# Burning down old alfalfa, time to replant?



## Hugh (Sep 23, 2013)

I want to burn down an old alfalfa stand in the next week or so using round-up. I plan to plow under the alfalfa (mold-board plow) after it has browned-out from the spray. If I do this by Oct 15, would it be safe to replant round-up ready alfalfa next June? any experience with this? thanks much,

Hugh


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## swmnhay (Jun 13, 2008)

Probably not.

If you did a annual hay crop and seed in fall that would be ok.

Or Winter wheat now??

Depends what your crop options are where you are at.


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## rjmoses (Apr 4, 2010)

You might have a problem with auto-toxicity. The alfalfa plant can have a very deep tap-root (up to 50' deep) and burning down with round-up at this time of year may not get all the roots. Also, the chemical that causes auto-toxicity may or may not decompose in your environment in time for replanting.

Here's an article that might help you decide:

http://www.uwex.edu/ces/crops/uwforage/AlfalfaTox-FOF.htm

Ralph


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## Hugh (Sep 23, 2013)

I found some local info and it recommends planting hay barley in the spring (after the fall spray and kill) and then seeding the alfalfa in the fall.


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## mlappin (Jun 25, 2009)

Really no need for the RU if your plowing.

We use a quart of RU and a half quart of 2-4d along with synergy and a mix of (5%) 28%N and 95% water as a carrier when doing burn down.


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## endrow (Dec 15, 2011)

mlappin said:


> Really no need for the RU if your plowing.
> 
> We use a quart of RU and a half quart of 2-4d along with synergy and a mix of (5%) 28%N and 95% water as a carrier when doing burn down.


OR You could say no need for plowing if you are spraying


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## Lostin55 (Sep 21, 2013)

Several folks have mentioned great ideas. You didn't say what your elevation was and if it is irrigated ground or not. Around here, just south and east of you, when fall planting it is common practice to have the second trifoliate showing going into winter. That puts the timing at about mid to late August for a fall planting. As for a spring planting, mine was seeded in April just before the irrigation water was turned into the canal system and just after the frost came out.

As to the spraying/ not spraying equation, it is very difficult to get a new stand growing in an old stand without being choked out. On the other hand, alfalfa likes tighter ground which would preclude plowing.

It just boils down to what your schedule allows and what options fit your budget. I have sprayed and then plowed on several occasions.It works for my program.


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## mlappin (Jun 25, 2009)

endrow said:


> OR You could say no need for plowing if you are spraying


I was working on the theory that if it is a old stand, then it might be getting rough anyways. While a plow isn't my favorite tillage tool at all, most likely something needs done to smooth it back out. I prefer to use a chisel plow followed up with a field cultivator then a cultimulcher.


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## Lostin55 (Sep 21, 2013)

What I wouldn't give for smooth ground....... What we do here is plow, disk X2, roller harrow X 2, level X 2, air seed with fertilizer, roller harrow again with no teeth to promote good seed to ground contact, then Corrugate 4" corrugations 30" apart through the entire thing for irrigating from the ditch. Smooth it isn't. Honestly, I would not know a cultivator or cultimulcher if I saw one. Not by that name anyway.

The reason I finally signed up rather than lurking like I have been for a while now is because I have learned a pile about how things are done elsewhere, and little things that might work for me.


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## Hugh (Sep 23, 2013)

The info I have says that the autotoxic chemical produced by alfalfa (medicarpin) is mostly in the leaves and the upper portion of the soil, thus my reason to plow and flip the whole mess under. I'm also thinking rain, snow melt, and irrigation will move the medicarpin downwards past the new roots as the new seedlings grow, and the soil microbe activity will help decompose the toxin. We are at 3000 feet and have sprinkler irrigation. Everything is always more complicated than I expect it to be.


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## mlappin (Jun 25, 2009)

I tried a single rotation of beans once, sprayed in the fall killed it all off, no-tilled beans in the spring followed by alfalfa the next spring, while it eventually all came in seemed like it had a mighty slow start, could have been the spring as well as I don't have anything to compare it to that year as it was the only field of hay I planted.

Normally we burn down in the fall, hit it again in the spring for any leftover green then no-till to corn, followed by no-till beans then back to alfalfa.


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## Hugh (Sep 23, 2013)

mlappin, how was the alfalfa yield on the beans to alfalfa situation?


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## mlappin (Jun 25, 2009)

Just depends on the year. I much prefer to do fall plantings actually.


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## rjmoses (Apr 4, 2010)

mlappin said:


> Normally we burn down in the fall, hit it again in the spring for any leftover green then no-till to corn, followed by no-till beans then back to alfalfa.


I prefer corn-->beans--wheat--->fall planting of orchardgrass/alfalfa. RR row crops help get rid of the weed seed bank. Wheat as last crop gives me time to do an Aug 15th- Sept 1st planting.

Ralph


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## rrg (Dec 1, 2011)

I have been considering starting over our alfalfa field as well. Sprayed it last saturday with a healthy dose of 24d. The seed "experts" here told me that it needs to go though 2 winters (freezes) in order to safely get rid of the autotoxicity.

I'm planning on using an annual rye grass (unless we can come up with something better) next year that way we still have enough hay for the cows. Then replanting alfalfa in 2015.

Good luck with what ever you decide to do.

Ryan


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## Hugh (Sep 23, 2013)

I think I've decided to burn it down with round-up now, plow it all under in ten days or two weeks, plant hay barley or grass in the spring, and plant the alfalfa seed in the late summer next year. This gives me another few months to think it over. Thanks everyone for the input...

Hugh


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