Tag Archives: soybean

Fire ants in crop fields and near homes – southeast VA

Fire ant mound around brace roots of corn plant, Suffolk, VA.

We have high numbers of fire ant mounds in our crop fields and around our farms this year. There have been some unfortunate encounters and this message is to make you aware of what these mounds look like and the potential for injury. Mounds look like large piles of loose dirt (keep in mind they have to start small at some point). They are often found around fence posts and mailboxes, but many are located in fields, pastures, and lawns. Field borders and paths are frequently infested. Fire ants sting, just like wasps and bees, and some people will be allergic and require medical interventions. People that are not allergic will have itchy, painful welts that often fill with fluid and may take days or a week or more to heal. Usually, you will have dozens or even hundreds of stings. This is because the swarm very fast and wait to sting all at once. Keep in mind that I have lived around them most of my adult life in North Carolina and we have come to accept them as part of our environment and have learned caution and awareness. I have been stung multiple times, usually once every few years, and usually when I am scouting crops. Be aware of where your feet are standing. Walk quickly when crossing a field because you can disturb them and get away without injury. Treatment options are below for mounds located near homes and barns. You do not want children or young animals near these things.

Fire ant mound around edge of soybean field, Suffolk, VA.

I would not attempt to clear your crop fields. A single acre can contain hundreds of mounds and millions of fire ants. Fire ants are predators and will eat caterpillars and other insect pests. They will not eat seeds and plants. Large mounds can damage equipment in rare cases. Products exist that can be applied to turf and lawns with year-long residuals (e.g., TopChoice). These products require a pesticide applicator license to purchase. Baits (e.g., Advion) are an alternative if you are not licensed to apply insecticides. These can be purchased online, many local retailers do not carry them yet. Surface treatments do not work because the colony can live very deep underground. Do not attempt to treat once the weather turns cold because it will not work. Wait until spring. Pray for a cold winter.

Be safe y’all and stay healthy. As always, reach out to me if you have questions or concerns. Keep in mind that I am NOT an urban or ornamental entomologist and I am NOT trying to sell you any specific product. FOLLOW THE LABEL WITH ANY INSECTICIDE.

Estimating Soybean Yields

Although it’s hard to accurately estimate soybean yields until maturity, doing so can give you an idea of your crops potential this year or differences between fields or soil  types.  Maybe you’re considering entering the soybean yield contest or maybe you just want some peace of mind.

Here are some general guidelines for estimating soybean yield.  Again, estimating soybean yield is inaccurate unless detailed sampling is done late in the growing season.  Estimates are usually not very good until the soybean approaches physiological maturity (R7).  Only about 50% of the total seed dry matter has accumulated by the R6 development stage.  Stresses during the R6 to R6.5 stages can result in large yield losses mostly by reduced seed size, but also by reduced pods or beans per pod.  After R6.5, stresses will cause a much smaller loss. 

To estimate yields, follow the steps below.  Be sure to sample in 5 to 7 different areas of the field.

1. Determine the number of row feet needed to make 1/1000th of an acre from the table below.  In narrow rows, one may use 3 or 4 side-by-side rows instead of one long row

2. Determine the plant population per acre.  Count the number of plants for the row feet determined above in 5 to 10 randomly chosen area of the field.  Multiply this number by 1000.  Average the number of sampling areas.  Note that the more areas of the field that you sample, the more accurate are your estimates.

3. Determine the number of pods per plant.  As you are making your stand counts, pull up 5 consecutive plants in the row you counting.  These 5 plants should be growing next to each other.  This will insure that you don’t just pull the best looking plants in the row.  Also, try to avoid gaps in the row as the plant next to the gap will have more pods than the average plant. Count the number of pods on these plants within the sample area and average.

4. Determine the pods per acre.  Multiply the plant population (step 2) by the pod average (step 3).

5. Determine the number of seeds per acre.  Multiply the number of pods (step 4) by 2.5 seed per pod.  This is an average number of seed per pod for most varieties.  Some varieties may have more, some less.

