564 Report of Experiments with different Manures 



straw, like the duplicate unmanured one, was, however, somewhat 

 shaded ; and like the latter, though it gave a somewhat deficient 

 first crop, gave at the same time rather more after-grass than the 

 plots most comparable with it. It remains to be seen, therefore, 

 whether the less exhaustion by the first crop hitherto, and the 

 greater return of constituents as manure in the consumption of 

 the second crop, will not, before long, tell upon the amount of 

 produce of the first crop. And how far the inefficiency of both 

 sawdust and cut wheat-straw was due to the slowness of their 

 decomposition, will perhaps be apparent in the course of years. 



The mixed mineral manures in conjunction with 400 lbs. per 

 acre, per annum, of ammoniacal salts, gave an annual produce 

 of more than 2 tons 19 cwts., and an annual increase (over the 

 unmanured) of 1 ton 15| cwts. of strictly Graminaceous hay. The 

 same mineral manures, together with double the above amount of 

 ammoniacal salts, gave even more produce and increase still. 

 The mineral manures and the double supply of ammoniacal salts 

 gave, on the average, 3 tons 3f cwts. of annual produce, and ] 

 ton 19f cwts. of annual increase of Graminaceous hay. 



When we bear in mind the fact, that the mixed mineral 

 manure alone scarcely increased the Graminaceous produce at all, 

 it would appear that the increase of such produce, upon the 

 super-addition of the 400 lbs., or of the 800 lbs. of ammoniacal 

 salts, was (so far as its nitrogen was concerned) at any rate 

 mainly due to that which was thus artificially supplied. Assum- 

 ing this to have been the case, it would result that the first 

 increment of 400 lbs. of ammoniacal salts ( = 100 lbs. ammonia) 

 yielded an increase of 1 ton 15f cwts. of hay, but that the 

 second increment of the same amount gave a further increase of 

 only 4f cwts. Tlie two together, as above stated, gave 1 ton 

 1 9f cwts. of increase. As the nitrogenous supply was increased, 

 the effect of a given amount of it was therefore very greatly 

 diminished. Nor is this result to be attributed to a deficiency 

 of mineral constituents where the larger amount of ammoniacal 

 salts was employed. The produce on the addition to the mineral 

 manure of the smaller amount of ammoniacal salts, was indeed 

 quite as heavy, if not heavier, than the soil and seasons were 

 suited to mature advantageously. Further evidence on the point 

 will be adduced in a subsequent section of the Report. But it 

 may be here stated in passing, that the crop grown by the larger 

 amount of ammoniacal salts — supplying as it did the enormous 

 quantity of 200 lbs. of ammonia per acre per annum — was so 

 over-luxuriant, as to be much laid, matted together, 'and dead at 

 the bottom, some time before the bulk was ready for cutting. 



It has been already stated that the trials with nitrate of soda 

 were not commenced until the last of the three seasons, over 



