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CROP WATCH

By Staff | Sep 8, 2011

I am sorry about last week’s accidental column rerun. Getting into Decatur at 11:30 p.m. and being tired when I sent it made me attach the 08032011 column instead of that for 08302011.

What a week it was for people on the east coast as they endured their biggest earthquake in more than 60 years as well as their largest hurricane in more than 100 years.

Based on what farmers in affected states are stating, many of their crop acres have suffered major damage and may not be harvestable. Is a meteor strike or a volcanic eruption next on their schedule?

As to the big event in our Midwest region it was another rainless week in most areas. This represented either the fourth or seventh consecutive week without measurable rainfall for many parts of each state.

This was right during important pod-filling stage for soybeans and was expected to be a major problem for grain fill for that crop. Quite a bit of the corn could still use rain to finalize grain fill.

However, for those acres where the ears have flipped down and the plants have turned brown, their fate has been sealed and rain now will not do much good.

Most areas finally got rain this past Tuesday, and it was very welcome. At this time we need to also begin to build the moisture profile for next season.

I had an interesting week in that I had to be on the program in Iowa Falls to present at a community college event, “The Road to 300 Bushels Per Acre.”

It was interesting to hear everyone’s perspective on what steps growers needed to follow to begin moving back up the yield ladder.

Seeing such a high percentage of the acres in the state producing their third consecutive yield decline due to disease problems seems to indicate that many farmers need to climb back to yield levels of six to eight years ago, before they think of 300.

The second interesting event was getting the opportunity to spend about six hours hearing a top notch micronutrient specialist sharing his thoughts on the entire issue and putting it in historical perspective.

The third event was getting to fly over central Iowa again to view the crop from the air to see what percentage of the corn crop had turned brown and what percentage remained green.

The crop report

Being able to get an aerial view over fields that you also get to walk seems to be a great way to fully evaluate both major crops. Getting such a view every two weeks allows one to see how fast any decline or improvement is occurring.

In 2010, the landscape across much of central and west central Iowa consisted of SDS everywhere interspersed with corn fields that looked like they were either on fire or had recently been napalmed.

This year, the soybeans look quite clean with the main problem being either lighter spots showing the effects of dry conditions or herbicide overlaps showing up as heavily yellowed plants. A close inspection is showing lower levels of SDS.

By comparison, a higher percentage of the corn fields are turning brown. This seems to be the effects of the disease affecting leaves above the ear on semi-tolerant varieties. In a few cases, I was able to compare ground views of the same fields and plots a day apart along with an aerial view.

Late last week as the temps climbed into the high 80s again the daily decline in the status of the corn plants was very evident. One farmer/aerial pilot from Illinois told of how the fields he flew over looked much worse at 3 p.m. than at 10 a.m.

What was likely happening was that Goss’ wilt works by plugging the plumbing system of the plants. If the climate conditions place a higher moisture demand on the plants and the plumbing is not working, the plants will wilt down or die.

The net effect is a reduction in the number of fill days for each corn plant. Losing 10 fill days to early death and another five due to excessively warm nights out of an expected 55 days of grain fill equals close to a 30 percent reduction in fill.

Though that sounds excessive, the shallow kernels verify this.

In parts of northern Iowa and seemingly all of south east Iowa between the wilt and dry conditions there are entire fields that look like they should in November.

How long will they stand and how good will the grain be? Growers will need to be scouting those fields and squeezing the stalks to judge which ones are at risk of serious lodging problems.

Farmers and agronomists from Nebraska and Colorado, who have worked with the disease for years, tell that it can liquefy the roots and stalks if conditions are favorable.

Micros in history

A big discussion point the past year has been the role of micronutrients in crop production. Many agronomists and fertilizer companies say that they are important and have been forgotten, while some experts say their role has been overstated.

Growers who have tried them have seen varied results, but not always. Where does the truth lie and who are actually the experts?

I had the chance of spending six hours over the weekend with a fellow who served 25 years as the micronutrient expert at a major Midwest university.

He worked more in the horticulture industry where specialty crops are often tissue tested and receive foliar nutrition weekly if needed. He related that most 45- to 60-year-old “experts” are basing their opinions on studies, trials and text books that were conducted and written in the 1950s and 1960s.

Those researchers concluded that there were enough of those micros stored in the soil to supply crop needs for the next 40 to 50 years. Based on what he is observing about crop health, as well as soil and tissue testing, that time period has expired.

Many of these micros are important in keeping the plants operating at peak efficiency and productivity as well as in top health.

Thus, we are now seeing hybrids with lower ratings being affected by a multitude of pathogens. If any cultural steps or pesticide can play a role in exaggerating such shortages or stressing the plants, it can push them into extreme disease susceptibility.

Lighter soils and those not receiving manure have been showing the problems the soonest.

Accepting this will be tough for some growers, but if they remember the past three seasons, what else makes sense? The issue now is – how do we fix it for next year and the years beyond?

Having three-year peer reviewed documentation about the problem to prove the concepts doesn’t do it. If the Pro Farmer crop size estimate is still too high and end of season estimates tell of a 130 or a 140 bushel per acre crop, then we adjust harvested acres down to 81 or 82 million harvested acres, we have a problem here and in other countries.

Stay tuned.

Scouting and soybeans

Don’t forget to watch for soybean aphids in later-maturity or later-planted fields that are still in the R5 to R5.5 growth stage. Getting a rain gives a hope that more pod fill can occur.

Allowing the insects to suck away seed-filling sap, especially with $13 beans, can be costly. Consider stripping with a fuming insecticide if needed. Be sure to observe harvest intervals.

The number of bean fields beginning to turn yellow in August is surprising, but a reality. They can only flip their leaves in response to dry soils before they start to senesce.

Prior to this, we have been seeing plants dropping their smaller pods and recently pollinated flowers.

Getting some rain this week plus additional amounts in the next week is crucial to good yields in many places.

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

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