Studies at USDA show that reducing tillage for some Central Great Plains crops could help conserve water and reduce losses caused by climate change. Researchers at the Agricultural Research Service Agricultural Systems Research Unit in Fort Collins, Colorado superimposed climate projections onto 15 to 17 years of field data collected at the ARS Central Great Plains Research Station in Akron, Colorado to see how future crop yields might be affected. They used projections of increases in atmospheric carbon dioxide levels to 550 parts per million by volume in 2050 – as well as a five-degree Fahrenheit increase in summer temperatures by the year 2050. Those projections were used to calculate a linear increase of both CO2 and temperature from 2050 to 2100.

For crop rotations of wheat-fallow, wheat-corn-fallow and wheat-corn-millet – the team used the Root Zone Water Quality Model (version 2) to see how yields might be affected in the future. Three different combinations of climate change projections were simulated – including rising CO2 levels, rising temperatures and a shift in precipitation from late spring and summer to fall and winter. They ran the model with the projected climate for each of the 15 to 17 years of field crop data for each cropping system. All three climate factors were used to generate yield projections from 2005 to 2100. The yield estimates for all three cropping systems dropped over time – though the declines in corn and millet yields were more significant than the declines in wheat yields.

USDA’s researcher also simulated earlier planting dates and no-till management to see if either would reduce yield losses. The no-till option was the only one that helped. With no-till in the wheat-fallow rotation – wheat yields were higher than with conventional tillage through 2075. The no-till advantage was lost by 2100 – when summer temperatures had increase by eight-degrees Fahrenheit.