The Question of Keeping Soybeans Green Late Season

[FarmerDan]

It might just be because I wonder, too. One of the most asked questions is how to keep soybeans green late into the season. And, while there are some logical answers, like plant forage 'beans or just plant 'beans a month before you want them to be 'attractive,' I wonder if planting a full season (or short?) from a maturity group intended for a zone much further south (or, is it north?) of me would be of any value?

My wife says I'm a complicated guy, but I can't work my way thru this one. Without getting into everything I think I need to get, I'm in Group IV. Naturally, we go buy our seed and what's available are varieties best suited for yield, Group IV beans.

As I understand it, there are two main factors pushing soybean development - temperature and photoperiod (length of day). Forget temperature for a moment.

The decreasing day length is what triggers flowering. I don't know if this is correct for short, medium, and long season beans, but I'll say (sorta' correctly) 'bean vegetative growth continues for 30-40 days after flowering begins. When vegetative growth stops so does the attractiveness of soybeans as forage for deer.

Back to the soybean groups. For ag production, as I mentioned above, I'm in group IV. For my latitude here are some "photoperiod" (length of day) facts -

On June 30 in central VA we have 14.28 hours of daylight. A month later we are down to 13.87 and a month after that 12.98. I'd propose it's the rate of change in the amount of daylight that triggers flowering and determines the end of vegetative growth -- but I don't know. In July the average daily decrease in daylight is about half a minute a day. In August it's about a minute a day and in September it jumps up to a - minute-and-a-half.

To find the same rate of change later in the growing season south is the direction to look. For me, if I'm right (probably not as it's always more complicated) planting a full season group V or VI in my group IV zone later than would be common for ag production would maximize forage production (at the expense of 'bean production?)

I don't know. i'm sure there are lots of details I'm missing and my assumptions could be all wet. For obvious reasons, all the research is aimed at 'bean yields and not forage yields!

Is there any merit to this?

 

[S.T.Fanatic]

Learn something new everyday. I just figured it had to do with "how many day beans" you buy and when you plant them. Never knew photo period had anything to do with it. Guess the question I have then is why dont the beans turn at the same time? Some stay green much longer even when planted in the same area and not talking forage beans?

 

[yoderjac]

Dan,

I tried it several ways. My first attempt was to mix ag beans and Eagle beans. My hope there was to have some green attractive beans during our Oct archery season but still have the ag beans yellow so I could broadcast a cover crop. So, that is an example of a typical maturity group for VA mixed with the indeterminate Eagle beans. The problem with that approach was that the Eagle beans were so much more aggressive from a vegetative standpoint that by fall there was nothing but eagle beans growing. The ag bean were shaded out when young. I ended up bushhoging strips through the Eagle beans to surface broadcast my cover crop. That worked out pretty well. It was hard to bushhog all those great looking beans after all the work to establish them, but it actually creates more deer food. My deer don't just randomly walk through tall beans browsing them. The generally browse edges. The lanes created more edges and sure enough I actually got more browsing. So, if using both Eagle beans and Ag beans, I'd advise doing a portion of the field in each rather than mixing. That would have not achieved my objective but would provide both green attraction for early season and pods for late for folks up north.

In the last few years our deer numbers are down. I've been able to plant ag beans. Last year, I tried mixing an early ag bean variety with the normal maturity group for my area. My hope here was for early yellowing of a portion of the field to allow an earlier broadcast of the cover crop. There were no issues of competition, but I did not get the desired results. The field pretty much yellowed at the same time. I'm not sure why, but it was not worth the effort for me.

Thanks,

Jack

 

[FarmerDan]

Guess the question I have then is why dont the beans turn at the same time? Some stay green much longer even when planted in the same area and not talking forage beans?

I don't know. There are a lot of moving parts. You have all these groups and then there are maturity ranges within the group and somehow all of that ends up being long season, mid-season, and short season soybeans. My weak understanding is the difference is the time (number of days) of vegetative growth before flowering. A long season 'bean might require 60 days of vegetative growth before flowering IF the photoperiod is 'right" A short season 'beans might be in the vegetative stage only 30-days before flowering, given the right daylight situation. But, my understanding may be way off. When you grow ag beans for yield you just pick from your group and look at the chart for season length. Not much thinking to it.

