Category Archives: Soybean

Full-Season Soybean Seeding Rates: Maximize Your Yield and Reduce Your Risks

In general, high seed costs have resulted in a reduction in the number of soybean seed planted per acre.  For our full-season production system, most have reduced their seeding rate to 140,000 or less.  Some have even had success with rates as low as 80 to 100 thousand seed/acre.  My research over the years has shown that we only need, on average, about 70 to 80 thousand plants/acre to maximize our yield.  But is this too low? Yes, it could be – in some situations.

There is also interest in varying seeding rates.  I said many years ago that it appears that this is possible.  But our approach to variable-rate soybean seeding will be just the opposite of how we vary our rates with corn.  With corn, we increase seeding rate as our yield potential increases.  With soybean, we do just the opposite – we reduce our seeding rate as yield potential rises.  But, how much can we reduce seeding rate with rising yield potential?

To answer both questions – Is a final stand of 70 to 80 thousand plants too low? and How do I vary soybean seeding rates?, I analyzed over 10 years (over 25 experiments from 2003-2011) of on-farm and small-plot research to determine the optimal seeding rate for three different yield potentials.  The results along with my recommendations are shown below.

For low yields of 20-40 bushels/acre:

Plant 120 – 140 thousand seed /acre.

Why not less?  The data to the left indicates that the optimal seeding rate (area between the two vertical dotted lines) ranges between around 100 to 120 thousand seed/acre.  Why is this not my seeding rate.  There is too much variability in the data; therefore too much risk.  In some years, yields could have been reduced with this rate.  So, I’m hedging towards less risk at these yield potentials.

 

For medium yields of 40 to 55 bushels/acre:

Plant 100 – 120 thousand seed/acre.

You will notice that the optimal seeding rate has declined to around 90 to 110 thousand seed/acre.  Note that this is only about 10,000 seed less that the previous graph, but I lowered my recommendation by 20,000 seed.  Why?  There is little variability in these data; hence, I have more confidence.

 

 

For high yields of 55 to 70 bushels/acre:

Plant 90 to 110 thousand seed/acre.

Like low yield potentials, I’m starting to hedge a little here towards less risk although my data indicates that I can go lower.  There were cases where is took nearly 120,000 seed to get the maximum yields.

 

 

One comment that I get with these data is: “These data are old.  Does it still hold up with newer varieties?”  A good question!  So, I’ve conducted seeding rate experiments over the past 2 years and I’ll continue this coming year.  To summarize, the most recent data has not changed my recommendations – I think that these trends still hold true.  However, we did see some differences last year – a year of wet and cloudy conditions.  The data are below:

With our maturity group 4 trials, we saw yield continue to rise with seeding rate, and our yields were in the high range (about 50 to 60 bushels/acre).  But yields with the group 5 soybeans tended to level off at about 120 thousand seed/acre.   Why a different response and why did maturity group matter?

 

 

I think the answer is lack of sunlight.  Total photosynthetically-active radiation interception differences are one of the reasons that we get yield responses to seeding rate.  In most cases, this is a lack of leaf area; we are not intercepting all the light.  But, this was not the case in 2019.  We had what I normally consider enough leaf area, at least enough for a sunny year.  But we had less light in 2019.  The group 5 soybean did have more leaf area than the group 4 soybean; I’m assuming that these few extra leaves made up a little for the lack of light.  Cloudiness is one of the risks we take.  Still, I won’t change my recommendations based on last year since it was rather unusual.

In conclusion, if you want to chose the best full-season seeding rate in Virginia for your yield potential, my recommendations are:

Low yields: 120 to 140 thousand seed/acre

Medium yields: 100 to 120 thousand seed/acre

High yields: 90 to 110 thousand seed/acre

 

Herbicide Resistant Weeds Workshops Slated for Maryland, Virginia, and Delaware

A series of half-day workshops will be held in Maryland, Delaware and Virginia this winter for farmers interested in learning about the problems of herbicide resistant weeds and how to manage them. Hosted by University of Maryland Extension in collaboration with Virginia Tech and University of Delaware, these workshops are designed to equip farmers with the knowledge to improve weed control on their farms.

Farmers in the mid-Atlantic area are starting to see the impact of herbicide resistant weeds on their crop yields. With many problematic weeds now found throughout the region it is essential that farmers learn the key management strategies to control these weeds.

