48 CONTROL SERIES No. 60 



DEFINITIONS AND INTERPRETATIONS RELATING TO 

 FERTILIZERS. 



The following definitions and interpretations were adopted as official by- 

 vote of the Association of Official Agricultural Chemists at a meeting held in 

 Washington in November. 



Process tankages are products made under steam pressure from crude 

 inert nitrogenous materials, with or without the use of acids, for the purpose 

 of increasing the activity of the nitrogen. These products shall be called 

 "Process Tankages" with or without further quahfication. The water-insoluble 

 nitrogen in these products shall test at least fifty per cent (50 %) active by the 

 alkaline, or eighty per cent (80%) by the neutral permanganate method. 



Sheep manure, wool waste is the by-product from wool-carding es- 

 tablishments and consists chiefly of sheep manure, seeds, and wool fiber. 



Available phosphoric acid is the sum of the water-soluble and the citrate- 

 soluble phosphoric acid. 



Peat is partly decayed vegetable matter of natural occurrence. It is com- 

 posed chiefly of organic matter which contains some nitrogen of low activity. 



Charred peat is peat artificially dried at a temperature that causes partial 

 decomposition. 



Sulfate of ammonia is a commercial product composed chiefly of ammon- 

 ium sulfate. It shall contain not less than twenty and five-tenths per cent 

 (20.5%) of nitrogen. 



Cyanamide and urea nitrogen is synthetic non-proteid organic nitrogen. 



Dicalcium phosphate is a manufactured product consisting chiefly of a 

 dicalcic salt of phosphoric acid. 



Quicklime, burned lime, caustic lime, lump lime, unslaked lime are 

 liming materials that have a high content of calcium oxide, with magnesium 

 oxide, produced by heating suitable carbonates until substantially all the car- 

 bon dioxide has been ehminated. 



Hydrated or slaked lime is the product obtained by treating quicklime 

 with sufficient water or steam to combine with its oxides. 



Air-slaked lime is the product obtained by exposing quicklime or hydrated 

 lime to the atmosphere until partially carbonated. 



Ground limestone is the product obtained by grinding calcareous or dolo- 

 mitic limestone. Not less than seventy-five per cent (75%) shall pass a 100- 

 mesh sieve. It shall contain calcium and magnesium carbonates equivalent 

 to not less than ninety per cent (90%) of calcium carbonate. 



Ground shell lime is the product obtained by grinding the shells of mol- 

 lusks. Not less than seventy-five per cent (75%) shall pass a 100-mesh sieve. 

 It shall contain calcium and magnesium carbonates equivalent to not less than 

 eighty per cent (80%) of calcium carbonate. 



Marl, ground shell marl., is the product obtained by grinding natural 

 deposits of shell marl. Not less than seventy-five per cent (75%) shall pass 

 a 100-mesh sieve. It shall contain calcium and magnesium carbonates equiva- 

 lent to not less than eighty per cent (80 %) of calcium carbonate. 



Waste lime, by-product lime, is any industrial waste or by-product con- 

 taining calcium or calcium and magnesium in forms that will neutralize acids. 

 It may be designated by the prefixation of the name of the industry or process 

 by which it is produced, i.e., gas-house lime, tanners' lime, acetylene lime- 

 waste, lime-kiln ashes, calcium silicate, etc. 



Gypsum, land plaster, or crude calcium sulfate, are products consisting 

 chiefly of calcium sulfate. They may contain twenty per cent (20%) of com- 

 bined water. (They do not neutralize acid soils.) 



