The goal of this project was to begin a process of analyzing the potential for increasing on-farm water storage and the utility of sub-irrigation as a climate change adaptation strategy. To gain understanding of the opportunities and barriers to on-farm water recycling in the Great Lakes region, we had conversations with drainage contractors, agency staff, extension specialists, irrigation dealers, and farmers who have and have not installed on-farm water recycling, both in one-on-one settings and in groups. We used historic yield data, climate projections, and a drainage model (DRAINMOD) to estimate potential yield benefits that could be achieved by the Ohio Wetland Reservoir Subirrigation System water recycling systems under projected future climate conditions.
This project was funded through GLISA’s small grants competition in 2014 and was a collaboration between Dr. Jane Frankenberger from Purdue University and Drs. Barry Allred and Larry Brown from Ohio State University. GLISA staff and faculty provided historical climate data (temperature, precipitation, solar radiation), projected climate data (bias-corrected regional climate simulation output), historical agricultural data (planting date, flowering date, maturity date), and data analysis for the project team.
Project resulted in multiple conference presentations, several peer-reviewed journal articles, and stakeholder engagements (led by project PIs). Fact-sheets were developed by the project PIs and distributed at drainage workshops by the project leaders. Findings from this project were incorporated and expanded on in a successful grant proposal to the USDA National Institutes of Food and Agriculture program. More information about that specific project can be found at (www.transformingdrainage.org).
The following articles from this research have been published in peer-reviewed journals:
- Gunn, K.M., Allred, B.J., Baule, W.J. and Brown, L.C., 2019. Investigating maize subirrigation strategies for three northwest Ohio soils. Journal of Soil and Water Conservation, 74(2), pp.111-125.
- Gunn, J., B. Allred, W. Baule, L. Brown, 2019. Investigating subirrigation strategies for three northwest Ohio soils. Submitted to the Journal of Soil and Water Conservation, In Press
- Gunn, K., W.J. Baule, J. Frankenberger, D. Gamble, B. Allred, J. Andresen, L. Brown, 2018. Modeled Climate Change Impacts on Subirrigated Maize Yield in Northwest Ohio. Agricultural Water Management, 206, 56-66.
- Baule, W.J., B. Allred, J. Frankenberger, D. Gamble, J.Andresen, K. Gunn, and L. Brown, 2017. Northwest Ohio Crop Yield Benefits of Water Capture and Subirrigation Based on Future Climate Change Projections. Agricultural Water Management, 189, 87-97.
The project was focused on evaluating the potential of on-farm water recycling and subirrigation as a climate adaptation strategy for agricultural production in Northwestern Ohio. Given the dynamic nature of ground water movement and agricultural production, daily time series of temperature, precipitation, potential evapotranspiration, and solar radiation are needed to examine the potential impacts of climate change on agricultural production. A delta-approach, where observed weather series are adjusted by the relative amounts of projected change from climate models, was adopted due to the inability of the regional climate models (RCMs) to simulate the day-to-day variability in precipitation frequency and amounts, which are critical for agricultural assessments. Data from three RCMs from the North American Regional Climate Change Assessment Program (NARCCAP) were analyzed for the mid-21st Century for relative changes compared to the late-20th century in temperature, precipitation, and solar radiation. These change factors were then applied to observed time series at three locations to create perturbed future scenarios of climate for Northeast Ohio. These data series were used as inputs into a statistical yield prediction model for three subirrigated field sites in the region and a dynamic drainage model to evaluate the potential effects on crop yield. GLISA staff conducted the climate data, model analysis, and scenario generation. Staff and faculty from Ohio State, the USDA, and Purdue performed the yield modeling. Results from these studies have been disseminated in peer-reviewed journals, conference proceedings, and in extension meetings with agricultural producers and extension specialists.
The stakeholders with whom we discussed this practice already understood that climate change, or increasing climate variability, will lead to increased need for and benefits of practices that enhance water storage on the farm. The potential for this practice was viewed as very positive, even though most stakeholders raised valid questions about costs in land, construction, and time.
On-farm water recycling ponds are rare in the Midwestern landscape today, but a few examples exist in the Great Lakes region. They have been implemented primarily where both irrigation is needed for high value crops and groundwater is inadequate to provide the rates needed. Regulatory considerations related to groundwater withdrawals impacts have also played a role, although that was not explored in depth and more study is needed.
Crop yield benefits of irrigation from ponds can be considerable. At the experimental field sites, corn yield increased by an average of 20% under historical precipitation and was projected to increase by 28-30% (depending on the model) under modeled climate for 2041-2070. For soybeans, the yield benefit increased from 12-13% under historical precipitation to 20-24% in the modeled 2041- 2070 climate.
The on-farm economic benefits will depend on the price of the crops, the specific soils at each location, and other considerations. On-farm water recycling systems are most economical in locations such as:
where high value crop like seed corn or specialty crops are grown, as irrigation is more likely to be profitable; and,
where costs of excavating a pond can be offset by economic opportunities for the soil and/or where a pond is already planned or exists, for example due to road construction.