Terminating Alfalfa

I have been working on reducing tillage and eliminate most chemical usage on my farm.

I need to terminate 5 acers of alfalfa this fall or spring to plant corn.  The alfalfa is on it's 7th year and has thinned out.  I drilled cover crops into it a few times this year to increase over all yields.

The best that can come up with is to harvest the feild in the next 2 weeks, sweep plow at about 3", plant a 5 way cover crop that will winter kill, in the spring run the crimper roller, and then use my no till drill.  I plan on putting down lime this fall to soil test and 3 tons of compost per acer after I seed but before the corn starts to grow.

Dose anyone have a better idea on how to terminate 5 acers of alfalfa or am I missing something?

Welcome to Permies, Bob.

Phew, that's a tough one! It's been a long while, but growing up I recall many hours on a full size tractor with a deep plow, converting alfalfa fields to grain production as part of a crop rotation in less than stellar soil.

I believe it's necessary to go pretty deep to cut off the roots; otherwise the alfalfa just comes back. It's mighty hardy stuff.

I honestly don't know how to combine this with a no till philosophy, on a 5 acre scale. The only sites I see advocate a "chemical" route, which is sort of off limits in the discussions on this site.

From my perspective, I don't think deep plowing, every 5-7 years, would necessarily destroy the soil structures that no till methods seek to preserve. My 2c.

I'm thinking of a sweep plow and only setting it to 2 to 3".  Think of it more like metal blades that you run parallel to the ground a few inches below the surface cutting everything.  From what I have read it should terminate most of the alfalfa.

As of right now I'm planning on growing sweet corn and stagger the planting.  If the buyer pulls before spring and I'm not able to find a new buyer than I will most likely plant a pasture mix.

I have harvested 10 acers of corn silage with a 2 row pull behind chopper before.  I like alfalfa silage better than corn silage for my farm at this time.  

Bob Glass wrote:I'm thinking of a sweep plow and only setting it to 2 to 3".  Think of it more like metal blades that you run parallel to the ground a few inches below the surface cutting everything.  From what I have read it should terminate most of the alfalfa.

That's an interesting approach. I haven't used a sweep plow -- sounds like a useful tool. What is your soil and subsoil? My instinct is "the deeper the better" but that's your call based on local conditions. It sounds like the sweep plow won't really mix soil layers, which fits your approach.

I hope you'll post your results come spring. It will be helpful to many here.

Our soil is 5 to 7" loamy with red clay.  I know at some point I will want to mix a bit of clay back into the loam, but that might be years down the road.  With long alfalfa stands you get huge deep root systems and if well taken care of long term soil moisture will be the big issue even with irrigation.  

Sounds challenging! You've done a ton of homework to manage this transition in your soil. Please keep us in the loop!

I was thinking about converting my small front lawn into alfalfa to help feed my 2 goats alfalfa over winter.  My brother says it's impossible to get rid of alfalfa especially since I don't have a plow but I was thinking it could all be covered with cardboard and bark if I ever wanted something different.

I think a sharp shovel, matched with persistence, would control alfalfa just fine. My 2c.

For those with only garden scale background, a sweep plow functions like a stirrup or scuffle hoe.

Growing up, terminating alfalfa was the only time we still used a moldboard plow. Our neighbor did it like you described, he didn’t get 100% kill but close enough. He had to have a lot of overlap on the sweeps and coulters set deep so the shanks didn’t plug.  We simply didn’t have a big enough tractor to pull sweeps through that kind of root mass.

I just want to add in here that there are so many NRCS/Extension/USDA etc grants for going no-till and other new practices. If you're switching over, don't leave the money on the table. Make sure you do the paperwork prior to changing your practices

Many farmers love the no till concept but also admit that there are times one or two tillings per year is best for your soil.  Taking the alfalfa above ground for silage might make your effort to change.crops profitable, and turning those massive alfalfa roots into tilth by a plow would help your field retain water.

