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Agronomy Notebook



Assessing early season soybean injury

Spring 2014 has been quite challenging with wet soil and cold temperatures.  We’ve received several calls and e-mails regarding soybean seedling damage (from those who have actually been able to plant).  It appears that some soybean fields were hit with a “trifecta” of stress issues. What should we be looking for in terms of frost, PPO herbicide injury, and disease?

Frost 

Frost can occur at air temperatures between 32 to 36 degrees F while a freeze requires temperatures less than 32 degrees. From the weather records I have looked over, air temperature dropped as low as 34 degrees F in northern Ohio on May 16.  Soybean plants should be assessed for frost damage at least five days after suspected injury to inspect for regrowth.  If damage occurs above the cotyledons, the plant will likely recover.  If damage occurs below the cotyledons, the plant will not recover.  Look for a discolored hypocotyl (the “crook” of the soybean that first emerges from the ground) which indicates that damage occurred below the cotyledons. … Continue reading

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Why do my soybeans look like they are dying?

This week we have had numerous reports throughout Ohio, Indiana, Illinois and Kentucky regarding soybeans that are not looking as healthy as we like. The majority of soybeans have the outside of the cotyledons that look brown as well as the hypocotyl, especially when in the neck stage.This appears to be happening to all varieties from all companies, so it is not product specific.So what is going on?From what  I can tell there are two things happening.First, the vast majority of fields with this issue have been sprayed with a PPO inhibitor containing the active ingredient flumioxazin.These herbicides would include Valor®, Valor® XLT, Envive®,Enlight®, and Gangster®.
The herbicide label of Valor® actually states,“Crop injury may occur from applications made to poorly drained soils under cool, wet conditions.Risk of crop injury can be minimized by not using on poorly drained soils, planting at least 1.5 inches deep and completely covering seeds with soil prior to preemergence applications.” Several areas impacted received over 3” of rain which would constitute “poorly drained”in my opinion.
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What causes purple corn?

Cool and wet weather at early stages of corn development, as we are experiencing this year, are ideal for the appearance of purple plants. What causes the plants to become purple? Some of the reasons are given below:

• Purple leaves are caused by a pigment called anthocyanin. When sugars produced by the chlorophyll cannot be deposited in the growing stalks, leaves, and roots, they are converted to anthocyanin pigment which is red to purple in color.

• Acidic soils with pH lower than 5.5 may also cause seedling purpling.

• Wet soils can also inhibit the nutrient uptake and cause purple leaves.

• Purpling generally occurs between V2 to V5 stages of growth. By V8, purple leaf syndrome disappears and color becomes normal healthy green again.

• Any plant stresses which reduce uptake of phosphorus may result in purple leaves and stalks. Root restrictions may also cause phosphate deficiency symptoms.… Continue reading

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Early season corn growth and development

A corn plant requires the accumulation of Growing Degree Units (GDUs) to reach maturity. This is regardless of the number of calendar days it takes to accumulate them. A 105-day hybrid requires about 2600 GDU’s to reach Black Layer and a 114-day hybrid requires about 2800. You can use this information to your advantage because we know about how many GDU’s need to accumulate for each growth stage. In other words, if you know the planting date, we can predict when the hybrid will pollinate. This can help growers make timely applications of herbicides and fungicides. Also, it can predict when optimum timing is for foliar fertilizer applications.

 

Calculating GDUs

To calculate GDUs, record the minimum and maximum temperatures for the day. Add them together and divide by two. Next subtract the base threshold of 50 degrees F. Because optimum corn growth takes place between 50 degrees and 86 degrees F, the lowest temperature that can be used in the formula is 50 degrees F, and the highest temperature is 86 degrees F.… Continue reading

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Planting corn after a failed wheat crop

fairfield-county-wheat

Late fall planting, harsh winter conditions and/or excessive rainfall can all lead to an undesirable wheat stand in the spring. Often growers would like to turn those failed wheat acres into a corn field and questions arise as to how to best ensure a successful transition.

