Steps like using precision agriculture and cover crops not only can sequester carbon but also can benefit soils.
There aren’t many topics that cause flushed faces and steam-churning ears akin to the cartoon character Yosemite Sam to occur like manmade climate change.
Multiple studies published in peer-reviewed scientific journals show 97% or more of actively publishing climate scientists agree that human activities over the past century are spurring climate change. That’s according to NASA.
Many politicians, though, disagree. Farmers and agricultural workers also have doubts. A survey of 6,795 people in the agricultural sector in 2011-2012 by Purdue and Iowa State Universities shows that although 66% of corn producers believe climate change is occurring, just 8% pinpoint human activities as the main cause.
Climate change happens over the long term, so it’s not as simple as proclaiming climate change is or isn’t occurring based on a one-year drought or flood. Looking back over time, though, science shows it is rapidly occurring largely due to man-made emissions, says Mike Lohuis, Monsanto’s agricultural environmental strategy lead.
“In northern latitudes, we are seeing the biggest changes of all, with ice melts occurring in glaciers,” he says.
When combined with technologies like seed coatings and earlier-maturing varieties, climate change is helping to spur Canadian farmers to plant corn and soybeans where they could not decades ago. On the negative side, though, increased atmospheric carbon dioxide is better for weeds than for crops.
“An increase of just 50 parts per million (ppm) of atmospheric carbon dioxide – say, from 350 to 400 – causes many weeds, especially invasive weeds, to double in size,” says Jerry Hatfield, laboratory director of the USDA-ARS National Laboratory for Agriculture and the Environment in Ames, Iowa. “We have yet to have an agronomic crop that does that.”
Another telling factor: Current atmospheric carbon dioxide concentrations of 400 ppm are at a level they last were over 2 million years ago during the Pliocene Epoch, says Lohuis.
The current parts-per-million level of atmospheric carbon dioxide last occurred during the Pliocene Epoch over 2 million years ago, says Monsanto’s Mike Lohuis.
Farmers Are A Solution
The good news: Many farmers already follow practices that can help mitigate climate change.
“Sustainable agriculture can equal modern agriculture,” says Dion McBay, sustainable development lead for Monsanto.
In December 2015, Monsanto announced it was making its operations carbon neutral by 2021. Last May, it released a study titled Charting a Path to Carbon Neutral Agriculture: Mitigation Potential for Crop Based Strategies. This report, commissioned by Monsanto and prepared by ICF International, highlights the potential for reducing U.S. greenhouse gas emissions with crop-based strategies.
They include two specific practices.
Sustainable nutrient management. The report found that precision agriculture, specifically variable-rate technology and swath control using GPS guidance, boosts input efficiency. “Anytime we can use less to produce more, we can become more sustainable,” Lohuis says.
Sustainable tillage and use of cover crops. Tilled soils boost the oxidation of soil organic carbon to carbon dioxide. Not only does soil lose carbon – a vital soil health component – but also it releases carbon dioxide into the atmosphere.
Decreasing or nixing tillage can benefit both the soil and atmosphere. Meanwhile, residue left on the soil surface can be good for soil health and store carbon in the soil.
These near-term strategies have potential for sequestering carbon. Monsanto officials say if 60% of cropland not currently using these strategies adopt them by 2030, over 100 million metric tons of annual carbon dioxide emissions reductions could be achieved from U.S. agriculture alone. That’s equal to the carbon absorption potential of more than 2.5 billion tree seedlings grown for 10 years. More than 90% of this potential could be achieved in corn and soybeans.
“Practices that help mitigate climate change like cover crops and precision ag are also those that benefit soil health,” says Lohuis. “Increasing use of cover crops and no-till will also increase microbial populations and increase nutrient cycling.” Besides sequestering carbon, this will make fields more productive and also help reduce erosion, he says.
Yield potential will be largely neutral from these steps, says Lohuis. “Expect long-term profitability to go up,” he says.
Cover crops have untapped potential in agriculture,” he adds. So far, cover crops have only a 3% to 5% adoption rate.
Low crop prices pose a challenge to cover crop expansion. Long term, though, increased nutrient cycling will help fertilizer efficiency rates without sacrificing yields, says Lohuis.
This gives growers an opportunity to leave their farms in as good a condition or better for the next generation, says Brian Frishmeyer, technical sales agronomist for Channel. Besides slicing erosion, soil biology benefits that result from the planting of cover crops aid soil structure and soil permeability. Increased competition between cover crops and weeds can also slice weed pressure, he adds.
Excess residue can be a challenge at planting, though, particularly when it comes to no-till corn. Still, technologies like Precision Planting’s Delta Force technology help no-tillers plant at a consistent depth. This aids emergence while retaining residue that boosts soil carbon and protects soil.
Surface residue also enhances subterranean creatures that carve soil tunnels that aid water infiltration.
“When you look under residue, you can see night crawlers that move through the soil profile,” he says.
Long-term strategies for mitigating climate change from the Monsanto report include the following.
Ethanol production from corn and stover. In the U.S., excess corn not needed for food can be used for ethanol production. Meanwhile, sustainable corn stover (stalks, leaves, and cobs remaining after harvest that exceed soil-health maintenance needs) can be a renewable source used in biofuel production. This strategy aims to offset fossil fuel emissions. Meanwhile, collecting sustainable stover helps farmers who wrestle with excessive residue after harvest.
- Optimization of available crop residues. The report states that available corn stover could be cofired alongside coal in coal-fired power plants to offset fossil fuel use. It could also provide a renewable energy source.
- Available corn stover could also be processed into biochar (plant-based charcoal) that could be incorporated into the soil to boost soil health and store carbon.
- The long-term strategies include ethanol production and optimization of crop residues. These have the potential to annually reduce 54 to 80 million metric tons of carbon dioxide by 2050, but technological and economic barriers currently exist for adoption of these strategies. Thus, more research and investment into these strategies are needed.
Good Place to Be
The fear of climate change regulation among farmers is real. Still, chill.
“If farmers are doing things to prepare for climate change, such as nutrient management, that is a good place to be as it gives them a social license to operate,” says Lohuis.