PRIMGHAR, Iowa — Many farmers experienced over 50 inches of rainfall in 2018. Normal rainfall is about 30 inches a year. Normally our drainage systems need to help remove 3-to-6 inches of excess water; however, in years like 2018, it was more than 15 inches or 300-to-500 percent of normal drainage. This pushed systems past capacity.
Iowa State University Extension and Outreach can help farmers and landlords address the issues of drainage.
Topics to consider:
- Use free ISU Geographic Information Systems (GIS) images to access the current and future drainage needs on your farm. Corn and soybean crops can tell us how well they are doing during the growing season using infrared satellite images that are very detailed. On a recent farm, four tile joints needed to be found to make new hookups and the free map images helped find them within 3-foot.
- Lay out a long-term plan to improve the drainage and a plan to pay for it. Planning a drainage system is a lot like planning a highway system which has gravel roads connected to county blacktops and state highways and finally interstates. Each part is a vital part of the overall system that needs to collect and move the excess water away. Each drainage pipe has a capacity with an associated cost that must be justified with higher yields and timely field operations. It is essential that there be no bottle necks in the system that cause traffic jams.
- Use free websites to calculate the performance of plastic drainage tubing. The drainage tile size, smoothness and slope are all needed to calculate the performance of the system, and it is now easy to use university websites to calculate these complex drainage capacities.
- Review current research and practices on drainage and water quality. Learn about the research on the drainage recycling projects that are planned and what the expected benefit will be for the farmers and the environment.
- Consider new surface intakes that take less maintenance and solve side-hill seeps. Surface intakes remove ponded water in our fields, but require maintenance to unplug cornstalks and debris that can plug tiles. Consider new intakes that use the Earth’s gravity to keep them clean and discuss where to put them to make it convenient to clean.
ISU Extension and Outreach Ag Engineering Specialist Kris Kohl can help offer solutions to drainage problems and direct you towards possible solutions. To speak with Kris, call 712-732-5056.
— Kris Kohl, Agriculture Engineering Specialist, Iowa State University Extension and Outreach
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