65 



from the results obtained; but as they stand, the above 

 figures point to a striking increase in feeding value per 

 acre, resulting from the use of sulphate of ammonia with 

 superphosphate. A number of manurings were tested 

 in the same way; but this gave the highest live weight 

 increase. 



In the following year, however, when the same plots 

 were again grazed with sheep, but no further manure was 

 applied, sulphate of ammonia and superphosphate gave com- 

 paratively poor results. The produce was still not far short 

 of double that of the unmanured plot ; but the mineral 

 manures particularly basic slag gave relatively much 

 better results. This is very much what we should expect 

 from the consideration of the principles controlling the action 

 of sulphate of ammonia. A residue is left beyond the first 

 year after application ; but a considerable loss of nitrogen 

 takes place by drainage, especially during the winter. This 

 loss is less in the case of grass land than from arable ; but 

 still sulphate of ammonia cannot be expected to produce 

 relatively good results in the second season after application, 

 compared with mineral manures, the valuable constituents of 

 which are held safely by the soil. That the time elapsed since 

 the sulphate of ammonia was applied had some influence in 

 causing the inferior returns in the second year of experiment, 

 seems more probable from the fact that in the autumn and 

 early winter of 1897-8, when all the plots were grazed by 

 store cattle, the plot manured with sulphate of ammonia and 

 superphosphate carried the largest amount of stock ; being 

 equalled only by that dressed with half a ton of basic slag. 

 So that up till then at least, it was still doing well. 



It will be noticed that, in these Northumberland experi- 

 ments, no other purely nitrogenous manures were employed ; 

 so that no further light is thrown on the effect of sulphate of 

 ammonia compared with nitrate of soda. 



The available experiments, therefore, all seem to show 

 that sulphate of ammonia has a good effect on the feeding 

 value of the crop, besides giving a large increase in its 

 bulk. Used occasionally, and in moderate quantity say, 

 from i to li cwt. per acre the necessary minerals being 

 also present in the soil or manure, sulphate of ammonia will 

 give a better result on the average than any other purely 

 nitrogenous manure, if both the quantity and the quality 

 of the produce be taken into account. 



We have now considered the general principles involved in 

 the use and action of sulphate of ammonia, and its effect on 

 the chief farm crops individually, as shown by experiment. 

 The conclusion arrived at is that, when used judiciously, 

 sulphate of ammonia is a most valuable nitrogenous 

 manure. But it must be repeated that it supplies only 



