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Subirrigation is employed to supply water to crop root zones via subsurface drainage systems, which are typically installed for the purpose of excess soil water removal. Crop yield increases due to subirrigation have been demonstrated in numerous studies, but there is limited information regarding yield under future climate conditions when growing season conditions are expected to be drier in the U.S. Corn Belt. DRAINMOD was calibrated and validated for three locations with different soil series in northwest Ohio and used to investigate maize relative yield differences between subirrigation and free subsurface drainage for historic (1984–2013) and future (2041–2070) climate conditions. For historic conditions, the mean maize relative yield increased by 27% with subirrigation on the Nappanee loam soil, but had minimal effect on the Paulding clay and Hoytville silty clay soils. Maize relative yield under free subsurface drainage is predicted to decrease in the future, causing the relative yield difference between free subsurface drainage and subirrigation practices to nearly double from 9% to 16% between the historic and future periods. Consequently, the subirrigation practice can potentially mitigate adverse future climate change impacts on maize yield in northwest Ohio. [ABSTRACT FROM AUTHOR]

Drainage water management (DWM) is promoted as an agricultural best management practice that reduces subsurface drainage volume and thereby the transport of soluble nutrients to streams. This study was conducted on private crop fields to quantify the effect of managed subsurface drainage on daily subsurface drainage volume, in poorly drained and somewhat poorly drained soils of northwest Ohio. A paired zone approach was used where a part of each field was conventional free draining and the other part was under drainage water management. At each site, comparison of median daily subsurface drainage volume from the two zones indicated that drainage water management was effective at reducing daily subsurface drainage volume. A linear mixed model procedure was applied to determine the percent reduction in daily subsurface drainage volume as a result of drainage water management. Using the paired dataset at each site, the model predicted the total daily subsurface drainage volume from the managed zone as a function of the observed total daily subsurface drainage volume from the conventional zone. The percent reduction of daily subsurface drainage volume varied from 40% to 100% depending on site. While the magnitude of the reduction of the daily subsurface drainage volume is site specific, the general expectation is that if DWM is instituted broadly and appropriately in northwest Ohio, mean daily subsurface drainage volume would lessen on an annual basis. Such reduction may eventually translate into a reduction in nutrient loads exported from farm fields. [ABSTRACT FROM AUTHOR]

Climate change projections for the Midwest U.S. indicate a future with increased growing season dryness that will adversely impact crop production sustainability. Systems that capture water for later subirrigation use have potential as a climate adaptation strategy to mitigate this increased crop water stress. Three such systems were operated in northwest Ohio from 1996 to 2008, and they exhibited substantial crop yield benefits, especially in dry growing seasons, but also to a lesser extent in near normal or wet growing seasons. The goal of this research was to estimate the increase in crop yield benefits of water capture and subirrigation systems that can be expected under projcted 2041–2070 climate conditions in northwest Ohio. Historical subirrigated field crop yield differences with fields having free drainage only, relative to growing season dryness/wetness, were used to determine future northwest Ohio subirrigated field crop yield increases, based on the modeled climate for 2041–2070. Climate records for 2041–2070 were projected using three bias corrected model combinations, CRCM + CGCM3, RCM3 + GFDL, and MM5I + HadCM3. Growing season dryness/wetness was classified based on the difference between rainfall and the crop adjusted potential evapotranspiration using the 1984–2013 climate record at the three system locations. Projected 2041–2070 growing season precipitation varied substantially between the three model combinations; however, all three indicated increased growing season dryness due to rising temperature and solar radiation. The overall subirrigated field corn yield increase rose to an estimated 27.5%–30.0% in 2041–2070 from 20.5% in 1996–2008, while the subirrigated field soybean yield increase improved from 12.2% in 1996–2008 to 19.8%–21.5% for 2041–2070. Consequently, as growing season drought becomes more frequent, the crop yield benefits with water capture and subirrigation systems will improve, and these systems therefore provide a viable climate adaptation strategy for agricultural production. [ABSTRACT FROM AUTHOR]