Simon Knutson, geo-coach with Agri-Trend Geo Solutions, has been fielding a lot of calls about drainage. Here’s what he has to say:
We come across a huge number of acres that have small glacial depressions that are often too wet in spring to farm through or that collect rainfall during the growing season and cause crop losses. Some of these depressions have held water for the past couple of seasons because of higher than average rainfall, but when we talk to farmers they usually tell us they have farmed through them for most of the past 10 or 20 years. When farmers have to farm around small depressions they not only lose efficiency, but also regularly overlap their applications of fertilizer and pesticide, meaning there are areas of the field that might get two or three times the prescribed amounts, and this could lead to high concentrations of nitrates or chemical residues ending up in streams or permanent wetlands in the catchment area.
Because most of these depressions are too deep for surface drains, we’ve been investigating the idea of using subsurface drainage. The idea here is to lay a perforated pipe that will allow each depression to drain, and connect as many depressions as possible with each length of pipe. In many cases the best option may be to consolidate multiple smaller depressions into one or more larger areas that may then become permanent wetlands, giving the farmer far fewer obstacles to farm around, and helping create or preserve habitats at the same time. Unlike traditional tile drainage where pipes are laid in a grid formation throughout the entire field, this type of subsurface drainage would only require pipe to be installed between the depressions to be drained (the rest of the field probably doesn’t have any drainage issues).
The benefit of this approach over traditional tile drainage is that the cost will be much lower; tile costs around $600 to $800 per acre on the entire field, whereas with a precision subsurface method you only pay for what’s needed. I haven’t figured out exact numbers yet, but in my opinion its realistic to think we could bring 20 to 30 acres back into production for $10,000 to $15,000.
In order for precision drainage to work, you’d need detailed elevation mapping of the field, including measurements of all the depressions and areas where the water may end up. Once we have the elevation data and drainage designs, we (Agri- Trend Geo Solutions) work with the farmer to install the drainage.
QUESTION: IS TILE DRAINAGE
worth it? What’s the most effective way to connect depressions using subsurface drainage in my fields?