Tag Archives: maturity group

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.

Good Soybean Yields in Virginia for 2017

It was a challenging harvest season, but we harvested our last plot today.  Yields were very good, ranging from the upper 40’s to upper 70’s.  Across all maturity groups in our variety tests, full-season yields averaged 63.3 bushels/acre and double-crop averaged 60.0 bushels/acre.

Virginia soybean are now predicted to average 45 bushels/acre, a new state record.  We are just shy of the predicted national average.  Over the last 20 years, we have been increasing yields at a rate of 0.6 bushels/acre per year.  This is quite a feat!  While better genetics are part of this increase, I think that most of the increase is coming from better overall management of the crop.  This management includes long term (e.g., better soil quality, etc.) and short term (e.g., timely planting, etc.). 

Of course, we cannot forget the weather.  It was relatively cool during the critical pod and seed development stages.  More importantly, rain came at the right time.

2017 Virginia Soybean Variety Results

Below are some preliminary results to our soybean variety tests.  I caution you that these are preliminary – some changes could still be made.  But, I feel pretty good about the data presented here.  Some double-crop data from Orange and Painter is still outstanding due to variability.  We will be trying to determine its cause and have those data available ASAP.

What’s the Best Soybean Maturity Group for your Farm

Yields are coming in from our variety tests – yields are good, not great, but good, ranging from the upper 40’s to low 70’s.  I hope to get a summary of the maturity group (MG) 3 and 4 tests out soon.  Be looking for them.

In the meantime, a questions that continues to arise if “What is the best maturity group for my farm?”  Or “What’s the best maturity group for my field?”  This is a very valid question.  Some years MG 4’s will shine and other years the MG 5’s are best.  Occasionally, MG 3 or 6 look good (the 6’s have been performing very well lately – as long as the frost holds off until mid-Nov!

An attempt was recently made (and published) to redrawn the MG lines in the U.S (Mourtzinis and Conley, 2017) – see the map to the upper right.  The researchers used variety test data from nearly all states to come up with the map shown.  While this map is more-or-less accurate when looking at the U.S. as a whole, it is not when you look closer (i.e., at individual states).

To better answer your questions regarding MG’s in Virginia, we took 10 years of our variety test data (around 15,000 plots) and began evaluating the probability of:

  1. a relative maturity (RM) yielding at least as high as the other RM’s tested at that location
  2. a RM yielding significantly higher than the other RM’s tested at that location.

Results are shown in the following graphs. Note that we split the results into full-season and double-crop soybean.  We have also divided each MG into early-, mid-, and late-RM’s.  The total bar height answers question 1 – the probability that the RM does at least as well at the others.  For instance, as expected, there is an 80 to 100% probability that MG 5’s will yield at least as much as other relative maturities in Blackstone (Southern Piedmont, droughty clay soils).

The hatched part of the bars answer question 2 – the probability that the RM yields significantly more that the other RM’s.  Using the Blackstone example, the 5’s yield significantly more than other MG’s 30 to 60% of the time.

Of course the “devil is in the details”.  There are soil properties and environmental conditions that control which RM is best in a given year.  If interested, contact me; I’ll give you my preliminary thoughts on that.  Rainfall is definitely the biggest influence – not how much we receive but when it falls; but that is random in Virginia.  There are other issues.

 

To summarize:

  • MG 3’s and 4’s are best suited for the most northern and western location (Orange).
  • MG 5’s perform best in our most southerly locations (Blackstone and Suffolk).  But, the late 4’s can make a strong showing in some years, especially at Suffolk (I think I know why; its not just when the rain fell. Contact me.)
  • Both MG 4’s and 5’s perform well at Warsaw (we can’t explain the full-season late-4 results, yet).  Note that yield potential of the later 5’s decline with double-crop plantings at this northerly, but Coastal Plain site (probably frost damage).
  • All MG 4’s (early, mid, and late) perform best when planted in May at our Eastern Shore location (Painter).  There are curious things happening here (while not that far south, its our most easterly and probably the most consistently favorable environment for growing soybean).  Note that early- and mid-4’s are no better than 5’s when planted double-crop.

1st Attempt at a Relative Maturity Map in Virginia

I’ve made an attempt at drawing a Virginia map.  But do not read too much into this!  This is based only on 5 locations (although 10 site-years and thousands of plots at each location) and the “devils in the detail”.  An I did not use GIS to draw this map (the lines are not 100% accurately located).

Do not assume that I want you to plant only these RM in these areas, only that these tend to do best in most years.

How do you use these data?  Make most of your chosen varieties fit these results.  However, allocate a smaller acreage to those RM’s that can occasionally break records.

On a closing note, these data also indicate that early RM’s do better on our best, most productive land.  But, that’s a topic for next week.

Greater Yields are Possible for Double-Crop Soybean in 2017!

It appears that wheat harvest will be 1 to 2 weeks ahead of schedule this year.  We actually harvested some high-moisture wheat and planted soybean plots behind it today (May 31) in northeast N.C.  This is good news for soybean.  Earlier planting means greater yields!  This is clearly shown by the recent data obtained from our multi-state, multi-year double-crop project.

With earlier planting, have my recommendations for double-crop soybean changed?  In general no.  But below are a few things to consider.

Seeding Rate:  In general, you can probably back off on your seeding rates from what you were planning if you get your double-crop soybean in by mid-June.  I’d suggest that you start out with 120-160,000 seed/acre (depending on when you start planting) and gradually ramp that up by 20-30,000 for each week delay in planting.  For more information, see my recent blog, Soybean Seeding Rates for June and Later.

Relative Maturity:  Actually, my standard recommendation still stands, more or less.  Plant as late of a relative maturity (RM) as possible that will mature before the frost.  However, there are now some caveats.   By planting a week earlier, you’ll gain about 3 days in maturity.  Although a slightly later RM may work, I wouldn’t count on it – frost date will affect this more than planting date.  So, don’t plant a later RM.

But, can you plant an earlier RM, say go from an early-5 to a late-4?  Possibly.  Why do I say this?  Two things.  First, by planting a week or two earlier you have greater yield potential (see the above graph), which is due to the ability to grow more leaves.  So your yields are not necessarily so dependent on leaf area as they are with a late-June to early-July planting.  A slightly earlier RM planting in early- to mid-June will only have slightly less leaf area than a later RM.  And, we have generally found that under greater yield potentials, early RM will yield more than later ones.  Still, these are not great reasons to change your RM.  Generally, stick with what you planned.