31 

 Humus (Partially Dry, Pulverized Peat). 



Stone Meal. 



Manufactured by William N. McCrillis. 



None of the potash was soluble in water. There was 6.44 per cent of carbon 

 dioxide present. The analysis indicates the presence of 5.18 per cent of calcium 

 carbonate and 4.91 per cent of magnesium carbonate. 



The material is ground metamorphic rock. The first year's value of the plant 

 food which it contains may be approximately gaged by its content of phosphoric 

 acid, potassium oxide, calcium oxide and magnesium oxide soluble in dilute hydro- 

 chloric acid. A part of the two latter elements being present as carbonates would 

 have a small effect in reducing soil acidity. Assuming that one ton was used per 

 acre, this effect would be, roughly, 1/100 as much as one ton of finely ground lime- 

 stone. In terms of commercial valuation this would be about 50 cents. The 

 equivalent of phosphoric acid and potassium oxide soluble in dilute hydrochloric 

 acid and contained in one ton of the stone meal could be purchased in form of high 

 grade chemicals soluble in water for about 33 cents, making the total commercial 

 valuation of the plant food contained in one ton of the stone meal that might be 

 considered effective during a period of from one to five years, about 83 cents. 



DEFINITIONS AND INTERPRETATIONS REGARDING FERTILIZERS. 



On recommendation of the Committee on Definition of Terms and Interpreta- 

 tion of Results on Fertilizers, at a recent meeting of the Association of Official 

 Agricultural Chemists, the follo\'\'ing definitions and interpretations were adopted 

 as official. 



Meaning of Term "Finely Ground." 



The term finely ground in the definition of basic phosphate slag shall refer to 

 actual size of particles as determined by the use of standard sieves, as follows: 

 seventy per cent (70%) or more should pass a 100-, and ninety per cent (90%) or 

 more should pass a 50-mesh sieve. 



Nitrate of Potash (Commercial Potassium Nitrate). 

 Nitrate of potash is a salt containing not less than twelve per cent (12%) of 

 nitrogen and forty-four per cent (44%) of potash (KjO). 



Interpretation of Brand Name to Include the Analysis or Grade of Fertilizer. 



The committee recommends and urges the practice of including the analysis 

 or grade of fertilizer with the brand name, both by the manufacturer on sacks and 

 in printed literature and by the control official in his reports and publications. 



Activity of Water-Insoluble Nitrogen in Mixed Fertilizer. 



The alkaline and neutral permanganate methods distinguish between the better 

 and the poorer sources of water-insoluble nitrogen, and do not show the percentage 

 availability of the material. The available nitrogen of any product can be measured 

 only after carefully conducted vegetation experiments. 



(a) The methods shall be used on mixed fertilizers containing water-insoluble 



