Nearly 80% of Americans believe temperatures are definitely on the rise. Yet, very few members of the general public understand the key role that no-tillage will play in battling global warming over the next 90 years.

While many Americans don’t believe all the global warming threats and fears being promoted by many scientists, they understand what their backyard thermometers are telling them, says Jon Krosnick, a Stanford University social psychologist.

Results from a recent Associated Press poll indicate that as many as 80% of our citizens are convinced that future climate changes represent a serious threat to both the environment and food production.

No-Till Is The Answer

Some ag scientists say a major hope for salvaging expected crop yield losses that could occur with global warming is the expanded use of no-till. By keeping the soil surface covered with residue, no-till can not only overcome higher-temperature concerns, but will help conserve water as available supplies continue to dwindle.

These conclusions are among findings from an innovative Agricultural Research Service (ARS) study in Colorado that looked at 17 years of actual crop and climate data from the Central Great Plains Research Station in Akron, Colo.

Using 16 computer-simulation programs created for other agricultural research projects, the scientists summarized potential climate changes between now and the year 2100 for the semiarid central Great Plains.

Over the next 90 years, the Colorado scientists anticipate that global warming will lead to rising carbon-dioxide levels, higher temperatures and a shift in significant rainfall from late spring and summer to the fall and winter months.

When data from these three factors were combined with software modeling, yields dropped with three crop rotations between now and 2100. The three options that were evaluated included wheat-fallow, wheat-corn-fallow and wheat-corn-millet rotations.

Data indicates that carbon-dioxide levels are projected to increase from 380 parts per million in 2005 to 550 parts per million by 2050. By 2050, the scientists anticipate that Colorado’s average summer temperatures will rise by 5 degrees F.

The study indicates that a decline in corn and millet yields would be more significant than a drop in wheat yields. Yield declines will be due to average temperature increases that will slow plant growth while boosting the crop’s demand for water.

Less Tillage Pays

The scientists also looked at the climate change ramifications of growers planting 30 days earlier and also using no-till to overcome global-warming conditions.

While advancing planting dates didn’t pay off, switching to no-till definitely made a difference. By leaving crop residue on the soil surface, evaporation will be reduced and the soil will be able to retain more available water.

In the wheat-fallow rotation where no-till was used, wheat yields were higher than with conventional tillage, says Laj Ahuja, ARS research leader for this project. He says this demonstrates that both crop rotation and reduced-tillage practices will have a greater impact on yields than the benefits from changes in carbon-dioxide levels.

But when the scientists predicted what might happen 90 years from now, even the advantages for no-till would likely go away if summer temperatures increased by an average of 8 degrees F.

“The negative effects of warmer temperatures would outweigh the benefits of higher atmospheric carbon dioxide on all the crops in these rotations,” says Ahuja. “High levels of carbon dioxide enhance photosynthesis in crops like wheat and help plants retain water by causing the stomatal pores on their leaves to partially close.”

He says anticipated changes to the climate will make water scarcity worse for many crops in semiarid areas. Similar techniques could be used elsewhere in the country with different crops whether irrigation is used or not.

Yet, even as we look for more ways to deal with global warming in the coming years, expanding the country’s no-tilled acres will continue to rank at the top of the list.