AMES, Iowa -- A potential problem for Iowa fruit and vegetable growers has been turned into a liquid asset, thanks to a one-year research project conducted by Iowa State University Extension and Outreach and funded by the Leopold Center for Sustainable Agriculture.
High tunnels are inexpensive, simple, passive-solar greenhouses in which crops are grown directly in the soil. They allow growers to extend the season and produce high yields of quality produce earlier and later than field-grown crops, thus getting to the market earlier and commanding a higher price.
However, soil around a high tunnel can erode or become saturated after rainfall. Approximately 900 gallons of water will flow from the roof of a 30-ft. by 96-ft. high tunnel during a half-inch rain event. Extension specialists developed a system to catch, store and reuse rainwater for irrigation inside a high tunnel. A prototype was built and tested during the 2011 cropping season at the ISU Armstrong Research and Demonstration Farm near Lewis.
The system is described in a new publication and 10-minute video produced by Iowa State University Extension and Outreach, “Rainwater Catchment from a High Tunnel for Irrigation Use.” The resources show growers how to add gutters and storage tanks with a pump to their own high tunnel.
Shawn Shouse, agricultural engineer for ISU Extension and Outreach, estimates the cost to build the rainwater catchment system at about $1,200. It could provide up to half of water needs inside the tunnel, depending on weather and crops, but it should not be a grower’s only source of water.
Linda Naeve, program coordinator for ISU Extension and Outreach’s Value Added Agriculture program, is aware of several growers who are adding gutters, storage tanks and a pump to their high tunnels this season.
The publication (PM 3017) is available to download at the Extension Online Store, https://store.extension.iastate.edu/, or from the Leopold Center website, http://www.leopold.iastate.edu/marketing/resources#tunnels.