By Harry Brook
The urge is almost irresistible. Take out all trees, bush, and fill in the sloughs and wet areas. One nice, open field maximizes field efficiency and machinery use. More acres means more crop, right? Not necessarily! Wetland and bush patches do provide a useful purpose related to crop production. It isn’t just for wildlife or biodiversity. Also, it is illegal to drain wetlands, without a license or authorization from Alberta Environment. Failure to get approval can mean you are liable for costs to re-establish the wetland.
Those producers who are yield-mapping their fields know some areas are less productive than others. If an area is low yielding, it probably has some clay in the subsoil with poor topsoil. The wetlands you drain will not be very productive as, even drained, they will collect and hold water in wet years. Often, especially in our county, there is a salinity issue and a bathtub ring of salts around the margin of the wetland. This will limit crop growth and yield. Also, annually cropping those areas will only result in the salinity problem getting worse. It is doubtful those areas around and in low areas will be productive parts of the field.
So, what advantages do you get from leaving wetlands? There are several and they include greater resilience during drought in the area immediately adjacent to the wetland. The wetland acts as a reservoir to hold and slowly distribute moisture to surrounding soils. They can prevent overland flooding and sheet erosion. They can act as a biological filter for fertilizers and pesticides and can actively store carbon.
Furthermore, wetlands are a refuge for biodiversity and insect populations, which can provide improved pollination of canola within about 100 meters of the wetland. They also act as a refuge for predatory insects, helping control crop-damaging insect pests. You could lump all these benefits under ecological services. Just for esthetic reasons, wetlands provide habitat for wildlife. Ducks and geese habitat provide nesting areas and hunting opportunities in the fall.
Just because you fill in or remove a wetland doesn’t change the fact that water has to go somewhere. Removing wetlands is expensive and rarely productive. They are a general cost, not profit, to the field. If you fill in wetlands, there will be more overland flooding and this creates problems between neighbours. You move water off your farm and you flood your adjoining land.
If you have livestock, those potholes are valuable sources of water for cattle and other grazing animals. You usually see that livestock producers leave their wetlands because they know the value of them.
Flagstaff County’s Agriculture Service Board has developed a program to provide the grass seed, labour and machinery to seed down small areas around wetlands, free of charge. The idea is to seed areas that are frequently too wet to farm, adjacent to wetlands, that can provide forage. Rather that struggle each year to seed these awkward areas, a grassed area will provide some feed and improve the field efficiency of the rest of the field.
Wetlands are an overall benefit to both the agricultural producer and society at large. There are many benefits to retaining them, as opposed to removing them. For those interested in seeding small areas adjacent to wetlands, contact the County about our latest program to promote wetlands. There is benefit there for all producers.