Chemigation Calculator

Calculate fertigation and chemigation injection pump rates, product volumes, and costs for applying chemicals through irrigation systems.

System flow rate (GPM)

Field size (acres)

Target rate (lb nutrient/acre)

Product concentration (%)

Product density (lb/gal)

Irrigation run time (hr)

Start delay (%)

End flush (%)

Product cost ($/gal)

Tab to move between fields

Product volume (gal)

1,059.6

Injection rate (GPH)

110.37

Total nutrient needed (lb)3,750

Total product needed (lb)11,718.8

Injection window (hr)9.6

Injection rate (mL/min)6,963.3

Dilution ratio (water:product)544

Concentration in water (ppm)780.6

Product per acre (gal/acre)8.48

Total product cost ($)$9,006.27

Cost per acre ($)$72.05

Water applied (in)0.17

How to Use This Calculator

Enter System flow rate (GPM), Field size (acres), and Target rate (lb nutrient/acre).
Set Product concentration (%), Product density (lb/gal), and Irrigation run time (hr).
Adjust Start delay (%), End flush (%) as needed.
Review Product volume (gal) and Injection rate (GPH).
Use Total nutrient needed (lb) and Total product needed (lb) to inform your decision.

How the result changes with Product concentration (%)

System flow rate (GPM): Total irrigation system flow rate in gallons per minute.
Field size (acres): Area being treated in this irrigation event.
Target rate (lb nutrient/acre): Desired application rate of active nutrient per acre.
Product concentration (%): Active ingredient concentration in the product. UAN-32 = 32%, 10-34-0 = 34% P2O5.
Product density (lb/gal): Weight of product per gallon. UAN-32 = 11.06, 10-34-0 = 11.65.
Irrigation run time (hr): Total duration of the irrigation event.
Start delay (%): Percentage of run time before starting injection (to fill system).
End flush (%): Percentage of run time after injection stops (to flush lines).
Product cost ($/gal): Cost per gallon of fertilizer or chemical product.

Total nutrient needed (lb): Total pounds of active nutrient for the field.
Total product needed (lb): Pounds of product to supply the required nutrient.
Product volume (gal): Gallons of product to inject.
Injection window (hr): Effective injection duration after start delay and end flush.
Injection rate (GPH): Required injection pump setting in gallons per hour.
Injection rate (mL/min): Injection rate for small pump calibration.
Dilution ratio (water:product): Ratio of irrigation water to injected product.
Concentration in water (ppm): Final nutrient concentration in irrigation water.
Product per acre (gal/acre): Gallons of product applied per acre.
Total product cost ($): Total cost of chemical/fertilizer product.
Cost per acre ($): Product cost per treated acre.
Water applied (in): Total irrigation depth applied in inches.

Identify Input Parameters
4 parameters
System flow rate (GPM) = 800, Field size (acres) = 125, Target rate (lb nutrient/acre) = 30, Product concentration (%) = 32 = 9 input(s) provided
Calculate Product volume
Product volume = totalProductLbs / productDensityLbPerGal
1059.6 = 1059.6
Calculate Injection rate
Injection rate = productVolumeGal / effectiveInjectionHr
110.37 = 110.37
Calculate Total nutrient needed
Total nutrient needed = targetRateLbPerAcre * fieldAcres
3750 = 3750
Calculate Total product needed
Total product needed = totalNutrientLbs / concentrationFraction
11718.8 = 11718.8