Kernels of Knowledge: How Land-Use Decisions Affect Crop Productivity

(Scott Bauer, U.S. Department of Agriculture Agricultural Research Service)

Model predicts smaller decrease in total corn yields than previous estimates.

(August 28, 2018) - When considering changes in crop spatial distribution patterns, empirical models projected total corn yields in the lower 48 states to decrease 20 to 40% by 2050.

The Science

Farmers tend to grow crops on land with optimal water and nutrient conditions. When these conditions become less than optimal, farmers might shift planting dates, switch to or develop a different crop variety, or even look for new places to grow, therefore changing crop spatial distribution patterns. Researchers showed that changes in crop spatial distribution patterns, as an integral part of land cover and land use, could modulate crop yields in response to Earth system changes.

The Impact

Previous empirical studies could be significantly biased in assessing the effects of Earth system changes. Why? These studies ignored changes in where crops were grown.

Summary

Numerous studies using statistical approaches have confirmed a link between crop yield and climate variability. A crucial assumption in these studies is that crop spatial distribution patterns are constant over time. However, for some crop-region combinations, this might not be valid because of a shift in spatial distribution patterns made possible by crop technology advances and competing land-use demands. Analyzing data from the lower 48 states in the United States, Pacific Northwest National Laboratory scientists investigated how county-level changes in crop spatial distribution patterns regulate state-level corn yield responses to Earth system changes. They found that corn yield response to Earth system changes varied with the crop’s spatial distribution pattern, with distinct effects at the state level. The observation-based empirical models established in this study projected total corn yields in the contiguous United States to decrease by 20 to 40 percent by 2050 under changing crop spatial patterns, compared to 26 to 52 percent with crop distributions held constant.

The Department of Energy Office of Science, Biological and Environmental Research supported this research as part of the Integrated Assessment Research program through the Integrated Multi-sector, Multi-scale Modeling (IM3) Scientific Focus Area.

Publications

G. Leng and M. Huang, “Crop yield response to climate change varies with crop spatial distribution pattern.” Scientific Reports 7, 1463 (2017). [DOI: 10.1038/s41598-017-01599-2]