Sessions will cover integrated weed management tactics; palmer amaranth, common ragweed and marestail control strategies; and developing a weed management plan. There is no charge to attend and lunch will be provided. Pesticide (commercial and private) and CCA continuing education credits will be offered.

Workshop locations and times are listed below. Please RSVP to the respective meeting location to provide an accurate meal count.

February 25th (12 pm to 5 pm) Old Beale Sanctuary, 369 Queen Street,Tappahannock, VA 22560

To register call the Essex County Extension Office: at (804) 443-3551

February 26th (8 am to 1 pm) St. Mary’s County UME Office, 26737 Radio Station Way, Leonardtown, MD 20650. To register call the St. Mary’s County UME Office at 301-475- 4484

March 4th (8 am to 1 pm) Harrington Volunteer Fire Company, 20 Clark St, Harrington, DE 19952. To register call the UD Carvel REC, at 302-856-2585 (ext 540)

March 5th (8 am to 1 pm) Somerset Extension Office, 30730 Park Drive, Princess Anne, MD 21853. To register call the Somerset County Extension Office at 410- 651-1350

March 6th (8  am to 1 pm) Frederick County UME Office, 330 Montevue Lane, Frederick, MD 20712. To register, call the Frederick County UME Office at 301-600- 3576

March 7th (8 am to 1 pm) Chestertown Volunteer Fire Company, 211 Maple Ave, Chestertown, MD 21620. To register call the Kent County UME Office at 410-778- 1661

For more information contact Ben Beale at 301-475-4481, Michael Flessner at 540-315-2954, Matt Morris at 301-600-3578 or Mark VanGessel at 302-856-7303.

Dicamba Training Opportunities

If you intend to apply Engenia, Xtendimax, or FeXapan this year, you need to complete the annual dicamba specific training requirement in addition to being a certified pesticide applicator. In Virginia, this training is conducted by the registrants (manufacturers), but can also be completed in another state including registrant training, state mandated training, and state approved training. Both in person and online training is acceptable. Training is not product specific; you do not have to take the training from the registrant of the product you apply.

Make sure to document your training.

Here are links to find a training event near you or complete online:
BASF

Bayer

Corteva

University of Nebraska

Please note that some some events require pre-registration.

The following links are under revision for 2019 but will be useful shortly:
Mississippi State Extension

Improving Your Soybean Variety Selection Decisions – What maturity is best?

Variety selection continues to be one of the most important decisions that we can make.  It is also one of the first steps to take that insure success.  It’s a hard choice because there are so many varieties available.  Still, this choice is one that will affect your profitability throughout the year.

Soybean yields in our variety tests have increased by an average of 0.4 bushels per year over the last 30 years.  Some of this increase is due to better varieties, some is due to better management.  In those tests, the highest and lowest yielding varieties varied by 20% or more (8-10 bushels).  It is therefore clear that making the wrong choice will seriously impact next year’s soybean crop.  Unfortunately, environment (rainfall, temperature, soil type, field, etc.) affects yield variation more than variety – there is always lots of year-to-year and site-to-site variation.  Still, each variety has specific strengths and weaknesses that make it more or less suited for any given situation.

Putting the Right Variety in the Right Field

With all this variation, it is very important that you place the right variety in the right field.  This will be influenced by 1) planting full-season or double-crop; 2) maturity; 3)herbicide tolerance; 4) disease and/or nematode tolerance; and finally 5) yield potential.  There are also a number of other factors that differentiate varieties such  as shattering and lodging susceptibility, height, branching ability (thin vs. bushy), seed size, seeds/pod, protein and oil content, other specific traits, etc.), but these will rarely affect your bottom line.   Although all of the top five things I listed are important, yield potential is clearly what is of most interest.  However, if you do not pay attention to numbers 1 through 4 first, your yield potential can be low.

To cover all of the things that make variety selection important would take more words than this blog will allow, so we will first focus on the choosing the right maturity.

