ACTUAL VALUE OF MANURE 223 



before they reach the land. In the yard or stable 

 much urine may run to waste. Ammonia will 

 volatilise as gas in the stable during the decom- 

 position of the urine. The mixed manure and litter 

 may again suffer loss by drainage if exposed to rain. 

 Considerable further loss of nitrogen may occur during 

 the fermentation in the manure heap, free nitrogen 

 being evolved. In the case of ordinary farmyard manure 

 less, and sometimes much less, than one-half the 

 nitrogen that left the animal is finally brought on to 

 the land. Any loss of urine, or drainage from the heap, 

 will also seriously diminish the supply of potash. 



The results obtained by manuring barley crops at 

 Eothamsted and Woburn illustrate the varying manure 

 values of the nitrogen of oilcake when appHed to the 

 land in various stages of use. Kape cake ploughed 

 into the land at Eothamsted before sowing barley has 

 yielded an average return of about 80 per cent, of that 

 yielded by a similar amount of nitrogen applied as 

 nitrate of sodmm.^ Decorticated cotton cake is con- 

 sumed at Woburn by sheep feeding off swedes. Its 

 average effect on the following barley crop is about 46 

 per cent, of that yielded by the same quality of nitro- 

 gen as nitrate of sodium applied directly to the barley. 

 Cake and other foods are consumed at Woburn by 

 fattening bullocks in deep stalls or boxes. The manure 

 is left undisturbed till the feeding is completed, then 

 taken out and clamped, and finally applied as a top 

 dressing to barley in a very well-rotted condition. 



' Applied to mangels, the average return from rape cake and nitrate 

 of sodium is at Rotliamsted very similar, though in individual seasons 

 the differences are considerable. 



