This registration is generally made at the State experiment station, and the director of the station is instructed to take samples of these brands and have them analyzed, and publish the results together with the analysis guaranteed by the maker.

These analyses are published in bulletin form and should be in the hands of every farmer who makes a practice of using commercial fertilizers.

The manufacturers of fertilizers comply with the law by printing on the bag or package the per cents of plant food in the fertilizers, and these statements in the great majority of cases agree favorably with the analyses of the experiment stations, but they do not in all cases state what materials were used to furnish the different kinds of plant food, and it is not always possible to find this out by analysis.

Low grade materials.

For instance in mixing a fertilizer one manufacturer may use dried blood to furnish nitrogen and another may use leather waste or horn shavings.  The latter contains more nitrogen than the dried blood, but they are so tough and decay so slowly that they are of little benefit to a quick growing plant.

Inflating the guarantee.

Although the dealer states correctly the per cents of plant food in the fertilizer, he is quite frequently inclined to repeat this in a different form, and thus give the impression that the mixture contains more than it really does.

The dealers also give the nitrogen as ammonia because it makes a larger showing.

Phosphoric acid is often stated as “bone phosphate” because in this the amount appears to be greater.

For example, an analysis taken from a fertilizer catalogue reads as follows: 

Ammonia 2 to 3 per cent. 
Available Phosphoric Acid 8 to 10 "
Total Phosphoric Acid 11 to 14 "
Total Bone Phosphate 23 to 25 "
Actual Potash 10 to 12 "
Sulphate of Potash 18 to 20 "

A better statement would be as follows: 

Nitrogen 1.65 per cent. 
Available Phosphoric Acid 8 "
Total Phosphoric Acid (furnished in Bone Phosphate) 11 "
Potash (furnished in Sulphate of Potash) 10 "

Ammonia is reduced to terms of nitrogen by multiplying by .824.  All bone phosphate is forty-six per cent. phosphoric acid.  When bone phosphate is given instead of phosphoric acid it simply makes the mixture appear to have more in it, and when both phosphoric acid and bone phosphate are stated one is merely a repetition of the other.  The same is true of the statements, potash and sulphate of potash, one is a repetition of the other only a different form.

VALUATION