Renewable Farming

If western Corn Belt drought forecast is correct, this biological “insurance” could help

“Over the last 20 years, we’ve never seen a drought situation looking like this through February. There’s extensive drought in the Northern Plains. There’s exceptional drought in the four-corner states. But there’s little drought in the eastern half of the U.S.”

February 24, 2021 — That report is from Eric Snodgrass, principal atmospheric scientist at Nutrien Ag Solutions. He’s quoted in today’s Daily Scoop, a Farm Journal e-mail update. Our clients in the western corn belt have already been wary that the 2021 season could unfold like last year’s: challenging to get planting done, then a dry summer.

Thus in recent weeks, we’ve been running simple greenhouse tests of bacterial and fungal “endophytes” from Adaptive Symbiotic Technologies (AST). Their companion microbial blends, BioEnsure and BioTango (BE/BT), are already among the most-tested biologicals in agriculture. But… we wanted to see the real-time effects of those living organisms up close. And especially, we wanted to compare the root structures of young corn foliar-sprayed with BioEnsure and BioTango, compared with controls.

These photos are a followup to a similar test we reported February 17. That trial using a dozen corn plants checked out the impact of BioEnsure and BioTango used as a seed treatment. The photos here reflect a foliar spray at V2 with the same products, at recommended rates. Our previous report explains much of the background facts about AST’s discovery and development of these endophyte organisms. They live inside your crop, in a symbiotic or mutually beneficial relationship, and help their host plant survive through stress periods such as extreme heat, drought or cold.

Since our concern this season is a summer with long, rainless periods in June through August, that’s what we simulated in our potted corn seedlings. 

When we showed our tests to AST’s chief product developers — Dr. Rusty Rodriguez and Dr. Regina Redman — they indicated that our small experiments showed responses like those they’ve seen in their lab and client fields for years. Our little greenhouse tests are thus largely redundant; they don’t prove anything new. But it was especially helpful for us to carefully extract treated versus untreated corn roots from the small pots, and crumble away the dirt.

Spectacular may be an overstatement, but these foliar-treated seedlings had more than twice the root mass of untreated corn. Even more significant: Soil clung to the roots firmly in the BE/BT treated seedlings. That indicates rapid early growth of mycorrhizal fungi in the root zone. These natural fungi serve as a powerful extension of roots. They grow partially inside root hairs and extend well into surrounding soil, absorbing water that roots alone can’t find or take up. The mycorrhiza also exude solvents which absorb and transport soil nutrients ten times more effectively than root hairs alone. 

This has to be part of the beneficial processes from the BE/BT organisms. 

The bottom photo in this report shows the three sets of roots in our experiment. Left to right:

1. Four untreated control seedlings. These went through two successive “drought” stresses. The pots were not watered for several days, until the leaves curled and wilted. Then they were watered to test recovery ability. Most of the seedlings endured the first dry spell. But after that single watering (60 milliliters in each pot), they were again starved for moisture. After a full wilt, they were watered again. But the untreated four corn plants failed to recover. Our effort was to simulate what happens in a hot, dry July-August — rainless weeks, then a storm with an inch or two of rain, followed by more dry weeks. Even if corn survives, it’s losing yield potential and test weight.

2. Four seedlings foliar-sprayed with BioEnsure and BioTango at V2. These all survived two “drought” episodes. They showed moisture stress during the dry spell, but not as severely as the untreated four. Our greenhouse temperatures ranged from 60 degrees F. overnight into the 80s on sunny days. 

3. Four seedlings foliar-sprayed with BioEnsure and BioTango at V2, and given normal moisture consistently. The effort here was to compare how badly the treated set No. 2 suffered from the dry spells — even though it had the benefit of BE/BT endophytes. There was an obvious benefit in growth both above ground and in the root zone, given normal moisture plus the biological organisms. This is consistent with Regina Redman’s field research showing that even in normal years, the BE/BT organisms show yield benefits that pay for the products. (See the AST website for data.)

Our experiments with seed treatment and foliar treatment showed essentially the same benefits. AST recommendations accommodate your preferred application method: Pre-treated seed, planter-box seed treatment with a talc lubricant, or foliar.



 Update February 25, 2021:  Here’s the latest U.S. Drought Monitor map.