Field Calibration Procedures for Animal Wastewater Application Equipment Eileen A. Coite Agricultural Extension Agent Wayne County

Reasons to Calibrate Know application rate Maintain uniformity across fields Identify where/when system is lacking Compensate for equipment aging and component wear Recommended at least every 3 years New NPDES permit = Yearly

Factors that influence the need to calibrate Age, wear and tear on equipment –Pump wear –Nozzle wear Quality of wastewater –Salts and sand particles Clogging –most often solid set

Other factors to consider Excessive pressure –Greater potential for drift –Accelerated wear on sprinkler nozzle Nozzle wear –Increased discharge rate –Decreased wetted diameter Pump wear –Reduced operating pressure and flow

What you will need Watch Measuring tape Collection containers

Other useful tools Wind meter Flags

Collection Containers Rain gauges work well Uniform opening and cross section with graduated scale At least 4 inches deep Same height, no more than 36” above ground Above crop canopy

When to Calibrate Periods of low evaporation Best before 10am or after 4pm Days with a light wind (<5 mph ideal) Cool, cloudy days –anytime with <5 mph wind velocity

Calibration Procedures Pull out reel, start up pump Measure wetted diameter Determine number of collection gauges and spacing between –25’ or less –Minimum of 16 gauges (more if WD >400 ft) Equally space gauges from gun cart to outer diameter (at least one wetted diameter from either end of pull)

Calibration Procedures Record starting time of collection Allow system to pass completely through collection gauges Record pressure at reel and gun Measure travel speed Record ending time of collection Immediately record amounts collected in gauges

Calibration Procedures Travel speed: Reel vs. observation

Calibration Procedures

Calibration Calculations Identify gauges outside effective lane spacing for overlap volume Superimpose these gauge volumes for overlap, add volumes together Calculate average application depth Calculate deviation depth for gauges Calculate average deviation depth

Calibration Calculations Calculate precipitation rate Determine application uniformity U c = average depth-average deviation x 100 average depth

Calculation Exercise Divide into groups Use collected example farm information Determine uniformity for farm

Calibration Results Higher values=more uniform 70-85% uniformity is GOOD <70 usually means system adjustments are required –Contact irrigation dealer or Certified Technical Specialist for assistance

Calibration Summary Calibrate to maintain application uniformity and identify equipment maintenance needs Recommended minimum of 3 years Use proper equipment and set up Calibrate during periods of low evaporation, with calm wind

Calibration Summary Record collections immediately Do the math Make adjustments and seek assistance if necessary

Who Needs to Calibrate???