© 2017 ~ Cold War Organics
calculate phosphate application

IMPORTANT NOTES: Please make certain that your soil pH is in the correct range before using this form. The application rate that this form suggests is for Correcting an Imbalance Only and does not include fertilization for crop removal. Applications of CWO products (as directed) will provide required fertility.

1. Find the method that was used to determine your phosphorus (or phosphate) level.
2. Determine the status (e.g., VL, M, etc.) or use the status given on the lab report.

Typically, soil test reports express phosphorus (P) in parts per million (ppm). Sometimes P levels are reported in pounds per acre (ppa).
To convert ppa P to ppm P, divide by 2
To convert ppm phosphate (P2O5) to ppm P, divide by 2.3
To convert ppa P2O5 to ppm P, divide by 4.6
To convert ppm P to ppa P2O5, multiply by 4.6
To convert ppm P to ppa P, multiply by 2.3

NOTE: Status values are in part per million (ppm)

Status Bray 1 Bray 2 Olsen P Mehlich 1 Mehlich III Morgan P
Very low 0 – 8 0 – 11 0 – 3 0 – 5 0 – 13 0 – 3
Low 9 – 17 12 – 25 4 – 7 6 – 15 14 – 30 4 – 8
Medium 18 – 26 26 – 42 8 – 13 16 – 30 31 – 50 9 – 20
High 27 – 39 43 – 59 14 – 22 31 – 50 51 – 100 21 – 41
Very high 40+ 60+ 23+ 51+ 101+ 42+

Application rates in the table below are in pounds P2O5/acre (ppa)

VL L M H VH
80 70 50 25 10

– Cold War Organics –

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