 

[yoderjac]

Learn something new everyday. I just figured it had to do with "how many day beans" you buy and when you plant them. Never knew photo period had anything to do with it. Guess the question I have then is why dont the beans turn at the same time? Some stay green much longer even when planted in the same area and not talking forage beans?

All plants have a level of genetic variety of characteristics. This protects the species against calamity from some condition that wipes them all out. Some will have a genetic disposition that allows them to resist the adversity be it weather, disease, predator, or something else. Most of the crops we grow today have been selected for desirable characteristics and cross bread and re-selected over many generations. Soybeans are no exception. We have many strains of soybeans that have been bread to meet the needs of farmers. Maturity group is simply one of these characteristics.

Thanks,

Jack

 

[S.T.Fanatic]

So in all reality if one wants to broadcast covers into standing beans and only use the beans as a summer and late season attractant we should be planting the earliest maturing beans we can get our hands on. My cover crops that were broadcast into standing beans last September didn't do much of anything last fall because there was to much shade. I I would have planted an early maturing variety I'm guessing i would have had much better germination of my covers. Going to have to look into this in the future.

The one nice thing with the MDHA beans is that it is a mixture of several varieties of beans. Some turn early some stay green for quite a while. I guess I'd rather have them turn early and key in on the newly growing covers and leave the beans alone until it turns cold.

 

[FarmerDan]

So in all reality if one wants to broadcast covers into standing beans and only use the beans as a summer and late season attractant we should be planting the earliest maturing beans we can get our hands on. My cover crops that were broadcast into standing beans last September didn't do much of anything last fall because there was to much shade. I I would have planted an early maturing variety I'm guessing i would have had much better germination of my covers. Going to have to look into this in the future.

The one nice thing with the MDHA beans is that it is a mixture of several varieties of beans. Some turn early some stay green for quite a while. I guess I'd rather have them turn early and key in on the newly growing covers and leave the beans alone until it turns cold.

I think this is the debate I'm having, at least with myself. Yoder, in a sample of one (see above) planted short-season and 'normal' season beans all mixed together. They all turned yellow at the same time.

If you tried that with 100 different varieties, you might find some that do exactly what you want. Assuming all are planted at the same time, some stay green a long time. Some yellow quickly. And I think this assume seeds intended for the same group zone.

But, what happens if you go outside the intended zone?

I'm not sure we will ever know the answer to the question. Researchers plant short-season, medium-season, and long-season 'beans side by side. What are they interested in? Soybean yield. The factors we are most interested in are there, but of no commercial value. So, they don't get published. I guess that's true. But, I'll keep looking....

 

[Mortenson]

Sometime look at a soybean field at the edge of town that's mature and ready to harvest. Then look at the plants right under the street light. They'll be green and growing.

 

[Plottin'booners]

In Wisconsin I have good luck splitting the planter but not mixing the seed with 1.8 and 3.0 soybeans. Seems to give me about 2 weeks of a difference. The trick is to plant as long of day and still get them to change before they get frosted if you still want pod fill. I don't know how that would work in the South with your short days but really late frost date.

 

[FarmerDan]

In Wisconsin I have good luck splitting the planter but not mixing the seed with 1.8 and 3.0 soybeans. Seems to give me about 2 weeks of a difference. The trick is to plant as long of day and still get them to change before they get frosted if you still want pod fill. I don't know how that would work in the South with your short days but really late frost date.

I think maybe the missing piece for me is planting date. Tell me yours?

 

[Bill]

I'm thinking of planting some in August this year. I won't get any pods but maybe they will be green when everything else is yellow. .?? Not sure but I've wanted to try. I broadcasted beans, rye and radishes into my yellowing beans last September. Turned out only the rye really did anything.

 

[FarmerDan]

I'm gonna stick these here so I don't lose them. Back later to digest the findings.

