Minnesota: Extension Begins Drainage Trial

Installing subsurface drainage system. Photo: University of Minnesota

This past fall, I made the decision to invest in a new subsurface drainage system at the Northwest Research & Outreach Center (NWROC) in Crookston.

Over the next several years, I will be taking northwest Minnesota farmers on this journey with me as I evaluate my investment. Like any major financial investment, there is some amount of risk involved in this decision. Times are hard right now, and not everyone can take on the risk of installing a new subsurface drainage system. We are doing this to help you decide whether investing in drainage is right for your farm.

I was willing to take this on because I do not believe that installing drainage is that much of a risk. I invested in drainage because I believe it will improve the profitability of our operations.

Previous drainage research conducted at NWROC from 2001 to 2004 indicates that we should look beyond grain yield as the only way to profit from subsurface drainage installation. The study showed that drainage had a limited impact on grain yield, but it increased grain protein content in spring wheat and soybeans.

This research also found that subsurface drainage increased soil temperature. Higher soil temperature combined with lower soil moisture improves field workability in the spring and fall. This will save another valuable resource during planting and harvest: time.

This past October 2019, I designed and installed our new subsurface drainage system with the help of Ellingson Companies. The system currently drains 30 acres of a 60-acre field owned and farmed by the NWROC. I divided the 60-acre field into four 15-acre plots: two drained and two undrained. We designed the system so that we have the option to install drainage on the other 30 acres in the future.

My plan is to monitor the improvement in crop yield compared with our historical averages and calculate the return on investment for our newly-drained field. I am also partnering with Extension soil health specialist Anna Cates to look at changes in carbon pools now that we have made a fundamental change in soil conditions.

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I will also measure the amount of fertilizer (nitrogen and phosphorus) lost in both surface runoff and subsurface discharge. If we see high levels of fertilizer coming off the field, I will work with our NWROC farm manager and our Extension nutrient management team on different strategies to lower the concentrations. Lowering fertilizer application rates is by no means the only way to reduce nutrient loss in drainage discharge.

We can also look at how to place fertilizer so that it avoids transport into tile drains, and when to delay fertilizer applications based on the weather forecast. Our goal will be to minimize fertilizer losses while maintaining a profitable operation.

Down the line, I would like to build on this research by exploring new ways to filter residual nutrients out of drainage water without impacting in-field operations. Two notable examples of current technologies that can do this are denitrifying bioreactors and phosphorus removal structures.

Any profit we make from our farm operations goes right back into a general fund to support the research that goes on here. That means that our investment can pay off in more ways than one. If we can increase profits on this field, it will help NWROC faculty and staff keep answering the critical questions that you have about agriculture in the Red River Valley.




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