New studies from the USDA look at how reduced tillage could help conserve water and reduce losses caused by climate change. This article from the Agricultural Research Service (ARS) says researcher Laj Ahuja is leading a team at the ARS’ unit in Fort Collins, CO, looking at the relationship between climate projections and 15 to 17 years of field data and how that is affecting crop yields in the Midwest.
The projections included an increase in equivalent atmospheric carbon dioxide (CO2) levels from 380 parts per million by volume (ppmv) in 2005 to 550 ppmv in 2050. The projections also included a 5-degree Fahrenheit increase in summer temperatures in Colorado from 2005 to 2050. The ARS scientists used these projections to calculate a linear increase of CO2 and temperature from 2050 to 2100.
Ahuja’s team used the Root Zone Water Quality Model (version 2) for crop rotations of wheat-fallow, wheat-corn-fallow, and wheat-corn-millet to see how yields might be affected in the future. They simulated different combinations of three climate change projections: 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.
When they looked at all the factors, they saw yield projections over the coming 100 years drop for corn, millet and wheat, with the biggest drops in corn and millet. The researchers found that after an increase in summer temperatures by 8 degrees or more, even no-till would not halt crop losses.