Relative Maturity Choice: Spreading Out Environmental Risk

First, I should say something about early planting of an early-maturing variety.  I define this as planting in April or early May a variety that is about one full maturity group earlier than the maturity that is most adapted, based on historical data, for your area.  First, early-planted early-maturing varieties will always have a greater risk of poor quality seed.  The seed of these varieties are maturing during September and early October, when the weather is relatively warmer.  Warm and wet weather are perfect conditions for seed decay.  2018 has been one of the worse years for this, primarily due to excessive rainfall and much warmer September temperatures.  To the right is an example of a maturity group (MG) 3 soybean planted in April in Madison County (MG 4 is the most adapted maturity for this area).  Clearly, you don’t want to end up with this.  While early maturing varieties have their advantages, their associated risks should keep the percentage of acres planted to a minimum.

On the other hand, do not keeping all varieties in a tight maturity range.  The performance of varieties within a certain maturity range will almost always depend the environment that they experience during pod and seed fill.  If conditions are good (adequate rainfall, moderate temperatures, good soils) during that time, yields will be high.  Unfortunately, the weather cannot be predicted in our humid southeastern U.S. environment.  While late-July and early-August are generally our hottest and driest times of the year, we have just as good of a chance of going through a hot and dry period in June as well as July as well as August, and sometimes in September.          Still, on average, certain relative maturity ranges yield more than others in the south central part of Virginia.  Below are the average yield balance (no. of bushels/acre greater or less than average) of a range of soybean maturities tested in our full-season variety tests over the last 10 years, separated by location.

I’ll use our Southern Piedmont location (Blackstone) as an example of a location that shows the greatest yield gap between the earliest and latest varieties (nearly 15 bushels!).  This is likely due that area typically experiencing the more stress (hot and dry) from late July through August than other regions.

Similar but on the opposite end of the spectrum, MG 3 and 4 varieties work best at the Northern Piedmont (Orange) location.  Maturity group 5 varieties generally not as adapted in that northerly environment.

The northern and southern Coastal Plain sites (Warsaw and Suffolk) behave similarly to Blackstone – MG 5 outperform MG 4 varieties; but the yield gap between relative maturities is not as wide.

Our Eastern Shore location does not follow the same trend of MG 5’s being the highest average yielding varieties as one moves south and east.

Note that maturity group (MG) 5 varieties relatively better in the more eastern and southern locations of Virginia’s mainland, while MG 4 varieties tend to do better in our most northwestern location (Orange) and on the Eastern Shore (Painter).  While MG 3’s don’t yield as well, the group 4’s are the highest yielding.  Why?  I attribute it to two things: yield potential and temperature.  In general, this site has over time been one of our highest yielding sites.  Although rainfall patterns are similar to other locations in Virginia, it is our coolest location (and there is usually a breeze) – both likely a water effect.  Therefore, the site experiences less stress.  So, pushing the critical pod- and seed-filling stages slightly earlier in the year are not as problematic.

So, should you stick only with maturities that perform best on average?  Not necessarily.  Using Blackstone as an example, note that although the late-group 4 varieties yield less than MG 5’s on average, they yield much better than earlier 4’s.  And late-4’s yield just as well as 5’s in Orange and Suffolk.  I stress that these are averages – 10-year averages of all varieties within those relative maturity ranges.  Is it possible for the MG 4 varieties to yield more than the 5’s in Blackstone or Warsaw?  Is it possible for MG 5’s to yield more in Painter?  Yes!  It just does not happen as often.

We took that same data and calculated the probabilities, not absolute yields, of obtaining similar or greater yields of all relative maturity groupings tested.  The results are below.

Once again, to use the Blackstone data as an example, we can see that growing a late-MG 5 variety will yield at least as much as all of the other relative maturities 90% of the time (bar height).  In addition, there is a 50 to 60% chance (height of the hatched portion of the bar) that the 5’s will yield significantly more than the 4’s.  So, it seems that you will never go wrong with those varieties, correct?  You’ll probably (~80% chance) not go wrong by growing a large percentage of those varieties, but should you should you only plant MG 5’s?  I suggest that you do not grow only MG 5 varieties.  There is still a 10 to 20% chance that the 5’s will yield less than the other maturities.  Plus, there is a 60% chance that late MG 4 varieties will yield just as much as MG 5 varieties (and a 30% chance that they will yield more).

Painter is another good example.  Although there is a yield gap between the 4’s and 5’s, there is a 50 to 70% chance that MG 5 will yield as well as MG 4 varieties.  And there is a 30% chance that they will yield more!  You can use the same thought process for the other locations.

