3105.90.00 - Other

This HTS category, 3105.90.00, encompasses "Other" mineral or chemical fertilizers not specifically classified under preceding subheadings within 3105. It serves as a residual category for fertilizing substances that contain combinations of nitrogen, phosphorus, and potassium, but do not fit the more precise descriptions of mixed fertilizers containing all three elements (3105.20.00), diammonium hydrogenorthophosphate (3105.30.00), or ammonium dihydrogenorthophosphate (3105.40.00). This classification is also distinct from goods in tablets or small packages (3105.10.00).

The primary distinguishing factor for 3105.90.00 is its broad scope, covering any fertilizer formulations that contain two or three of the primary fertilizing elements (N, P, K) but do not meet the specific chemical or physical criteria of the other subheadings. This could include complex blends or compounds of nitrogen and phosphorus that are not explicitly listed elsewhere, provided they are intended for use as fertilizers.

Within this "Other" category, further subdivisions exist to provide greater specificity. Subcategory 3105.90.00.10 specifically addresses potassium nitrate-sodium nitrate mixtures, a common type of fertilizer that doesn't fit the more general chemical formulas of other subheadings. The remaining goods that fall under 3105.90.00 are then directed to the 3105.90.00.50 "Other" subheading, acting as a final catch-all for any remaining fertilizers within the scope of 3105 that have not been classified elsewhere.