Soil Fertility & Sewage Sludge

Policies

• Soil fertility practices must improve the quality of the soil, either maintain or increase the amount of phosphorus, potassium, nitrogen and organic matter,and reduce soil erosion without the addition of synthetic fertilizers
• Farming practices must follow at least one of the sustainable farming or in conjunction with multiple of the techniques listed below:
  • Sewage sludge
  • Crop rotation
  • Green manure
    • Cover crops
    • Living mulches

*Supplemental animal, plant, compost, or manure materials can be used in place of the options listed above, but these techniques must be reported and reviewed by the USDA board before certification of use.

• Sewage sludge requirements
  • Farmers must attempt to close the "nutrient loop" between human consumption of nutrients and the nutrients put into the soil.
  • Class A biosolids that have been sufficiently heated to destroy pathogens are allowed, this includes heat-dried biosolids, biosolid composts, and biosolid blends (Crogger, 2014).
  • Class B biosolids are prohibited due to higher levels of pathogens, which would make them unsafe for human consumption (Dring, 2015).
• Crop rotation requirements
  • At least one of the rotations should include a nitrogen-producing legume such as peas, beans, alfalfa, etc. This will help increase the nutrient content of the soil in a way that leads to less runoff and pollution of waterways (“Healthy Farm Practices: Crop Rotation and Diversity”).
  • The amount of rotations used is at the discretion of the farmer, but one rotation should be used to make food for people, not just feed for animals. So, feed corn and soybeans is not an option for farmers wishing to get organic certification.
• Green manure requirements
  • Cover crops
    • Must reduce soil erosion, reduce nitrogen leaching, provide weed and pest suppression, and increase soil organic matter without the addition of synthetic fertilizers (Kaspar, Kladivko, Singer, Morse, Mutch, 2005).
    • The selected cover crops must be from the plant species listed below. If a selected plant species is not listed, farmers must report the chosen plant species for review from a USDA board to certify before use.

1. Winter wheat
2. Barley
3. Triticale
4. Winter rye
5. White clover
6. Annual ryegrass
7. Oilseed radish
8. Oriental mustard
9. Forage radish

• Tillage is allowed if the winter cover crop would continue to grow in the spring and interfere with the growth of the main crop. For example, plant species such as Winter rye, triticale, and winter wheat. Otherwise, if the plant species is not one of the listed winter cover crops, tillage is not permitted.
• Mined minerals are prohibited due to the toxic and energy intensive process it entails, and the strain it puts on the environment (Dring, 2015).

Works Cited

Cogger, Craig. “Using Biosolids in Gardening and Landscapes.” http://cru.cahe.wsu.edu/CEPublications/FS156E/FS156E.pdf .

ECFR - Code of Federal Regulations, www.ecfr.gov/cgi-bin/text-idx?SID=acaf6d1887c3dc73d3ef4edd0c490b88&mc=true&node=se7.3.205_1203&rgn=div8.

“Healthy Farm Practices: Crop Rotation and Diversity.” Union of Concerned Scientists, www.ucsusa.org/food_and_agriculture/solutions/advance-sustainable-agriculture/crop-diversity-and-rotation.html#.WqlmUejwY2w.

Kaspar, T.C., Kladivko, E.G., Singer, J.W., Morse, S., Mutch, D.. 2005. Potential and limitations of cover crops, living mulches, and perennials to reduce nutrient losses to water sources from agricultural fields. Retrieved 2/18/18 from https://www.epa.gov/sites/production/files/2015-07/documents/2006_8_25_msbasin_10c

Stephen. “Green Manure Cover Crops Organic Sustainable Soil Fertilizers.” Alberta Urban Garden, www.albertaurbangarden.ca/2015/03/08/green-manure-cover-crops-organic-sustainable-soil-fertilizers/.

Dring, Rachel. “Human Manure: Closing the Nutrient Loop.” Sustainable Food Trust, http://sustainablefoodtrust.org/articles/human-manure-closing-the-nutrient-loop/.