v1.4 (2026-08-23) · Penn State Extension recommendations calibrated for Pennsylvania mineral soils plus the adjacent Mid-Atlantic region. Lime requirement uses Penn State AASL's Mehlich Buffer / Exchangeable Acidity method — the method Penn State publishes today. Published categories for soil-test nutrients: Below Optimum / Optimum / Above Optimum. Defensible for fields tested by Waypoint Analytical PA, A&L Eastern, or Spectrum Analytic when Mehlich-3 extraction is used. Includes secondary nutrients (Mg, S) and micronutrients (B, Zn) that Iowa PM 1688 does not cover. This is a soil-fertility recommendation source; it is intentionally NOT a nutrient management plan (NMP) and does not encode state P-Index, NRCS 590, or manure application limits.
Explicitly excludes Delaware, New Jersey — this method over- or under-applies on those states' soils.
Build-up to target. Zone Forge computes this source's supported nutrient rates in-app and cites the published method. Its published lime method is computed in-app too.
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