Will straw mulch kill my cover crops?

Hi All-

This is my First Post

I have recently started working with my dad on his new farming ventures. The property is a 15 acre lot in south jersey (zone 6B) with 4-5 acres of field and 10 acres of mixed hardwood and conifers. Our focus this spring will be soil development, particularly a 3/4 acre lot. This lot was run through the ringer this past year (tree and stump removal and a whole lot of tractor driving) and we are looking to rebuild.

We are working toward a no-till operation. My plan was to develop a nice polyculture of cover crops on the lot (radishes, broad leafs, legumes, etc). Some seeds with be planted using an earthway seeder and some will be broadcasted. Following the seeding, I had planned on mulching with a nice layer of semi broken down shredded leaves and then a layer of straw to help the buckwheat and all get a head start over the natural grasses/weeds.

BUT- My question is, will residual herbicide on straw prevent my broad leaf cover crops from germinating and taking hold? Does anyone have any experience with this? From what I've read, I'll be pretty hard pressed to find straw that is not treated with herbicide before the grain is harvested. I'm not concerned about the herbicide except for its effects on the covercrops.

Let me know what you think y'all!

I'm doing cover crops for the first time on my property this year (I've only had it one year) and am doing radish, clover, sunflower, mustard, and a few others.
I have some straw bales that have been sitting around since last summer, and another I spread out last summer. The one I spread out seems to have no effect on anything growing around it, though as far as pesticides go I can't make any definitive statement.
I have not yet put it down as a mulch because the cover plants are not grown up enough to poke through and I dont want to deny them Sun.
As chemicals go they do degrade and decompose over time. Microbial activity can speed this up, so I've been dumping piss on my bales and rolling them over every whenever to get them composting prior to using them. Industrial farming often has to repeatedly use chemicals because they often break down quickly.
It may be worthwhile to find out how your straw was grown if you are concerned about the chemicals in them.
I'm not sure on this, but i *think* the crops that straw is grown from is less chemical intensive than other kinds of crops. Ive not seen anything in my reading on straw bale gardening that indicated concern for chemicals but maybe I just didn't get to it.

I should add I did use fresh storebought straw last summer as a mulch in my raised beds and it appeared to have no effect, least of all on pests.
The only concern I would have is too thick of mulch could prevent the sun from getting to germinating seeds.

hau Charlie, welcome to Permies.

As far as straw goes, what kind of straw? Wheat, Barley, Rye straws generally do not have herbicide sprayed on them prior to harvest, it simply isn't needed to defoliate since the plants die as the grains mature.
Rice straw on the other hand, always tends to be sprayed with defoliant since the plants don't die as the grains mature (you can actually double crop rice just by harvesting with out spraying any herbicide).

If you are worried about cides, soak the bales of straw completely before you use them, this will leach most of the residuals out.

A mulch layer around 3 inches thick will do the job of weed suppression yet still let your desired seeds germinate.

Daikon radish is one of the best large root vegetables to use for de-compaction of soil the roots can get huge which will put back lots of humus as they decompose in the soil. They also attract good fungi and microbes.

If you are trying to improve the soil quickly, broadleaf plants, while good, will shade thin leaved plants which could stunt their growth. We plant in stages so all plants have equal opportunity to sprout and grow.
You also have to account for length of time from planting to germination, the plants with longer germination times need to go in first and you work your way to the seeds with the shortest germination time.

Multi plant type cover cropping means you will need to do some planning to get it right. No-Till is actually fairly easy and if you have a crimper, cutting isn't required.