If you Appreciate Your Lake, you should Love Your Soil
Summer is in full swing and our lakes are busy. What is more paramount to Minnesota than summer time at the lake; swimming, fishing, boating, water skiing, paddle boarding, the list of fun goes on and on.
But many of our lakes are hurting.
Decades of use, and sometimes abuse, have led to water quality declines for many of these precious resources. Just last summer, one of the most popular and enjoyed lakes in our region, Upper Whitefish, had a major weed and algae bloom. For much of the summer, vast areas of the lake were unusable for recreation. In agricultural regions of our state we’ve unofficially given up on our lakes and rivers, with as much as 98% of the waterbodies in some watersheds failing to meet minimum water quality standards.
What is it that we appreciate about our lakes and how do we protect these values?
Upper Whitefish early August 2018 photo Credit: WAPOA, Kent Brun
Over my years as a resource professional I’ve seen results from several surveys on what people value in the Lakes Region. Without exception, ninety percent or more of the people who respond to these surveys say they put a high value clean water. And that’s where I see the breakdown – the connection between clean water and the health of our soils.
Clean water starts with healthy soil.
Soil health is defined by the USDA Natural Resource Conservation Service as “the continued capacity of soil to function as a vital living ecosystem”. Soil function is the ability of soil to cycle nutrients and water. Eighty five to ninety percent of nutrient cycling is through biology, so without living soil comes the inability of soil to function and to clean water. Impaired water has excess nutrients or temperature, a sign the soil within the watershed is not properly functioning.
To value soil is to value water.
Water doesn’t always move vertically in the soil profile to the water table. In our glacially formed soils, there is most often a restricting layer of fine silt and clay that hold water in the soil profile. Any time there is a slope to the landscape, water travels vertically through the soil profile until it hits this restricting layer where it starts to move horizontally through the soil following the landscape topography, like a shallow underground river. This is why deep rooted and perennial plants are so important. It’s not just that riparian buffers filter sediments that travel over land, deep and diverse root systems capture nutrients that are moving with water within the soil profile, absorbing them through the biology of the rhizosphere and keeping pollutants out of the lakes we appreciate so much.
Squash and cover crop
The solution to preventing nutrient loading to our lakes seems clear to me. Capture water and hold it on the landscape in the soil profile. Not just any soil, but healthy, living, carbon rich soil. The soil health principles lay a road map to do this.
Keeping soil armored with growing plants or mulch protects from erosion and stabilizes soil temperatures to support the living organisms in the soil.
Minimizing soil disturbance preserves soil structure and avoids disturbing the home of the soil organisms. Some organisms, like mycorrhizae fungi (a type beneficial fungus), can’t survive when soils are frequently tilled or plowed. Additionally, reducing, or eliminating, pesticides and synthetic fertilizers avoids the disruption of the soil food web allowing it to fully function.
Keeping living roots in the soil feeds the soil microbiome. Plants exude as much as 30% of the photosynthate (plant snot) they produce through the roots to the rhizosphere. This exudate is the base of the food chain for the biologically rich zone surrounding, protecting, and supporting the root of the plant. The plant feeds the biology and the biology feeds the plant.
Increasing the diversity of plants supports the diversity of organisms below ground. Different types and species of soil organisms are supported by different types of plant exudate from different species of plants, and even different stages of plant growth. Diversity above ground equals diversity below ground.
Integrating livestock closes the equation. All ecosystems have a predator/ prey relationship. Historically the richest and most productive soils evolved with large herds of migratory herbivores. Science has yet to replicate what comes out of the back of the cow. How we manage and utilize the assets of livestock is paramount to soil health.
If you appreciate your lake, try to understand the issues and the connections between your actions, your soils, and our water. Clean lakes begin with healthy soils and that takes all of us.