The transition starts with killing the existing wheat stand to avoid the competition of early season weeds. Then nutrient management and the intricacies associated with the existing nutrients and future nutrient recommendations need to be addressed. Growers then need to identify tools and keys to ensure a successful stand establishment is obtained. In addition, insect pressure is greater in volunteer wheat stands and need to be controlled to ensure a prosperous corn crop.

The first step is to kill the remaining wheat crop prior to planting the corn. Corn is very sensitive to early season competition and killing the growing wheat will eliminate that competition.… Continue reading

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Tips for high yielding soybeans

Rotate: The highest soybean yields often are in fields that have been continuous corn, have high yield potential soils and often have plenty of manure.

Proper fertility levels: Soil test: pH 6.5-7, 30-60+ pounds per acre Phosphorous, 200 to 300 pounds per acre K depending on soil type. Adequate drainage is a very important consideration also.

Variety Selection: Varieties that are proven to have above average yield potential while considering defensive characteristics such as Sudden Death Syndrome, Phytophthora Root Rot, Brown Stem Rot, White Mold, Frog Eye Leaf Spot.

Use treated seed. Acceleron seed treatment gives you protection against early season diseases. Upgrade to Acceleron with Poncho/Votivo for protection against bean leaf beetle, nematodes and other spring pests such as seed corn maggot, which is more likely in high amounts of decaying matter, even if tilled. Bean leaf beetle are most likely if you have the first planted beans in the area.… Continue reading

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Starter fertilizer in corn production

Starter fertilizer in corn production has traditionally been recommended for fields with cool soil temperatures, including exceptionally early planted or no-till fields, or those with high residue cover. In cool soil conditions, starter fertilizer placed near the developing seed provides easily accessible nutrients until soil conditions improve and an adequate root system is established. Starter fertilizer has also been recommended for fields with low phosphorus levels, and research studies have proven the value of this practice. However, some growers seeking to exploit grain price opportunities are evaluating whether starter fertilizer can play a more prominent role in increasing corn yields.

Starter fertilizer is defined as small amounts of plant nutrients — nitrogen (N), phosphorus (P) and potassium (K) — placed in close proximity to the seed, usually at planting.  Placement can be directly below, to the side, or to the side and below the seed. Growers sometimes consider broadcast or liquid fertilizer application to the soil surface as “starter”; however, these should not be included because nutrient placement is positionally unavailable to early seedling growth.… Continue reading

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What’s the right seeding rate for soybeans?

I am in Ukraine on a training mission to assist growers here in growing better corn and soybeans. One question that keeps coming up is, “What is the right seeding rate for soybeans?” Some of them have told me that it’s 1 million seeds per hectare. I think in terms of 1 million for wheat, but a hectare is 2.47 acres, so 1 million is 405,000 seeds per acre — still too high. Take into account that they use brown bag seed, so add maybe 20% due to reduced quality seed — still too high. And oh, by the way, this brown bag seed seems to tolerate very high levels of “gleefosat” herbicide applied over the top.

I give them the same answer I do when the question comes up in Ohio — we need about 100,000 plants per acre at harvest to achieve full yield. You just calculate backwards to determine your losses to germination percent, emergence, disease, insects, crusting, excessive moisture, etc.… Continue reading

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Boost corn yields

We will be discussing the proven methods you can use to boost corn yields this year. I am sure you are already using most of these ideas. I challenge you to pick at least one idea that fits your farming practices and try to improve it.

• Use minimum or no-till — especially on erodible land. It helps in conserving moisture loss reduces soil erosion and minimizes compaction.

• Set a realistic yield goal — It should be based on your soil type, organic matter and historical data. Goals based on 2012 or 2013 alone will be unrealistic. So you may want to use last five-year average as a guide.

• Study yield maps — Analyze your yield data field by field with your Seed Consultant and try to Match hybrids with soil types.

