30 



cost of labor and operating expenses. The analytical data have been presented 

 in about the same form as in previous years, and the tables will be found self- 

 explanatory. 



Lime-Fertile. —According to the literature of the manufacturers who put 

 out this material, it is composed of 80 per cent, carbonate of lime (fine ground 

 limestone) and 20 per cent, of fine ground phosphate rock, which are claimed 

 to act as carriers for certain soil bacteria. Our analysis would indicate that 

 the product was a mixture of carbonate of lime and ground rock phosphate, 

 which, to say the least, would not produce an ideal vehicle for soil bacteria. 

 Limestone analyzing 50 odd per cent, of calcium oxide can be purchased de- 

 livered at points in Massachusetts at $5 to $6 per ton, and Tennessee Ground 

 Phosphate Rock, analyzing about 40 per cent, phosphoric acid, is quoted at 

 $7 to $8 per ton, f. o. b. Mount Pleasant. Allowing $10 per ton for freight 

 and war tax, and 20 per cent, additional to change the price to a retail basis, 

 would make the product cost at retail about $21 per ton. Three hundred 

 pounds of this ground phosphate rock would furnish somewhat more phos- 

 phoric acid than is found in a ton of the Lime-Fertile, and would cost about 

 S3.25. To make up a ton would require 1,700 pounds of fine ground limestone, 

 which would cost $5.10; allowing $2 per ton for mixing, would make the cost 

 of a ton of the mixed product $9.85. The bacteria for any legume can, be 

 purchased from the Department of Microbiology, Massachusetts Agricultural 

 College, in quantities sufficient for one acre, for 25 cents. It will be seen, 

 therefore, that Lime-Fertile can be duplicated for about $10 per ton, including 

 the bacteria. The retail price charged for Lime-Fertile was $50 to $55 per 

 ton. It will be noted that the material does not furnish potash, and the cal- 

 cium oxide present is depended upon to liberate a sufficient quantity of actual 

 potash from the soil for the needs of the crops. The use of carbonate of lime 

 in the form of fine ground limestone, or for that matter hydrated or slaked 

 lime, will do just as much good in this respect as Lime-Fertile. It might be 

 said in this connection that it is somewhat doubtful if lime is actually instru- 

 mental in liberating potash from insoluble compounds in the soil. On the 

 other hand, lime does seem to possess the property of liberating insoluble 

 phosphoric acid compounds in the soil. The Lime-Fertile does not furnish 

 any nitrogen directly, but the lime which it contains is depended upon to 

 sweeten the soil, thereby making a better environment for soil bacteria which 

 cause a more rapid decomposition of the existing organic matter, thus liberat- 

 ing its nitrogen. Lime also favors the development of certain bacteria which 

 add nitrogen directly to the soil and of species of nitrogen-fixing bacteria oper- 



