THE CHANGES TAKING PLACE DURING THE 

 STORAGE OF FARMYARD MANURE. 



By E. J. RUSSELL, D.Sc, F.R.S., and 

 E. H. RICHARDS, B.Sc, F.I.C. {Rwpert Guinness Research Chemist), 



Rothamsted Experimental Station. 

 CONTENTS. 



PAGE 



Introduction ........... 495 



The changes observed in the manure heap 504 



The study of similar cases. 



Bacterial decomposition of protein ...... 522 



The decomposition of sewage 525 



Laboratory experiments with farmyard manure to test the deductions 



drawn from the above ......... 528 



The cause of the loss of nitrogen 642 



Practical conclusions and Summary 552 



Inteoduction. 



This investigation began in an attempt to account for the loss of 

 nitrogen that occurs during the cultivation of land rich in organic 

 matter or liberally supplied with farmyard manure. For example, 

 the Rothamsted plots receiving annual dressings of farmyard manure 

 return in the crop only about one-third of the added nitrogen ; no great 

 quantity is stored in the soil, and there is little apparent drainage water, 

 although no doubt some seepage occurs. Altogether little more than 

 one-half of the nitrogen can be accounted for, and it is difficult to avoid 

 the conclusion that some escapes in the gaseous state, being liberated 

 as the result of biochemical processes in the soil. Similar results have 

 been obtained for prairie soils : the amounts of nitrogen lost from the 

 soil are much greater than those recovered in the crop. 



Direct experiments with soil are in progress in our laboratories ; but 

 it will readily be understood that an amount of nitrogen which is of 



