170 



Charcoal as a Fertilizer. 



Vol. X. 



etalk, and potash with a small proportion of 

 lime, to all other plants. 



Upon the subject of charcoal possessing 

 the power of condensing^ ammonia, permit 

 me to give a few quotations from Dr. Lie- 

 big's great work on Agricultural Chemistry; 

 epeaking of the property of clayey soils and 

 soils that contain iron, of absorbing annno- 

 nia, he says: "Soils therefore which contain 

 oxides of iron and burned clay, must absorb 

 ammonia, an action which is favoured by 

 their porous condition ; they further prevent 

 the escape of the ammonia once absorbed by 

 their chemical properties." "The ammonia 

 absorbed by the clay or ferruginous o.xides 

 is separated by every shower of rain, and 

 conveyed in solution to the soil. Powdered 

 charcoal possesses a similar action, but sur- 

 pa.'ises all other substances in the power 

 which it possesses of condensing ammonia 

 within its pores, particularly when it has 

 been previously heated to redness. Char- 

 coal absorbs ninety times its volume of am- 

 moniacal gas, which may be again separated 

 by simply moistening it with water." De 

 Saussure. 



He is here speaking, of ammonia alone; 

 but when carbonic acid is present in the 

 charcoal, the ammonia enters into chemical 

 combination with it, and forms carbonate of 

 ammonia; and as charcoal possesses the 

 power of holding carbonic acid, even when 

 moist, and as water does not destroy its 

 chemical properties as long as the charcoal 

 holds it, it also holds that which is in chemi- 

 cal combination with it. 



In another place, while speaking of the 

 source of carbon and nitrogen, he says, " It 

 must not, however, be left unmentioned, that 

 common wood charcoal, by virtue of its or- 

 dinary well known properties, can com- 

 pletely replace vegetable mould or humus.''' 

 "Plants thrive in powdered charcoal, and 

 may be brought to blossom and bear fruit, if 

 exposed to the influence of the rain and the 

 atmosphere." "Charcoal is the most indif- 

 ferent and most unchangeable substance 

 known ; it may be kept fi)r centuries with- 

 out change, and is therefore not subject to 

 decomposition. The only substances which 

 it can yield to plants, are some salts which 

 it contains, amongst which is silicate of pot- 

 ash. It is known, however, to possess the 

 power of condensing gases within its pores, 

 and particularly carijonic acid. And it is by 

 virtue of this power that the roots of plants 

 are supplied in charcoal exactly as in humus, 

 with an atmosphere of carbonic acid and air, 

 which is renewed as quickly as it is ab- 

 stracted." 



An important consideration here presents 

 itself; this highly valuable substance — char- 



coal — "may be kept for centuries without 

 change, and is therefore not subject to de- 

 composition." Soils, therefore, once well 

 supplied with this article, will never again 

 need an application, unless that supply has 

 been removed from them by some unusual 

 means. This is a gratifying circumstance, 

 for though it may be somewhat expensive at 

 first to get it and place it in the soil, we 

 have reason to think we will never have it 

 to do over again. 



Liebig also says : " Charcoal in a state of 

 powder, must be considered a powerful means 

 of promoting the growth of plants on heavy 

 soils, and particularly on such as consist of 

 argillaceous earth." 



It would appear from a quotation already 

 made in this communication, that vegetable 

 manures to a certain extent, may be dis- 

 pensed with altogether — the plants depend- 

 ing for their carbonic acid and ammonia on 

 the supplies given to the charcoal by the at- 

 mosphere and the rain and snow. This looks 

 at the first glance, like supporting the theory 

 that plants can grow without manures — a 

 theory which, it appears to me, could have 

 originated only in minds that were short of 

 comprehension — but a little reflection will 

 show that such is not the case. It must not 

 be forgotten that I have used the expression 

 vegetable mannres, not saying anything 

 about the alkalies. As most vegetables do 

 not give sufficient alkalies to plants, but 

 supply carbonic acid and ammonia, and as 

 these substances under certain circumstances 

 are supplied in sufficient quantities by the 

 atmosphere, it will be seen that so far from 

 the plants growing without the manure, they 

 have a constant and proper supply of the 

 substances yielded by manure when the soil 

 in which they grow has a proper proportion 

 of pulverized charcoal. All that plants need 

 under such circumstances for their healthy 

 and productive growth, is the right kind of 

 alkalies and in right quantities. 



Care should be taken that the charcoal be 

 well pulverized, for it has been ascertained 

 that during the process of burning the wood 

 to get it, the openings of the pores become 

 closed by a vitreous matter — probably caused 

 by the fire molting the silicate of potash — 

 and thus deprive it of the power of absorb- 

 ing gases. I5y crushing it other openings 

 are made, which unless the charcoal is again 

 subjected to fire, will not become closed. 



Charcoal possesses another property, which, 

 in cold soils, is of groat importance, namely, 

 that of absorbing heat, and thus furnishing 

 warmth to the soil — this it does by virtue of 

 its black colour. 



In consequence of charcoal possessing the 

 power of absorbing carbonic acid, it is a 



