Unleached wood ashes is generally the most available source from which to obtain this alkali. The ashes of all kinds of wood contain potash (more or less according to the kind—see analysis section V.) If the ashes are leached, the potash is removed; and, hence for the purpose of supplying it, they are worthless; but unleached ashes are an excellent source from which to obtain it. They may be made into compost with muck, as directed in a previous chapter, or applied directly to the soil. In either case the potash is available directly to the plant, or is capable of uniting with the silica in the soil to form silicate of potash. Neither potash nor any other alkali should ever be applied to animal manures unless in compost with an absorbent, as they cause the ammonia to be thrown off and lost.
From what other sources may potash be obtained?
How may we obtain soda?
In what quantities should pure salt be applied to the soil?
Potash sparlings, or the refuse of potash warehouses, is an excellent manure for lands deficient in this constituent.
Potash marl, such as is found in New Jersey, contains a large proportion of potash, and is an excellent application to soils requiring it.
Feldspar, kaolin, and other minerals containing potash, are, in some localities, to be obtained in sufficient quantities to be used for manurial purposes.
Granite contains potash, and if it can be crushed (as is the case with some of the softer kinds,) it serves a very good purpose.
SODA.
If applied in large quantities will it produce permanent injury?