Below are the same graphs for double-crop tests.The Right Mix of Maturity Groups in Virginia.  So, what is the right mix of maturity groups?  I suggest the following:

Southern Piedmont

  • Plant 60 to 80% of your land to MG 5 varieties. We have also found that later maturities generally do better on our more droughty soils, so take that into consideration if possible.
  • Plant 20 to 30 % to late-MG 4 varieties (4.7-4.9). If possible, plant these on your higher-yielding soils.  We have found that this range of maturities have our greatest yield potential throughout Virginia if the weather cooperates.
  • Plant 0 to 20 % to mid-MG 4 varieties. These are risky, especially on droughty soils or in double-crop settings.  It is highly likely that these varieties will experience some (or a lot) of stress during the seed and pod fill stages.  Plus, seed quality will almost always be poorer than other maturities.  If you do grow these, harvest as soon as possible as seed quality will continue to degrade with time.  Don’t plant these in April or early May. This places the most critical times of development (pod and seed fill) during late-July and August.  And seed quality will be even worse since they will likely mature during the warmer part of the year.  Still, yield potential can occasionally be quite high.

Southern Coastal Plain (same comments apply regarding droughty soils and seed quality)

  • Plant 30 to 60% of your land to MG 5 varieties.
  • Plant 30 to 50 % to late-MG 4 varieties (4.7-4.9).
  • Plant 10 to 20 % to early- and mid-MG 4 varieties.

Northern Coastal Plain (same comments apply regarding droughty soils and seed quality)

  • Plant 30 to 60% of your land to MG 5 varieties. In double-crop systems, reduce that percentage to 30 to 50%.
  • Plant 30 to 50 % to MG 4 varieties (4.7-4.9). In double-crop systems, increase that to 50 to 70% late-4’s and plant 10-20% early-or mid-4’s.
  • Plant 0 to 20 % to late-MG 3 varieties.

Eastern Shore (same comments apply regarding droughty soils and seed quality)

  • Plant 20 to 40% of your land to MG 5 varieties.
  • Plant 50 to 70 % to late-MG 4 varieties (4.7-4.9).
  • Plant 10 to 20 % to early- and mid-MG 4 varieties. Plant 0-10% in double-crop.
  • Plant 10 to 20% to late-MG 3 varieties.

Northern Piedmont (same comments apply regarding droughty soils and seed quality)

  • Plant 0 to 20% of your land to MG 5 varieties. Don’t plant MG 5’s double-crop.
  • Plant 60 to 80 % to MG 4 varieties (4.7-4.9).
  • Plant 10 to 20 % to mid- or late-MG 3 varieties.

The proportion of MG 4 and 5 will ultimately depend on your risk tolerance.  Note that as you move west and north, the risk of an early frost is greater; therefore, growing lots of late-maturing varieties may not be a great idea, especially double-crop, and the probability of slightly earlier maturities doing better is greater.

Hopefully, this will give you some guidance in choosing your maturities within the next few weeks.

IMPORTANT:  Keep in mind that the yields and yield balances shown are an average of all varieties in those relative maturity groupings.  This does not mean that every variety in those grouping perform in this manner on every field.  Make sure that you first the variety that meets your match your field’s pest management needs; then, select a high-yielding variety within that relative maturity range.

 

Virginia 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.
The Virginia Soybean Association in cooperation with Virginia Cooperative Extension sponsors this program.
There are four Soybean Yield Contest categories: 1) Full-Season, Non- irrigated; 2) Double-Crop, Non-irrigated; and 3) Irrigated (Full-Season or Double-Crop; and 4) Most Efficient. A full-season system is defined as the grain or seed harvest of one summer crop (soybean in this case) from the same field in one year. Double-crop is defined as planting soybean immediately following grain harvest of barley or wheat; thus harvesting two crops from the same field in the same year. If soybeans are planted after a cover, silage, or hay crop of small grain, then the entry will be considered full- season. If field has been irrigated one or more times, the entry will be considered an irrigated field and the will be placed into the irrigated contest. Yield alone (bushels/acre) determines the winners in the first three categories.
Notice of intent to participate must be submitted to your county/city Extension Agent’s office 5 days before harvest or in an acceptable time frame for your Extension Agent. Extension Agents shall maintain the original set of record sheets and applications of all participants and send a copy to Dr. David L. Holshouser, Extension Agronomist, Tidewater Agricultural Research and Extension Center, 6321 Holland Rd, Suffolk, VA 23437 by Dec. 31.
Application forms and a complete set of rules and regulations can be found on the Soybean Yield Contest website.