• Do soil tissue tests — These tests should be conducted at the right time and the advice of the consultant followed.… Continue reading

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Sub-surface soil compaction

Compaction that occurs below the soil surface is even more important than surface crusting. It is hard to diagnose and can cause serious yield losses if not corrected. Soil compaction can occur throughout the growing season and can cause poor crop growth.

• If the soils are wet, tillage implements can cause soil compaction just below the depth of the operation.

• Large farm equipment like tractors, manure spreaders, trucks, planters and combines can cause compaction within the root- zone, especially, when the soils are wet.

• If tillage operations are always performed at the same depth, a hardpan can develop just below the depth of tillage operation. Weight of the tillage machines can cause compression of the soil particles causing compaction.

• Wet soils, especially those with higher clay content are more likely to develop a hardpan. The depth of the compacted layer can be determined by slowly digging and moving the soil with a shovel and exposing the top of the compacted layer.… Continue reading

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Soil compaction and soil health

What are the causes of soil compaction?

Soil compaction is one of the most important factors that can affect soil health and reduce crop yields. In the early 1980s, Purdue University soil scientist Gary Steinhardt and Ohio State University Ag Engineer Randall Reeder were making farmers aware of the compaction problem and its effect on yield reduction. Compaction may be caused in many ways. We need to diagnose the reasons for compaction before corrective measures can be taken. Surface compaction can occur from the impact of rain drops or in the form of crusting due to excessive rains and ponding. It may also be caused by the impact of irrigation water.

• If the soil is left bare and is exposed to hard rains or irrigation water, the impact of water breaks down the larger soil aggregates and the granular structure of the soil on the surface are degraded, causing compaction.… Continue reading

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Managing crop residue

Corn growers know the satisfaction of seeing newly emerged, uniform rows of green corn plants set against the backdrop of dark, rich soils. By contrast, it can be painful to see an uneven stand from the truck window when driving past a field.

The cause of an uneven stand could be excess crop residue in the planter row.

“Corn residue will delay and outright interrupt plant establishment, and suppress the resulting plant population,” said Andy Heggenstaller, DuPont Pioneer agronomy research manager. “Corn residue is always a management issue, and high-yield production systems increase residue levels.”

Stand establishment is more of a challenge for corn than it is for soybeans, because corn is typically planted earlier, into cooler and wetter soils. Also, soybeans can accommodate reduced emergence by adding additional pods to make up for yield that could be lost from lower plant populations. That’s why hitting optimum corn plant population levels is so important.… Continue reading

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How deep should you plant?

Just when we thought we knew virtually everything about growing corn, scientists keep on finding new things about growing this amazing crop. Most farmers plant corn seed between 2 to 2.5 inches deep. However, new evidence suggests that we should be planting corn seed even deeper.

• Research studies conducted in Indiana recently found that it may be better to plant corn even deeper rather than shallower to get more consistent results. Generally, deep means 3 inches or more and shallower means less than 1.5 inches.

• Paul Jasa, an Extension Ag Engineer for the University of Nebraska indicated that his research with no-till planting indicated that corn should be planted at around 3 inches depth, particularly in continuous no-till planting. They got more consistent results from deeper plantings than shallower planting. In their continuous no-till trials in Nebraska, corn planted three inches deep yielded 217 bushels per acre, and corn planted 2.25 inches deep yielded 199 bushels per acre.… Continue reading

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Get ready for earlier planting in 2014

I am a strong proponent of early planting. This year early planting may not have helped but it did not hurt either. Why is earlier planting so important and how does it work?

• The easiest and least expensive way to make greater use of the free solar energy, without too much extra cost in machinery and with the currently available hybrids, is by planting early.

• It is an established fact that in most situations, early planting produces higher yields. However, the reason for higher yields is not explained. It has to do with the sunlight!