"Planting late-maturing rather than early-maturing varieties at any time results in a longer vegetative period with the resulting effect of reproductive development occurring later in the growing season."
http://www.deltafarmpress.com/soybeans/soybean-maturity-group-planting-date-and-development-related

http://msue.anr.msu.edu/news/should_you_plant_earlier_maturing_soybean_varieties

 

[Plottin'booners]

I would always plant them early rather than late to get more growth. I would use the maturity range to keep them green. Soybeans are not like corn needing certain degree days until mature. They go on length of daylight. Shorter day varieties start filling pods sooner because if they don't they could freeze off in the north. I have started experimenting the other way planting shorter day beans like .8 maturity. I have plenty of greens for them to eat until it freezes so I want am going to try and get the leaves off by late August to early September to try and get more growth on brassicas broadcast into the soybeans early for our stress period in the winter. I am still learning alot about soybeans on my plots and in my fields but is definitely the most versatile plant you can use in my opinion. Food for the summer and winter.

 

[FarmerDan]

In Wisconsin I have good luck splitting the planter but not mixing the seed with 1.8 and 3.0 soybeans. Seems to give me about 2 weeks of a difference. The trick is to plant as long of day and still get them to change before they get frosted if you still want pod fill. I don't know how that would work in the South with your short days but really late frost date.

Thank you for this, sir! It's led to to a lot of interesting new information and thoughts. I don't know where you are in WI? I guess your 1.8 might give it away. A group 3 'bean -- or the zone -- runs across the top 20% of Illinois. From 1.8 to 3.0 is 200 - 250 miles different north to south. That makes a significant photoperiod difference.

 

[Plottin'booners]

Southwest corner of Wisconsin. For my AG soybeans I plant a little bit of 2.0 to combine 1st and usually plant the rest of my soybean acres to 2.4 or 2.5. A few people have tried some 2.7 but run the risk of early frost getting them. The year I tried 3.0 in the food plots we had a warm late fall so they still made good soybeans but I wouldn't risk it for the AG fields.

 

[homegrownbucks]

I have planted eagle beans in wi and they did stay green longer than the normal ag beans, when the frost hit the tops died but the lower leaves lived on for a while. We late plant beans as part of a fall attraction mix to reliably have green fall beans.

 

[FarmerDan]

Learn something new everyday. Guess the question I have then is why dont the beans turn at the same time? Some stay green much longer even when planted in the same area and not talking forage beans?

I've learned a lot about soybeans in he last four days. And, I've thought some about this question. My first answer is, nothing's perfect! Could it be slight differences in fertility / moisture? Probably not. What I learned is the are lots of other reasons other than photoperiod for why beans leaves turn yellow! Nitrogen deficiency. Iron chlorosis. Potassium defficiency. Spider mites. Soybean cyst nematodes. And the list goes on....

 

[FarmerDan]

So in all reality if one wants to broadcast covers into standing beans and only use the beans as a summer and late season attractant we should be planting the earliest maturing beans we can get our hands on. My cover crops that were broadcast into standing beans last September didn't do much of anything last fall because there was to much shade. I I would have planted an early maturing variety I'm guessing i would have had much better germination of my covers. Going to have to look into this in the future.

The one nice thing with the MDHA beans is that it is a mixture of several varieties of beans. Some turn early some stay green for quite a while. I guess I'd rather have them turn early and key in on the newly growing covers and leave the beans alone until it turns cold.

Don't know where you are (in MN?). If you planted Group 2 'beans, move up a group or two. Use a Group 1 or Group 0. I guess saying that is easy. Finding the seed, maybe not so much. And, hey, I'm just sharing what I learned this week. Take it for what it's worth!

 

[FarmerDan]

I found this chart and it sums up everything I need to know.....assuming the Stonville, MS tests translate to other areas. I have great confidence!

To make it simple, I should be buying Group IV beans to optimize yield.

But, I'm going to plant Group 3 beans where I want the leaves to drop early so I can over seed rye into the soybeans. Then, I'm going to plant a bag of Group 5 beans where I want them to stay green into October!

If the chart gives contains valid clues, then if I plant the group 3 beans June 1st, the leaves will be yellowing about September 9th and gone by the end of September.

The Group V beans, also planted on June 1st will be green until October 6th at which time the bean pods will be fully filled. Leaves will be off the plant by the end of October.

If you look at the chart, all the difference is the time the plant is in vegetative growth.

That's my theory and I'm going to try it....if I can find the right maturity (group) beans!

 

[Plottin'booners]

Your stressed beans will turn first. Hillsides, shallow soil, compacted soil. Also we if we get dry in August then get rain again in say early September and they aborted some pods they will stay green longer because they don't have pods to fill.