41 



years, 1890-96, have been : From nitrate of soda, containing 

 41 Ibs. of "nitrogen, employed with ash constituent manures, 

 28-6 bushels ; from rape-cake, containing 82 Ibs. of nitrogen, 

 27*1 bushels; from farmyard manure made from 188 Ibs. 

 of nitrogen in food and litter, applied as a top dressing, 

 26-8 bushels. 



In the barley experiments, with precisely similar manures, 

 the return from the nitrate of soda was 41 bushels ; from the 

 rape-cake, 37*4 bushels ; from the farmyard manure, 42-8 

 bushels. Both in the experiments with wheat and barley the 

 rape-cake thus appeared as inferior in effect to one-half its 

 equivalent in nitrate of soda. The comparison made is, how- 

 ever, distinctly unfair to the cake, owing to the unequal 

 quantities of nitrogen and ash constituents supplied in the 

 comparative experiments. 1 



We turn next to the results obtained by consuming cake 

 on the land. The present rotation experiments at Woburn, 

 already described (Table V.), furnish us with a comparison of 

 the effects of the manure of cake-fed sheep with that given by 

 a nearly corresponding dressing of nitrate of soda. In eleven 

 annual experiments, the consumption of about 21 Ibs. of 

 nitrogen as decorticated cotton-cake by sheep feeding off 

 turnips increased the following crop of barley by 3 bushels ; 

 while, at the same time, the application of 20 Ibs. of nitrogen 

 as nitrate of soda increased the barley crop by 6'1 bushels. 

 The nitrogen of cake consumed on the land had thus about 

 half the manurial value of the nitrogen as nitrate of soda. 



Woburn supplies us with trials of farmyard manure, made 

 under the most favourable circumstances, from food and litter 

 containing a known quantity of nitrogen. This manure has 

 been continuously applied as a top dressing for twenty years 

 to both wheat and barley. How does the nitrogen of food 

 when converted with great care into farmyard manure compare 

 with the nitrogen of nitrate of soda ? To obtain the best 



1 The produce with nitrate of soda alone, without superphosphate or 

 potash salts, was during the seven years, for wheat 22-6 bushels, and for 

 barley 30 - 4 bushels. To compare these crops with the produce from the rape- 

 cake is as unfair to the nitrate as the comparison above is unfair to the cake. 

 The cake in fact contained some ash constituents, and was applied to a plot 

 containing residues of farmyard manure. 



D 