6. Determine pounds of seed per acre.  Divide the seeds per acre (step 5) by 3000 seeds per pound.  This number can vary from 2500 to 3500.  Higher numbers represent smaller seed that are more likely during late-season drought.  Smaller numbers represent seed that form with abundant August/September rainfall.  You may want to obtain a low, medium, and high estimate.

7. Determine the yield estimate.  Divide the pounds per acre (step 6) by 60 pounds per bushel.

As an alternative to calculating your numbers, you can use the chart below to determine how many pods or seed per pod you would need at three different plant populations to obtain a certain yield.

2020 Virginia Soybean Yield Contest

Each year, the Virginia Soybean Association in cooperation with Virginia Cooperative Extension sponsors a soybean yield contest.

The purpose of the Virginia Soybean Yield Contest is to emphasize and demonstrate the practices necessary to produce maximum economic yields, to recognize those producers who grow high-yielding soybeans, and to gather data on the practices utilized by these outstanding producers.

There are three Soybean Yield Contest categories: 1) Full-Season, Non-irrigated; 2) Double-Crop, Non-irrigated; and 3) Irrigated (Full-Season or Double-Crop). 

Any grower (owner-operator, tenant, or tenant-landlord team) who is a member of the Virginia Soybean Association and produces 10 acres or more of soybeans within Virginia’s boundaries is eligible.  Participants may enter one, two, or all contests. 

Details of the contest can be found at the Soybean Extension & Research webpage. Please contact your local Virginia Cooperative Extension office if you wish to enter the contest, preferably at least 5 days before harvest. 

Virginia Tech Eastern Shore AREC Virtual Field Day

Please find the 2020 Virginia Tech Eastern Shore Agricultural Research and Extension Center Virtual Field Day available via YouTube. Pre-recorded sessions can be viewed in one playlist or you can pick and choose individual topics using the hyperlinks in the attached program.

Playlist link: https://www.youtube.com/playlist?list=PLldHHn24T22mXiFp8Hq9hEn-YPb4gMTM0

The program with clickable links is found by clicking: https://www.pubs.ext.vt.edu/content/dam/pubs_ext_vt_edu/spes/spes-239/SPES-239.pdf

As always, contact us with questions vis email, YouTube comments, or Facebook. Please let us know of any further research or Extension questions that you may have. We hope to see everyone again at our Painter, VA location in person in Summer 2021!

Stay healthy and take care!

Virginia Tech Eastern Shore AREC research plots. Photos by At Altitude Gallery, Cape Charles, VA ( https://ataltitudegallery.com/ ).

Planting Tips for Profitable Double-Crop Soybean

   Before I get into tips for soybean, I must emphasize one must focus on the entire double-crop wheat-soybean system.  Both crops must contribute to profit; one crop cannot carry the other.  You will may save some input costs such as lime, fertilizer, and rent (making those seasonal cost spread over two crops) with the double-crop system, but certain costs such as soybean seeding rate will increase.  In the end, these inputs roughly equal out with the exception of land rent that can vary greatly over Virginia.

   With that said, the most important thing to insure a profitable double-crop system is yield, yield of both crops.  Without a minimum of 80+ bushel/acre wheat and 33-35+ bushel soybean, the system will not likely be as profitable as the full-season soybean system, especially with today’s low prices. 

Assuming that you will intensely manage both crops during the growing season (note that intensely managing does necessarily not equate to greater input costs, but instead greater attention), the most important thing that anyone can do right now for greater yields is to harvest the wheat crop as soon as possible, and then immediately plant the soybean.  Our 3-year, 5-state (PA, MD, DE, VA, NC) project conducted just a few years ago clearly confirmed that this is one of, if not the most important decision that a double-crop farmer can make.  In that project, we generally showed a rapid decrease in both wheat and soybean yield with delayed harvest and planting after mid-June.  Wheat yield declined anywhere from 0.5% to 2.5% per day, depending on location and year, versus wheat that was harvested at 18-20% moisture.  This was largely due to rapidly declining test weights afterwards.  And we also noted that quality decreased in many test locations. Note that if wheat is harvested this wet, then it will need to be dried almost immediately.  I don’t recommend this unless you have a continuous-flow drier or have a buyer willing to take the high-moisture wheat without severe price dockage. 

