Crop consultant Bob Streit: In-furrow biologicals can help late-planted corn accelerate early growth

Below we've pulled excerpts from Iowa crop consultant Bob Streit's most recent recommendations on coping with this cool, rainy spring. Our calls from farmers indicate that those who've patiently built up soil life and thus absorbent soil structure are seeing a real advantage from their soil's ability to sponge up rain and provide a workable seedbed sooner than most of their neighbors.

May 15, 2019 — If you've read this site for several years, you know our theme has always favored building  soil health which can withstand weather stress that's too cool, too wet or too dry. Our big surprise along the way was to discover that WakeUP amplifies the benefits of beneficial microbes and fungi, whether applied in-furrow, on the surface, or grown naturally with cover crops. That's a major difference between WakeUP and ordinary surfactants. It mobilizes nutrients within your crops.

Here's a summary of Bob's observations as of mid-May:

We have to remain optimistic, but the collapse of the Chinese trade talks took the markets down again made it such that taking prevented planting may make the most sense given the fact that having a very high percentage of the corn crop being planted in saturated soils and likely mudded in. That may not be worth the battle.

This may change by midweek, as the NWS forecast is for warmer and drier conditions thru the end of the week and warmer for the next 10 to 14 days. It just looks like many growers will be huddling with their crop insurance agents over the next two weeks and working thru their individual plans if conditions don’t change to warmer and drier.

The state-by-state estimates of the planted corn and soybean acres were released later than normal Monday. In the big six corn planting states the planted figure weighted for acres was about 16%. Iowa came in at 36% with the majority of that being between Hwy 30 and I-80 west of Hwy 14. All points east were in the 2% to 10% range. Farmers are reporting standing water in many spots in Ohio.

I did see one field SW of Des Moines on Sunday where corn was near the V3 growth stage. Most of the early planted corn has sprouted and a portion of those fields have emerged but not spread their leaves enough to see the sprouts from the road. On top of the rain delays, the temperatures remained 10 to 15 degrees below normal in most Midwest states. The growing degree  accumulation during the last 15 days of April tallied from about 100 in the Nashua, IA area to 140 in the southern reporting sites. In the first 11 days of May the GDU accumulation was very near half of normal.

Thus corn not in the ground isn’t too far behind what is still in the bag. Those figures can be seen by logging onto the ISU Environmental Mesonet site. A week ago people in NW Iowa and out into Nebraska were still scraping ice off the windshield in the mornings.

Fertilizer Issues: Normally a portion of the spring and early season fertilizer supplies is sourced from southern locations and moved by barge up the Mississippi. The high water levels remain yet from last fall and current projections say that such deliveries may not occur until June. That has fertilizer dealers scrambling to figure out where they can source materials they need to lay in for the corn acres in their areas.

Does that mean growers have to be resourceful in finding a new way to supply N to their corn crop until late season N supplies are delivered? Does that mean using foliar applied 46% by tall tired dry spreaders, or Y-dropped 32%, supplemented by foliar applied free living Nitrogen fixing bacteria?

In the last method there are several species of Azotobacter bacteria, vinelandia and crococum from the USDA collection that can be foliar applied along with one of two liquid products (either a combination of 1 gal of molasses and fish or 1 qt. of a mineral/sugar mix to supply food to the microbes) that has been used by a few growers in the past to allow the plants to fix 50 lbs. of N from the atmosphere, which is 78% N.

I have seen it work in past seasons and documented with a SPAD meter. However, if the microbes are needed the brewers need to start brewing to meet any needs.

 Until now the soils have remained very cool and N loss from leaching should have been minimal. Once their temps reach above 50F there could be losses from leaching or denitrification. Last year too many fields turned a ghastly yellow by mid-July. Those were the fields that nobody bragged about. Out of necessity growers may have to decide what best management practices may make their operations be the stingiest with nitrogen.

 Cold Soil, Reduced Biological Activity and Sidewall Compaction 

The slow soil warm-up will have consequences by having low levels of biological activity to begin the season. This could limit the amount of nutrients available until their root systems are able to scavenge for placed fertilizer or the soil warms to the point that biological activity frees those nutrients up. Nutrients placed with the furrow jet or 2 X 2 equipment should help feed the plants early and help them develop faster. Higher soil P levels should be very beneficial this spring.

This year the cold soils may make the application of a biological mix more important to overall productivity. With today’s emphasis on soil health the main lesson to be learned is that soil fertility is much more a biological equation than a chemical one. Any step or product that accelerates root zone biology should be viewed as beneficial. A product such as BioDyne 401 or 801 applied in furrow or broadcast would be very helpful in increasing nutrient availability.

Sidewall Compaction

Because planting has been delayed the toughest thing might be to wait to plant until the soils are dry enough to avoid causing both traffic compaction as well as sidewall compaction. The best way to make this judgment call will be to dig up a few shovels of soil and see if the dirt crumbles or if you can shape it like putty. If it is still the latter, you increase your chances of having the opening discs forming compacted sidewalls that limit root growth during the season that will reduce root size and expected nutrient and water uptake during the season. Then if conditions turn hot and dry during June as predicted, the narrow and restricted root system will not be able to keep up with the above ground plant needs. 

Cutworms

 The black light traps catches at several land grand universities have been heavy and indicate that any corn no-till planted into a green field where the green mass is terminated by any herbicide could have been an attractive egg laying site to the invading moths. If that includes some of yours, you will want to scout those fields early to make sure the hungry larvae don’t rely on eating your small plants for lunch.

Bob Streit is an independent crop consultant and columnist for Farm News. He can be reached at (515) 709-0143 or www.CentralIowaAg.com.