[What should be learned before purchasing amendments for the soil?

What do you know of silica?]

Many farmers will find it expedient to purchase bones, or bone dust, and manufacture their own super-phosphate of lime; others will prefer to purchase the prepared manure. In doing so, it should be obtained of men of known respectability, as manures are easily adulterated with worthless matters; and, as their price is so high, that such deception may occasion great loss.

We would not recommend the application of any artificial manure, without first obtaining an a.n.a.lysis of the soil, and knowing _to a certainty_ that the manure is needed; still, when no a.n.a.lysis has been procured, it may be profitable to apply such manures as most generally produce good results--such as stable manure, night soil, the improved super-phosphate of lime; or, if this cannot be procured, guano.

NEUTRALS.

SILICA.

_Silica_ (or sand) always exists in the soil in sufficient quant.i.ties for the supply of food for plants; but, as has been often stated in the preceding pages, not always in the proper condition. This subject has been so often explained to the student of this book, that it is only necessary to repeat here, that when the weakness of the straw or stalk of plants grown on any soil indicates an inability in that soil to supply the silicates required for strength, not more sand should be added, but _alkalies_, to combine with the sand already contained in it, and make _soluble silicates_ which are available to roots.

Sand is often necessary to stiff clays, as a _mechanical_ manure, to loosen their texture and render them easier of cultivation, and more favorable to the distribution of roots, and to the circulation of air and water.

CHLORINE.

[How may chlorine be applied?]

_Chlorine_, a necessary const.i.tuent of plants, and often deficient in the soil (as indicated by a.n.a.lysis), may be applied in the form of salt (chloride of sodium), or chloride of lime. The former may be dissolved in the water used to slake lime, and the latter may, with much advantage, be sprinkled around stables and other places where fertilizing gases are escaping, and, after being saturated with ammonia, applied to the soil, thus serving a double purpose.

OXIDE OF IRON.

[How may the protoxide of iron be changed to peroxide?]

Nearly all soils contain sufficient quant.i.ties of _oxide of iron_, or iron rust, so that this substance can hardly be required as a manure.

Some soils, however, contain the _prot_oxide of iron in such quant.i.ties as to be injurious to plants,--see page 86. When this is the case, it is necessary to plow the soil thoroughly, and use such other mechanical means as shall render it open to the admission of air. The _prot_oxide of iron will then take up more oxygen, and become the _per_oxide--which is not only inoffensive, but is absolutely necessary to fertility.

OXIDE OF MANGANESE.

This can hardly be called an essential const.i.tuent of plants, and is never taken into consideration in manuring lands.

VARIOUS OTHER MINERAL MANURES.

LEACHED ASHES.

[Why are leached ashes inferior to those that have not been leached?

On what do the benefits of leached ashes depend?

Can these ingredients be more cheaply obtained in another form?

Why do unleached ashes, applied in the spring, sometimes cause grain to lodge?]

Among the mineral manures which have not yet been mentioned--not coming strictly under any of the preceding heads, is the one known as _leached ashes_.

These are not without their benefits, though worth much less than unleached ashes, which, besides the const.i.tuents of those which have been leached, contain much potash, soda, etc.

Farmers have generally overrated the value of leached ashes, because they contain small quant.i.ties of available phosphate of lime, and soluble silicates, in which most old soils are deficient. While we witness the good results ensuing from their application, we should not forget that the fertilizing ingredients of _thirty bushels_ of these ashes may be bought in a more convenient form for _ten_ or _fifteen cents_, or for less than the cost of spreading the ashes on the soil. In many parts of Long Island farmers pay as much as eight or ten cents per bushel for this manure, and thousands of loads of leached ashes are taken to this locality from the river counties of New York, and even from the State of Maine, and are sold for many times their value, producing an effect which could be as well and much more cheaply obtained by the use of small quant.i.ties of super-phosphate of lime and potash.

These ashes often contain a little charcoal (resulting from the imperfect combustion of the wood), which acts as an absorbent of ammonia.

It is sometimes observed that _unleached_ ashes, when applied in the spring, cause grain to lodge. When this is the case, as it seldom is, it may be inferred that the potash which they contain causes so rapid a growth, that the soil is not able to supply silicates as fast as they are required by the plants, but after the first year, the potash will have united with the silica in the soil, and overcome the difficulty.

OLD MORTAR.

[What are the most fertilizing ingredients of old mortar?]

_Old mortar_ is a valuable manure, because it contains nitrate of potash and other compounds of nitric acid with alkalies.

These are slowly formed in the mortar by the changing of the nitrogen of the hair (in the mortar) into nitric acid, and the union of this with the small quant.i.ties of _potash_, or with the _lime_ of the plaster.

Nitrogen, presented in other forms, as ammonia, for instance, may be transformed into nitric acid, by uniting with the oxygen of the air, and this nitric acid combines immediately with the alkalies of the mortar.[AI]

The lime contained in the mortar may be useful in the soil for the many purposes accomplished by other lime.

GAS HOUSE LIME.

[How may gas-house lime be prepared for use?

Why should it not be used fresh, from the gas house?

On what do its fertilizing properties depend?

What use may be made of its offensive odor?]

_The refuse lime of gas works_, where it can be cheaply obtained, may be advantageously used as a manure. It consists, chiefly, of various compounds of sulphur and lime. It should be composted with earth or refuse matter, so as to expose it to the action of air. It should never be used fresh from the gas house. In a few months the sulphur will have united with the oxygen of the air, and become sulphuric acid, which unites with the lime and makes sulphate of lime (plaster), which form it must a.s.sume, before it is of much value. Having been used to purify gas made from coal, it contains a small quant.i.ty of ammonia, which adds to its value. It is considered a profitable manure in England, at the price there paid for it (forty cents a cartload), and, if of good quality, it may be worth double that sum, especially for soils deficient in plaster, or for such crops as are much benefited by plaster. Its price must, of course, be regulated somewhat by the price of lime, which const.i.tutes a large proportion of its fertilizing parts. The offensive odor of this compound renders it a good protection against many insects.

The refuse _liquor of gas works_ contains enough ammonia to make it a valuable manure.

SOAPERS' LEY AND BLEACHERS' LEY.

[What use may be made of the refuse ley of soap-makers and bleachers?

What peculiar qualities does soapers' ley possess?]

The refuse ley of soap factories and bleaching establishments contains greater or less quant.i.ties of soluble silicates and alkalies (especially soda and potash), and is a good addition to the tank of the compost heap, or it may be used directly as a liquid application to the soil.

The soapers' ley, especially, will be found a good manure for lands on which grain lodges.

Much of the benefit of this manure arises from the soluble silicates it contains, while its nitrogenous matter,[AJ] obtained from those parts of the fatty matters which cannot be converted into soap, and consequently remains in this solution, forms a valuable addition. Heaps of soil saturated with this liquid in autumn, and subjected to the freezings of winter, form an admirable manure for spring use. Mr. Crane, near Newark (N. J.), has long used a mixture of spent ley and stable manure, applied in the fall to trenches plowed in the soil, and has been most successful in obtaining large crops.