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CROP WATCH

By Staff | Oct 20, 2017

Years ago the Grateful Dead rock group out of San Francisco released an album entitled “What a long strange trip this has been.”

While we have yet to see how the last 2.5 months of the 2017 season turn out, a similar title could accurately describe this season. The planting season was delayed by cool and wet weather and so far the harvest season has been a waiting spell as well. We all knew that most of the fields in the state needed moisture to begin to fill the empty soil profile, but we could have survived without the last four inches of rain that fell late in the week. It was well predicted but welcome by farmers who were hoping for dry weather to make further progress in getting the crops harvested. A week ago when a similar amount of rain fell the combines were rolling within two days in many fields, as the amounts that fell soaked in immediately. This weekend there was standing water in quite a few fields. We have to hope that most farmers will be able to get back to work with harvest shortly.

Corn harvest news as of Oct. 15

Quite a few fields began their noticeable plant health about six weeks earlier. Some turned bright yellow and stayed that way. Others exhibited a cannibalization of the upper leaves as the plants were scavenging for any nitrogen they could find to facilitate grain fill. The final group began to die from both the top and bottoms leaves as has become common. So now the stalks that have declined are showing signs of stalk decay and are getting soft. As soon as we have any 20 to 25 mph winds a percentage of the plants in affected fields could exhibit stalk lodging. The plants that were under severe moisture stress from extreme lack of rain of from lighter soils have been melting and losing their tops.

The grain moistures have not come down much, as expected. When rain events arrive it is possible for grain moistures to increase a bit, but can lose it as fast as the moisture can be held near the outside of the kernel and not penetrating very deeply. A return to the 70s could help the grain to continue drying at the normal .25 to .5 per day. However as the days get shorter and the daily highs keeping inching lower the daily moisture loss slows measurably.

So far the problems with ear molds have been more of an issue in states to our south. This could change now as higher humidity levels return and the husks have continued to open more. There is not much that can be done proactively except to monitor the fields and get an identification of any suspected infected ears. The greatest caution will have to come from the major grain handlers and their potential feeding customers who are up on the latest recommendations on feeding tolerances and species intake recommendations.

If harvest is delayed much in the areas that experienced lots of moisture stress the amount of mold growth could increase. The main impact that could be expected may be with the consumers of the DDGs coming from the ethanol plants who ended up processing that grain.

As to yield the general trend has been to see higher yield than expected, as the cooler than normal August helped to reduce daily moisture use and the expected severe moisture stress. There were not many days of harvest last week in central Iowa. As one moves north of Hwy 3 not much progress has been made with either corn or beans harvest.

Soil health

With help from the University of Nebraska the Soil Health Institute has been able to conduct field work and plot trials to help generate information useful to growers wishing to improve the soil in their fields and the crops growing on it. The facts they have generated so far have helped to create a list of do’s and don’ts for other participants to follow if they are considering using cover crops or another soil saving or increases soil health benefits. Two of the main conclusions so far have been: that increased carbon levels in each field increase moisture infiltration rates and total amounts of moisture held in the profile. The second main benefit from using cover crops so far has been a 70 percent reduction in nitrate leaching.

What several experienced agronomists and industry people hope to learn so as to be able to provide guidance to growers as to how much and how fast the soil health scores can be increased with different practices, such as using cover crops, working in green manure, applying fresh or composted manure based on differed species and amounts, or with the application of different microbes or microbial brews. In time the hope is to also be able to give guidance on what practices or products need to be avoided if soil health and productivity are to be maintained or built.

Green stem beans

In areas a higher percentage of the corn has been harvested than have the beans, with some of that due to the so called ‘green stem’ problems. In the past it has been easiest to blame the application of fungicides which were meant to limit disease loss. Now we have seen a few more university research put on their thinking caps and consider the entire growing conditions and how the plants have responded physiologically. Now they believe that what is affecting the plant and its physiology is that stress early in the season reduced the pod and seed number, thus the overall photosynthate needs of the plant. The improved late season growing conditions increased the sugar production in the plant, creating an excess which have helped to keep the plants healthy, green and full of sap. It seems to make sense.

The high horsepower rotary combines have fared the best with green beans, especially if they have a draper head to even the flow on material into the throat.

Soil sampling

Even though getting the combines running as soon and as much as possible is first on your mind, one idea is to clarify which fields need to have their samples pulled and analyzed again. With the expected time crunch between the harvest and planned tillage program, it will be too easy to skip the sampling that is important to monitoring fertility levels in each field. So give it some quick thought and then give a call to the person or ag service that can do the high quality sampling you need done.

If people ask me my opinion I typically advise pulling samples according to management zones/soil types rather than grids and then have a more complete test run. This would include having micros run on third to half of the samples. Then select a few sets of samples and have them analyzed using the Haney protocol. If your lab does not perform that test, then Ward Labs in Kearney is one of the two labs performing the advanced or updated Haney and has specialists who can explain what the results mean. They already run samples for outside labs which don’t regularly perform those tests.

Residue management

As the season gets later and the weather gets cooler, the speed at which the corn residue will degrade slows based on soil temperatures and a few other factors. Those include plant populations, plant height, whether or not any nitrogen or sulfur was applied to the residue, tillage performed (if any), previous herbicide usage and the populating and species of microbes flourishing in the soil. Paying attention to stalk decomposition, especially in second year corn is important to good seed placement, formation of a deep and fully functioning root system, rapid and even emergence and early release of captured nutrients.

If you have been seeing slow decomposition of stalk in your fields or have been rolling your bean fields to tamp the root balls deeper into the profile, consider using a product like BioDyne 501 on your stalks to recycle the nutrients quicker and help reduce the level of disease inoculum for 2018.

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

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