292 IMPROVEMENT OF THE SOIL 



with bases, and the whole taken together has been called geine 

 and humus. But' when the fermenting heap is exposed to the 

 rains, the salts and the vegetable matters are dissolved by the 

 water, and pass down into the soil or run to waste ; hence, 

 the reason for the direction above given, to place under the 

 heap a thick bed of earth or swamp-muck, to absorb these 

 liquid matters. 



When these changes have proceeded awhile, the whole mass 

 is converted into an effectual manure, into geine and salts, fit- 

 ted for any soil or crop. If the heap contain a large quan- 

 tity of animal matter , the tendency to putrefaction is much 

 increased, a much larger quantity of ammonia is formed, and 

 also a larger quantity o( nitrates. 



3. If the manures are carried, in their green state, direct- 

 ly upon the field, as a top dressing, the air of course, and 

 not the crop, receives the larger portion of their valuable 

 products. But if they are spread, and turned into the soil, 

 the changes which we have described take place much more 

 slowly, a circumstance which, on many accounts, is highly 

 favorable to vegetation. The plant requires a constant and 

 regular supply of nutriment, and this process supplies it. 

 The heat, which always attends their decompositions, acts 

 with great power, and with the best effect, especially in cold 

 wet soils. The gaseous matters are directly absorbed by 

 the loam, and more perfectly retained than they can be in 

 the heap. Still it may be doubted, whether the manure, from 

 its diffusion through the soil, is as favorably situated for those 

 chemical changes, which must take place, before it can nour- 

 ish plants. It may well be doubted whether so large a quan- 

 tity of soluble geine and salts will be furnished in this way, 

 as when placed under fitting circumstances in heaps, and 

 whether more vegetable matter will not be dissipated in the 

 air. 



If, however, soils are wet and cold, manures should be ap- 

 plied in the green state, rather than permitted to ferment in 



