Drainage Contractor

Smoke test demo can show a lot about fields

August 10, 2015  By Drainage Contractor

Aug. 10, 2015, Union City, Ohio — Ohio State University’s upcoming Manure Science Review will feature a demonstration of smoke testing — a way to show how fast a liquid can flow through and out of a farm field.

Manure Science Review is an annual learning event for farmers and others in the industry. This year’s event is set for Aug. 12 in Union City, Ohio. Frank Gibbs, retired from the U.S. Department of Agriculture’s Natural Resources Conservation Service (USDA-NRCS) and now with Wetland and Soil Consulting Services, based in Rawson, Ohio, will give the demonstration.

Earthworm holes and cracks in the soil, called “macropores,” can play big roles in the flow of liquids from a farm field. Generally, macropores improve a soil by helping water soak in and crop roots go deeper. But they also can give liquid manure a path to a fast, early exit — a waste of valuable crop nutrients and a possible source of water pollution.

A smoke test provides a visual representation of a soil’s macropores. It shows where they are and the flow they can carry. The test involves pumping smoke into a farm field’s underground plastic drainage pipes. The smoke travels laterally through the pipes, which have drainage holes all along them; rises through those holes; then rises through macropores and up through the soil. Eventually, white smoke swirls at the soil surface.


The process goes in reverse for a liquid, which starts at the soil surface, moves downward through the macropores, enters the drainage holes, and collects in and flows through the tiles, which then empty into a waterway.

Understanding that flow can improve both a farm’s bottom line and water quality. Steps can be taken to keep liquid-manure nutrients in a field where they’re needed — as fertilizer for crops and a way to boost yields — and out of streams and lakes where they can cause such problems as algal blooms. Possible ways to stop the outflow of liquid manure from drainage tiles include adding shutoff valves to the tiles and digging catch basins.

Details about the event and how to register are available at go.osu.edu/MSR2015. Registration is $30 and includes a continental breakfast and lunch.

For more details, contact Mary Wicks at 330-202-3533 or wicks.14@osu.edu.

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