Lebanon Crop Management Video


14 April 2016

Sprayer Calibration Pressure Speed

Del Voight- Penn State Extension

Sprayer Calibration.

This method is very useful for those growers utilizing the pressure speed type sprayers.  For spray monitors I will post another method to check the flow sensor and ensure tips are operating.

Being with Extension for 20 years I have had the pleasure of calibrating numerous sprayers.  I have calibrated anything from mules pulling a sprayer to small back pak sprayers to 100 foot spray monitor driven sprayers.  I can say that the most common problem I encountered is improper nozzles or nozzles not matching on the sprayer.   Some County Agents in Oregon found 86% of the sprayers calibrated by agents to be in need of adjustment and those in need of adjustment were due to failed spray nozzles.  In many cases where pesticides fail the sprayer is the main issue.  One farm had repeat failures of a product and a simple boom height adjustment resulted in no more problems.  Here are some brief pointers in the proper calibration of sprayers.  A fact sheet on Calibration of Sprayers is available at the Extension office.  If you need specific assistance do not hesitate to call me or a local agent or crop consultant for help.
Pre calibration
1.       Pesticides are dangerous….wear rubber gloves and coveralls to complete this operation.
2.       Take all nozzles and screen devices off sprayer (this includes the agitation nozzles inside the tank) and clean in soapy solution
3.       With nozzles off ,run water through the whole system.
4.       Check all parts for cracks. Pay attention to hoses and replace damaged hoses as needed.
5.       Consider low drift nozzle replacement.  Standard flats will lose 25% of spray to drift able fines while new air induction nozzles will lose only 1% to drift able fines. 
6.       Be sure that screens, washers, and tips are replaced in each of the nozzle bodies.  A missed screen can result in a 25% over spray for that nozzle.
Calibration (This is the simple form and is highly accurate)
1.       Measure spacing of nozzles and refer to the chart for the course length. (This is also the nozzle width for backpack sprayers.)
2.       Measure off the course length on a typical soil surface you plan to operate the sprayer.  Use bright colored markers to mark the ends.
3.       Fill the sprayer halfway with water and hook to the tractor or mules you plan to use to spray with
4.       Travel at a speed you are comfortable spraying at and operate the tractor and sprayer together without the pump running between the course flags.
5.       Use a time piece to determine how long it takes to run the course.  Do this three times to gain an average speed in seconds.
6.       With the sprayer on a level surface turn pump on and begin spraying in place.  Adjust pressure regulator to desired output.  Start at 40 psi.
7.       Collect with a device that reads ounces for the same time it took to run the course.
8.       Ounces equals gallons per acre

Great References
Tee Jet References
Hardi Sprayer
Green Leaf Sprayers

1.       For new sprayers and at least once per year all nozzles should be checked for even output.  Either catch water for a set amount of time or use a flow meter to determine the output of each nozzle. On rate controlled devices this is the most crucial part of the calibration.
2.       If a single nozzle is out of flow with the others by 10% replace the nozzle.  This can occur with brand new nozzles so it will need to be done whether old or new.
3.       If error in rate is <10%, or Adjust travel speed, if error in rate is >10% but less than 25%, or Change nozzle size, if error in rate is >25%
4.       Pressure must be increased 4X to double sprayer output
5.       Twice the speed = one-half the output
6.       If you plan to use other than water for a carrier you will need to adjust the volume of water up to compensate for the differences in the density of the carrier.  For instance liquid nitrogen weighs 11 lbs versus water at 8 lbs so if the desired output is 20 gallons per acre of UAN then the calibration with water would be about 22 gallons of water.  Spray rate controls will require you to enter the correct conversion factors which are contained in many sources of spray nozzles and user guides.

On a typical 100 acre farm spray bill simply by calibrating $500 to $1000.00 can be saved by preventing over application which reduces the amount of pesticide in the environment and ensures proper application rates for efficient performance from a given product.

Tip:  Instead of  placing 50 or 100 mesh screens at each nozzle place a large in line screen that leads to each boom section thereby allowing for easy cleanout between batches.

05 April 2016

Risk of Freeze Damage to Winter Grains

Del Voight - Penn State Extension

As winter grains are in a susceptible growth stage and the second  impending freeze forecasted for tonight. It might be a good idea to print off this fact sheet and review what to expect.  In as little as 2 hours of a freeze below 30 the result could  impact the crop yield of this 2016 crop as it has progressed beyond normal growth from early seeding last fall. As it begins to form the head at jointing  stage it must be protected from weather, pests and nutrient deficiencies. Here is a  photo I took about a week after a 19 degree overnight temperature of some tip burn from some wheat in the jointing stage. This has little impact on yield.   It takes time to really assess these fields perhaps 10 days to really know and assess damage. Time will tell how deep the freeze occurred and the impact on the head.

Here is a picture of what the plant is doing right now at jointing with the hollow stem and the small seed head forming above that point.  (Source Arkansas University Extension)  I was involved in some cases where liquid nitrogen applications  burned the wheat below the head and this resulted in a complete loss in the fields that were burned by the liquid N. This would be similar to this situation if the freeze reaches and destroys the tender seed head inside.
Dr Chad Lee in Kentucky has a nice factsheet detailing wheat and freeze damage.  The table below is an excerpt from his writings and it provides the temperature and hours to become an issue.  Freeze damage affect on Wheat.(Kentucky Extension)
Table 3-3. Freeze injury in wheat.*
Growth stageFeekesZadoksApproximate injurious temp. (2 hrs)
Primary symptoms
Yield effect
Tillering**1-520-2912°FLeaf chlorosis; burning of leaf tips; silage odor; blue cast to fieldsSlight to moderate
Jointing(6-7)31-3224°FDeath of growing point; leaf yellowing or burning; lesions, splitting, or bending of lower stem; odorModerate to severe
Boot1041-4928°FFloret sterility; spike trapped in boot; damage to lower stem; leaf discoloration; odorModerate to severe
Heading10.1-.550-5830°FFloret sterility; white awns or white spikes; damage to lower stem; leaf discolorationSevere
Flowering10.51-.5460-7130°FFloret sterility; white awns or white spikes; damage to lower stem; leaf discolorationSevere
Milk11.17528°FWhite awns or white spikes; damage to lower stems; leaf discoloration; shrunken roughened or discolored kernelsModerate to severe
Dough (11.2)11.28528°FShriveled discolored kernels; poor germinationSlight to moderate
*Information in this table assumes timely rainfall events occurring after the freeze event.
Frost can also impact other crops as well.  The tips of alfalfa might get frosted off but the most severe impact will be from small grains that are now for the large part in the jointing stage.
So the action is to wait and see what the plant tells you in the next week to determine if the freeze impacted the head development. If this frost continues here is a great factsheet that might prove useful. Cultural Impacts in wheat