FERTILIZERS AND MANURES. 



59 



value. Before largely applying it, experiments should be 

 made on a small scale, as some marls, upon trial, are 

 found to be injurious. 



Charcoal renders the soil light and friable, gives it a 

 dark color, and additional warmth for early crops. The 

 bed whereon charcoal has been burnt is always marked 

 by a most vigorous growth of plants when it becomes 

 sufficiently mixed with earth. It contains also small 

 quantities of salts of potash and other fertilizing salts. 



It absorbs both carbonic acid and ammonia from the 

 air, and yields them to the roots of plants. It is most 

 marked in its effects on plants which require abundant 

 nitrogen. As it is indestructible, its beneficial effects 

 last as long as it remains in the soil, supplying the root- 

 lets of plants with carbonic acid, which is renewed as fast 

 as abstracted. Its good effects begin to be seen when the 

 dust is applied at the rate of forty bushels per acre. Char- 

 coal is invaluable for destroying the odor of decaying 

 animal matter, retaining all the gases in its own sub- 

 stance ready to yield them up for the use of plants. 

 Hence, the best application of this substance is not 

 directly to the soil, but to compost it with putrescent 

 animal matters, urine or night soil, of which it will ab- 

 sorb all the odor and fertilizing gases given off during 

 their decomposition. Composted with the last-named sub- 

 stance, it becomes poudrette, and is second only to guano 

 as a fertilizer. 



In striking cuttings or potting plants, fine charcoal is a 

 valuable substitute for sand, plants rooting in it with 

 great certainty. Plants will flourish in powdered char- 

 coal alone with considerable vigor, and, added to the 

 other materials used in potting, it is found greatly to pro- 

 mote healthy growth in most plants. 



Fine charcoal can be obtained in considerable quanti- 

 ties from the old hearths where it has been burned; also 



