INSPECTION OF COMMERCIAL FERTILIZERS 47 



Secondary fertilizer components are those other than the "primary fertilizer 



components" that are essential to the proper growth of plants and that may be 

 needed by some soils. Some of these components are calcium, magnesium, sulfur, 

 manganese, copper, zinc, and boron. 



Sheep manure — woo! waste is the by-product from wool-carding establish- 

 ments consisting chiefly of sheep manure, seeds, and wool fiber. 



Soft phosphate with colloidal clay is a very finely divided low-analysis by- 

 product from mining Florida rock phosphate by a hydraulic process in which the 

 colloidal materials settle at points in artificial ponds and basins farthest from the 

 washer, and are later removed after the natural evaporation of the water. 



Sulfate of ammonia (commercial ammonium sulfate) is a commercial 

 product composed chiefly of ammonium sulfate. It shall contain not less than 

 twenty and five-tenths per cent (20.5%) of nitrogen. 



S 

 five 

 sulfate 

 chlorine. 



Sulfate of potash (commercial potassium sulfate) is a potash salt con- 

 taining not less than forty-eight per cent (48%) of potash (K 2 0) chiefly as sulfate, 

 and not more than two and one-naif per cent (2.5%) of chlorine. 



Superphosphate is a commercial phosphate, the phosphoric acid (P 2 6 ) con- 

 tent of which is due chiefly to mono-calcium phosphate. (The grade that shows 

 the available phosphoric acid should always be used as a prefix to the name. 

 Example: l(i per cent superphosphate.) 



Tankage (without qualification) is the rendered, dried, and ground by-product, 

 largely meat and bone from animals (slaughtered or that have died otherwise). 



A unit of plant food is twenty (20) pounds, or one per cent (1%) of a ton. 



Unleached wood ashes are ashes from burned unleached wood that have had 

 no part of their plant food removed and that contain four per cent (4%) or more 

 of water-soluble potash (Iv.O). 



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

 ing 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. 



Interpretations 



Activity of water-insoluble nitrogen in mixed fertilizers. 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 materials. 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 

 nitrogen amounting to three-tenths of one per cent (0.3%) or more of the weight 

 of the material. If a total nitrogen exceeds the minimum guaranty and is ac- 

 companied by a low activity of the insoluble nitrogen, the over-run shall be taken 

 into consideration in determining the classification of the water-insoluble nitrogen. 



(f>) The water-insoluble nitrogen in mixed fertilizers showing an activity below 

 fifty per cent (50%) by the alkaline method and also below eighty per cent (80%) 

 by the neutral method shall be classed as inferior. This necessitates the use of 

 both methods, also the provision as to over-run in (a), before classifying as inferior. 



Amount of chlorine permissible in fertilizers in which the potash is 

 claimed as sulfate. The chlorine in mixed fertilizers in which the potash is 

 claimed as sulfate shall not exceed one-half of one per cent (0.5%) more than what 

 is called for in the minimum potash content based on the definition of potash as 

 formulated by the Committee. Calculate as follows: 0.05 times the percentage of 

 potash found plus 0.5. 



