| 71 / | HD | CHEMISTRY: FERTILIZERS |
| 1 | DF | PROCESSES AND PRODUCTS {5} |
| 31 | DF | .~ Inorganic material {5} |
| 32 | DF | .~.~ Phosphorus-containing {1} |
| 33 | DF | .~.~.~ Phosphates {6} |
| 34 | DF | .~.~.~.~ Alkali metal and ammonium only {2} |
| 36 | ![]() | .~.~.~.~.~ Alkali metal- and ammonium-containing |