E. J. Russell and E. H. Richards 516 



The loss of nitrogen is now seen to be almost proportional to the 

 loss of dry matter, and runs more closely than the ammonia does. 



Turning now to the heaps that rose to 71° C: the further rise in 

 temperature is associated with a correspondingly increased loss of dry 

 matter and of ammonia, but not of total nitrogen ; this suffers a 

 smaller loss. 



The following rules hold for all the covered heaps we have examined : 



The loss of ammonia is determined by the highest temperature 

 attained. 



The loss of total nitrogen follows the loss of dry matter so long as 

 the temperature does not rise too high (above 50° C). But if the 

 temperature goes up much higher (to 70° C), then the decomposition 

 of the comj)lex nitrogen compounds no longer keeps pace with the 

 other decompositions, and the result is that the loss of nitrogen shows 

 a relative falling off. 



From the practical point of view it is important to note that we 

 could only in one case make the heap sufficiently compact to avoid 

 losses of nitrogen. 



The loss of nitrogen is not peculiar to our heaps, it is shown in all 

 the compact heaps of which we have been able to find any record ; we 

 have set out the data in Table II. 



Table II. Loss of nitrogen during storage of farmyard manure as 

 recorded by other ex'perimenters. 



WoMirn experiments^. 1899 1900 1901 



Loss of nitrogen 30-7 173 18-9 



Berry's experiments^. 



Loss of nitrogen ... ... 19-9 — — 



Loss of dry matter ... ... 11-0 — — 



Under cover, cement floor. 



Wood's experiments^. 



Animals receiving Roots, hay and 

 roots and hay only cake 



Loss of nitrogen 10-6 26-9 



Loss of dry matter ... ... 16-2 18-6 



Manure left undisturbed in feeding box. 



Goodwin and RusselVs experiments*. 



Bullock receiving 



Rich cake Poor cake 



Loss of nitrogen ... ... 15-4 13-3 



1 See Journ. Roy. Agric. Sac. 1902, 63, 85-87. 



2 Berry, West of Scot. Bull. No. xiv. 1914. ^ Wood, This Journ. 1907-8, 2, 207. 

 * Journal S.E. Agric. Coll. 1905, No. 14, 187. 



Journ. of Agric- Sci. vin 34 



