1864.] CHEMISTRY OP MANURES. 203 



evidently there will be a disparity in the results, which will appear 

 inexplicnble. or which will perhnps be attribute', by the advocates 

 of rival theories, to this or that property of the manure employed. 

 But it is not necessary to go beyond the soil itself in search 

 of such declensions from type. Defects of the soil occur, frrade 

 below irrade, th'ough all the possible varieties of poverty, down 

 to absolute barrenness ; and the characters and causes of defective 

 fertility differ fully as much as do its innumerable degrees. One 

 soil, for instance, will contain but a poor supply of one or more 

 of the essential cinereal ingredients of the plants to be grown, or 

 will even be totally deficient thereof. Another, well endowed with 

 cinereals, duly apportioned to supply the desired rotation of crops, 

 will be deficient of carboniferous material, or non-retentive of 

 moisture, or not porous enough to hold a sufficient supply of air. 

 A third, perfect perhaps in those respects, will fall short as to the 

 peculiar physico-chemical properties necessary for the absorption, 

 or generation, or retention therein, of ammoniacal supplies, in pro- 

 per proportion to the air and water, to the carbon, and to the 

 cinereals. All parties must assuredlv admit, with respect to such 

 soils, that their natural deficiencies, whether cinereal or ammo- 

 niacal, aerial, hygroscopic, or carbonaceous, may with propriety be 

 artificially made good, — so far as such amendment be economically 

 possible ; and, in each such case, some particular kind of manure 

 will of course prove specially beneficial for the growth of cr'^ps. 

 Thus much will be conceded by those who, with Baron Liebig, 

 most strenuously oppose the doctrine of " specific" manures. In 

 some cases, for example, nitrogen will be " specific" for corn ; 

 though only in the same sense, and in the same degree, that lime 

 will, in other cases, " specifically " benefit the same crop. 



Again, that leguminous crops rapidly assimilate atmospheric 

 ammonia by means of their widely-spread leafage, whereas the 

 cereals, with their scanty foliage, are much more dependent on their 

 roots for ammoniacal supplies, — these are facts which no one will 

 dispute. Th- use of fodder-crops and cattle-feeding, as means of 

 artificially accumulating the ammonia-supplies naturally difi"used 

 over the whole period of rotation, and bringing this concentrated 

 provision to bear on the cereals, which could not else absorb 

 ammonia at a sufficiently rapid rate to keep their nitrogenous on a 

 par with their cinereal, carbonaceous, and aquatic alimentation, — 

 this also will certainly be admitted by all. 



