- Jim Chamberlin
Soil Health, Part One
Jim Chamberlin, Happy Dancing Turtle’s Conservation Technician, also operates a 109-acre diversified farm and forestry operation near Deerwood, MN, with his wife, Audra. His knowledge about and enthusiasm for what we can do for soil and what soil can do for us will fuel this four-part series of blog posts.
Soil health is defined as the “ability of soil to function as a living ecosystem.” Over the next four blog posts, we will walk through six soil health principles:
Minimize Soil Disturbance
Armor the Soil
Keep Living Roots in the Soil
Manage for Context
Introduction: Biology First
The definition of soil health as the “ability of soil to function as a living ecosystem” sounds simple enough, but our entire food system has been built around looking at soil as a storage medium for chemical nutrients. Having researched organic (the true meaning of organic originated as recognizing the living, biological component of soil) methods of growing food for over thirty years, it is inspiring to see the science catching up to what organic growers have always known, that biology matters.
Soil function is the ability of soil to store and cycle nutrients and water. Approximately 85-90% of nutrient exchange is through biology, which drives the chemistry to feed plants. Biology also drives the formation of soil structure, increasing water-holding capacity. Without having a diverse living component, soil can not properly function. Poor soil function leads to lower nutrient levels in our food, declining quality of our water, and a general decline in the health of our environment, which includes us as people.
The good news is, we are gaining a better understanding of what it takes to build soil health, and there are several widely recognized soil health “principles” we can follow to get us there. These principles act as a guide to create the life-supporting conditions in our soil that allow it to properly function. It is important to recognize the difference between these principles and the tools/ practices that support them.
For example, cows, cover crops, no till, and precision agriculture are all tools/ practices that can support soil health principles, but using them in isolation from other tools, or in a way that doesn’t support the soil health principles, will not assure soil health. By implementing three or more of the soil health principles well, you will see positive changes in the health of your soil, crops, and livestock.
In the publication Conquest of the Land Through 7000 Years, USDA Soil Conservation Service Undersecretary Dr. Lowdermilk, on the heels of the 1930’s dust bowl, wrote about his ventures visiting past civilizations and how populations have thrived or failed based on how they treated the soil. Done poorly, agriculture causes damage, divisiveness, and scarcity. Done well, agriculture heals our land, our water and our communities.
Principle 1: Minimize Soil Disturbance
A few years ago we had a storm hit our home. I’m not sure if it was a full blown tornado, but I woke at 3 AM to the “train” sound howling outside the window. We never made it to the basement before it was over. The next day all you could see outside our window was green. We lost several large trees and had to replace the roof on our house and garage. With some help from our kids and a good roofing contractor, within a month or two things were back to normal.
That’s what it’s like for the macro and microorganisms living in your soil every time the soil is plowed, tilled, or sprayed. Their home is being destroyed and needs to be rebuilt.
Minimizing disturbance is the first key to soil health. Tilling, disking, and plowing break soil aggregates into smaller particles, reducing pore space and limiting the soil organisms ability to move in the soil. It also releases carbon, contributing to the growing climate issue, and depletes soil organic matter, an important component of healthy soil. These smaller soil particles plug soil pores, reducing water infiltration into the soil profile and increasing runoff downstream and making crops more susceptible to drought.
Applying synthetic fertilizers and pesticides also disrupt the soil food web, often in ways we don’t fully understand. The bottom line is, minimizing practices that disturb the soil helps set the stage for a diverse and healthy soil community.
Large scale farmers often look to find a balance between herbicides and tillage when terminating a cover crop, or when controlling weeds. One promising tool to terminate a crop and reduce soil disturbance is a cover crop crimper, which if used at the right time of maturity, on the correct crop, will lay it flat and crimp it every 4-6 inches, and effectively kill it. Farmers have good luck with this on cereal rye, often no till drilling soybeans into the standing rye when it first starts to flower, then crimping it down just as the beans start to germinate. The soybeans grow through the residue, and the cover crop suppresses weeds before and after it is terminated.
Other ways to terminate an existing stand without herbicides or tillage are planting annual cover crops that die over winter, using livestock to graze a crop back, or mowing it short with a flail mower. Chisel plowing and disking are less aggressive forms of mechanical disturbance used to avoid herbicide use. That said, data supports that herbicides may be less damaging to soil life than tillage based on how often either is used.
On a small scale I’ve found that raised beds provide a viable no-till option. If you stay on top of weeding and keep the beds well mulched, over time weeds become manageable. Controlling grasses with rhizome roots is most important. Shallow hoeing with a sharp tool is light and effective work. Use the right hoe for the work you need to do. On a larger scale I try to keep tilling to once every four years or more, by establishing a crop rotation that builds on previous years.
Year one: Potatoes. Work up soil the fall before and seed to cool season annual cover crop (brassicas, oats, peas). Plant potatoes in the spring, then cultivate to control weeds and hill. Seed walkways to low growing annual/ perennial cover crop(white clover, brassicas, cereal rye) in July, or 30-45 days after planting. In the fall plant garlic where potatoes were dug and mulch heavily. We plant around Oct 1st in North Central Minnesota.
Year two: Garlic. Harvest in July leaving mulch in place, or adding more.
Year three: Companion planting. Strip till garlic rows if needed.
Here are two possible suggestions:
1) Brassica, onion, celery
2) Three (four?) sisters, corn, beans, squash, (sunflowers)
Year four (five and six?) - perennial biomass/forage of grasses and forbes. Shoot for 30% legumes.
Keep rows well-mulched throughout the first three years. Chop and drop weeds that haven’t gone to seed with weed whip or mower. Hand pull large weeds that have gone to seed. Frost seed (on frozen ground with 2” or more of snow) a diverse mix of legumes and grasses going into year four.
In the next blog post, learn the next two soil health principles, Armor the Soil and Keep Living Roots in the Ground. In the meantime, if you live and tend soil, whether a little or a lot, appreciate the “weeds” as you minimize disturbance.