Mixing 24d

[dcsobob]

After reviewing the literature on my new 12vdc 40gal sprayer, I come to realize that part of my issue with my pastures not performing properly is my failing to properly calibrate and determine my GPA and GPM (but I did learn new acronyms). I think I've corrected that lack of knowledge.

So...here is the setup. 4, 1-acre pastures setup for rotation. 1, 1.5 acre pasture. 12vdc 2.2GPM 40gal boom sprayer. 3 nozzles, 40" spacing for a total of 10' coverage.

After reading and talking to the manufacturer, and creation of a spreadsheet (i'm a geek) I know now the GPM for my DF2.5 brown nozzle for each PSI and Speed setting. I've not personally calculated this yet, but for sake of this post will take the values giving. So, after verifying the math, i now see that at 30PSI and a speed of 3.5mph my sprayer will put out 18.2GPA. My mistake, and corrected after a call to the manufacutrer, was assuming that this was total output of the sprayer. I now understand that the 18.2 GPA is PER nozzle (40" spacing). So, I have 3 nozzles which equates to just at 55 gallons of output in an acre.

I attempted to recover 2 dead pastures with laredo bermuda. Sprayed a 2% mix of glysophate on the pastures that killed most of it. Then turned the pastures to 6" with my roto tiller. Then seeded with laredo bermuda using broadcast. Got no bermuda but a fine bumper crop of what appears to be goatweed and a bunch of other crap. I have since been told that I should have sprayed another 1% solution on the ground after tilling to kill any seed/roots that my tiller turned up. Anyway, now I need to kill the weed so I can see if I have a viable bed of grass to work with or if I need to retill and plant in some fescue before winter.

My confusion is mixing ratios. In my reading of all the labels for the various 2-4d products, I am only seeing that I need to put 2qts per acre. no indication of what water quantity to mix with. Does it matter? the only label that mentioned mixture said no more than 2qts in 10 gals. There is no way to run this sprayer to achieve that GPA without changing the tip to a DF1.0, at about 4mph. That would give me about 11 GPA coverage.

When I did roundup to kill the pastures the first time it was easy. 2% mix. my failure there was calculating GPA/GPM of my little 25gal sprayer. I can't find that mixture ration.

What am I missing here?

Thanks

 

[Foodplot]

First, 55 gallons of fluid per acre is very high volume. I usually apply fluid at around 15 gallons per acre.
I'd suggest this approach, which is how I teach my students to do it:
Hang a bucket under each nozzle. Make one full pass down your pasture at your normal speed and using your normal pump pressure with plain water. Measure how many gallons total across all three buckets. Let's say it's two gallons.
As your coverage area is 10 feet wide, determine how many trips across your pasture you'll need for full coverage. For ease of math, let's say ten. Ten times two gallons per path is twenty gallons for that pasture. If you KNOW that pasture is exactly one acre, you are applying 20 gallons of fluid per acre.
If the herbicide manufacturer recommends two quarts per acre, just add your two quarts to 20 gallons of water in your tank (less two quarts if you are obsessive-compulsive) and go kill things.
This simple calculation allows for no overlap, so you might want to add some extra water to your tank.
If you want to calculate the GPA separately, which you don't really need with this method, but may need if you don't know your acreage, then figure out the square footage of that test pass you did when collecting water from the nozzles. If you have a ten-foot wide coverage area, and your pass was a thousand feet long, then that pass covered ten thousand square feet. An acre is 43,560 square feet, so you covered 0.23 acres with two gallons. 2/0.23 = 8.7 gallons/acre.
Glyphosate and 2,4-D can be tank mixed and you can apply them adequately using as few as 10 gallons of fluid per acre depending on your sprayer and the type of plants you're killing.
Hope this helps.

 

[dusty3030]

I try to calibrate a rig at 10 gallons per acre. That makes the math easy for sure. You can add a valve and pressure gauge to any sprayer and get it as exact as you want to fool with. Whatever vehicle you are using makes a difference. Low tech like the a tractor spray rig we would run it at full PTO rpm (to make sure we had full flow on PTO pump) in a gear that was a speed that would work with the ground conditions usually around 6 or 7 mph is about as fast as you could go without rattling the drivers teeth out.

So, if you are calibrated at 10 gallons per acre and you have a 25 gallon tank and you want 2qts per acre of 2,4D then you would mix in 5 quarts for a full load which would cover 2.5 acres of ground.

I've attached some good reading for you. Good luck.

Boom Sprayer Setup and Calibration
Fine Tuning a Sprayer with "Ounce" Calibration Method - Home - Virginia Cooperative Extension

 

[dcsobob]

I'll definitely give that test a shot Foodplot. Thanks.

I guess my followup to you would be how you determine what speed and pressure you are using to get a total of 15GPA out of your pump?

I know my pasture is pretty close to an acre due to the fencing I setup, basically a 210' square box. so, withing about 500sq ft.

I understood the math of the test, but just have not done the test yet. Will do several calibration tests this weekend, both just measuring flow output at pressure and the one you mentioned.

LIke I said, whats bothering me (until I do my own test) is the flow gpm that the manufacturer is telling me for the sprayer. I've looked up the deflector spray tips on several sites and they are all pretty consistent. 30 psi gives you .43 GPM out of a DF2.5 nozzle, speed irrelivant. So, for three nozzles that should equate to 1.29 gallons out of the sprayer in a minute.

