Dean Craine, general manager of AgriEnergy Resources, opened the ACRES USA conference in Omaha this afternoon with a challenge: “Grow the largest population of benefical soil organisms you can. A living soil is the most productive, cost-effective soil.”
Nov. 30, 2016 — by Jerry Carlson Dean told farmers that after building up populations of good fungi, bacteria, protozoa and other creatures in the soil food web for more than 20 years, AgriEnergy has “raised 200-bu. corn with only 35 units of nitrogen, banded with the row.”
He said “The only way to build soil tilth — a living soil structure — is with biological activity in the soil.”
Biological activity persists in the soil in the fall anywhere in the aerobic zone where temperatures remain around 50 degrees. Thus, applying residue breakdown products in the fall can give you a head start on converting raw residue to next year’s available fertility.
Howver, fertilizing heavily with nitrogen, such as broadcast AMS or knifed-in anhydrous, can retard the populations of natural nitrogen fixing organisms in the soil. He urged “spoon feeding” fertility through the season, starting with in-furrow nutrients along with living biological inoculants.
Stimulating fungal and bacterial activity in the root zone amplifies the synergism between roots and mycorrhiza: “The roots feed the microbes, and the microbes feed the roots.”
Dean reported a number we’ve never heard before: The roots of a 200-bu. corn crop exude up to 10 tons of carbon-containing exudates into the soil during the growing season. These are sugars, phenoloic compounts, amino acids, ectoenzymes and a compound which Dean labeled “mucilage,” like the glue. These exudates are food for soil organisms, which act as multipliers for crop roots. Mycorrhizae, for example, have 10 times more “dissolving power” than roots for converting soil nutrients to plant-available forms. All soil nutrients must be made soluble before the plant can take them into metabolism.
The mucilage compound helps build the granular, coffee-grounds soil structure needed to hold water and allow free gas exchange: carbon dioxide out and oxygen in.
Such a structuring means that adding 1 gram of this mucilage exudate allows soil to hold 1,000 grams more water. This isn’t something which happens with added salt fertilizer — it’s only from active soil life.
Farmers in the ACRES audience confirmed Dean’s points from their own experience. Another aid for biological life, said one member of the audience, is adding gypsum and high-calcium ag lime, in a 50-50 ratio. (We’ve seen that effect on our Renewable Farming research ground.)
As evidence for the current trend in “growing more soil life naturally,” Dean reported that when AgriEnergy started more than 20 years ago, organic farming was just beginning. Now, certified organic growers make up half of their client base. Many of them are growing 200-bu. corn, organically. (One of those organic growers told me that his net income from corn was over $1,000 per acre in 2015. He was asking me where he could buy a farm in Iowa.)
Here’s a photo of the “Biological Farming handout which AgriEnergy included in the registration packet for ACRES conference participants.