important as Buying Local Food

Jack Johnson Helps Connect Children to Their Land, Water and Food

Consumed: First Fictional Film to Cover Concerns of GMOs

Results of Glyphosate Pee Test Are in ‘And It’s Not Good News’

EcoWatch Daily Newsletter

Serena and Venus Williams have been known to follow a vegan diet. Edwin Martinez / Flickr / CC BY 2.0

By Whitney E. Akers

  • "The Game Changers" is a new documentary on Netflix that posits a vegan diet can improve athletic performance in professional athletes.

  • Limited studies available show that the type of diet — plant-based or omnivorous — doesn't give you an athletic advantage.

  • We talked to experts about what diet is the best for athletic performance.

Packed with record-setting athletes displaying cut physiques and explosive power, "The Game Changers," a new documentary on Netflix, has a clear message: Vegan is best.

Read More Show Less
An illegally trafficked tiger skull and pelt. Ryan Moehring / USFWS

By John R. Platt

When it comes to solving problems related to wildlife trade, there are an awful lot of "sticky widgets."

Read More Show Less
Sponsored
Pexels

By Franziska Spritzler, RD, CDE

Inflammation can be both good and bad.

On one hand, it helps your body defend itself from infection and injury. On the other hand, chronic inflammation can lead to weight gain and disease.

Read More Show Less
Pexels

By Dan Nosowitz

It's no secret that the past few years have been disastrous for the American farming industry.

Read More Show Less
Pexels

By Gavin Van De Walle, MS, RD

Medium-chain triglyceride (MCT) oil and coconut oil are fats that have risen in popularity alongside the ketogenic, or keto, diet.

Read More Show Less
Sponsored
Pexels

By Bijal Trivedi

The Centers for Disease Control and Prevention (CDC) released a report on Nov. 13 that describes a list of microorganisms that have become resistant to antibiotics and pose a serious threat to public health. Each year these so-called superbugs cause more than 2.8 million infections in the U.S. and kill more than 35,000 people.

Read More Show Less
Rool Paap / Flickr / CC BY 2.0

By Franziska Spritzler, RD, CDE

Inflammation can be good or bad depending on the situation.

Read More Show Less

By Joe Vukovich

Under the guise of responding to consumer complaints that today's energy- and water-efficient dishwashers take too long, the Department of Energy has proposed creating a new class of dishwashers that wouldn't be subject to any water or energy efficiency standards at all. The move would not only undermine three decades of progress for consumers and the environment, it is based on serious distortions of fact regarding today's dishwashers.

Read More Show Less