ORGANIC MANURES. 61 



mooted, as to the comparative advantages of long and short 

 manure the fermented and unfermented. This must de- 

 pend on the use for which they are designed. If intended for 

 the garden beds, for loose, light soils, or as a top dressing for 

 meadows or any crops, or if needed to kill any noxious seeds 

 incorporated with the heap, it should be fermented ; if for 

 hoed crops in clay or loamy soils, it should be used in as 

 fresh or unchanged a condition as possible. Loose soils are 

 still further loosened for a time, by long manure, and much 

 of its volatile parts is lost before it is reduced to mold. Ad- 

 hesive and compact soils, on the contrary, are improved by the 

 coarsest manures. These tend to the separation of the earth ; 

 and all the gases which are set free in fermentation, are 

 combined and firmly held in the soil. 



Decomposition of Manures. Three conditions are essen- 

 tial to produce rapid decomposition in manure ; air, mois- 

 ture, and a temperature above 65 ; and these, except in 

 frosty weather, are generally present in the heap. The 

 gradual chemical changes going on in all manures,- but most 

 actively in the excrements of the horse and sheep, when they 

 have sufficient air and moisture, induce an elevation, which 

 keeps them always above the temperature of the sur- 

 rounding air. If the manure be trodden compactly, and satu- 

 rated with water, the air cannot circulate ; and if its tempera- 

 ture be likewise kept down, it will be preserved a long time 

 unchanged. The fermentation of manure should go forward, 

 when thoroughly blended with all the vegetable and liquid fer- 

 tilizers about the premises, and also including ashes, charcoal, 

 gypsum and coal-dust ; the last three substances combining 

 with and retaining the ammonia as it is formed. Over 

 all these should be placed a good coating of turf, peat, or fine 

 mold, which will absorb any gases that escape the gypsum, 

 and other absorbents. 



Old mortar or effete lime may also be added, for the forma- 

 tion of nitric acid. It draws this not only from the materials 

 in the heap, but largely also from the nitrogen of the air ; it 

 having been ascertained in the manufacture of salt-petre, 

 (nitrate of potash,) that the amount of nitrogen in the salt, 

 is greatly increased above that in the manure used. The 

 absorption of nitre by lime, in a course of years, is very large, 

 as is shown by the practice of the Chinese farmers, who to 

 secure it for manure, will gratuitously remove the old plas- 

 ter on walls and replace it with new. 



If required to hasten decay, and especially, if there be in- 



