Agronomy Notebook

Corn pre-harvest considerations

Across Ohio, the corn crop in general is set up for high yields based largely on ample amounts of precipitation and moderate temperatures during most of the 2013 growing season. Lately, rainfall has been at a premium with some areas receiving adequate moisture and others needing a good shower to finish the crop. The questions that remain are, will my corn crop mature and what should I be looking for prior to harvest? This update attempts to address both of those questions.

Overall GDU (heat) accumulation during 2013 is currently below normal across most of Ohio. As a result, corn grain fill, drydown and harvest maturity are delayed. Prevailing weather conditions between now and harvest will dictate how fast field drying will occur versus harvesting at higher moisture and using artificial drying methods for the corn crop. The rule of thumb, based on research conducted at Ohio State University, is that field drying rates of standing corn range from half to three-quarters of a point of moisture per day up until mid-October, and decline to a quarter to half a point until early November.… Continue reading

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Corn and stress during grain fill

After lot of rain in April and May and a late start in planting, I was hoping that this growing season might turn out to be alright, but it has turned hot and dry. I guess we can’t count our chickens until the Fat Lady, Mother Nature, has sung her final tune! What are the effects of stress during the grain-fill period?

• After pollination we need 50-60 days, depending on the relative maturity of the hybrid, for the grain-filled period. This is when the plants’ primary focus is to fully develop the kernels.

• If there is severe heat or moisture stress during the grain-fill period, the plants start to cannibalize their leaves and stalks to fulfill the growing needs of their progeny.

• Plants, like animals, don’t want to produce runts. So, if there is stress during the grain-fill period, the plants start to abort the youngest kernels causing tip die-back so the remaining kernels can fully develop.… Continue reading

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Will corn dry down in 2013?

Are we going to have wet corn this year? I am afraid so, unless you were able to plant early. We are facing the following scenarios this year for corn yields and maturity:

• Rains in April and May delayed corn planting in most of the Corn Belt.

• Weather has been cooler than normal and we are at least 12 to 15 days behind normal and about 20 days behind last year, if corn was planted by May 15. Corn planted in late May and early June has just finished pollinating.

• After pollination, It takes 45 to 50 days to reach maturity.

• When planted late, corn hybrids require fewer growing degree days to reach maturity than earlier planted corn if the temperatures are near normal in July and August.

• The yields are generally higher when it is cooler because the plants have a longer grain-fill period. The plants just live longer in cooler weather and yield more but that delays reaching physiological maturity or 32% kernel moisture (black layer).… Continue reading

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Corn pests to watch for

We have talked about corn leaf diseases and foliar fungicides in this space recently but we need to watch out for insects also. Some of the important insects that might “bug” us are discussed below:

• Corn rootworm beetles larvae attack the roots during June and early July and the adult beetles clip the silks and may interfere in the pollination process during July and early August. Watch out for these insects if you are growing GMO corn where the trait has failed or the non-GMO corn if you have not used insecticide.

• Japanese beetles have copper and green color and eat the green silks as well as leaf tissue. Adult may be found during July and August.

• European corn borer larvae are dirty white to tan with dark spots and a dark brown to black head. Young larvae feed on the leaves. Before tasseling the larvae feed deep inside the leaf whorl and produce shot holes.… Continue reading

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Corn pollination progressing well

Ohio corn growers have a pretty good looking corn crop to date. Growth and development has been fast and furious as the corn has had all the heat and moisture for excellent growth. Many areas of Ohio have had 17 to 19 inches of rainfall since April 1 and we have accumulated near 1,700 Growing Degree Days since May 1. Most of the corn crop was planted the first 10 days of May. Bottom line is, we are ahead of normal for heat unit accumulation and rainfall. Due to the excellent condition of corn, many of these acres have had a fungicide application to protect the genetic

potential of the corn crop.

Although it has been very hot and humid, pollination has progressed at a normal pace and kernel set looks good. Here are some facts about corn pollination that has taken place in your fields.

