Nitrogen Sources

Manure and compost-based products

1. Manure—Animal manures supply different amounts of nutrients depending on the animal species, feed, bedding and manure storage practices. The amounts of nutrients that become available to the plants depend on the time of year the manure is applied and how quickly it is worked into the soil. Existing soil conditions also affect how quickly the nutrients in the manure are available. 2. Compost—For a product to technically qualify as compost under the NOP, it must start with a carbon to nitrogen ratio between 25:1 and 40:1 and be maintained at a temperature of between 131°F and 170°F for 15 days, during which time the materials must be turned a minimum of five times. If compost is made in this manner, then it can be applied to plants with no restrictions of timing. 3. Compost Tea—Long favored by organic gardeners and biodynamic farmers, compost tea is coming under criticism by the NOP because improperly made compost tea may have the potential for spreading food-borne pathogens onto plant parts destined to be eaten raw by people. It continues to be a major topic of discussion among federal regulators.

Plant and seaweed products

4. Alfalfa meal or pellets contain around 3 percent nitrogen and are commonly used as an animal feed. This is an excellent fertilizer material in high-value horticultural crops but would probably be too expensive for field crops. It is thought to contain unknown growth factors which make its mineral content more effective as plant nutrients.5. Leaf and plant-waste compost is increasingly available, or you can make it yourself. In many cases, the compost is a good product, but it is sometimes ridden with “impurities” such as car waste, pesticides and garbage.6. Soybean meal is about 6 – 1.4 – 4 NPK; it can be useful, but is extremely expensive. Organic farmers should be careful about not using conventional GMO soybean meal although it is not specifically prohibited under the NOP.7. Most seaweed fertilizers come from kelp that has been harvested, dried, and ground. Kelp meal can be applied directly to the soil or in starter fertilizer8. Dried raw seaweed tends to contain about 1 percent nitrogen, a trace of phosphorus, and 2 percent potash, along with magnesium, sulfur, and numerous trace elements. Raw seaweeds are prepared by various methods and sold under a number of brand names.

Animal By products

9. Blood meal is dried slaughterhouse waste and allowed under the NOP, even from non-organic animals. Blood meal contains about 12 to 13 per cent nitrogen and unless used carefully, it can burn plants with ammonia, lose much of its nitrogen through volatilization and encourage fungal growth. It is also very expensive.10. Feather meal is a common by-product of the poultry slaughter industry and is allowed under the NOP. Although total nitrogen levels are fairly high (7 to 10 percent), the nature of feathers is such that they break down and release their nitrogen much more slowly than many products of similar price.11. Fish meal and fish emulsion are, like most animal by-products, rich in nitrogen. Fishmeal contains about 10 percent nitrogen along with about 6 percent phosphate. It is most frequently used as a feed additive but can be used as a fertilizer

Other nitrogen sources

12. Most organic farmers try to supply their nitrogen needs with legumes in the crop rotation or with manures and composts. Sodium nitrate or Chilean nitrate were added to the NOP National list after much discussion.

Phosphate Sources

There are 3 main types of mineral phosphate:

13. Colloidal phosphate from clay14. Soft rock phosphate mostly from ancient sea deposits, and 15. Hard rock phosphate from volcanic deposits.

Potassium Sources

16. Potassium sulfate and potassium magnesium sulfate (langbeinite) are allowed under the NOP if you can clearly document that you are using a mined source that has not been treated with acid or any other chemical reaction to make the potassium more available. Potassium sulfate is the better choice for high Mg soils, but it is fairly reactive and must be used carefully. There are synthetic forms of potassium sulfate, so make sure you are getting the mined product.17. Granite dust is often sold as a “slowly available” potash source for organic production. Granite dust typically contains from 1 to 5 percent potash depending on overall mineral composition of the rock, but granite is mostly feldspar, a highly insoluble mineral, so little of that potassium is easily available.18. Another source of slowly available potash is the clay-type mineral glauconite, commonly sold as greensand. Total potash content of greensand is around 7 percent, all of which is deeply locked into the mineral and only slowly available..

Calcium Sources

19. Lime and gypsum are valuable products to moderate the soil pH and deliver essential calcium. Here in New York, few soils need more magnesium! Our glacial heritage has left us with soils high in Mg, with the tendency to become hard, compacted, and crusty. This soil condition favours certain tough species of weeds.

Secondary and Minor Nutrients from Rock Powders

20. Micronutrients can be supplied in small quantities in a variety of rock dusts. Certain types of synthetic micronutrients may be allowed in tiny quantities in a mixed organic fertilizer if it can be shown (with a soil test) that they are correcting a documented deficiency