The following nonsynthetic substances may not be used in organic crop production:
(a)
Ash from manure burning.
(c)
Calcium chloride, brine process is natural and prohibited for use except as a foliar spray to treat a physiological disorder associated with calcium uptake.
(e)
Potassium chloride—unless derived from a mined source and applied in a manner that minimizes chloride accumulation in the soil.
(f)
Sodium fluoaluminate (mined).
(g)
Sodium nitrate—unless use is restricted to no more than 20% of the crop's total nitrogen requirement; use in spirulina production is unrestricted until October 21, 2005.
(i)
Tobacco dust (nicotine sulfate).
Code of Federal Regulations
[68 FR 61992, Oct. 31, 2003]