Pollination and fertilization of the embryos is one of the most important stages of corn crop development.… Continue reading

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Critical stages to scout your corn fields

Corn needs a lot of tender loving care throughout the growing season and to raise a successful crop, it needs special attention during the following critical stages:

• At seedling emergence, young plants face many hurdles such as nutrient deficiencies, seedling diseases like Pythium and Stewart’s bacterial blight, slugs and insects like black cutworms. Adequate stand establishment is crucial for a good crop.

• At V3-V4 stage, make sure that weeds are in control. Apply post-emergence herbicides, if necessary. Even small weeds can affect yield.

• At V6-V8 stage, be sure to side-dress with nitrogen before the plants are too tall, if you are going to apply additional nitrogen. Check for deficiency of nutrients like sulfur, magnesium, zinc and other micronutrients.

• Pollination is the next most critical stage. Make sure that insects like Japanese beetles, western corn rootworm beetles are not clipping the silks. Use insecticides if needed to control these pests.… Continue reading

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Corn growth progressing quickly

The fast growth stage of most of the corn is kicking in. This is the time when you can almost watch the corn plants grow. It is now starting to grow rapidly from puny little seedlings to the juvenile stage and become adults. Corn plants are ready to hit the grand growth stage.

At V7 stage, the corn plant is already deciding how many rows of kernels it can put on. Row numbers are always in pairs and primarily controlled by the hybrid genetics but environmental factors such as population, water and nutrient availability, heat and drought can influence it. Depending on the conditions, a couple of rows may be added or subtracted from the genetic potential of the hybrid.

• During V8-V9, potential ear shoots start to develop at every above ground node except the upper six to eight nodes. Only the upper one or two ear shoots eventually form the ears.… Continue reading

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Assessing soybean stands

As the soybeans respond to the warmer temperatures and sunshine around the state, it is time to assess the stands to make sure they are setting things up for success this fall.

‘Most of the soybeans in Ohio are emerged and growing very fast. Now is the time for growers to access the quality and plant populations of their fields,” said Jeff Rectenwald, Asgrow DEKALB agronomist. “This weekend there has been some hail and growers will be in fields checking plant populations.”

Ohio State University and other university research from throughout the Midwest research found that base soybean populations as low as 100,000 can still produce solid yields. To get a stand count, Rectenwald suggests making a hula hoop out of three-eighths inch EVA tubing connected with a brass nipple connector. The hoop diameter should be 28.26 inches to help calculate 1/10,000th of an acre. The hoop should be thrown out in the field and the plants inside it should be counted and multiplied by 10,000.… Continue reading

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Double-crop considerations after wheat

In Mid-June last year we were running full bore with wheat harvest and double-crop soybeans because the hot and dry weather pushed things along rather quickly. This year, the wheat in places looks like it is turning rather quickly but when you get out in these fields it looks like the maturity is a little behind schedule. I think we’ll still probably be running quite a bit of wheat at the end of June and the beginning of July, which is about normal.

This year, with the wheat crop is pushing just a little later, there is still quite a bit of interest in double-cropping because we do have good soil moisture. The demand for the double-crop soybean seed has been strong this year from guys with a lot of wheat acres out.

In preparation for harvest it’s a good idea to leave 8 to 12 inches of stubble out there to maintain soil moisture. … Continue reading

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Plan to scout now

Finally corn and soybean fields are planted, are up and growing. Some growers were able to plant early and the crop emerged and started growing. For many other growers, corn and soybean planting didn’t start until the first to the middle of May and the crop struggled to get out of the ground due to cooler temperatures and water issues. Be it sidewall compaction, insect feeding, and disease, the emerging crop in 2013 had these issues to contend with. What happens in the next 80 to 90 days will have a major effect on maximizing yield potential. So much can happen and with uncertainty of the crop’s success, the need to scout all crop fields is very important and beneficial.

A good tool for part of your scouting plan is to carry the Corn and Soybean pocket Field Guide from Purdue or Ohio State University as well as pen and paper to record your findings.… Continue reading

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Assessing Ohio’s corn emergence issues

While the conditions for emerging crops have generally been close to ideal in many fields, problems have been showing up.

Dekalb Asgrow agronomist Jeff Rectenwald has come across some problems with crusting in fields.

