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CROP WATCH

By Staff | Jul 1, 2016

How could we possibly shift from cool and wet to frying pan hot with desert-like conditions in a few days?

Remember that several good climatologists said that such a shift took weeks or months and not just one day. But here we are with our lawns turned brown, our corn plants rolled tight by 7 a.m. staring into the sky hoping for rain clouds that could move in our direction.

It sure feels a lot more like La Nina that El Nino, just like the top three climatologists predicted. A quick summary of the areas and Midwest illustrates how erratic the movements of the storms have been so far.

Can the Fourth of July possibly be next weekend already? The first part of the growing season is over and the weather will begin to heat up. The holiday is over the weekend so work schedules will be jumbled for many people.

Enjoy the peace and quiet of any celebration you might be attending in your locales. Remember the holiday signifies and respects the fact that it took only a small band of revolutionaries willing for fight for the independence of their country to found this nation, while farmers and businessmen dedicated their lives and determination to farm the ground and establish a sound economy. How does the vote in Britain leaving the EU dovetail into the same thoughts?

Our current weather

Currently the weather stats record conditions for June in the Midwest have been the second driest in 23 years and the second hottest in the last 25 years. If you are living and growing crops near Cedar Falls or Dubuque and the passing storms have dropped 4 to 6 inches of rain in the past three weeks, things are great.

If you live in westcentral, southwest, or southeast Iowa or any other locations where rainfall totals for June have been less than a half-inch, you have your worries about when the next good rain will arrive. Hot and dry is not what you want for optimum yields.

While most fields have an adequate supply of moisture to complete plant growth, the supply is finite and we have to hope root growth of our major crops makes the moisture accessible. The rolling of the leaves in corn signifies that evapotranspiration, daily moisture use, rate is high and exceeds what the roots are able to pull in each day.

In high yield discussion the speakers tell growers, especially those who are able to irrigate to make sure plants are never moisture stressed. The daily ET is a function of plant growth stage, temp, humidity level, the amount of solar radiation and wind speed.

With head-high corn the amount used each day is about two-tenth per day. At tasselling on a hot, dry windy day a corn plant will try to suck three-tenth from the soil. Ideally it cools off and we get good showers to supply the needed rain. We shall see.

Crop growth

Corn growth was phenomenally fast the last three weeks. Hot temps and adequate moisture allowed it. Soybean plants that took forever to reach V3 all of a sudden have reached the sixth and eighth trifoliate leaf stage and are blooming.

In the tallest fields soybeans are close to canopying 30-inch rows. A person planning on raising above-average bean yields needs to be working on his/her predetermined plan to coax those yields by applying added Y-dropped and foliar applications of nutritional, hormonal, and biological products.

Extra branching and added potassium and sulfur can make a huge difference in final yields. What was your plan to supply them and have you completed that program?

In most cases added micronutrients that trigger deeper root growth are important. Biologicals or bacteria that trip the hormonal trigger for added branches and pods should go be applied soon to manipulate plant architecture.

You have to think like a plant and figure out what they are hungry for. Does your soil have those nutrients available or do you have to supply them before the rows close?

Taking leaf samples and getting them analyzed now can provide a road map of what is needed. This is when the champion bean growers use their imaginations and goals of achieving top yields.

This is when we like to apply the Seed Set. Having bean prices up near $11 provides the incentive to make it happen. As Larry the Cable guy would say ‘Git er done.’

Weed growth

The broadleaf weeds emerging and growing in the bean fields have responding to the extra heat by growing faster than the crops. Pigweed species have an ecologically advantage over the bean plants in that they are a C4 rather than a C3 plant, which refers to how they use carbon dioxide to form sugars.

They become tougher to kill after they have reached 4-inches tall and formed extra growing points.

Flexstar or generic versions are the product of choice before July 1. The label and rotational requirements after July 1 restrict its use for fear of carrying over to damage the 2017 corn, which we saw in 2015.

Then it is time to use Cobra-type products. We have seen the performance of Full Tech product from Spray Tech Inc. It appears that 90 percent to 95 percent of the burn is prevented and weed control looks very good. Avoiding the burn is double important in a dry year in that regrowing leaves requires moisture and there’s no supply in many areas.

On 4- to 12-inch weeds herbicide rates at the high end of the range are suggested. It may also be time on level fields for row crop cultivators to be used.

Not having to dump at least five different products into the tank and having a compatibility agent included is also an advantage.

Check strips from recent seasons have proven there can be a 15-bushel-per-acre penalty from burning the leaves off after flowering starts or by tying up specific nutrients with a chelating herbicide.

Diseases

For several weeks now leaf diseases have been appearing in corn fields in northern Iowa where moisture levels have been high. Those growers should monitor their plants to see if the lesions begin to appear on any upper heaves.

Applying needed micros can help arrest disease development and better provide for plant health and immune response.

Three agronomists in Iowa have been watching corn plants and looking for the caramel-colored lesions near ground level or slightly below. They can now be easily found in V12 corn plants across the state, north to south and east to west.

Based on eight years of observations, multiple microscopic observations and immunoassay strip tests used the bacterial disease is back for the 2016 season.

What has proven to be the consequence is akin to saying “It’s just a small attic fire, so why worry?”

As a word of advice, check your fields and see if you spot the bruising and small lesions and take action soon. Look down and not up. If you take note of the many soybean fields with almost solid volunteer corn populations a lot more farmers had problems with the disease in 2015 than is acknowledged.

What those lesions mean is the causal organism is beginning to plug the plants’ plumbing tissue hindering their ability to meet moisture demands.

In the end plugging will occur and produce amalyse to dissolve woody tissue in the stalk. If a corn grower does nothing it is his or her bushels lost.

Based on in-field observations made last week on V14 corn, V6-7 BioEmpruv applications were preventing the lesions. Those growers have made their second application already.

If it works like it did in 2015 they will get the extra bushels as their big payoff as long as rains arrive.

Keeping the plants alive longer should improve the chance of getting the timely moisture while they are still green.

The list of things to think about and carry out doesn’t get any shorter yet. It makes me think of Einstein’s admonition of “You can’t solve tomorrow’s problems with yesterday’s thinking.”

Good luck.

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

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