Conquering Climate Change

Soybean Industry Seeks Answers to Anticipated Shifts

Climate change has become a familiar term.  And while scientists do not fully understand yet how climate change may affect agriculture in the Midwest this century, they do agree that changes are likely.  A number of efforts are underway involving several different disciplines to help soybean farmers adapt to those anticipated atmospheric changes.

“There is some uncertainty about the impact climate change will have on specific areas.  Scientists feel pretty confident about temperature changes but less certain about rainfall patterns.  The scientific community does anticipate that weather will become more volatile,” says Don Hofstrand, co-director, Agricultural Marketing Resource Center.  “Soybean varieties will need to be developed that can flourish under various conditions.”

Futuristic Research

Researchers at the University of Illinois and USDA/ARS SoyFACE (Soybean Free Air Concentration Enrichment) facility are exploring a variety of climate change factors and their impact on soybeans.  Researchers at the facility are able to grow soybeans under actual field conditions in the type of atmosphere predicted for mid-century.

“One of our current treatments is to look at impacts of combined temperature and carbon dioxide interactions,” says Don Ort, SoyFACE coordinator.  “For the study, we have increased the canopy temperature by 3.5°C, with and without elevating the carbon dioxide levels.  Higher temperatures may shorten the growing season and lower yields, while we anticipate elevated carbon dioxide will partially mitigate the negative impacts.”

Ort explains the temperature treatment is being applied year round, so the soil will remain heated even when the crop is not in the ground.  He anticipates a higher temperature will accelerate carbon cycling, work against carbon sequestration and possibly boost nitrous oxide emissions.  Warmer soil may also affect moisture content and seed germination.

“Warmer temperatures may also keep microbial activity going longer.  We anticipate a change in ‘who’ we will find in the soil,” says Ort.  “We want to know both whether our hypotheses are true, and if true, to what extent we see these changes.”

In other work, Ort and colleagues are looking at the effects of surface level ozone on soybeans.  “Ozone is a very dynamic atmospheric pollutant and affects soybean cultivars differently,” he says.  “We have identified cultivars that show considerable tolerance and those that are highly sensitive.  We cross the most sensitive and most tolerant to produce recombinant inbred lines.  By planting and analyzing the progeny, we hope to be able to decipher the genetic basis of tolerance and isolate the DNA of sensitivity and tolerance.”

Seed Company Efforts

Ort says several seed companies have been watching SoyFACE research with interest.  Private research is also underway to help soybean farmers be in tune with climate change.

“Recent years seem to be more variable than in the past, creating a need for varieties that can perform well across a wide range of conditions that fluctuate year to year,” says John Soper, PhD and senior research director, soybean product development, Pioneer Hi-Bred.  “We are responding by ensuring that our varieties contain defensive trait genes required for a wide range of disease, pest and environmental stresses.  We are using Accelerated Yield Technology (AYT) to build in top-end yield potential.”

Monsanto research focuses on such relevant areas as stress tolerance, insect- and disease-resistance and a broad portfolio of germplasm for developing well-tailored varieties for a broad range of environments.  Calvin Treat, director of global soybean breeding, says the current pace of change may allow for gradual shifts in maturity groups and proper placement of varieties for the best chances to succeed. Better scientific understanding and approaches for improving soybeans are advancing rapidly.  Treat says that will translate into new variety development to ensure successful soybean crops for decades to come.

“Farmers will need to maintain flexibility,” sums Hofstrand.  “Farmers may not know the challenges that confront them until the change is upon them, especially with weather volatility.  In addition, any climate change legislation will impact farmers.  A number of opportunities may be available to sell carbon offsets that supplement farmer income.”

Soil Solutions

Jerry Hatfield, director, National Laboratory for Agriculture and the Environment, Ames, Iowa, agrees.  He says carbon sequestration is already a strategy some farmers are implementing through no-till practices.  Carbon sequestration can help reduce runoff and leaching.  Better soils produce more crops with better use of soil water and nitrogen.

“The problem is that as we have cultivated land, we have removed soil carbon.  This decreases the water-holding capacity and nutrient availability, so soil is more dependent on having nutrient and water inputs at the right times for maximum production,” he says.

“Continued soil degradation will reduce the potential productivity capacity.  The variation in crop production will rise with variable weather during the growing season.”

Hatfield says fields with conventional tillage have greater variation than fields with long-term no-till. “Success will come from those willing to evaluate cropping systems and take a long-term view of building a more resilient system to the increasing climate variation,” he says.  “Our soil system is a critical part of resource management. Degraded soils will not be as productive nor provide the resilience to climate variation that farmers need.”

Sidebar/What Can We Expect?

Gene Takle, Iowa State University atmospheric science and agricultural meteorology professor, says farmers can expect to see an impact from a number of climate changes:

• The frost-free period may be longer, but the growing season required may be shortened.  Nighttime temperatures rose more than daytime temperatures over the last 30 years, and summer daytime maximum temperatures dropped.
• Pests over-wintering may be more of a problem due to fewer extreme cold events.
• More freeze-thaw cycles are likely, but that might be better for breaking down hard-pan soils and allowing more winter recharge of soil moisture.
• Higher day-to-day and year-to-year variability in temperatures could damage crops or delay spring planting and crop growth.
• Precipitation is difficult for models to simulate.  A complicating issue is location close to regions of high precipitation gradients.  Annual precipitation is much less in western Iowa than eastern Iowa and less in northern Iowa than southern Iowa.  In Illinois, there is less in the north than the south, but east-west differences are small.  If precipitation patterns shift eastward, Iowa would be more affected than Illinois, but both would be affected by a northward shift of higher rainfall.
• Reduced wind speeds could affect pollination and pest and pathogen dispersion.
• Increased precipitation likely would be accompanied by more cloudiness and less solar radiation, particularly in spring, and would slow early-season crop growth.
• Higher temperatures promote generation of tropospheric ozone from automobile exhaust.  Ozone may account for up to 30 percent yield loss over the next century.
• Higher temperatures and more soil moisture could lead to faster plant breakdown to form carbon dioxide out of soil carbon, increasing the loss of soil carbon.
• Since many weeds respond more quickly to elevated carbon dioxide than crops, herbicides may become less effective on weeds.
• Crops grown under high carbon dioxide environments would tend to conserve water better and increase their water-use efficiency.

*Content Funded by the Soybean Checkoff