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CROP WATCH

By Staff | Oct 2, 2009

October is here already. Only three months left in the year and so much to get done yet. Depending on how much rain fell in your respective areas last week many farmers headed to their fields with their harvesting equipment by Monday or Tuesday this week.

Now we can finally see how right or how wrong everyone’s guess was on crop size as well as being able to judge which management practices helped the crop respond to the season to maximize yields.

I am in the crowd that thinks corn yields have been overstated. For example, with all of the SDS in soybeans and corn plants that died three weeks ago along with the many waterholes evident from the air, how is it possible that the percent of the crop rated good-to-excellent has not declined? If one can see the problems from the road without even walking into the fields for a close inspection, why doesn’t that decline in crop quality show up on those vague surveys?

We have been lucky enough to get an additional two weeks of growing weather beyond when we easily could have had a frost in mid-September. By this weekend we will know if all of the late-planted and slow-developing corn and bean acres in the northern Midwest made it thru this cold air invasion, or if Jack Frost killed it dead.

If there are a billion bushels of corn production at risk nationwide, as one person who gets around the area conceded, the huge corn crop may not materialize.

The bean crop

The bean harvest has commenced across much of the state and yield reports are coming in from all the areas. Thus far the yield reports are ranging from the low-40s to the mid-70s.

Several factors seem have been influencing factors on where each fields falls into that range. Since the soils were so wet in May and June, the degree of soil drainage that existed for each field and soil type is having a big influence on how well the plants tolerated the cooler and wetter conditions.

On top of that hindrance the cool, cloudy July and August seemed to eliminate about 25 percent of the flowering from the crop. I am in the group of crop scouts and growers who looked at the beans, saw about 25 percent fewer nodes and pods, and did not expect good things from the bean crop.

Then we had parts of the state dry out through July and August while other parts couldn’t shut the rain off. Though it is early yet in the harvest many of the early yield figures seem to indicate that the bean crop might be 8 to 10 bushels per acre better than we expected on the well-drained fields. If they are that good, their status as a crop that can respond favorably to stress will be reinforced.

Other things that will be forthcoming from the bean yield reports will be how many bushels were gained by one or two aphid sprayings, how much a seed-applied Nic was worth, and how many bushels were saved with a fungicide application.

In 2008 we saw that aphids control was often worth 15 to 24 Bu/A. With scant yield comparisons, 2009 fungicide use on soybeans appears to be worth 8 to 10 Bu/A.

We will be collectively smarter in a few weeks when more yield comparisons have been made. One interesting set of trials we have in place is the use of a bacterium that was selected for its ability to release an organic acid that frees up the phosphorous from the soils, making it available to plants.

I placed it with about 10 people and thus far the results have been very encouraging. Fields that hold a very low P soil content appear able to grow plants that show no signs of deficiency. Gustavo and Jorge will be happy to hear of the results.

The corn crop

The hail fields are still out there and will need early attention depending on how badly they were injured. A portion of them were shredded by machinery and tilled several weeks ago. Many that sustained large hail hits browned within a week and have stood since then as stark reminders of what nature can do.

Now those that are left are getting dry enough that harvest is close. I have inspected several lately and what is apparent is that kernel fill is and was commensurate with the percent of leaf tissue remaining.

The intactness of the stalk and remaining strength is also dependent on the ability and capacity of the plants to form photosynthates. Many now have extremely weak and diseased stalks.

Affected growers will be torn as to what to harvest first, weak-stalked corn that is likely to lodge, or beans that could be lost to late season hail or other weather delays.

Starting about two weeks ago in parts of the state, and now over a wider area due to last weekend’s 40 mph winds there are corn fields containing plants that are toppling over.

The stalks have gotten softer due to problems with anthracnose and fusarium. They typically stand for about six weeks after forming the blacklayer.

With that maturity benchmark being reached two to three weeks after the plant browned it appears they won’t follow that rule.

If the large moisture front and strong winds predicted for this Thursday and Friday reach Iowa we have to hope that the winds arrive before the rains do. Wet soggy stalks don’t have as much strength as dry, leathery ones do. We will just have to hope for the best.

Test weights appear to be light in the corn that yellowed and browned-up early. The ears producing those kernels are typically spongy when twisted, all indicating that grain fill was incomplete.

Grain quality from damaged plants is something that pathologists are now testing to see if mycotoxins are present. No general announcement has been made about the test results yet.

Much could still depend on how wet conditions are the next three week in different sections of the state. One related factor is that different influences caused significant tip kernel abortion. The husks were not forced open and higher moisture levels were retained inside allowing the different colored molds to form and be evident upon inspection.

Residue management

Most growers saw that second year corn in their neighborhood was often a calamity. We are in many ways set up again for similar problems in 2010 with a late-developing, wet crop in the field and projected late harvest after the ground has cooled off.

It is time to be proactive and take concrete steps to make sure that the corn residue is managed properly so it is in the proper stage of decay before next year’s crop is growing.

Typically, freshly harvested stalks have a C:N ratio of 80 or 100:1 and they don’t rot until the nitrogen amount in the system is increased and the C: N ration is in the 16 or 20:1.

Either 28/32 percent N and liquid S or dry fertilizer grade AMS can be applied to the stalks to facilitate this degradation. If there are still stalks in the field from 2008 or 2007 then strongly consider adding a bacterial package such as Z-Hume and sugar to build the microbial population needed to perform the residue reducing task.

The sharp operator will free up a rig and applicator to get the stalk reducing application made early when the soils are still warm rather than waiting until harvest is finished.

If the job is done correctly the soil humus amount will be increased and the nutrients will be recycled much sooner making them available to next season’s crops at an earlier date. Maintaining or even building this humus level is what allows our soils to be productive by retaining moisture and nutrients and hosting the many species of soil inhabitants.

Good luck with harvest and be sure to observe all safety precautions.

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