Johnson Grass - It's Coming.....

Over the summer around my neck of the woods, in addition to the usual milkweed, stick-weed, Queen Anne's lace that I see in fields as I drive around the area, this year for the first time, I really noticed small patches of Johnson grass taking hold.  On our farm, we don't have it - yet, but killed a patch that was beside to our land next to a highway.  I see a LOT of it along the roads.

 

Not sure where the seeds are coming from, maybe trucks hauling square and round bales through the area are dropping Johnson grass seeds.  We have an autumn olive problem around here too and one of the main culprits over the years is wild life eating the seeds and poop them out onto other properties as they move around.  Maybe that's where some of the Johnson grass is coming from.

 

So I want to be prepared for this potential invasion.

 

I understand the herbicide part of killing Johnson grass, but have some questions about toxicity of Johnson grass and how to understand/deal with it.

 

The concern is not necessarily stress and/or frost induced prussic acid.  I think I might understand this.  Sounds like the cure for prussic acid is to wait for a couple weeks after a post drought rain or a frost and it dissipates?  If you bale Johnson grass, wait about a month and the prussic acid dissipates too?  I can find much info Johnson grass and prussic acid issues, however, straighten me out if any of the above isn't accurate.

 

The concern is nitrate poisoning.  How does it occur, is the toxicity permanent?  In other words, we get a frost or drought stress period, will the nitrate levels go back down to a safe level prior to cutting/baling or is there another trigger for nitrate poisoning?  I'm to understand that if the nitrates are in Johnson grass when cut, you're stuck with it whereas prussic acid dissipates over time?

 

I gather horses can tolerate Johnson grass better than cattle due to how they process gas.  Sounds like cattle will bloat and suffocate on toxic Johnson grass?

 

When you find Johnson grass, how do you deal with the toxicity - especially nitrate poisoning side of it?

 

Some I read say it's great hay, some say it is a noxious weed.  I don't want any part of it (I think), but would like to know the fall-out if there is a patch that comes up in my fields over next summer and beyond.  I think in our area, ready or not - Johnson grass is coming....

 

Thanks,

Bill

Johnson Grass - It's Coming.....