3. It in part prevents the leaching out of the soluble parts of the ash.
4. It keeps the compost moist.
The first-named office of charcoal, i. e., absorbing and retaining gases, is one of the utmost importance. It is this quality that gives to it so high a position in the opinion of all who have used it. As was stated in the section on soils, carbonaceous matter seems to be capable of absorbing every thing which may be of use to vegetation. It is a grand purifier, and while it prevents offensive odors from escaping, it is at the same time storing its pores with food for the nourishment of plants.
Explain its action as a divisor.
How does charcoal protect composts against injurious action of rains?
How does it keep them moist?
2d. In its capacity as a divisor for manures, charcoal should be considered as excellent in all cases, especially to use with strongly concentrated (or heating) animal manures. These, when applied in their natural state to the soil, are very apt to injure young roots by the violence of their action. When mixed with a divisor, such manures are diluted, made less active, and consequently less injurious. In composts, manures are liable, as has been before stated, to become burned by the resultant heat of decomposition; this is called fire fanging, and is prevented by the liberal use of divisors, because, by increasing the bulk, the heat being diffused through a larger mass, becomes less intense. The same principle is exhibited in the fact that it takes more fire to boil a cauldron of water than a tea-kettle full.
3d. Charcoal has much power to arrest the passage of mineral matters in solution; so much so, that compost heaps, well supplied with muck, are less affected by rains than those not so supplied. All composts, however, should be kept under cover.
4th. Charcoal keeps the compost moist from the ease with which it absorbs water, and its ability to withstand drought.
What source of carbon is within the reach of most farmers?