“Soil crusting and crop emergence seems to be a widespread problem in Ohio this spring. This not a hybrid specific issue, it is environmental and soil type specific,” Rectenwald said. “Growers need to be scouting their fields to determine which fields may be a candidate for rotary hoeing.”

No-till seems to have helped the situation in at least one Clark County field planted in late April with a population of 34,000.

“There are no problems, a near perfect stand. So far, no-till this spring looks pretty good. In most cases it is less susceptible to pounding rains causing emergence and crusting problems,” Rectenwald said.

Soil crusting, of course, can result in uneven emergence, though uneven emergence can be the result of several other factors as well.… Continue reading

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Pythium problems showing up in Ohio

It is an unsettling sight no soybean grower wants to see — entire fields dying shortly after emergence. This, though, is an unfortunate reality in some fields around Ohio.

On May 14, Asgrow Dekalb agronomist Jeff Rectenwald was scouting fields for a customer in Auglaize County when he came across the aftermath of Pythium seedling blight.

“I ran across entire soybean fields dying from seedling blight as they were emerging from the soil surface,” Rectenwald said. “You can see the fungal lesion at the top of the hypocotyl’s arch as the soybeans were breaking the soil surface.”

The soybeans were planted on May 2 and will be replanted, Rectenwald said. Regular scouting around emergence is important in quickly identifying the problem.

Unfortunately, the rain and persistently cool soil temperatures this spring are optimum conditions for a large and diverse group of pathogens called water molds, according to Anne Dorrance, Ohio State University Extension plant pathologist. … Continue reading

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Evaluating early corn populations

Accurately assessing corn stands is one of the first crop scouting exercises Ohio corn growers should conduct on their fields. The 1/1000th acre method is commonly used to evaluate emerged corn seedlings. Count the number of seedlings in a length of row equal to 1/1000 of an acre based on row width (Table 1). Multiply the number of plants by 1,000 to get plants per acre. Repeat this at several locations throughout the field to determine an average.

I like to make a rope 17-feet 5-inches long and make a knot at both ends and drag it through the field making several counts along the way to get an accurate evaluation. Another method is to count 150 plants and measure the distance from start to finish with a measuring wheel. Divide the number of feet traveled into the appropriate factor in Table 1 to determine plant population. Because a longer row length is counted, the samples are more representative and fewer locations are required.… Continue reading

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The role of seed germination in a successful 2013

By John Brien, AgriGold agronomist

Planting is one of the most anticipated times of years for farmers. The weather warms up, the soils dry out and there is another opportunity for them to try their hands at producing that record yielding corn crop. High yields begin at planting and will not be finalized until harvest. One of the steps to high yield is getting the “dormant” corn seed to germinate.

Germination is simply the process that allows a seed to sprout or begin to grow. Although the definition is simple, the actual process is anything but simple. The germination of a corn seed requires soil moisture to “reawaken” the seed and adequate temperatures to speed along the enzymes and chemical reactions that allow the cells in the corn plant to grow and reproduce.

Corn growers know the importance of germination, but often don’t believe they have much of a role in that process.… Continue reading

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Reading soil test results

By Dave Nanda, Seed Consultants, Inc.

Labs may differ in the data presentation and analysis but your understanding of the basic items would help you in ordering fertilizers for your fields. A soil test is a way of estimating the nutrients that may be available to the crop. Keep the following points in mind as indicated in a report by Jim Johnson of OSU:

• The top section of the report identifies the soil sample; the middle tells you about the results; and the bottom indicates the recommendations.

• Cation Exchange Capacity or (CEC) indicates the particle size of the soil. Sand has low CEC and clay and organic matter have high CEC. Soil CEC ranges from 5 to 40.

• Organic matter is the percent of organic content of the soil. Ideally, you would like to have 5% organic matter (OM) but a number between 1% to 3% is more common.… Continue reading

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Prepare for larger soybean seed size this spring

By Jeff Rectenwald, Asgrow Dekalb Technical Agronomist

The 2012 growing conditions resulted in production soybean seed being larger in size for many seed products. Therefore, planting equipment manuals should be reviewed to determine the appropriate settings, calibrations, and disks for delivered seed. Seed size should be checked when seed is delivered to determine if different disks or other equipment may be required.

