Rethinking Soil
As I grew up in the 1980’s and 1990’s, I saw the shift in thinking from plowing the soil to leaving the trash in place. By leaving it there, farmers were seeing less erosion and seeing more moisture left in the soil. Over time many systems developed. Some went completely away from tillage (no-till). Some did what they called minimum tillage (min-till). And some did a hybrid of each — they tilled where the seed would be planted and left the area between the rows untouched (strip-till).
Switching to less tillage meant that one of the key weapons against weeds was taken away. For centuries, farmers have relied on plows, discs, and cultivators to control weeds. Concurrent with the rise of reducing tillage was the development of herbicides. Some are non-selective (kill any plant) and some are selective (kill only certain plants). Before the crop emerged, and after harvest, the non-selectives could be used to keep a clean field. While the crop was growing the selectives could be sprayed on the crop to get rid of all competitors.
The system has worked well. Soil erosion has been reduced. There’s more water for the crop. But nature always has a way of fighting back. Weeds eventually resist the chemicals we apply. The same process happens when we use antibiotics to attack the microbes in our bodies.
Let’s back up a bit. Did you notice the terminology there? I referred to plant residue as “trash.” A good field was seen as “clean.” Nature doesn’t see plant residue as trash. It’s the food for organisms living in the soil. Nature also doesn’t see bare soil as desirable. The soil is nearly always covered with many species of plants — dead or alive.
Experiments in my garden
After spending my summers days helping farmers grow crops, I come home to play in my garden. Eleven years ago when we purchased the property we live on now the garden area was neglected. It was a hard piece of soil that had been used to park a boat trailer on. The ground was so hard and dry that the weeds didn’t even want to grow there. After a few years of playing around with growing vegetables, I was offered the use of a rototiller to give it a good till.
My productivity suffered for a few years after that. I should have known better.
Knowing the success of reduced tillage, I adapted it to my garden. Vegetable crops don’t give much residue, so I covered it in wood chips. I immediately saw the benefit of moisture conservation.
What I didn’t see right away was the building of the soil. I had to keep adding wood chips each year as the old layer thinned out. I knew it was breaking down, but until recently I didn’t see it as food for the underground population of soil organisms.
When digging carrots a few years ago, I really saw the difference. I hadn’t tilled the soil for five years and yet here were 6–8” carrots coming out of the ground perfectly formed. The top few inches of soil was darker than the light brown it started as. It was also softer and more mellow than when it started.
The shifting conversation
At about the same time as I was seeing the change in my garden, I was learning of the soil health movement. I soaked in any information I could get on it. There are five tenets of the movement, and I’d seen most them at work in my garden.
Cover the soil as much as possible
In my garden, this meant importing wood chips, but on a farm this can mean leaving residue on the surface after the crop or growing a cover crop when the cash crop is not.
Minimize disturbance
In my garden I still need to dig holes to plant my seedlings, I still need to pull back the mulch and lightly till to plant seeds, and I still need to loosen the soil to pull my root crops. But I never rototill, and I never dig and turn the soil over. On a farm, this could mean using no-till principles on crops that do well in it — such as corn, soybeans, and wheat — and minimize the disturbance in crops that cannot be no-tilled — such as potatoes, sugar beets, and carrots.
Keep living plants growing as long as possible
In the garden I have crops growing most of the year, but in agricultural systems, there may be months after harvest when nothing is there. Nature tries to correct this by growing what we call weeds. Instead of letting nature do it, pick the plants that are going to benefit the crop next year and won’t compete with it. Its commonly called cover cropping. Essentially, its directing the plants that grow on the soil when you don’t have a cash crop.
Increase the diversity of the plants grown on the soil
In my garden, I have a lot of diversity. They generally stay in blocks for ease of planting, watering, and harvest but this coming year I’m going to mix it up even more. I’ll inter-plant ones that do well together and try to always have something with active roots filling the space. On a farm this can mean diverse cover crops, inter-cropping (two or more easily separated crops at the same time), or planting a non-competitive cover crop once the cash crop is established.
Integrate animals
Unless you count the birds and cats roaming through the garden, I’m probably not going to get far on this one. Even for most farmers, this is not an option. In my garden, I can keep adding compost and farmers can add manure or composted manure if they don’t want to get into livestock.
I’ve hardly scratched the surface on this topic. We all are just starting to scratch the surface on it. What I like about it so far is that it’s a conversation and it recognizes ambiguity and uncertainty. I’m thankful for all of the people over the last few decades that have experimented with soil health and have kept the conversation going. I look forward to the next few decades as I bring more to my garden and see what new things farmers can bring to their land.
