Dairy Channel: Carbon sequestration research and its implications for agriculture

Last year I participated in a statewide research project designed to determine how much carbon is contained in soils under various management systems.

We (18 extension agents covering 22 counties) sampled soils under permanent forest cover, long term pasture, conservation tillage, conventional tillage, continuous cropping and rotation systems.

The work was coordinated by Randall Reeder, an Ohio State agricultural engineer.

The study was funded by the Ohio State School of Natural Resources’ Carbon Management and Sequestration Center, under the direction of Rattan Lal.

Soil samples. We sampled the soils to determine soil organic matter (OM) content, soil density and soil moisture content.

Organic matter is 58 percent carbon.

We also collected and weighed all surface residue from a 1 square foot area at each sampling site, determined moisture content of this residue and analyzed this residue for OM content.

This research and many similar projects around the world are aimed toward finding ways to counteract the release of carbon into the atmosphere by the burning of fossil fuels, destruction of wetlands, and soil tillage.

Tillage results in the destruction of organic matter, just like burning it in a fire.

Greenhouse gases. The accumulation of “greenhouse gases” is thought to increase the atmospheric temperature of the earth, a phenomenon known as global warming.

Eighty percent of greenhouse gas is carbon dioxide.

Atmospheric carbon dioxide levels have increased steadily and at an increasing rate over the past 75 years.

Research is underway to determine whether and how rapidly global warming is occurring.

However, many scientists around the world are convinced that global warming and the accompanying weather changes, melting of glaciers and ice caps are detrimental to the future of our planet.

The rate of burning of fossil fuels is not likely to slow down much in the near future, so many people are trying to find ways to offset the accumulation of atmospheric carbon by sequestering it in soils, forests and wetlands.

Soil carbon. The Soil Science Society of America published a fact sheet Oct. 25, 2001, outlining the society’s position regarding soil carbon.

The opening paragraph in this fact sheet states, “Increased long term (20-50 year) sequestration of carbon in soils, plants and plant products will benefit the environment and agriculture.

“Crop, grazing and forestlands can be managed for both economic productivity and carbon sequestration.

“In many settings this dual management approach can be achieved by applying currently recognized Best Management Practices (BMP’s) such as conservation tillage, efficient nutrient management, erosion control, use of cover crops and restoration of degraded soils.

“In addition, conversion of marginal arable land to forest or grassland can rapidly increase soil carbon sequestration.”

Sequestering. Rattan Lal says American soils currently sequester about 17 million metric tons of carbon per year, but have the potential to sequester an estimated 288 million metric tons per year – approximately 15 percent of total U.S. carbon emissions.

Lal believes policymakers will have to provide economic incentives for farmers and landowners to manage their land differently to keep carbon in the soils and plants.

Such policies would include encouraging the use of no-till and conservation tillage, encouraging the use of cover crops in crop rotation cycles, expanding Conservation Reserve Programs, maintaining root biomass year-around on grazing lands, maintaining continuous canopy cover in forestlands, expanding urban forests and many other programs to increase biomass and organic matter reserves.

Benefits. Every one seems to agree that the benefits of these carbon accumulation approaches extend well beyond the environmental benefits.

Even if you don’t believe global warming is occurring, the implementation of land management practices to improve carbon sequestration will lead to both increased soil organic matter and increased above-ground carbon sequestration.

These practices will greatly improve soil structure, increase soil porosity and water-holding capacity, improve productivity and profits.

The combination of reduced input costs (reduced fuel, machinery and labor inputs) reduced erosion, improved water utilization and soil health will provide the economic benefits needed to encourage more widespread adoption.

Think this way. Current fuel and fertilizer prices should make you pause to think of ways to wring more profit from your acres.

As I visit and talk with farmers I see numerous inefficiencies that are costly. Here are a few that could mean the difference between profit and loss:

* Excessive fertilizer and lime applications.

Test your soils and apply only the nutrients your crops need. Excess nutrients are not only wasteful; they rob you of profits and are a risk to the environment.

* Wasted trips over fields. Many of you can do more to combine operations and reduce trips for tillage, fertilizer applications and pesticide applications.

* Inefficient use of nitrogen. Incorporating nitrogen can allow you to reduce applications by 25-50 percent.

Every pound you lose into the air cost you profit and add a greenhouse gas (ammonia) to the atmosphere.

Manure use. * Ineffective use of manure nutrients.

Our research in Columbiana County shows you can use liquid dairy manure to provide all the nitrogen you need to produce corn yields equal to those attained with commercial fertilizers.

Plus you will have additional nutrients (phosphorus and potassium) left over for additional crops in the rotation.

Incorporating manure will increase the available nitrogen for corn from 25 to 50 percent.

If your neighbors can smell the manure you are applying to your fields, you are wasting nitrogen, reducing profits, and polluting the air.

Get help. I can help you with these management challenges. The information, technology and equipment are available to you.

(The author is an agricultural extension agent in Columbiana County. Questions or comments can be sent in care of Farm and Dairy, P.O. Box 38, Salem, OH 44460.)

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