Although we found a benefit to the wheat crop, probably the bigger benefit however to harvesting wheat at high moisture is earlier planting of the soybean.  On average the soybean yield began to decrease about ½ bushel/acre per day by mid-June, but this increased to 1-2 bushels per day once we got into late-June (more northerly Mid-Atlantic states) and early-July (more southerly Mid-Atlantic states).   This resulted in a major income difference. 

Just to re-emphasize this most important point, harvesting the wheat and planting the soybean ASAP is the most important thing a farmer can do to make this system as or more profitable than a full-season soybean system.  The current weather is not helping with this (we could have harvested much of our wheat this week), but hopefully next week will bring drier weather.

Here are some other tips that are very important when planting double-crop soybean.

Variety Selection. Select the latest maturing varieties that will mature before the frost.  This will assist with growing as much leaf area and having as many reproductive nodes as possible.  Plant the earlier maturing varieties in this maturity range on your best soils and the later relative maturities on the poorer-yielding land.

Always Plant in Narrow Rows.  I prefer 15 to 20 inch rows seeded with a planter that singulates the seed.  Seed singulation insures uniform seed placement within the row and no big gaps between plants.  The other option is to plant with a drill, which achieves the narrow rows but results in what many refer to today as a “controlled spill”.  This results in many gaps, 2 or 3 seed planted in the same place, and generally lower yields (we proved this in some on-farm double-crop studies in the early 2000s).  Still, a drill is better than 30-inch (or wider) rows at such a late planting date.

Seeding Rate. Beginning next week in Virginia, plant 140,000 to 160,000 seed/acre and increase that rate by 20,000 seed/acre with each successive week.  This will of course put the seeding rate up to 200,000 to 220,00 plants by the first full week of July, sharply decreasing your profit with greater seed costs and lower yields.  Again, this is to insure maximum leaf area and node development.  Note that as one moves north and west, greater seeding rates may be needed due to the shorter growing season (e.g., northwest Virginia may require a greater seeding rate than southeast Virginia, or North Carolina). If using a drill, I suggest increasing these rates by 10%.

Insure Good Soil-to-Seed Contact. First, adequately spread the wheat residue.  No planter will uniformly plant through inches of matted residue. Then make sure the planter is properly set to 1) cut the residue, 2) penetrate the soil to the proper seeding depth, and 3) ensure good soil-to-seed contact.  These steps must take place in order. And they affect each other; a mistake in accomplishing one of the steps can result in mistakes in the other two.  I suggest waiting until late morning to begin planting to insure that the small grain residue to dry – unless the residue is dry, cutting through it will be a problem, resulting in hair-pinning of the residue and prohibiting proper soil-to-seed contact. 

Plant into soil moisture.  If there is plenty of moisture, you can plant as shallow as ¾ inch and get good and rapid emergence.  If a little dry on top, you can plant as deep as 1.5 inches.  With warm soil temperatures, soybean will generally emerge well from this depth and may even emerge from even deeper depths (but I don’t recommend).  Unless you farm in wet, poorly drained soils or are growing continuous soybean, I don’t usually recommend a fungicide seed treatment during June and July due to warm soils.  Double-crop soybean usually emerge quickly if planted into soil moisture and will “out-grow” any seedling disease.

Insure Nitrogen Fixation. If soybean have not been grown in a field for the past 3 years, then be sure to apply inoculate to the seed with the proper bacteria.  This will insure adequate nitrogen fixation by the soybean plant. There is no need to apply nitrogen; definitely don’t apply more than 25-30 pounds/acre or you will inhibit this vital biological process. As a side note, we did find a fairly consistent 1 bushel yield increase with starter N at 25 lbs/acre due to slightly better early-season growth; but this did not pay for the cost of the N – so I don’t recommend.

Fertility (P, K, S, etc.).  Keep in mind that the straw contains quite a bit of nutrients.  If the straw is harvested, make sure that you are replacing those nutrients that are leaving the field.  For more information, see our VCE publication,  The Nutrient Value of Straw.  And make sure that you are being paid more for the straw than these nutrients and organic matter is worth!

