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Interpreting soil test report #926103

Asked March 16, 2026, 12:59 PM EDT

Assume a soil test reports the following recommendations. nitrogen: 2 lb phosphate: 4 lb potassium: 6 lb Does this mean? 2lb elemental nitrogen [100/N * 2 lbs of (N)PK listed on fertilizer bag] 4lb P2O5 (phosphorus pentoxide) [100/P * 4 lbs of N(P)K listed on fertilizer bag] 6lb K20 (potassium oxide) [100/K * 6 lbs of NP(K) listed on fertilizer bag] The words phosphate and potassium seem to indicate elemental phosphorous and elemental potassium. Which is correct, is it the element or the compound? It makes a big difference. Thanks

Wayne County Michigan

Expert Response

Yes, that is an important question! We provide recommendations in pounds of N (total elemental nitrogen), P2O5 (phosphate) and K2O (potash).

Thank you for contacting Ask Extension! Replied March 17, 2026, 1:27 PM EDT

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