Early Harvest Reports – Soybean Seed Quality is Not Good

David Holshouser, Soybean Agronomist & Hillary Mehl, Plant Pathologist

We appreciated the rainfall this year.  It should lead to some very good yields in many parts of Virginia.  However, the same weather conditions for high yields has led to some of the worst seed quality that we’ve ever experienced.  This is in addition to the pod splitting and seed sprouting that we began observing last month.

We began seeing extremely poor seed quality in our May-planter maturity group (MG) 3 soybean in our Orange variety test last week.  The early MG 4 soybean did not look much better, but they were not yet mature.

The photo on the left is the worst that has been called to my attention.  These are April–planted early MG 3 soybean from Madison County.  To use the farmer’s words, “A real kick in the stomach.”  Soybean in this shape are pretty much a total loss.  It is especially hard when the yield potential was outstanding.

Below are photos from Westmoreland and Dinwiddie counties showing similar results.  We are not seeing the same problems in our May-planted MG 4 soybean in Suffolk, but are seeing quite a bit of purple seed stain in some varieties.

So, what caused this?  From these photos, we are seeing signs of several diseases, including Phomosis/Diaporthe, Cercospora, and anthracnose just to name a few.  However, we have not yet confirmed the diseases – samples are on the way to the Tidewater AREC’s disease lab.

But that is just the possible diseases.  What caused the disease to be so bad?

I think that we can blame it largely on excessive rainfall (and many rainfall events) and a very warm September.  Most of the seed diseases come on strong during maturation; hence, our early MG soybean, especially those planted in April and early-May experienced those conditions.

Below is a weather summary from the month of September in Orange County, showing 2018 and long term average temperatures and accumulated precipitation.  Notice the high rainfall, especially during the latter part of the Month, when our MG 3 and early-4 soybean were maturing.  Secondly, notice the temperatures during that same time period.  This set up nearly perfect conditions for many seed diseases to form.

  

What can we do about it?  Unfortunately, we cannot control the weather.  And what we have done this year cannot be undone.  But, here are a few pointers for that may help this and in future years.

  • Harvest as soon as possible after soybean are mature. The diseases will only continue to grow and develop.  If you have drying capability, harvest at a little higher moisture and dry it down to 13%.
  • Plant varieties best adapted to your farm(s). While you have discovered (and heard me – David – say) that early-planted early-maturing varieties have very good yield potential if we have a cool and wet July and early-August (not the normal), there is always the risk of poor seed quality.  Only if September is cooler than average and rainfall is not excessive will this system give us good quality seed.  Year in and year out, May-planted late-MG 4 and MG 5 soybean are our best overall choice.  Also, it is rare that double-crop soybean have poor seed quality.
  • Select disease resistant varieties. Most companies do not list resistance to many of our seed diseases, but we have seen differences in varieties.  Look over our final soybean variety test results for more information on seed quality scores and purple seed stain ratings.
  • Select disease-free varieties. Next year, notice your seed quality.  While most companies will not bag disease-ridden seed, some could sneak through.  Seed treatments may be in order.
  • Minimize insect damage to pods. Though not necessary for infection, insect damaged pods are more likely to be colonized by fungal pathogens.
  • What about foliar fungicides? We have not found that foliar fungicides can overcome warm and wet conditions during seed maturation, especially when applied to the R3 stage.  Will a later application help?  That is hard to say. In some cases, applying a fungicide at R5 will improve seed quality, but this is not a sure thing and a yield is unlikely to be improved with later applications.

Soybean Sprouting in the Pods/Pod Splitting

We are seeing immature soybean once again sprouting in the pods in Suffolk and Gloucester County, and I heard of this happening in other states.  This seems to occur every 3-6 years somewhere.  Although I don’t have a great explanation for why this occurs, it usually happens when there are good growing conditions early followed by 2-4 weeks of drought stress during pod formation, and then excellent conditions return for seed fill.  Typically, it happens in big-canopied soybean (lots of leaf area) with lots of yield potential, but not enough pods (or big enough pods) to fulfill that potential.  I think that the seeds enlarge so much that the pod splits.

