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CROP WATCH

By Staff | Jun 12, 2009

June is here and with it is weather that feels more like mid-April. While we should be having temperatures in the mid to high 70s we have to wear heavyweight jackets to keep out the cold and the wind.

At this point it looks like the NASA, AMA, and Illinois meteorologists who took note of the lack of sunspot activity and interpolated that to deduce that we would have a cooler summer could be accurate in their predictions.

Under those circumstances much of the corn crop in Iowa is further along by June 10 and runs less of a chance of being harmed if the weather continues cooler than normal. Typically by this time the frontal boundaries are well established and have moved north of Iowa already.

This year we have had a minimal amount of storm and tornadic activity, likely due to the fact that warm air is a requirement for the billowing storm clouds to form.

Most of the farmers in the eastern two thirds of Iowa have fields that are close to or above field capacity. Conditions have changed to those in the western third and growers in that area are now hoping for rain.

Likewise growers in much of Minnesota, Wisconsin, and South Dakota are in an area that is beginning to show up on the Palmer Drought chart. It is surprising how rapidly conditions can change.

The markets have continued their move upwards as several fundamental are forcing the market to realize that grain supplies may not be as plentiful as previously expected. The funds are moving back into commodities as the stock market remains too risky for formerly bearish investors.

“Does that mean that grain prices will match those of 2008” is what some are asking. That appears doubtful as the different sectors that support grain prices are not making money. The best of the ethanol plants are making a few cents per gallon.

All segments, hogs, cattle, dairy, and poultry are and have been losers for some time and everyone is asking when that might change. Thus those will have to change to build a solid foundation under further price moves.

Field observations

The earlier planted corn that is following soybeans on better-drained fields is looking good and growing rapidly. The color looks good and much of it has reached the V5 or V6 growth stage and is shooting up in height.

The projected date of tasseling is somewhere between July 5 and July 10. Conversely the corn crop planted late or situated on ground that has remained wet and cold is reacting poorly to a cool root zone and reduced availability of nutrients.

About a week ago many of the corn-on-corn acres began to show uneven growth with a yellowish caste. The actual cause is likely linked to several factors including limited root growth, slow nutrient release, possible allelopathic effects, and nitrogen tie-up by the undecomposed residue.

Having this happen is almost a yearly event and the best way to cure the problem is for the soils to dry and get warmer. Let’s see if and when that happens.

In the northern parts of the state crop scouts and farmers are noticing the early stages of root rot. By now many of the acres have been planted for six weeks, but soil conditions haven’t improved beyond being April-like. If you have a field or fields that seem to be going backwards it would be wise to dig seedlings and observe the root system. If the root tissue has begun to turn brown or seems stunted it might be that fusarium or pythium could be appearing. Both are related to wetter soils and stressed plants.

Most soybean fields are running a few weeks, and growth stages, behind where they should be. This delay means that the plants may not form as many nodes as needed for top yields. In 2007 the first planted bean plants began flowering by June 10, or about 10 days ahead of normal.

In 2008 many of the bean plants began flowering about two weeks later than normal. Bean plants cannot physically or physiologically flower until they had reached the V5 stage.

Normally, with normal temps, the plants form a new growth stage every 3.8 days. These cooler temps have to be slowing down that growth rate. Thus the next two weeks could be very important toward determining bean yields. How many nodes will the plants have when they get to the longest day of the year?

One has to ask what growers like Ray Rawson of northern Michigan learned and taught his colleagues what could and should be done to the plants to enable them to form the three to five branches and enough flowers to get an adequate pod count.

Given the fact that new crop beans are now worth $10 per bushel, it now looks like a good year to perform those management steps. Getting those done by the V3 or V4 stage has proven to be important.

Lots of side dressing was being done the last two weeks. Lots of rigs were in the fields as many growers were applying the last portion of the intended amount of nitrogen. One other factor was that the cost of the N has dropped dramatically and the cost benefit ration looks much better than it did in January and February.

Thus many growers are either using the late spring N test to verify a shortage of NO3-N or are noticing the field’s yellowish appearance before they make the decision that it is time to be proactive and supply the needed nitrogen.

Weed control

It was common three to four years ago to see fields where one wasn’t sure if it was supposed to be a corn or bean field, or what was under the mass of broadleaves. This year we are seeing that more growers laid down residual herbicides or that they are trying to eliminate the early weed and grass competition. Hopefully that doesn’t mean a third application of a glyphosate product will be needed, but if that is the case, so be it.

One research project that was meant to document the amount of yield loss that could be credited to early season grass and weed completion was completed by a weed specialist at the University of Guelph. In that project they examined the amount and quality of light that was being robbed by the undesired plants instead of being reflected by the soil onto the bottom side of the leaves.

They found that letting the competing plants remain beyond the one-inch size changed the leaf size, leaf orientation, root system size, and overall yield.

Insects

There are now a few species of insects that are now causing problems in certain fields and certain portion of the state. The first one to mention is the cutworms. Illinois and extreme eastern Iowa apparently had several flights of the moths drop in during April.

Since the moths will lay eggs over a longer time period the cutting can be spread over a similarly longer time. Having cooler temps and good moisture helps to create a situation where the plants can recover from the cutting damage.

About a week to 10 days ago, the lightning bugs appeared, which means the growing degree units accumulation reached 625. That meant that it was also time for the rootworm eggs to hatch and the small larvae to begin feeding.

If you have any second-year corn fields that have had problems in recent years with corn rootworms, now is the time to check for the small larvae and signs that the roots are being fed upon. Remember that insects rarely read the book.

Expect the unexpected.

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