Location: Soil Drainage ResearchTitle: Northwest Ohio crop yield benefits of water capture and subirrigation based on future climate change projections Author
Submitted to: Agricultural Water Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/29/2017
Publication Date: 5/17/2017
Citation: Baule, W., Allred, B.J., Frankenberger, J., Gamble, D.L., Andresen, J., Gunn, S., Brown, L. 2017. Northwest Ohio crop yield benefits of water capture and subirrigation based on future climate change projections. Agricultural Water Management. 189:87-97. Interpretive Summary: Historical crop yield data from subirrigated and free drainage only fields, together with historical climate data and model-derived climate projections by three model combinations from the North American Regional Climate Change Assessment Program (NARCCAP) were used to estimate the increasing crop yield benefits of subirrigation under future climate conditions. Bias-corrected climate projections for Northwest Ohio using the three models suggest that by mid-century (2041-2070) average daily temperatures will increase by 2.9 to 3.6 degrees C. Precipitation projections showed substantially more uncertainty among the three models, with one model projecting an increase and two a decrease in average growing season precipitation. Solar radiation was also projected to increase during the growing season by all three models, and together with the rising temperature will drive a substantial increase in growing season potential evapotranspiration (PET) for both corn and soybeans. Due to the projected increases in PET, occurrences of a crop water deficit (precipitation minus PET) were projected to be more common in all three models, even the model in which growing season precipitation was projected to increase. Five dryness/wetness categories based on quintiles of growing season crop water deficit for each crop (corn and soybeans) during 1984 to 2013 were used to substantiate the benefit of subirrigation under various climate conditions. In the future (2041 to 2070) far more growing seasons are likely to be consider dry or very dry based on crop water conditions from 1984-2013. The historical crop yield benefit observed at all three sites can be expected to increase even more under future climate conditions. For corn, the observed yield increase of 20.5% from 1996-2008 was projected to rise in mid-century to a yield increase of 27.5% to 30.0% with subirrigation. For soybeans, the observed subirrigated yield increase of 12.7% was projected to grow to a yield increase of 19.8% to 21.5% in the 2041-2070 period. The increased yield benefits predicted using all three model combinations, even one in which precipitation was projected to increase, shows the importance of PET projections which were calculated using the Priestly-Taylor method, which takes into account both solar radiation and temperature. These results imply that given the predicted greater frequency of drier growing seasons for northwest Ohio in 2041-2070, agricultural systems combining water capture, storage, and subirrigation reuse, can in coming years potentially have a very positive impact on sustaining agricultural production in northwest Ohio and other regions within the Midwest U.S., and should be studied more widely as a climate change adaptation strategy.
Technical Abstract: Climate change projections for the Midwest U.S. indicate increased growing season crop water deficits in the future that will adversely impact the sustainability of agricultural production. Systems that capture water on site for later subirrigation use have potential as a climate adaptation strategy to mitigate increased crop water deficits. Three such systems were operated in northwest Ohio from 1996-2008; and these systems exhibited substantial crop yield benefits, especially in dry growing seasons, but also to a lesser extent in near normal or wet growing seasons. This investigation used historical subirrigated field crop yield differences (with respect to non-irrigated control fields with free drainage) to determine an overall estimate of future northwest Ohio subirrigated field crop yield increases, based on the modeled climate for 2041 to 2070. The projected climate records for 2041 - 2070 were obtained using three bias corrected climate model combinations, CRCM+CGCM3, RCM3+GFDL, and MM5I+HadCM3. Growing season dryness/wetness was quantified based on growing season crop water deficit calculated by subtracting the crop growth stage adjusted potential evapotranspiration from precipitation, and categorized based on the 1984 - 2013 record at the three system locations. Projected northwest Ohio growing season precipitation for 2041 - 2070 varied substantially between the three climate model combinations; however, all three were in agreement on increased growing season crop water deficits due to rising temperature and solar radiation. The overall subirrigated field corn yield increase rose to 27.5% - 30.0% in 2041 - 2070 from a value of 20.5% in 1996 – 2008, while the subirrigated field soybean yield increase improved from 12.2% for 1996 - 2008 to a range of 19.8% to 21.5% for 2041 - 2070. As growing season drought becomes more frequent, the crop yield benefits with agricultural water capture and subirrigation systems will improve, and these systems therefore provide a viable climate adaptation strategy for agricultural production.