Spraying Herbicide

[Pete7]

I need to put Goal 2XL on some 8" wide garlic rows to knock down the broadleaf weeds. Need to use 4 oz per acre in 20 gallons of water, per the label. I can figure out from a chart the nozzle (tip) size needed at my tractor speed (4MPH), but the label says to use 4 nozzles on a row (2 on each side of the row with one pointed ahead and one behind). Since each of these 4 nozzles is essentially spraying in the same spot, I figure I need to have each nozzle sized so that it puts out 1/4 the 20 gallons per acre (GPA) rate. Do I got that figured right? Seems to me if each nozzle is putting out at the 20 GPA rate and each is spraying the same spot I'd get 80GPA put down in the row. But I'm just not sure I'm thinking about this right.
Pete

 

[JMS MN]

GPA is figured on the ground you are covering. Rows might be 8 inches wide, but how wide between rows? Test your sprayer over a known area, using clear water. Then do the math. If your rows are 32 inches apart, and you cover 8 inches per row, you are covering 1/4 of the total area.

 

[Nancy Howell]

Consult with your local agricultural extension agent and he can tell you the formula to calculate how to set your sprayer. He should give you a distance to use based on the number of acres you are going to spray and your nozzle configuration. Mark off that distance and time how long it takes for your tractor to cover that distance at 4mph.

Then put plain water in your sprayer. You don't have to fill it, just use enough to do the testing. Put an empty bucket under each nozzle. Turn the sprayer on and run for the same length of time it took your tractor to travel the set distance. Measure how much fluid was sprayed.

For a boom sprayer where each nozzle only covers the area once, each ounce is equivalent to 1 gallon of spray. If each nozzle put out 20 ounces of spray in that time period, that would equal 20 gallons of weed killer per acre.

From the nozzle configuration you gave in your post, you have two nozzles spraying the same area. If each nozzle was putting out 20 ounces, since your nozzles are spaying the same area twice, that would be a total of 80 ounces or 80 gallons.

The mixing directions in your post stated you needed 4 oz of herbicide to 20 gals of water per acre. This means each of your nozzles should put out 5 ounces of spray in the time period it took your tractor to cover the test distance.

You can decrease the amount of fluid sprayed by either increasing the speed of your tractor or decreasing the tank pressure.

If the nozzles aren't putting out enough, decrease the speed of your tractor or increase the tank pressure.

You may have to repeat this several times until the nozzles are putting out the desired amount of gallons per acre. You check each nozzle to make sure you are getting even distribution.

I will be calling our ag agent tomorrow and I will ask him about your post. Its been a while since I've calculated a spray configuration different from the one we use and I'm a little hazy on all the details. Email me if you need to.

 

[Wesley Stephens]

I use the 1/128 method to calibrate a sprayer and it works very well. If you google North Carolina Agricultural Chemicals Manual, you will find specific instructions for several methods of calibrating sprayers of all types, and info. on how to calibrate spreaders, etc...

 

[Pete7]

Thanks for the info. With every ones help I got the sprayer all set up and everthing sprayed today!
Pete