I do not care about 100% kill as I'm not a grain or vegetable farmer.  We just raise pigs, chickens, and most years we will plant 5 acers of sweet corn for someone else to market.  Most years we will sell the last cutting of hay.

I do feel that soil disturbance if done correctly with the right follow up can be beneficial.  In the last 5 year I have found that going no till has cut back on fuel and time so far.

I try to work full time my glass shop most of the year.  Wife and kids do most of the farm work unless it is feild work or a large project.  

This is a very helpful conversation to me. I'm trying to establish some small (mostly about 10'X10') plots that I can rotate through small grain production and flax production. My main goal is to get the soil healthy after it was under plastic to kill off an "invasive" species. I have a couple of these plots that are very weedy. I originally prepared them by using a scythe to cut all vegetation off at ground level, added a bit of hand-weeding to eliminate as much crabgrass and blackberry as I could, then planted a cover cover crop of oats which winter-killed. After that I planted the whole lot to flax. I got a pretty good crop of flax that first year of desired harvest--that was 2022. I also planted rye that year and then followed the rye plot with flax in 2023 (this year). That plot had way too much weed pressure and though I did harvest some flax it was a lot less than ideal for flax production, even at my tiny level. I want to be able to plant either fall rye (with a legume and a mustard for companions) but I fear that the weeds have filled in too much. I'm curious about whether anybody is using cardboard to terminate vegetation, then planting without tilling and what results you've had. Perhaps I should start that as a thread, but it also seems like a relevant question here.

First of all, do you really need to terminate the alfalfa? If it's starting to thin out then it's already making way for other plants to take over. I also recall a study that looked into the prospect of no-tilling corn into an alfalfa field and there was only a 15% or so loss of yield for the corn, but the overall yield of biomass was much greater than a sole corn or alfalfa field. I think it makes an excellent companion crop if it's not too dense of a stand, since it will fix nitrogen and pull water and nutrients from deep in the soil. A vigorous variety of corn should grow over it with ease so long as it has been mowed/grazed a couple times right before sowing. And a cover crop as you planned would also help to suppress it.

If you are really determined to terminate it however, I think your plan sounds pretty good. I haven't heard of a sweep plow but from what I can tell it just cuts through roots without inverting the soil? That is certainly preferable to a moldboard plow, which may do a better job of severing roots but will wreak havoc in your soil.  The sweep plow might even be better than discing, but still bear in mind that any extensive tillage below the top couple inches of soil will cause considerable damage that takes time to heal.

Nate's on to something. Maybe you could leave the alfalfa and let it go away gradually but still performs useful services like fixing nitrogen, loosening the soil deep down, and pumping exudates into the root zone to feed bacteria and fungi. New plantings of corn would benefit from all of these things and overtop the remaining alfalfa rapidly, shading it out and finishing the job.

I did a few fast google searches and found.
Where alfalfa and corn gets planted at the same time.  The alfalfa competed on the corn and took a small loss on the corn, but you had a great stand of alfalfa for the fall.
I also saw where they would do the first harvest of the alfalfa, spray the alfalfa, and then plant corn.  I did not see anywhere it was talked about where chemicals were not used.  I also feel that the spring alfalfa would suck up a lot of water that the corn would not be able to use.  With wanting to plant sweet corn I would want to get planting as soon as posable in the spring.

I still need to do more reading and thinking on not terminating the alfalfa.  

What about direct sowing the corn and crimping the alfalfa with a roller? You wouldn't kill it all outright, but you'd knock it back pretty hard and it wouldn't be transpiring a lot of water as the corn got established.

Bob Glass wrote:I did a few fast google searches and found.
Where alfalfa and corn gets planted at the same time.  The alfalfa competed on the corn and took a small loss on the corn, but you had a great stand of alfalfa for the fall.
I also saw where they would do the first harvest of the alfalfa, spray the alfalfa, and then plant corn.  I did not see anywhere it was talked about where chemicals were not used.  I also feel that the spring alfalfa would suck up a lot of water that the corn would not be able to use.  With wanting to plant sweet corn I would want to get planting as soon as posable in the spring.

