548 Oil Cake and Farmyard Manure. [dec, 



litter, it was well trodden to a firm, compact mass ; all the con- 

 ditions, in fact, for preserving it from decomposition appeared to 

 be observed, and yet in spite of this nearly 1 5 per cent, of the 

 nitrogen was lost. 



It appears, then, that in the circumstances above described 

 the normal loss of nitrogen is about 15 per cent., and this ap- 

 parently cannot be reduced, though it may easily be increased. 

 The changes bringing about the loss have been much discussed 

 but are not yet understood. The loss is more serious than it 

 appears, for, in addition to the 15 per cent, mentioned, a certain 

 amount of the easily available ammoniacal nitrogen is converted 

 into slowly available insoluble bodies. 



These experiments also afforded an opportunity for com- 

 paring the relative value of peat moss and straw as litter, as 

 owing to a fire at the farm it was necessary to' buy all the 

 straw. The same price was paid for both, viz., £2 per ton. 



The two chief manuriai functions of litter are to add fertilising 

 material to the manure, and to retain volatile, but valuable, 

 nitrogenous compounds. 



As regards the addition of fertilising matter, analysis of the 

 two substances gave the following percentages : — 



Peat Moss. Straw. 



Nitrogen ... ... ... .. ... ... "83 '49 



Phosphoric acid - lo -32 



Potash '17 1-64 



Peat moss, it will be seen, contains more nitrogen than straw, 

 but less phosphoric acid and much less potash. This important 

 point needs to be fully emphasised ; farmyard manure made 

 with straw litter, contains sufficient potash for ordinary pur- 

 poses, and potassic manures in consequence are not much 

 needed. But when peat moss is substituted for straw, there is 

 no longer a sufficiency of potash, and these manures must 

 therefore be applied ; they are very cheap and the saving in 

 nitrogen more than recompenses the farmer for his outlay. 



With regard to the absorptive power of the two substances, 

 it has been pointed out above that the minimum loss of nitrogen 

 in good farming practice is not less than 1 5 per cent. It is easy 

 to exceed this, and 30 or 40 per cent, would not improbably be 

 lost in many cases. Both straw and peat, in common with other 

 cellulose substances, have the power of absorbing ammonia, 



