v2.2 (2026-08-21) · UMass CAFE — Soil & Plant Nutrient Testing Laboratory. PSNT corn-silage Table 3: 'Nitrogen Management with the Pre-Sidedress Nitrate-N Test (PSNT)' (updated June 23, 2026), https://www.umass.edu/agriculture-food-environment/crops-dairy-livestock-equine/fact-sheets/nitrogen-management-pre-sidedress-nitrate-n-test-psnt. Other nutrient tables: Hashemi, Weis, Kraemer & Spargo, 'Nutrient Recommendations for Field Crops in Massachusetts' (updated April 30, 2026), https://www.umass.edu/agriculture-food-environment/crops-dairy-livestock-equine/fact-sheets/nutrient-recommendations-for-field-crops-in-massachusetts. Lime block: Spargo, Allen & Kariuki (rev 2013), 'Interpreting Your Soil Test Results'. https://www.umass.edu/agriculture-food-environment/sites/default/files/fact-sheets/pdf/spttl_2_interpreting_your_soil_test_results_0-ua.pdf
State extension method. 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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