Enlist Soybean Varieties for Double-Crop Production Systems

Although it appears that we can use existing stock of labeled dicamba products (XtendiMax with Vaporgrip Technology, FeXapan, and Engenia) for Xtend soybean varieties, some may want to switch to or use Enlist varieties to control resistant or hard-to-kill weeds in their double-crop system.

Therefore, I’m listing this past year’s results of the performance of Enlist varieties from our variety tests. Note that most of maturity group (MG) 4 varieties. I tested no late-5 or 6 varieties.

Again, the varieties that you have already selected are likely the best-performing ones for your fields; therefore, I do not recommend changing unless you need the Enlist system to control weeds in certain fields.

Note that relative yield is the yield relative to all varieties tested within a relative maturity group (e.g., early-4, late-4, early-5, etc.). Relative yield of 105 means that the variety yielded 5% greater than the average of the entire test.

Xtendimax, Engenia, and FeXapan Registrations Vacated. What now?

The dicamba products Xtendimax, Engenia, and FeXapan had their registrations vacated June 3, 2020 by the U.S. Court of Appeals for the Ninth Circuit. The EPA announced June 8, 2020 a final cancellation order for these products.

Existing stocks, in possession on June 3, 2020 (the date of the court’s decision), can be used by farmers and commercial applicators by July 31. Use of these products must be consistent with the previously approved label.

The EPA’s full statement is here:  https://www.epa.gov/sites/production/files/2020-06/documents/final_cancellation_order_for_three_dicamba_products.pdf. Details on use of existing stocks are on page 11.

More background information can be found here

Tavium (dicamba + S-metolachlor) is also still legal to use. Tavium was not mentioned in the lawsuit making Tavium the only way to legally apply dicamba to Roundup Ready 2 Xtend soybeans or Xtendflex cotton. This product is already in short supply and may be difficult to acquire. Tavium cannot be used on double crop soybean.

There are effective alternatives to dicamba. In RR2 Xtend soybean, I recommend Flexstar GT in place of dicamba. This product is not currently in short supply, but there is potential for that to occur. So I encourage farmers that plan to use Flexstar GT to go ahead and acquire it. Other alternative products can be found in Table 5.54 on page 5-182 of the Pest Management Guide. Additionally, information on controlling Palmer amaranth in soybean is here: https://www.pubs.ext.vt.edu/2808/2808-1006/2808-1006.html and common ragweed is here: https://www.pubs.ext.vt.edu/content/dam/pubs_ext_vt_edu/spes/spes-143/SPES-143.pdf. In cotton, most varieties have the option of using Liberty, which is my recommendation in place of dicamba. But other alternative products can be found in Tables 5.112 and 5.113, starting on page 5-344.

Farmers should consider changing soybean herbicide traits for double crop acres or any soybean ground that has not yet been planted. LibertyLink, LLGT27, and Enlist are all good options in place of RR2 Xtend. Farmers may also consider a Roundup Ready variety as well, to potentially save tech fees compared to RR2 Xtend, but there are very few of these even before this announcement. I realize changing this late in the year may not be feasible and the best performing varieties may not be available. If farmers choose to change varieties, make sure that the variety has both strong yield potential and the herbicide trait of choice.

This ruling does not apply to dicamba products such as Clarity and Banvel, that are not labeled for use in Xtend traited crops, so these can continue to be used in pastures, corn, and other labeled uses. Dicamba products that are not labeled for use in dicamba-tolerant crops have been and continue to be illegal to use over-the-top of RR2 Xtend soybean and Xtendflex cotton.

This ruling comes at the absolute worst time during the season. There may be temptation to use dicamba illegally, but I strongly encourage us all to think about the implications of such actions on agriculture. These products have been and will continue to be under scrutiny from the non-ag public.

Should Court Ruling on Dicamba Affect My Seed Choice for Double-Crop Soybean?

The court ruling yesterday has given a devastating blow to farmers that are depending on the Roundup Ready 2 Xtend herbicide program for their soybean. There seems to be much discussion regarding clarification of this ruling, including when the ruling can take effect and a possible “existing stocks” provision.