Should there be a need, ordering and purchasing now could save valuable planting season time.
Larger seed can be planted as efficiently as smaller seed providing planting equipment has been adjusted, calibrated, or retrofitted. If the planter is a vacuum metering type planter, refer to the manufacturer manual regarding disk size and manually check to see how seed fits within the disk cell. A larger disk should be selected if one seed cannot fit properly into a cell and a smaller disk used if two seeds can fit into a cell.… Continue reading

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Temperature swings can hurt wheat

Extreme changes in temperature are the biggest concern wheat producers have for the development of their crop this season, a Purdue Extension agronomist said.

Temperatures in recent weeks have risen to between 50 and 60 degrees and then dropped to single digits.

“The cycling of cold to warm temperatures is a great recipe for freezing, thawing and winter heaving,” Shaun Casteel said.

Winter heaving occurs when moisture in the soil expands as it freezes and then contracts as the ice thaws. The soil gets pushed up and down, shoving young plants higher out of the ground and exposing roots. The plants’ lack of access to soil moisture and soil contact could result in stand loss, Casteel said.

Another weather concern is that there has been little snow to protect wheat from extreme cold.

“A lot of wheat fields no longer have a blanket of snow for insulation, and they’re exposed to the cold weather,” Casteel said.… Continue reading

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Glyphosate Resistant Weeds


By Dave Nanda, Seed Consultants, Inc. 
Director of Genetics & Technology

Those of you who were able to attend our winter meetings heard from our Agronomy staff about the presence of glyphosate resistant marestail in Indiana and Ohio and how to control it. Listed below are some of the facts about glyphosate resistant weeds.

• Glyphosate resistant crops were introduced in 1996. It was a good technology which needed good stewardship to extend the use of this herbicide. It was adopted by the growers and quickly became popular because of the dramatic price decrease and ease of weed control in corn and soybeans.

• University Extension personnel and Crop Consultants advised the farmers against continuous use of glyphosate resistant corn and soybeans.

• However, trait, chemical and some seed companies were promoting it; growers liked the easy and cheap weed control system and everyone was trying to make quick buck.… Continue reading

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Fertilizer, soil pH and Cation Exchange Capacity

By Dave Nanda, 
Director of Genetics and Technology 
for Seed Consultants, Inc.

Soil pH, and Cation Exchange Capacity (CEC) — how are they related and do they affect fertilizer inputs? Some of the facts below should clarify their relationship.

• Soils are made up of sand, silt, clay and organic matter. The CEC of a soil tells us about the texture of the soil. Soils with higher clay and organic matter content have higher CEC values. The CEC value of the soil in a field is fairly constant but can be changed over time with the addition of organic matter, through the use of cover crops and manure, for example.

• Positively charged particles are called cations and negatively charged particles are called anions. The CEC is the measure of how many negatively charged sites are available in the soil.

• According to David Mengel of Purdue University, most common soil cations are calcium, magnesium, potassium, ammonium, hydrogen and sodium.… Continue reading

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Changing soil pH on your farm

By Dave Nanda, Seed Consultants, Inc.

We have discussed what pH is and the importance of having balanced pH during the last three weeks. Many physical, chemical and biological processes necessary for crop survival, growth and yield are affected by soil pH. I would like to discuss how you can adjust the pH in the soils on your farm.

• For high yields we must balance soil pH depending on the crops we intend to grow. For growing corn, beans, wheat and alfalfa, we need to have a soil pH values of 6.0 to 6.8. Balanced pH is critical because it can affect nutrient availability, soil-applied herbicides and their degradation, potential for aluminum or iron toxicity, as well as nitrogen fixation by legumes.

• Some soils have a tendency to become acidic over time due to weathering of soil minerals and release of acidifying metals, leaching away of calcium, potassium, magnesium and sodium, decomposition of organic matter, and application of ammonia-based fertilizers.… Continue reading

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