Category Archives: Soybean

Do I plant soybean or wait for rain?

Until these big high-pressure systems sitting in the eastern part of the country move east, it looks as if we are in for another week or so of dry weather. This is not good for soybean planting, any way you look at it.  So, what should we do?

There are basically three options:

Plant shallow in dry soil and hope for enough rain to get the seed out of the ground. If you decide to take this approach, you want to ensure you achieve uniform seed depth and that you are not allowing the seed access to moisture below the seed that could lead to variable emergence. This approach would be less risky in clean-tilled situation where you are more confident that you have dried the soil out at shallow depths. Soybean seed will sit in the ground for several weeks and still emerge well when rainfall occurs. Some worry about “cooking” the seed during this period.  Although it is true that the seed will continue to respire and its ability to germinate will decline, the bigger risk is that you catch a small rain that allows the soybean seed to imbibe water but not enough to get it out of the ground.

Caution must be exercised in no-till systems.  With no-till the soil has not been uniformly dried out with tillage; therefore, there is non-uniform moisture distribution across the field.  This leads to uneven access to moisture and ultimately emergence variability. Parts of the field will have adequate moisture to get the soybeans out of the ground, other parts will be completely dry as in tilled conditions, and much of the field will be in between.  Those in-between areas are likely to have enough moisture to swell the seed and/or initiate germination but not have enough moisture to allow the seedling to emerge.  This is my least favorite option.

Plant deep to the moisture. Under most conditions, soybeans may be planted 0.75 to 1.5 inches deep. But I don’t usually like to go much over 1 inch deep, especially in May.  I want soybean to come out of the ground as fast as possible. With that said, we planted some at 1.5 inches last week. Soil temperatures are generally high enough right now for the seed to germinate and plants emerge relatively quickly. Soybeans should not be planted deeper than 2 inches. Many are not finding soil moisture at less than 2 inches. Even if there is moisture 1.5 inches down, exercise caution using this approach, especially your soils are prone to crusting, because a heavy rainfall could seal the soil before the soybeans emerge. In tilled conditions, the planter can push the soil down a little, creating a ridge of fluffy soil on each side.  A heavy rain will cause this soil to move into that furrow and possibly add another ½ to 1 inches of soil to your depth.  If you are going to go this route, check the emergence score on the variety.

Keep the seed in the bag until the next time we catch rain. This is the safest approach and the one that I am leaning to now. Based on historical data, we have another couple of weeks before we start seeing yield declines from delayed planting. Data from recent research throughout the Mid-Atlantic shows that each day delay in planting past mid-June can result in a ½ bu/A or more yield loss and in general these yield declines begin in the second or third week of June. We still have some time before we get to that point. The optimum planting date range for soybeans is late-April through mid-June, although it will vary from year-to-year and field-to-field based on rainfall, soil water holding capacity, and soybean maturity, but the goal is to get the soybean plants to lap the middles before reproductive growth begins. We still have still have time to do this in most cases. 

Waiting to plant is more of a concern for those who still have early-maturing varieties to plant (MG 3 and early-4), as these varieties will have less time for vegetative growth. I do suggest planting your earliest maturity groups first, whichever strategy you choose to employ.  Later maturity groups have more time for adequate growth when planting is delayed.

What about fungicide seed treatments? You have likely already decided on this and cannot change.  But fungicidal seed treatments are less likely needed in this situation where soils are warm. It looks as if temperatures will be warming all week, so I don’t see cold soils as a problem.

Whatever decision a grower makes, uniform seed placement in critical to achieve uniform emergence and ensure each seed has as equal of access to water as possible. I don’t get too concerned if some plants emerge just a few days apart, but we don’t need them emerging a week apart. Dr. Rachel Vann of N.C. State discussed the importance of uneven and delayed emergence in soybeans – How Important Is Uniform Emergence in Soybeans?  Still, keep in mind that although earlier emerging plants will usually yield more, the late emerging plant will still contribute to yield.  Due to soybean’s compensatory ability, the yield on the whole will differ little from only a few days difference in soybean emergence within the row.  If you know me, you know that I’m not a fan of planting with drills due to lack of equal spacing within the row.  This lack of even spacing will become increasingly important if plant emergence is not good. 

In conclusion, there are advantages and disadvantages to each planting option discussed, but we still have time to plant soybeans in our region before we see drastic yield declines. All options discussed will likely result in delayed emergence due to environmental conditions.

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. 

Spider mites in many crop fields

Observations from the field this week indicate that there are spider mite infestations at some level in most, if not all, peanut, cotton, and soybean fields in the drought-stressed Virginia regions. Drying of corn and weeds is contributing to this problem. Let’s all hope we get the rain we need to make a good crop this season. Rainy, humid weather will favor fugus that kills mites, but its effect may be mitigated by extremely hot conditions. Just in case, and since our last bad mite year was 2011, see below for a refresh about spider mites and how to treat them in each crop…

Soybean

Concentrate on the field borders and look for the early signs of white stippling at the bases of the leaves. Do not confuse mite damage with dry weather injury, mineral deficiencies, and herbicide injury. Mite infestations will have some pattern, usually originating from field margins. Consider applying a miticide if more than 50 percent of the plants show stippling, yellowing, or defoliation over more than one-third of the leaves. Recommended products include Zeal and Agri-mek (other abamectin products are available, but not labeled for soybean). Lorsban and dimethoate are labeled and may require a second application. Bifenthrin will offer some suppression, but mite infestations will come back stronger.

Peanut

Heavy infestations usually occur first around the borders of peanut fields; then they spread inward throughout the fields. Avoid harvesting spider mite infested cornfields or mowing weedy areas next to peanut fields until peanuts are harvested. Spider mites will readily move into peanuts when corn dries down or is harvested. Be prepared to treat peanuts if adjacent corn is infested. Use adequate pressure and GPA to ensure penetration of the canopy. Comite is our only registered product that works. See graph below from Dr. Mark Abney at UGA.

Cotton

Mite damage first appears as a slight yellowing of the leaves, which later changes to a purplish or bronze color and is usually associated with webbing. Damage occurs especially in spots or on field edges but widespread defoliation is not uncommon if favorable conditions persist. I recommend abamectin (10 oz/A rate is usually sufficient) or Zeal for control. Bifenthrin, other pyrethoids, and especially acephate, will flair mites. If you are treating for plant bugs, I recommend Transform at 2-2.25 oz/A until wetter conditions prevail. Be mindful of the bollworm flight next week and do not make automatic sprays for worms until you confirm a problem in your field. Worm specific products (Prevathon, Intrepid Edge, Blackhawk) are better options than broad-spectrum insecticides (pyrethroids).

Our annual post-bloom survey starts next week. If you need help learning how to scout insect pests, call or text me on my mobile (919) 801-5366.

Virginia Ag Expo Canceled to COVID-19 Concerns

The 2020 VA Ag Expo has been cancelled. The Ag Expo committee with guidance from the Virginia Soybean Association and Virginia Grain Growers Association have made this difficult decision to ensure the health and safety of exhibitors and guests as a result of the COVID-19 pandemic. We will be reaching out to each exhibitor and sponsor to discuss our next steps. We appreciate your support and look forward to 2021!

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.

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.