Until the ambiguity around the decision is clarified, it’s worth thinking about seed choice. Assuming there is little that can be done about soybean already planted and growing other than alter your postemergence tank-mixes, you may have an opportunity to switch varieties for the upcoming double-crop soybean planting.

First and most important, do not change your variety selection if you have weeds that can be controlled without the addition of labeled dicamba products (Enginia, FeXapan, Xtendimax) to your herbicide program. The varieties that your have already selected are most likely to be best for your farm and will maximize your yield.

However, if you must add dicamba to your glyphosate to kill glyphosate-resistant marestail (hopefully you’ll take care of this weed before you plant), Palmer amaranth, or common ragweed, then you have some options with Liberty-Link, Enlist, Liberty-Link GT27, or a few other varieties that have stacked the GT and LL traits.

Like all herbicide-resistant traits, there are good varieties and there are some that don’t yield so well. I suggest that you refer to our Virginia Soybean Performance Tests 2019 or other good private and public resources to see how these have performed.

Seeding Rates for Late-Planted Soybean

The cool and wetter weather earlier in the month has delayed some soybean planting into June. In addition, some cotton growers have switched to soybean due to the same reason. The question that came to me often this week was “Should I increase my seeding rate?”

In general, our research has not found a dramatic yield response to more seed per acre until mid-June. This largely reflects the lack of decrease in yield due to late planting dates until about the same time. If planted by the first week of June, the soybean usually has time to build a canopy great enough to capture most of the light by flowering, and does not need the extra plants.

However, I usually recommend that you begin increasing seeding rates by about 20,000 seed per week beginning the first of June.

Therefore, I would suggest the following:

This week (June 1-6): 120,000 – 140,000 seed/acre

June 7-13: 140,000-160,000 seed/acre

June 14-20: 160,000-180,000 seed/acre

June 21-27: 180,000-220,000 seed/acre

On your better soils or with later maturing varieties, use the lower seeding rate. On your less-productive soils or with earlier varieties, use the higher rate. This will insure that you you have enough leaf area to maximize the yield for those planting date.

Will the cold weather harm my soybean this weekend?

The weather reports of near-freezing temperatures in some parts of Virginia has many concerned about their wheat, corn, emerged and non-emerged soybean. I’m one of them, but we must try to be optimistic about this threat.

My weather apps seem to indicate lows in the lower 30’s in some of most northern and western growing areas on Friday and Saturday nights. This is never good, especially in May. A frost may burn off some leaves if the air remains calm, but a slight breeze during the night can keep the air temperature surrounding the plants above freezing, and in-turn the soybean plant above freezing. And as long as the temperatures don’t drop below freezing for an extended period of time, I think that our soybean will be O.K.

Why do I say this? Usually, it will take air temperatures of 28 F or less to cause permanent damage. Why is this? First, the soil temperatures are warm, in the 50’s and 60’s and the soil will not warm as fast as the air. The air nearest to the soil won’t be as cold due to this; there will be a buffer area. Even if temperatures do get down to 31-32 F, plant cells will not freeze because they contain solutes, which lowers the freezing point of the tissues. For a more thorough explanation of freeze damage to soybean, I recommend this article on the University of Wisconsin’s Cool Bean website.

Just in case, we do have some soybean damage, Purdue University has an excellent article on the subject for corn and soybean, Symptoms of Low Temperature Injury to Corn and Soybean, which include some good photos of injury. The photos show likely seedling soybean survival and death examples. If our soybean have several leaves (V1-V2) and there are some out there, it’ll take very cold temperature to freeze the entire plant. Even if frost burns the leaves off, the growing points in the nodes of these leaves will likely survive and regenerate a new stem, leading to a bushier but healthy plant. But, we can worry about that next week.

The seed that are in the ground will survive. Again, the soil temperature will not drop dramatically with the cold weather. Still, soil temperatures in the 50’s is not warm. You’ll need a fungicide seed treatment protecting them. No seed treatment? We will have to wait and see. For more details, see my last article, Soybean Planting Tips for Cool Weather

Should you stop planting? We are not. I have a planter in the field today. But my seed are treated with a fungicide. But neither do you need to be in such a hurry. We generally don’t see a drastic yield decrease until planting is delayed after June.