So, my math says... An acre is 43560 sq ft. My sprayer does 10ft, so thats a straight line of 4356'. at 3mph (264FPM) thats 16.5 minutes to do. that swath. figure extra time for turning and i'm looking at 20 minutes to do the acre. So, if my math is right, that means that at 1.29GPM, in 20 minutes I will pump out 25.8 gallons? So basically that's the 1000' test you were talking about? BUT, if that is true, then the chart the manufacturer gave me is for total of 3 nozzles, not the one nozzle as indicated on their chart. I say that because their chart shows DF2.5 tip at 30PSI with 40" nozzle spacing (my spacing with 3 nozzles to give me 10' coverage) at 3mph is 21.3GPA per NOZZLE.

Ya'll can just slap me and tell me I'm overthinking this....it's okay.

 

[arlen4720]

I'll definitely give that test a shot Foodplot. Thanks.

I guess my followup to you would be how you determine what speed and pressure you are using to get a total of 15GPA out of your pump?

I know my pasture is pretty close to an acre due to the fencing I setup, basically a 210' square box. so, withing about 500sq ft.

I understood the math of the test, but just have not done the test yet. Will do several calibration tests this weekend, both just measuring flow output at pressure and the one you mentioned.

LIke I said, whats bothering me (until I do my own test) is the flow gpm that the manufacturer is telling me for the sprayer. I've looked up the deflector spray tips on several sites and they are all pretty consistent. 30 psi gives you .43 GPM out of a DF2.5 nozzle, speed irrelivant. So, for three nozzles that should equate to 1.29 gallons out of the sprayer in a minute.

So, my math says... An acre is 43560 sq ft. My sprayer does 10ft, so thats a straight line of 4356'. at 3mph (264FPM) thats 16.5 minutes to do. that swath. figure extra time for turning and i'm looking at 20 minutes to do the acre. So, if my math is right, that means that at 1.29GPM, in 20 minutes I will pump out 25.8 gallons? So basically that's the 1000' test you were talking about? BUT, if that is true, then the chart the manufacturer gave me is for total of 3 nozzles, not the one nozzle as indicated on their chart. I say that because their chart shows DF2.5 tip at 30PSI with 40" nozzle spacing (my spacing with 3 nozzles to give me 10' coverage) at 3mph is 21.3GPA per NOZZLE.

Ya'll can just slap me and tell me I'm overthinking this....it's okay.

For 1 acre, I would just put 3 pints of 2,4-d in, If you figured you pumped out 25 gallons, then put in 25 gallons of water. Just watch what you've done, and how much spray you got left, and let the good times roll.
You can go up to 4 pints to the acre.
For what its worth, my cheap little fimco puts about 20-25 gal down per acre at the speed I'm comfortable with

 

[dcsobob]

Thanks Dusty3030. I'll give that reading a look see. I think I have read one of the pieces before.. In my case not a PTO drive pump. 12vdc 2.2gpm, which should work well up to about 60PSI on my 2.5 tip.

So, my first test will be to hook the pump up to a 12v battery and just run an output test. Fill the tank up, set the pressure to 40 psi and capture output of all 3 nozzles in 2 minutes. Divide that by 6 to get the nozzle flow rate. see how close that matches to the manufacturer charts. at 40PSI on my DF2.5 tip I should get .5 gallon a minute. So, in 2 minutes I should get a full gallon. 1 or 2 mins, easy test. That will validate the flow. Once i have validated the output of the nozzles in GPM, the rest is just math.

Famous last words.

 

[Foodplot]

I guess my followup to you would be how you determine what speed and pressure you are using to get a total of 15GPA out of your pump?

I use PTO driven pumps, and have pressure regulators, so can vary both speed over ground and pressure to adjust flow rate.

LIke I said, whats bothering me (until I do my own test) is the flow gpm that the manufacturer is telling me for the sprayer. I've looked up the deflector spray tips on several sites and they are all pretty consistent. 30 psi gives you .43 GPM out of a DF2.5 nozzle, speed irrelivant. So, for three nozzles that should equate to 1.29 gallons out of the sprayer in a minute.

So, my math says... An acre is 43560 sq ft. My sprayer does 10ft, so thats a straight line of 4356'. at 3mph (264FPM) thats 16.5 minutes to do. that swath. figure extra time for turning and i'm looking at 20 minutes to do the acre. So, if my math is right, that means that at 1.29GPM, in 20 minutes I will pump out 25.8 gallons?

Sounds reasonable

So, to reduce output, you can 1) speed up your tractor, or 2) reduce pressure, while staying within mfg's specs for the nozzle. My experience with those little 12V pumps is that you often get less from them than their GPM rating. Regardless, once you figure out how much water it will take to cover your field, just add your 2 quarts of herbicide to that much water.

 

[dcsobob]

Thanks Foodplot. You last sentence pretty much answers what I was partially asking. 2qts is what I need to put out on the acre. My only concern was if the 2qts in 25 gallons vs 2 qts in 40 gallons made any difference. in my previous sprayings using my little 25 gallon tow behind on my lawn mower, i just poured 2qts into 25 gals and kept spraying the pasture until it was all gone. didn't bother with with the calibration. Could be why my weeds did not die very well.

 

[RPW]

One more thing, get a pH test kit (swimming pool). The correct pH of your water will enhance the effectiveness of the chemicals your using.

 

[Foodplot]

Within reason, it shouldn't make much difference, but the herbicide does need to stay on the plant for absorption through the leaves, not immediately run off, so try to get your volume of fluid to the 10-20 gallon per acre range if you can. Sometimes those little sprayers are low to ground and don't get good foliar coverage, which is required by glyphosate or 2,4-D. Make sure as much of the green stuff is covered as possible. You should also buy herbicide with a surfactant included, or add a surfactant to your tank. You probably know all this, but just in case... Best of luck with your project!