4 MASS. EXPERIMENT STATION BULLETIN 395 



phosphorus compounds narrows the ratios and establishes more favorable con- 

 ditions for rapid growth of the microorganisms responsible for the process of 

 decay. In the making of artificial manures, the addition of nitrogen and phos- 

 phorus to the organic materials is most essential. Potassium is generally added 

 to make the chemical composition of the finished artificial manure more compar- 

 able to that of the natural manure. Today anybody can make excellent manure 

 out of almost any kind of plant refuse by following simple directions. 



Experimental 



These experiments with artificial manure are supplementary to a series run 

 previously at this Station, but not published. The earlier experiment dealt with 

 the preparation of manure from various kinds of organic matter. Very small lots 

 of manure were prepared, and vegetation tests showed some signs of toxicity due 

 probably to the reagents used. In these small lots of manure, the temperature 

 did not rise during preparation as it does when larger masses are made. 



In the present experiments, larger quantities of manure were prepared from 

 different types of organic materials, in order to study the method of preparation, 

 rate of decomposition, heat and moisture relationships, and volume and appear- 

 ance of the finished product. Detailed chemical and vegetation tests were run 

 on the prepared manures to compare the different organic materials and the 

 different nitrogenous supplements used. 



Method Used for the Preparatioii of Artificial Manure 



Chopped corn stover, mixed deciduous leaves, and oat straw were the organic 

 materials used, in lots of one half ton on the dry basis for each pile. Two nitro- 

 genous supplements, used to aid decomposition of the organic matter, were com- 

 pared — Cyanamid (supplied by the American Cyanamid Company) and am- 

 monium sulfate. Enough limestone was added to the piles built with ammonium 

 sulfate to equal the calcium in the piles made with Cyanamid. The nitrogenous 

 supplements were used in sufificient quantity to supply 0.7 percent nitrogen, 

 based on the dry weight of the original organic material. Other supplements 

 added to make the finished product approach natural manure in chemical composi- 

 tion were the following: 16 percent superphosphate, at the same rate as the 

 ammonium sulfate; muriate of potash, at one third the rate of the superphos- 

 phate; fresh horse manure, 100 pounds per ton of dry organic material; and gar- 

 den soil, at the same rate as the manure. The garden soil and horse manure were 

 added as bacteriological inoculating agents. 



In building the stacks, a circular snow fence^ bin about nine feet in diameter 

 was used as a form. The snow fence was taken down and used over again each 

 time a new pile was built. The piles were made indoors on ground covered with 

 tarred roofing paper, and were built up in layers consisting of about six inches of 

 compacted organic material. The chemical reagents were sprinkled on, layer by 

 layer; and each layer was also sprinkled with water as it was being packed down. 

 Enough water was used to wet the material, but not enough to leach out at the 

 bottom of the pile. A half ton of dry organic material was about 350 cubic feet 

 in volume and made an initial circular stack about nine feet in diameter and six 

 feet high. A thermometer was placed in the center of each heap, enclosed within 

 an iron pipe so that the thermometer could be pulled up by a string to take the 

 readings. 



''The snow fence was similar to those used along roads by the Highway Department for the pre- 

 vention of snow drifting during the winter. The fence can be made of 4-foot wooden laths (like 

 those used in plastering), nailed 2 to 3 inches apart to two wires, thus making the fence flexible 

 and easily rolled up. 



