A safer alternative to Roundup

[super55]

Why use 2,4-D in conjunction with glyphosate for burndown if glyphosphate kills everything or does it have a residual that holds the weeds down longer than glyphosate?

2,4-D is used for broadleaf weeds. While glyphosate is a broad spectrum herbicide it does not do an extremely well job at killing broadleaf it will merely burn them down but they will usually come back. In fact some people have had success using glyphosate and spraying it on alfalfa to kill fescue. It will burn the alfalfa but it won't kill it.

2,4-D and glyphosate are post emergence herbicides. Relatively speaking in the form of poisons to kill plants they are fairly low impact because they must contact the plant in order to kill it. The soil does a pretty good job at making them inert relatively fast.

The real issue with runoff comes in the form of pre-emergent herbicides. Atrazine is a big one. This is the one that caused the 3 legged frogs and such. It is used heavily in big ag and sits in the soil preventing weeds from germinating. It sits in the soil for long periods of time and is prone to runoff. The other big culprit is phosphorus. Wonder why so many lakes have such heavy algae blooms now? It's from phosphorus runoff.

 

[mx1alex]

Why use 2,4-D in conjunction with glyphosate for burndown if glyphosphate kills everything or does it have a residual that holds the weeds down longer than glyphosate?

BTW - can you quantify the ag versus non-ag usage? I have not been able to find numbers on that.

Both products are cheap and it gives you better results. Also adding modes of action reduces the chances of resistance.

I don't have numbers in front of me but go into your closest home depot and look at how much 2,4-d they have on hand. Then go to your local ag supplier and see how much they have on hand. I'd sell over 1,000 gallons of concentrate to an individual farmer where a guy at home depot might buy a gallon or two of the ready to use stuff.

 

[mx1alex]

2,4-D is used for broadleaf weeds. While glyphosate is a broad spectrum herbicide it does not do an extremely well job at killing broadleaf it will merely burn them down but they will usually come back. In fact some people have had success using glyphosate and spraying it on alfalfa to kill fescue. It will burn the alfalfa but it won't kill it.

2,4-D and glyphosate are post emergence herbicides. Relatively speaking in the form of poisons to kill plants they are fairly low impact because they must contact the plant in order to kill it. The soil does a pretty good job at making them inert relatively fast.

The real issue with runoff comes in the form of pre-emergent herbicides. Atrazine is a big one. This is the one that caused the 3 legged frogs and such. It is used heavily in big ag and sits in the soil preventing weeds from germinating. It sits in the soil for long periods of time and is prone to runoff. The other big culprit is phosphorus. Wonder why so many lakes have such heavy algae blooms now? It's from phosphorus runoff.

Not all premerge herbicides move or are susceptible to runoff but you are correct in that atrazine does. It does not however create 3 legged frogs. Most of the "science" by Tyrone Hayes has been debunked. And the levels of exposure he was introducing in his research was 1000's of times higher than any frog would ever be exposed to.

Did The New Yorker Botch Puff Piece On Frog Scientist Tyrone Hayes, Turning Rogue into Beleaguered Hero? - Forbes

 

[super55]

Not all premerge herbicides move or are susceptible to runoff but you are correct in that atrazine does. It does not however create 3 legged frogs. Most of the "science" by Tyrone Hayes has been debunked. And the levels of exposure he was introducing in his research was 1000's of times higher than any frog would ever be exposed to.

Did The New Yorker Botch Puff Piece On Frog Scientist Tyrone Hayes, Turning Rogue into Beleaguered Hero? - Forbes

Thanks for clearing that up. You are correct they haven't proven that atrazine was the cause the of the Minnesota tripod frogs. The source I had read it from was that it was an endocrine disrupter for frogs and that the PPB is 30x lower than what is allowed for drinking water.

As EPA re-evaluates safety of herbicide atrazine, Minnesota conducts its own review | MinnPost

Herbicides can be a great tool. It seems almost a necessity too do a burndown with glyphosate before no-till planting. No-till planters were around long before glyphosate but it really took off afterwards and why not. It will give you a clean stand for your crop to grow. The thing that gets me is you see a clean field of picked soy or corn with little if any weeds in it. They'll go and plant and the crop will come up. These fields still look pretty clean and out comes the 60' boom sprayer to do a burn down.

A local farmer left a corn stand all summer without spraying for a fall alfalfa planting and throughout that whole summer there were barely any weeds in the field. Wouldn't this be the case with most fields? No till creates minimal soil disturbance so its not like a fresh seedbed is ready for weeds so why spray. Is it because they paid for RR seed so might as well spray because gly is so cheap? They can't claim crop failure if they don't spray? I know farmers are always about the bottom dollar and will save $$ any way they can but if it doesn't need it why apply.

 

[Smallplot]

A local farmer left a corn stand all summer without spraying for a fall alfalfa planting and throughout that whole summer there were barely any weeds in the field. Wouldn't this be the case with most fields? No till creates minimal soil disturbance so its not like a fresh seedbed is ready for weeds so why spray. Is it because they paid for RR seed so might as well spray because gly is so cheap? They can't claim crop failure if they don't spray? I know farmers are always about the bottom dollar and will save $$ any way they can but if it doesn't need it why apply.

You are going under the assumption of two things. First that the farmer is applying Gly and two, that because you don't see weeds from the road that they are not there. Weeds are best handled when they are seedlings, very small, and this is found by walking fields not driving by. No farmer in their right mind would pay to apply herbicide if it was not needed. A lot of the spraying you see on "clean" fields is a combination of residual herbicides with different modes of action or insecticides and liquid fertilizers. If one has 1000 acres and pays $25 an acre to spray, round up is not so cheap.

 

[super55]

I wasn't very clear on that post my apologies. To clarify, It was a stand of corn from the previous year that didn't get combined until well in the late spring due to moisture content and the field being so wet. The field set all summer with nothing but stalks in it. This field was directly in front of my house so I got to see it on daily basis. I'm good friends with the farmer so I asked him what he used to keep the field so clean throughout the summer. He told me nothing last application was over a year ago with roundup. If he doesn't disturb the soil he doesn't have very many weed issues. The land was then tilled. Fall planted alfalfa with oats as a nurse crop and the next spring had a standout crop of alfalfa.

This alfalfa was never sprayed. Weeds were managed by correct timing, utilizing a competitive nurse crop to compete with weeds and timely mowing.

Personally I am not against round-up. It works and offers minimal impact to the environment. But I also have learned that you will never win a argument with someone that is adamantly against the stuff. My wife is one of those people. The OP's horse owner friend no matter how much you try to advocate is not going to change their mind either. Heck, I've seen horse owners' treat their horses better than they do their siblings. If they don't want herbicides applied there are other options they just are more intensive and much slower to see the end result.

 

[Creamer]

You make a good point that I had not thought of regarding no-till - if you do not till you do not cover the weed seeds to get them to germinate or bring others to the surface. Thanks!

 

[Redneck in training]

You make a good point that I had not thought of regarding no-till - if you do not till you do not cover the weed seeds to get them to germinate or bring others to the surface. Thanks!

Problem with no till is that some weeds are naturally RU resistant (in ex. some strains of pigweed). Since pigweed germinates on surface no till creates ideal condition for it. Because all non-resistant weeds are killed RU resistant pigweed proliferates to catastrophic infestation. We got soybean seed contaminated with RU resistant pigweed two years ago. Our field looked great from distance but on close look it was all pigweed covering the soy plants.
RU resistant pigweed is becoming a problem in IL, IA, MS and I just read that it was found in Argentina and Australia.