When using organic nutrient sources—for example, compost, manure, green manures, meals, and so forth—recommendations for crop nutrient needs will need to be translated. Soil test reports do not give specific recommendations for using organic fertilizers/amendments. This is because the percentage and availability of plant nutrients in such materials is highly variable and usually depends on its source, method of storage, and the amount and type of materials used to make the nutrient source. Generally, the low nutrient content and often limited sources of many organic materials add to the difficulty in developing a specific recommendation. This guide is intended to help growers interpret soil test recommendations for using organic nutrient sources. Information presented applies to organic and conventional farms.
Contents of this paper
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Contents Introduction
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……………………………… | 2 |
| USDA National Organic Standards Summary on Soil Fertility Management | ……………………………… | 3 |
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National Organic Standards Summary for Fertilizers and Soil Amendments Use
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……………………………… | 3 |
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When Nutrient Levels Exceed Crop Needs
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……………………………… | 3 |
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Balance and Imbalance of Nutrients in Organic Nutrient Sources
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……………………………… | 4 |
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Nutrient Availability from Organic Nutrient Sources
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……………………………… | 4 |
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Increasing Soil pH, Calcium, Magnesium Levels
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……………………………… | 4 |
| Decreasing Soil pH | ……………………………… | 4 |
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Recommendations for Nitrogen, Phosphate, and Potash
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……………………………… | 5 |
| Soil Organic Matter Content | ……………………………… | 9 |
| Mineralization | ……………………………… | 9 |
| Using Compost | ……………………………… | 9 |
| Using Manure | ……………………………… | 14 |
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Additional Sources for Information
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……………………………… | 14 |
