Researchers at UNL report that yield gains in irrigated corn in recent years came mostly from climate change and improved agronomic practices rather than genetic technologies. Researchers examined irrigated corn yields between 2005-2018 in the Lower Niobrara (LN), Tri Basin (TB), and Upper Big Blue (UBB) Natural Resources Districts (NRDs) and found that climate-driven yield gain represented 48 percent of the total yield gain seen over the period. Agronomic practices were responsible for 39 percent of the gain, while improved genetics contributed 13 percent. Figure 4 illustrates the contributions to yield gains from the three factors in each NRD.
Figure 4. Yield Gain & Contributions
Most of the climate-driven yield gain was the result of an upward trend in solar radiation during grain-filling. Temperature changes led to a shorter vegetative growth stage which the researchers write, “led to a shift of silking and grain-filling earlier toward the summer solstice and, therefore, more-favorable weather conditions for grain-setting and -filling.” An increase in carbon dioxide concentration also contributed a small yield gain. Increases in average seeding rates, fertilizer rates, conservation tillage, and in-season applications of fungicides and insecticides also contributed to yield gains.
Increasing agriculture’s productivity will be necessary to meet growing population and food demands. The UNL researchers found yield gains from genetic progress are slowing. As such, they argue future production gains will rely on improved agronomic practices or increasing crop intensity where possible.