I still need to do more reading and thinking on not terminating the alfalfa.  

I can't for the life of me find the study I referenced but I'm quite certain it was on an already established stand of alfalfa. Of course first year alfalfa will perform differently to an old stand. I reckon that the former would be more competitive for water and nutrients because it hasn't yet developed much of a taproot. From what I've observed, established alfalfa seems to be harmonious; but admittedly I'm used to diverse pastures not so much row crops.

In any case, I think if you were to soon mow it and then sow a cover crop - preferably with cereal rye, even hairy vetch if you really want to smother it - it should suppress the alfalfa well and deprive it of the energy it needs to take off in spring, it may even partially winterkill. Then perhaps another mowing in the spring and/or crimping as Phil said. Then if it's still kicking somehow you can resort to the sweep plow or herbicide.

Hmm... this is an interesting read as I'm looking into cover crops to try to start growing in our field.  I've seen alfalfa recommended quite a few different places as a cover crop, but if it's that hard to get rid of without chemicals then I probably don't want to get it started on our land right now.

I did find a study on planting corn into an alfalfa feild.  It looks like it would work for dent corn, but not sure of early sweet corn.

Alfalfa will terminate by cutting it below the surface of the soil, but timing is key like with terminating a lot of cover crop.  From what I have read it dose not crimp well.  Alfalfa has a lot of long term benefits from alfalfa.

I have decided that I'm going to get cut, bailed, and sold in the next few weeks.

Indeed alfalfa, like any perennial, will not terminate by crimping; that was directed towards any annual cover crop species you may sow. But crimping a cover crop will do a good job of creating a thick mulch which will suppress alfalfa or any weeds. It would also maintain much needed moisture for quick germination of the corn. The ideal would be a front-mounted roller-crimper with a no-till drill coming behind. This would give the corn perhaps the best chance to quickly establish ahead of the alfalfa. Plus you could do it all in one pass. But that's assuming you have access to such a crimper and that the cover crop is in vegetative stage ny then. It's certainly a risk but has immense soil benefits when it comes together. Regardless of what you do, let us know how it goes.

John Warren wrote:Hmm... this is an interesting read as I'm looking into cover crops to try to start growing in our field.  I've seen alfalfa recommended quite a few different places as a cover crop, but if it's that hard to get rid of without chemicals then I probably don't want to get it started on our land right now.

Alfalfa, when not grown as a monoculture, is more of a companion crop than a cover crop, since the cover it provides is over a span of years rather than months. If you want to do cover crops I recommend going to Green Cover Seed's website and using the SmartMix tool (not necessarily endorsing to buy from them, it's just a good resource for selecting the right cover crop mix).

I have been growing a garden in an original alfalfa field, couple of observations/comments:

I tilled part of the field 6 inches prior to planting corn/potatoes/tomatoes:
- corn and tomatoes did ok, potatoes did not
- alfalfa grew back and the next year looked the same as the non-tilled area

I put black fabric down in the fall, pulled it up in May, that killed the alfalfa, didn't come back

Planting sun chokes in the alfalfa field in the fall, without any tilling or other work, leads to the sun chokes eventually outcompeting the alfalfa (the energy stored in the roots gives it the power to eventually grow above the alfalfa, whereas the plants would have given up)

M

I planted a meadow in my back yard instead of part of my lawn.  I think the seed mixture I used had a few plants of alphalfa and I think I am going to wet it really good and pull that crap out by the roots.  It seems like I have to dig around it a bit first to loosen the to and then it does indeed seem to have like a 3 foot root.  I would NOT plant aflalfa in your front yard or any part of your yard for goats.  There has to be something better.  The roots are no kidding 3 feet long.