Dave Brandt was probably the longest running no-till farmer in the state; he’d been running his land no-till since 1971. He experimented with fertilizers, cover crops, and different irrigation techniques and he’d been doing all of that for a very long time.
The guy was an institution all on his own; look at this.
The “A” profile in his soil is now 47 inches deep compared to less than 6 inches in 1971 and acts like a giant sponge for water infiltration and retention.
From 1971 through 1989 David used an average of 150-250 pounds of nitrogen fertilizer per acre to grow his corn crops. After adding peas and radishes as a cover crop mix, he cut his nitrogen needs in half and was able to get it down to 125 pounds per acre.
When he added multiple species and became more aggressive with his cover crop mixes, he was able to achieve an additional drop in applied fertility. His starter fertilizer is now just 2 lbs of N, 4 lbs of P, and 5 lbs of K. His corn crop now only requires 20-30 lbs of N throughout the entire growing season. He requires no fertility for his soybeans, relying on fertility gained solely through his cover crops. He uses only 40 lbs of 10 N – 10 P – 10 K for his small grains.
Ten years ago (source study published 2019) David stopped using any fungicides and insecticides. This occurred at a time when fungicide and insecticide use has increased significantly with the average commodity farmer.
Four years ago he stopped using any seed treatment, including neonicotinoids.
His cash crop yields have been increasing by an average of 5% annually for the past 5-6 years, with far less fertilizer and no fungicides, insecticides or seed treatment.
What started as a basic heavy clay soils when David purchased the farm in 1971 have been officially re-classified by Ohio State University soil scientists as a highly fertile silty loam soil.
I know I’ve said it before, but–that first point, there, about the “A” profile of his soil? Every time I think of it, I am taken aback with genuine awe.
So this is a picture of the soil horizons. The O profile/O horizon is stuff like fallen leaves, sticks, and so on, which are biodegrading into the A profile. A fair amount of soils might have no O profile at all.
If you are a gardener, the A profile is what you’re concerned with most of the time; it’s what we also call “topsoil.” Your seeds germinate into it, and shallower plants might root into it alone without ever reaching the B profile. Worms and other small delvers live in it. It’s what you’re amending, what you’re testing, what you’re tilling, what you’re trying to fill up with good microorganisms to work with your plants and provide you with food or flowers or cover.
I see this quote around sometimes, attributed to radioman Paul Harvey:
Man — despite his artistic pretensions, his sophistication, and his many accomplishments — owes his existence to a six inch layer of topsoil and the fact that it rains.
Without the topsoil, bluntly, we starve. And there are other problems, in places with a lack of it; without the topsoil, when the rains come, the water strikes hard soil. Hard soil doesn’t accept water easily, so instead it pools and runs downhill. That action makes flooding, makes flash floods, makes standing water that carries disease, it contaminates the water table. Cholera is a huge problem in places with a low A profile that receive too much water at once.
We are seeing topsoil depletion across the US. I can’t speak for other countries, but the heavy-tilling agricultural habits we’ve adopted here have obliterated inch after inch of our topsoil; in the 1800s the average depth was fourteen inches! Today it is six. Many suburban lawns have even less. This has knock-on effects we don’t even consider on the day-to-day (for instance, there’s some suggestion that the lower amounts of various minerals in vegetables and fruits today in comparison with earlier decades might be because of the lower amount of minerals in the soil for the plants to take up into themselves).
And this gentleman took soil that had been that abused and not only returned it to what it had been before the aggressive, destructive European agricultural policy had its way, but trebled that earlier depth.
His land protects the land around it from flooding. His land grows plants less susceptible to disease, because of all the various stressors and pressures those plants aren’t confronted with. His land almost certainly has a considerably higher concentration of microorganisms and it would follow that we’d also see greater diversity of macroorganisms thereby.
