Classification of micronutrients: chemically defined compounds fall outside fertilizer tariff heading; otherwise treat as fertilizers. Classification of micronutrients depends on chemical character: a separate chemically defined compound is excluded from the 'Other Fertilizer' tariff heading and must be classified under chemically defined compound chapters; if not chemically defined, and if it contains primary nutrients such as N, P or K or otherwise fits fertilizer descriptions, it is classifiable as an 'Other Fertilizer.' Administrative notifications under fertiliser control do not determine tariff classification.