The Tri-State Field Crop Fertilizer Recommendations for Indiana, Michigan, and Ohio has been revised and updated. Extensive research station and on-farm trials have been conducted over the past decade to validate and refine the guidelines. In general, the fertilizer recommendations originally published in 1995 provide a solid framework for managing fertilizers and soil fertility. However, some changes have been made to the recommendations, as shown in the summary below.
Visit the following links for complete information:
Executive Summary | Soil Sampling, Handling, and Testing | Soil pH and Lime Recommendations | Nitrogen | Phosphorus and Potassium | Calcium, Magnesium, and Sulfur | Micronutrients | Additional Resources | Authors and Acknowledgements
Plus, check out this video overview of the recommendations.
What has Changed? |
Why the Change? |
Soil Sampling |
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Sample every 3 to 4 years in a consistent way as the foundation for an adaptive nutrient management program. |
No changes. |
Soil pH and Lime Recommendations |
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Michigan and Indiana liming recommendations are consistent, Ohio recommendations are different. |
States label and regulate liming materials differently. |
Nitrogen Fertilizer Recommendations |
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Corn N recommendations are now based on economic model to maximize profitability. |
Fluctuating grain and fertilizer prices necessitate a focus on economics in addition to yield. |
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Wheat N recommendations have been updated. |
They are calibrated with recent field trials with modern varieties. |
Phosphorus and Potassium Recommendations |
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Management framework drops drawdown range, makes build-up recommended but not required. |
These recommendations are simplified to provide farmers with greater flexibility to manage nutrients profitably. |
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Default soil test P and K levels now based on Mehlich-3. |
These recommendations are consistent with current soil test extracts. |
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P critical level 20 ppm for corn and soybean, 30 ppm for wheat and alfalfa (Mehlich-3 P). |
This update is based on extensive field trials over past decade. |
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K critical levels are 100 ppm for sandy soils, 120 ppm silt and clay soils (Mehlich-3 K, all crops). |
This update is based on extensive field trials over past decade. |
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Grain nutrient removal rates per bushel of yield have decreased. |
Crops are yielding more but grain nutrient concentrations have decreased. |
Calcium, Magnesium, Sulfur Recommendations |
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Liming supplies sufficient Ca & Mg; S deficiencies remain infrequent but are increasing |
No changes |
Micronutrients |
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Most soils supply sufficient micronutrients; diagnostic tools are limited |
No changes |
