on Permanent Meadow Land. 561 



bonic acid it yields in its decomposition, upon the mineral con- 

 stituents of the soil. The plot where there were employed per 

 acre annually 2000 lbs. of sawdust (containing 4 to 5 lbs. of 

 nitrogen), yielded, however, an average annual produce of about 

 3^ cwts. less hay than the unmanured land. Where 2000 lbs. of 

 sawdust were employed icitli ammoniacal salts (Plot 5), there 

 were only 6 lbs. per acre per annum more produce than where 

 the same description and amount of ammoniacal salts were used 

 alone (Plot 4). When the same amount of sawdust was added 

 with a liberal mineral manure (Plot 9), the mixture gave annu- 

 ally about 2| cwts. more hay than when the same mineral manure 

 (Plot 8) was used alone. Lastly, when the sawdust was em- 

 ployed in admixture with both the ammoniacal salts and the 

 mineral manure (Plot 11), the produce per acre per annum was 

 about -I cwt. less than when the same ammoniacal salts and 

 mineral manure (Plot 10) were used without the sawdust. The 

 nearly a ton per acre per annum of organic matter rich in carbon, 

 in the form of sawdust, was then practically of no avail. 



As the previous enumeration and the Table show, the ammo- 

 niacal salts employed consisted of an equal mixture of the sul- 

 phate and the muriate of ammonia of commerce. This mixture 

 is reckoned to contain about 25 per cent, of ammonia, which is 

 equal to about 20*5 per cent, of nitrogen. The 400 lbs. of am- 

 moniacal salts per acre per annum, as used on several of the 

 plots, would therefore bring annually on to the land about 

 100 lbs. of ammonia. 



AVhere the 400 lbs. of ammoniacal salts were used alone 

 (Plot 4), they gave an average annual increase of 11 cwts. of hay. 

 The average annual produce by the ammoniacal salts was 1 ton 

 15 cwts. of hay. 



The " mixed mineral manure " alone (Plot 8), which contained 

 an ample supply of acid — phosphate, and sulphate of lime, and of 

 potash, soda, and magnesia, in the form of sulphates, but which 

 did not afford, in a direct manner, an increased supply of available 

 silica, gave an average annual increase of about 9j cwts. of hay 

 per acre. 



The ammoniacal salts alone, it has been seen, gave an annual 

 increase of 11 cwts. of hay; only 1| cwt. more, therefore, than 

 purely mineral manures. It will be shown, however, in some 

 detail in a subsequent section, that the description of the in- 

 crease differed exfremely in the two cases. In fact, where the 

 ammoniacal salts were employed, the increase was exclusively due 

 to the increased growth of Graminaceous plants — the so-called 

 Natural Grasses — there being scarcely a Leguminous plant to be 

 found upon the plot. Where the purely mineral manures were 

 used, on the other hand, the Grasses, properly so called, were 



