354 Bacteria in Relation to Country Life 



attributed to the exclusion of atmospheric oxygen. The 

 surface of the manure pile is in contact with the atmos- 

 phere, even when the air is effectively excluded from the 

 interior of the heap. It follows, then, that the larger the 

 surface exposed to the atmosphere, the better the oppor- 

 tunities for aerobic transformations in a portion of the 

 manure. It follows, also, that a tall, conical heap of 

 manure, or a flat heap with a rough, ridged surface, will 

 offer better conditions for aerobic changes than a flat 

 heap with a smooth surface. 



In the conservation of manure, therefore, advantage 

 is taken of this circumstance in that the material is not 

 only kept compacted, but its surface is kept smooth. 

 In order to make the exclusion of the air from the interior 

 of the heap effective, trampling by heavy animals is 

 more desirable than that by lighter animals. In some 

 places, the process of compacting is accomplished by 

 means of heavy rollers passed over the surface of the 

 heap. 



Effect of moisture. The exclusion of air is further 

 facilitated and the desirable bacterial changes favored 

 by controlling the amount of moisture. An excess of 

 water is to be avpided lest unlooked-for putrefactive 

 processes come to predominate and the accumulation of 

 sour substances take place. Careful observation will soon 

 show the farmer the right proportion of moisture to be 

 maintained in the manure. When the quantity of mois- 

 ture in the manure becomes insufficient, it should be 

 replenished either by the application of liquid manure 

 or water. Liquid manure should not be applied in a 

 thin stream, for the losses of ammonia may be markedly 



