PART V 



Bacteeia in Barnyakd Manube 



CHAPTER XXVII 

 MANURE: ITS COMPOSITION AND LOSSES 



Barnyard manure is rich in bacteria because it 

 offers conditions favorable for their rapid development. 

 The organic matter which serves as food for the micro- 

 organisms is not only present in much larger proportion 

 than it is in the soil, but its composition is such as to 

 be readily available to them. As the bacteria multiply 

 the manure begins to undergo a change. Its bulk be- 

 comes smaller; it assumes a darker color, . develops a 

 higher temperature, and finally shrinks more and 

 more in volume until, in the course of time, it contains 

 but a small fraction of its original bulk. The change in 

 the appearance in the manure is followed by a correspond- 

 ing change in its composition. A portion of its plant- 

 food is lost entirely by being changed into gaseous prod- 

 ucts which pass out into the surrounding air. The rest 

 is affected in its availability. 



Bacterial change in manure. — The nature of the bac- 

 terial change which manure undergoes bears a direct 

 relation to the composition of the latter. The proportion 



(303) 



