Fo. 14C] 179 



-^ith the «:a«es of the compost heap will cause much greater 

 'growths to occur than will be observed from the other portion 

 not so treated. The same results will occur with alumina (clay), 

 when mixed with a permeable divisor, and placed where the fer- 

 d;ilizing gases can pass througk the mass. 



From the foregoing it is then evident that when manures de- 

 compose in a soil fairly eharged with carbonaceous matter and 

 alumina, that portions in solution do not filter downward to any 

 material depth; and after assuming the ^gaseous form, that these 

 gases cannot pass upward through such soils into the atmosphere, 

 but are retained for the use of plants, if the manures from whi«h 

 these gases arise are at sufficient depth for the rising gases to meet 

 with a sufficient number of particles of the absorbing materials 

 iDefore their reaching the surface. 



The proper depth, then, to which manures should be buried m 

 the Soil, must depend in part on the quality of that soil. If the 

 surface soil be thin and underlaid by a pure sand or gravel as a, 

 subsoil, then, of course, the manure should not be so deeply 

 buried as to lose its soluble portions in this sand or gravel, but 

 should rather be underlaid by a few inches of soil, so as to absorb 

 the soluble portions of the manure. '' 



In a sandy surface soil, having but slight quantities of carbon 

 or clay, manures, as a general rule, should be more deeply buried, 

 -so that the resultant gases maybe all absorbed before their escape 

 ^t the surface ; while in black (carbonaceous) or clayey loams a 

 kss depth will secure the desired results. 



There are many other facts, however, which the judicious cul- 

 tivator of the soil must take into account before deciding on the 

 depth to which he will plant his manures. Thus the market gar- 

 dener, who averages three crops in the season from the €ame soil, 

 must place part, at least, of his manure near enough the surface 

 to decompose rapidly from the assistance of the sun's heat, atmos- 

 pheric influence, &c., which will take place at much greater 

 depth in well under-drained and subsoiled land; while the farmer 

 who wishes to lay down his land to grass, and would prefer that 



