Zone Forge reads your Arizona soil test in Arizona's own calibrated language — the critical levels and rate logic come straight from Arizona — University of Arizona Cooperative Extension (Olsen-P calibration), not a national average.
Per Arizona — University of Arizona Cooperative Extension (Olsen-P calibration) — below the critical level, a yield response to the added nutrient is expected.
Published source: Arizona — University of Arizona Cooperative Extension (Olsen-P calibration)
Arizona — University of Arizona Cooperative Extension (Olsen-P calibration). Zone Forge cites the publication on every recommendation.
Yes — the Arizona soil-test recommendation calculator is free and needs no signup. Enter your lab values for source-cited P, K and lime guidance.
Zone Forge reads every Arizona soil test in its own state's language, then builds source-cited fertilizer and lime recommendations and full variable-rate prescriptions. See the science →