Keep in mind that I’m talking about immature seeds and pods.  This can also occur after the crop matures (R7 to R8) when we get excessive rainfall after the seed in question has dried down.  But, I have not seen that yet this year.

There is little that you can do about it.  Those sprouted seed will usually dry up on the plant and be blown out the back of the combine.

Although there has to be some yield loss, I’ve not seen it to be very great.  And, I suspect that if you did not notice the sprouted seed, you probably would not know that you had a loss.

For more information, see previous blogs on this subject.

Wet Conditions May Lead to Soybean Seed Sprouting

The Good and Bad of a Wet September

Calibrate your yield monitor – a checklist

While this post is likely too late for corn, it does apply to other crops.  If you have yet harvested all of your corn, it’s never too late to calibrate your yield monitor.

First, I am no expert in calibrating yield monitors.  My experience with the process only involves showing up to the farm with an accurate weigh wagon (or we use their grain cart), riding with the combine operator as he harvests a known area of the field, weighing the load and obtaining a moisture from the load (with a calibrated moisture tester), then watch him do the calibration.

Still, I understand the need for calibration although it takes time and may mean looking in the manual to learn or refresh one’s memory on the process.

John Barker, Knox County Extension Educator (Ohio State Extension) wrote an excellent article, “It’s almost that time of year … Don’t forget to calibrate your yield monitor!”, which is a step-by-step checklist of how to do this.  I highly encourage all to read it.

We do have several weigh wagons located around the state that Virginia Cooperative Extension uses for our on-farm research.  If you want me or one of your County Agents to help with this process, let us know.

Finishing Out the Soybean Crop – What do we need for Good Yields?

In general, we’ve had a good, but not great year for soybean in Virginia.  Although many areas were hit with a 3 to 4 week dry spell during July, August rains kept us in the game.  However, we did not see the ample  rains or cool temperatures that we experienced in August of 2017, which resulting in record yields.  Below is a summary of August rainfall and temperature anomalies for the U.S.

 

 

 

 

 

 

 

 

As you’ll notice,  we had about average or slightly below average precipitation and average to slightly above average temperatures for most of Virginia’s soybean growing areas.

So, I do not suspect that our yields will be as good as last year.  Still, our earlier-maturing varieties planted in April or May should yield quite respectably considering that most have made over 50% of their yield – they have reached the R6 stage (see photo below).  Yield of our later-maturing varieties, planted in May and early June, and our double-crop plantings are not quite there yet – much of our yield is yet to be determined – R5 soybean have only made roughly 25% of their yield at that time.

So, what do we need for good yields?  Rain is obvious.  Full-canopied plants with adequate soil moisture will draw about 0.25 inches of water/day from the soil.  But, we also need cool temperatures – soybean do not generally like 90+ degree days, especially when forming seed.

Below is the 10 day rainfall and temperature forecast for the U.S., and it does not necessarily look good for us.  Note that the rainfall is predicted accumulation and the temperature map shows anomaly.  Although we should get some rain this weekend only (more in northern parts), temperatures are supposed to be above average.  But, forecasts are only forecasts.  The weather does change.  I hope we will get the needed rainfall that they are predicting this weekend.  But a big ridge appears to be setting up over the Mid-Atlantic states for next week.  This usually means warm weather and only at the edges of ridges do we normally see rainfall – note the heavy rainfall predicted from Nebraska through Michigan.

 

 

 

 

 

 

I don’t mean to discourage, just to inform.  We still have decent soil moisture, at least in the subsoil.  With rain this weekend, we should get through next week without too much harm to the crop.

Our double-crop soybean (assuming late maturity group 4’s and group 5’s planted in late June to July) are just now in the R5 stage – it usually takes 80 to 100 days from planting to reach R6, depending on maturity and planting date.  So some timely September rains will usually result in good double-crop soybean.

When will our yield be “made”?  Below is table showing the number of days to soybean physiological maturity (R7; 95% of yield has made).  When can we expect to be harvesting our soybean?  Full maturity is reached about 2 weeks after R7 and harvest can proceed after the soybean have dried down to a harvestable moisture, usually within a week after R8.