4. Valuation of Fertilizing Ingredients.—Perhaps there are no more numerous and perplexing questions propounded to the analyst than those which relate to the value of fertilizing materials. There is none harder to answer. As a rule these questions are asked by the farmer, and refer to the fertilizers put down on his fields. In such cases the cost of transportation is an important factor in the answer. The farther the farmer is removed from the place of fertilizer manufacture the greater, as a rule, will be the cost. Whether the transportation is over land or by water also plays an important part in the final cost. The discovery of new stores of fertilizing materials has also much to do with the price. This fact is especially noticeable in this country, where the price of crude phosphates at the mines has fallen in a few years from nearly six dollars to three dollars and forty-three cents per ton[1]. This decrease has been largely due to discoveries of vast beds of phosphatic deposits in Florida, North Carolina, Tennessee, and Virginia. The state of trade, magnitude of crops, and the vigor of commerce also affect, in a marked degree, the cost of the raw materials of commercial fertilizers.

5. Trade Values of Fertilizing Ingredients in Raw Materials and Chemicals.—The values proposed by the Massachusetts Experiment Station are given below.[2]

Cents per
pound.
Nitrogeninammonia salts, 19
““nitrates,14½
Organicnitrogenindry and fine-ground fish, meat, blood,
and in high-grade mixed fertilizers,18½
“““cottonseed meal, linseed meal,
and castor pomace,15
“““fine-ground bone and tankage,16½
“““fine-ground medium bone and tankage, 15
“““medium bone and tankage,12
“““coarse bone and tankage,7
“““hair, horn shavings, and coarse
fish scraps,7
Phosphoricacidsoluble in water, 6
““soluble in ammonium citrate,5½
““in fine bone and tankage,5½
““in fine medium bone and tankage,4½
““in medium bone and tankage,3
““in coarse bone and tankage,2
““in fine-ground fish, cottonseed meal,
linseed meal, castor pomace, and wood-ashes,5
““insoluble (in ammonium citrate) in
mixed fertilizers,2
Potashashigh-grade sulfate, and in mixtures
free from muriate,5
““muriate,4½

The manurial constituents contained in feed stuffs are valued as follows:

Organic nitrogen,15
Phosphoric acid,5
Potash,5

The organic nitrogen in superphosphates, special manures, and mixed fertilizers of a high grade is usually valued at the highest figures laid down in the trade values of fertilizing ingredients in raw materials; namely, eighteen and one-half cents per pound, it being assumed that the organic nitrogen is derived from the best sources; viz., animal matter, as meat, blood, bones, or other equally good forms, and not from leather, shoddy, hair, or any low-priced, inferior form of vegetable matter, unless the contrary is evident. In such materials the insoluble phosphoric acid is valued at two cents a pound. These values change as the markets vary.

The scheme of valuation prepared by the Massachusetts station does not include phosphoric acid in basic slags. By many experimenters the value of the acid in this combination, tetracalcium phosphate, is fully equal to that in superphosphates soluble in water and ammonium citrate. It would perhaps be safe to assign that value to all the phosphoric acid in basic slags soluble in a five per cent citric acid solution.

Untreated fine-ground phosphates, especially of the soft variety, so abundant in many parts of Florida, have also a high manurial value when applied to soils of an acid nature or rich in humus. On other soils of a sandy nature, or rich in calcium carbonate, such a fertilizer would have little value. The analyst in giving an opinion respecting the commercial value of a fertilizer, must be guided not only by the source of the material, its fineness or state of decomposition, and its general physical qualities, but also by the nature of the crop which it is to nourish and the kind of soil to which it is to be applied.