Renewable Farming

Recreational tillage — still more popular than cover crops

Our “mission” to encourage renewal of soil health faces a relentless force: The brute power of soil erosion by water, tillage, and wind.

As we cruise around Iowa this fall, it’s clear that favorable harvest weather also opened the opportunity for extensive fall chiseling and disking. We’ve even seen a few disked-up soybean fields.  We’re not fanatics for absolutely NO tillage. The data on light vertical tillage, blending cornstalk residue into the top few inches, looks   like a sound way to amplify micorrhizal residue digestion and hold soil in place. It’s also an effective way to trigger germination of cover crops like oats or cereal rye in heavy corn residue.

Then, when cover crops emerge, you can accelerate root growth with WakeUP.  It helps pump more photosynthetic sugars to roots, which exude that energy to stimulate microbial growth around the root. It’s the fungal complex which builds durable humus, and root sugars help multiply those beneficial fungi. Of course, excess tillage rips up the habitat of those delicate fungi.

The fall 2015 issue of the Leopold Letter summarizes sobering data on soil erosion, compiled by Iowa State University agronomist. Cruse is a crusader via presentations to farmers, including webinars which you can connect with via links on the Leopold Letter.  We found several eye-openers in the data pulled together by Cruse and his associates.

— Actual soil loss rates are much higher than traditional estimates indicate. 

— No-tilling corn and soybeans is far from adequate to avoid destructive soil loss, even on moderately sloping knolls. One photo shown by Cruse reveals how tillage and weathering has peeled topsoil from gentle knolls in north central Iowa’s “prairie pothole” country. 

— Aggressive tillage like disking or chiseling on slopes causes the entire tilled profile to shift downhill slightly with each pass. “Gravity works,” says Cruse. However, vertical tillage such as a Gen-Till, CurseBuster or Are-Way allows far less horizontal “drift” of soil. 

— One of the most effective ways to hold soil in place is permanent filter strips.  Back in 1980, we bought 160 acres of gently rolling land in northeast Iowa and built terraces with margins of permanent grasses above and below the terraces. Soon after ownership of that quarter-section passed to a large-scale operator, that grower tore out the terraces and no-tilled the ground. Every year, gullies emerge, scouring out “no-till” roots and residue. The county has had to excavate topsoil from bordering ditches to keep drainage from flowing over the roads. 

What we like to focus on is holding the soil ecosystem intact, and finding ways to amplify the natural rebuilding of stable humus. This requires fungal activity, and bacterial activity, along with larger organisms in the soil food web, like earthworms.  Pesticides complicate that effort, especially those which are highly toxic to beneficial bacteria.

To hear an online webinar by John Kempf of Advancing Eco Agriculture explain the reasoning for this, here’s the link to his presentation on YouTube.

We encourage you to scan that report by Laura Miller in the Leopold Letter, and then link to the webinar by Rick Cruse.  Let the chisel plow take a rest.  Give your fungi a chance.

Mycorrhizal fungi around roots

 

 

 

 

 

 

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