• We know that the longest day of the year in northern hemisphere is June 21st. During the two months period, from May 21 to July 21, we get more sunlight than any other duration of this length in the year. We can capture the greatest amount of sunlight if we plant early enough to have a full canopy by May 21.… Continue reading

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What factors affect test weight?

Many things can affect test weight. Some of the important factors that can influence test weight are listed below:

• Genetics of the hybrid plays an important role in test weight of the grain. Planting hybrids with genetic potential for higher test weight will generally yield grain with higher test weight if the kernels are fully mature.

• Early planting helps hybrid maturity and leads to higher test weight. Our studies for several years indicated that corn planted before May 10 had 1 to 1.5 pounds higher test weight than late May or June plantings.

• Lower grain moisture will have higher test weight since the kernel dry matter is heavier than water. Test weight is a volume-weight relationship. Drier grain shrinks and has higher test weight because we can pack more kernels into a “bushel basket.”

• Higher temperatures after the physiologic maturity or black layer tend to increase the test weight if kernels are mature.… Continue reading

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Time to consider fall weed control

It seems that fields with weed problems are more of the exception rather than the rule this growing season. Herbicide resistant weeds are also a growing problem.

To address the issue, some farmers are stepping up their weed control efforts to try and stay ahead of the problem.

“I think we have some weed issues, with marestail being No. 1,” said Doug Longfellow, who farms in Darke County. “Even though we had really good control early, I am looking across 15 acres of beans right now and I can see a couple dozen marestail plants that escaped. It looked good through summer until the soybeans started dying and these marestail started to emerge. We still have work to do, even though I thought we had a good program. I think the solution is going to be part cover crop and part a double application of 2,4-D in the fall and the spring.… Continue reading

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Reducing harvest losses in soybeans and corn

I know that most Ohio growers are already in the field busy with harvest. However, I thought it would be appropriate to remind growers of the importance of monitoring harvest losses throughout the harvest season, not just the first few days. We know that losing some grain during harvest is inevitable but measuring that loss behind the combine can pay big dividends to those who make adjustments during harvest. The combine owner’s manual is the best place to start in making sure that you don’t leave grain in the field above the normal and acceptable loss.

Every bushel of soybeans or corn left behind by the combine represents a loss in profits. While harvest losses cannot be completely eliminated, timely combine adjustments can reduce losses to 1 or 2 bushels per acre.

 

Measuring soybean harvest loss

To determine soybean harvest losses, count the number of beans on the ground in a 10 square foot area.… Continue reading

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Turning corn trash into treasure

As harvest continues around Ohio is it no secret that many growers are seeing strong numbers on the yield monitors, with many of the readings pushing the 200-bushel mark.

That is, of course, great news for farmers around the state, but it does bring some things to think about for Bill Mullen, Director of Agronomic Services for Seed Consultants.

“One of my big concerns with these big yields is the trash that will be left on the field,” Mullen said. “This leaves a very good supply of nutrients, but we’ve got to break it down from the stalks.”

As many visitors noticed at Farm Science Review, there is new technology out there that may help with this issue and many options to choose from, including some non-conventional .… Continue reading

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New process for estimating soybean yields

Soybean producers can easily get an idea of the yield potential of their crops with a Purdue Extension soybean specialist’s calculation method.

Soybean yield potential is built on many factors, including the genetics selected, management decisions during the season and the weather. Yield components of soybeans are pods, seed size and number of seeds per pod.

“Individual plant production varies, and every field will vary based on pests, soils, fertility and other factors,” said Shaun Casteel. “But I’ve simplified the process of estimating soybean yields so that producers can scout multiple areas quickly while maintaining representative estimates.”

Casteel’s system is based on estimated yield in one ten-thousandth of an acre. The basic formula involves multiplying the number of pods by the number of seeds per pod, then dividing that result by the seed size factor. That calculation will show the estimated bushels per acre.

To calculate, producers first need to count the number of pods in one ten-thousandth of an acre, an area determined by a 21-inch length of a row of plants and how far apart the rows were planted.… Continue reading

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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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