Question for the Soil Guys Here

[KSQ2]

We were not able to get the alfalfa in this spring with the rainfall — trust me, I’m NOT complaining! The soil is in good shape and shouldn’t need a tremendous amount of inputs when the alfalfa goes in this fall. The ground has been no-till ag ground for the last 12 years. We lightly worked the ground to prepare the bed this spring — I was emphatically told to make sure the ground is as level as possible for the sake of future haying. Here’s my question, what should I do with the ground this summer awaiting planting this fall? Right now it’s a conglomeration of forbs, Johnson grass and some other grasses. I’ve been told by some farming folks to work the ground all summer — I don’t want to do that. I’ve also been told to spray it as needed — I don’t really want to do that either. I want the ground to keep its good subsoil biology. Should I mow it to help keep the weeds at bay some and put the good stuff back into the ground? I’m not real worried about the Johnson grass, it will be dealt with — I’m planting RR alfalfa. I’m guessing we will be lightly working the ground again this fall, the rain probably eroded the field some and will need to be dealt with. But IF the ground is still relatively smooth/level, we will likely just terminate and no-till the alfalfa in. Help please!

 

[Mennoniteman]

I'd treat the "conglomeration of forbs, Johnson grass and some other grasses" as if it were a small grain growing for a fall planting, let it grow until 2 weeks before planting time then spray it dead. The more taller leafy growth a plant puts on, the bigger and deeper the root system grows for future OM. It will also be easier to work the ground in the fall if you don't mow, as mowing creates more sod than letting it grow taller. Save money on tillage and herbicide now and invest that $ in the fall.

 

[KSQ2]

I'd treat the "conglomeration of forbs, Johnson grass and some other grasses" as if it were a small grain growing for a fall planting, let it grow until 2 weeks before planting time then spray it dead. The more taller leafy growth a plant puts on, the bigger and deeper the root system grows for future OM. It will also be easier to work the ground in the fall if you don't mow, as mowing creates more sod than letting it grow taller. Save money on tillage and herbicide now and invest that $ in the fall.

Keep in mind that, if I follow your advice, johnson grass will be upwards of 7' tall. You don't think that will be a problem?

 

[Mennoniteman]

Keep in mind that, if I follow your advice, johnson grass will be upwards of 7' tall. You don't think that will be a problem?

I'm not familiar with Johnson grass, 7' tall will probably be a problem, plus the spreading root systems. I'd say if leaving the field fallow is not a choice you will need to keep the Johnson grass from going into seed heads, clethodim would kill the johnson grass, mowing would also keep it in check, and tillage would probably too.

 

[Native Hunter]

Mowing seems to meet your goals:
1. No disruption of soil biology
2. Mowing at the right time/s keep/s unwanted plants from making more seed
3. You control the amount of thatch at planting time

I will say that you are likely to be killing JG for years coming from the seedbank, but with RR Alfalfa, that shouldn't be a problem.

 

[KSQ2]

Mowing seems to meet your goals:
1. No disruption of soil biology
2. Mowing at the right time/s keep/s unwanted plants from making more seed
3. You control the amount of thatch at planting time

I will say that you are likely to be killing JG for years coming from the seedbank, but with RR Alfalfa, that shouldn't be a problem.

I was thinking the same thing.
Local alfalfa guys have told me the combination of regular mowing for hay, plus the glyphosate clears up the johnson grass problem quite quickly.

 

[cutman]

Could you plant buckwheat?

 

[KSQ2]

Could you plant buckwheat?

This is 10 acres and we’re not doing this for the deer, it’s for a hay. I do agree that the buckwheat could be a good soil builder, but I’m not sure it’s worth the expense and I’d rather not deal with the seed if it matures either; I believe it would compete with the alfalfa germinating before frost. I have used buckwheat in our plots quite a bit successfully for sure. But that was just in .5 acre or so experiments.

 

[yoderjac]

Sunn Hemp fixes a lot of N into the soil that your grasses would use. You would need to mow it in time for it to desiccate before your fall plant.

 

[catscratch]

Johnson Grass has lots of rhizomes. They can be bulky. Can that affect the planting of small alfalfa seed?

 

[KSQ2]

Johnson Grass has lots of rhizomes. They can be bulky. Can that affect the planting of small alfalfa seed?

We will either work the ground with a disk then later field cultivator, like we did this past spring. There has been johnson grass in this field for some time and the ground was still very well prepped, we just didn’t get our window. OR, if the field is still quite level (which I doubt after all of the rain) we will no-till; so I don’t anticipate a problem with seed/soil contact.
I believe plan will be to mow it field at least twice this summer, terminate in early September, then likely work the field a couple weeks later and let it set until planting. The good thing about working it quite a bit last spring is no cool season grass was allowed to go to seed, so the alfalfa hopefully won’t have much competition germinating this fall. The cool season grass that does come up with it will get terminated next spring. The main unknown right now is the possibility of using a brillion seeder. We have a neighbor who is looking to buy one now (they grow quite a bit of alfalfa and a LOT of teff grass); if he does, he said we can use it. That would most definitely require us to work the ground some, even if it is pretty level.
By “working the ground” to prep it for haying in the future, that means disking and then running a field cultivator at least once, followed by a harrow to really smooth it out.