Lesson 1Soil organic matter: functions, mineralization rates, and management implicationsExplores soil organic matter as a reservoir of nutrients, water, and biological activity. Discusses mineralization rates, environmental drivers, and management practices that build or protect organic matter in Midwest systems.
Organic matter contributions to CEC and waterNitrogen and sulfur mineralization processesTemperature and moisture effects on releaseResidue management and cover crop impactsTillage intensity and long-term SOM trendsLesson 2Common fertilizer sources, nutrient forms, and conversion to elemental N, P2O5, K2O (e.g., urea, ammonium nitrate, MAP, DAP, potash, sulfate, chelates)Reviews common fertilizer materials used in Midwest corn, including nitrogen, phosphorus, potassium, sulfur, and chelated micronutrients. Emphasizes nutrient forms, analysis, and converting product rates to elemental nutrients.
Typical N, P, K, and S fertilizer productsAmmonium, nitrate, and urea behavior in soilConverting analysis to lb nutrient per acreMAP, DAP, and potash handling and placementChelated micronutrients and compatibility issuesLesson 3Corn macronutrient uptake patterns and timing (N, P, K) by growth stageDescribes how corn uptake of nitrogen, phosphorus, and potassium changes by growth stage. Connects uptake curves to sidedress timing, starter fertilizer value, and strategies to reduce loss while meeting peak crop demand.
Early-season nutrient needs and starter useRapid uptake during V6 to tasseling stagesLate-season nutrient demand and remobilizationAligning N timing with crop demand curvesSynchronizing P and K supply with root growthLesson 4Secondary nutrients and micronutrients relevant to corn (S, Mg, Zn, B, Mn): roles and critical sufficiency rangesDetails the roles of sulfur, magnesium, zinc, boron, and manganese in corn physiology. Reviews deficiency symptoms, soil and tissue critical levels, and when supplemental applications are justified in Midwest production systems.
Physiological roles of S, Mg, Zn, B, and MnSoil and tissue critical levels for each nutrientVisual deficiency symptoms by growth stageSoil and foliar sources for secondary nutrientsWhen micronutrient fertilization pays in cornLesson 5Interpreting soil test reports: units (Bray/P, Mehlich-3, Olsen), extractant differences, and common lab recommendationsCovers how to read Midwest soil test reports, focusing on units, extraction methods, and calibration. Learners compare Bray, Mehlich-3, and Olsen P tests and translate lab results into clear, field-ready fertilizer decisions.
Common soil test units and conversionsBray, Mehlich-3, and Olsen P comparisonsInterpreting P and K calibration categoriesUnderstanding lab fertilizer recommendationsSampling depth, timing, and lab quality controlLesson 6Recommended soil test ranges for Midwest corn for pH, organic matter, Bray/Mehlich-3 P, exchangeable K, and micronutrientsSummarizes recommended soil test ranges for Midwest corn, including pH, organic matter, phosphorus, potassium, and key micronutrients. Links categories to expected yield response and fine-tunes fertilizer strategies.
Optimal pH and organic matter benchmarksBray and Mehlich-3 P target categoriesExchangeable K ranges by soil CEC classMicronutrient guideline levels for cornAdjusting targets for yield and rotationLesson 7Typical Midwest yield targets and corresponding nutrient removal rates (bushels/acre to lb nutrient/acre conversions)Links typical Midwest corn yield goals to nutrient removal in grain and stover. Teaches bushel-to-pound conversions, removal coefficients, and how to use them to design replacement and build-up fertilizer programs.
Nutrient content of corn grain and stoverBushel-to-pound nutrient removal factorsEstimating field-level nutrient exportsBalancing removal with fertilizer inputsPlanning build-up versus maintenance ratesLesson 8Soil texture, structure, and water-holding capacity: implications for nutrient retention and leaching riskExplores how soil texture and structure influence water storage, aeration, and root growth in Midwest fields. Links these properties to nutrient retention, leaching risk, and management practices that protect yield and water quality.
Classifying Midwest soil textures in the fieldStructure types and their impact on root growthAvailable water capacity and measurement methodsTexture effects on cation exchange and leachingTillage and compaction impacts on structureLesson 9Soil pH effects on nutrient availability and liming guidelinesExplains how soil pH controls nutrient availability, aluminum toxicity, and microbial activity. Provides liming guidelines for Midwest soils, including lime quality, rates, and placement to achieve target pH for corn rotations.
pH effects on macro and micronutrient solubilityAluminum and manganese toxicity thresholdsTarget pH ranges for corn and rotationsCalculating lime rates from buffer pH testsLime sources, fineness, and application timing
