
New York AGRicunTuRaAL EXpERIMENT STATION. 407 
without regard to the form in which it exists. The total phos- 
phoric acid is, therefore, the sum of the available and insoluble 
phosphoric acid, 
| Porasn. 
The term “potash,” as used in connection with the analysis of 
fertilizers, always means the compound containing potassium and 
oxygen, known as potassium oxide, though it originally meant the 
carbonate of potassium. Potash or potassium oxide is never 
found as such in fertilizers, but chemists use this form of express- 
ing results of analysis as a convenient standard for reference. 
Fertilizers generally contain potash in such forms as sulphate of 
potash, chloride of potash or carbonate of potash ; and the figures 
m the column under ‘“‘ DETERMINED aS PoTasH” represent the amount 
of actual potash (potassium oxide) that is equivalent to the sulphate, 
chloride or carbonate of potash present. The “ Potash soluble in 
water” represents the available potash and only this is deter- 
mined. The forms of potash commonly present in commercial 
fertilizers such as the chloride, sulphate and carbonate, are readily 
soluble in water and are, therefore, available as plant food. 
ToraL CONSTITUENTS OF FERTILIZERS. 
If we add together the figures representing the different con- 
stituents of a fertilizer (the nitrogen, the total phosphoric acid, ~ 
and the potash), we shall find, as a rule, that the sum amounts to 
only twenty or thirty per cent. or pounds per hundred. The 
question often arises “Why does the sum of the constituents in 
the analysis of a fertilizer amount to only twenty or thirty per 
cent., and what is the remaining portion, amounting to seventy or 
eighty per cent. made up of?” A few illustrations will, perhaps, 
suffice to make the matter clear. 
Taking, first, a high-grade fertilizer, we find by analysis that it 
contains three per cent. of nitrogen, eight per cent. of available 
phosphoric acid, two per cent. of insoluble phosphoric acid, and 
ten per cent. of potash. If the nitrogen comes from dried blood 
or meat, it will take about ten pounds of such material to furnish 
one pound of nitrogen. Since there are three per cent. of nitro- 
gen, or three pounds of nitrogen in 100 pounds of fertilizer, it will 
take 30 pounds of dried’ blood to furnish this amount of nitrogen. 
