When fresh manure is deposited in the soil, the same changes occur, but they then proceed more slowly, and experience has shown that a much smaller effect is produced on the crop to which it has been applied than when it has been well fermented in the heap. This effect is consistent with theory, which would further indicate that well-fermented dung must be especially advantageous when applied to quick-growing crops, and less necessary to those which come slowly to maturity. As a rule, well fermented manure is to be preferred, provided it has been well managed and carefully prepared; but when this has not been done, and the manure has been exposed to the weather, or made in open courts or hammels, the economic advantages are all on the side of the fresh dung. It may be questioned also whether, now that there are so many other available sources of ammonia, it may not in many instances be advantageous to use the dung fresh, conjoined with a sufficient quantity of some salt of ammonia, or other substance fitted to supply the quantity of that element necessary for the requirements of the crop.

After the farm-yard manure has been prepared at the homestead, it is often necessary to cart it out to the field some time before it is to be applied, and it is a question of some importance to determine how it may be best preserved there. The general practice is to store it in heaps in the corners of the fields, but some difference of opinion exists as to whether it should be lightly thrown up so as to leave it in a porous state, and so promote its further fermentation, or whether it should be consolidated as much as possible by driving the carts on to the top of the heap during its construction. Considering the risks to which the manure is exposed on the field, the latter plan would appear to be the best. It is advisable also to interstratify the dung with dry soil, so as to absorb any liquid which may tend to escape from it, and it should also be covered with a well-beaten layer of earth, in order to exclude the rain. Although these precautions must not be omitted if the manure is to be stored in heaps, it will probably be often found quite as advantageous to spread it at once, and leave it lying on the surface until it is convenient to plough it. The loss of ammonia by volatilization will, under such circumstances, especially in the cold season of the year, be very trifling, and the rain which falls will only serve to incorporate the soluble matters with the soil, where they will be retained by its absorptive power.

In the actual application of the manure to the crop, several points require consideration. It is especially important to determine whether it ought to be uniformly distributed through the soil, or be kept near the roots of the plants. Both systems have their advocates, and each has advantages in particular cases. The choice between the two must greatly depend upon the nature of the crop and the soil. When the former is of a kind which spreads its roots wide and deep through the soil, the more uniformly the manure can be distributed the better; but when it is used with plants whose roots do not travel far, it is more advantageous to accumulate it near the seeds. Obvious advantages also attend this practice in soils which are either too heavy or too light. When, for example, it is necessary to cultivate turnips in a heavy clay, the manure put into the drills produces a kind of artificial soil in the neighbourhood of the plants, in which the bulbs expand more readily than in the clay itself. On the other hand, when a large quantity of dung, in a state of active fermentation, comes into immediate contact with the roots, its effect is not unfrequently injurious. These and many other points, which will readily suggest themselves to any one who studies the composition and properties of farm-yard manure, belong more strictly to the subject of practical agriculture, and need not be enlarged on here.

In the present state of agriculture, a proper estimate of the money value of farm-yard manure is of much importance in an economic point of view, and many matters connected with the profitable management of a farm must hinge upon it. If an estimate be made upon the principle which will be explained when we come to treat of artificial manures, it appears that fresh farm-yard manure of good quality is worth from 12s. to 15s. per ton, and well-rotted dung rather more. It is questionable, however, whether the system of valuation which is accurate in the case of a guano or other rapidly acting substance, is applicable to farm-yard manure, the effects of which extend over some years. A deduction must be made for the years during which the manure remains unproductive, and also for the additional expense incurred in carting and distributing a substance so much more bulky than the so-called portable manures, and it would not be safe to estimate its value at more than 7s. or 8s. per ton.

Liquid Manure.—This term is applied to the urine of the animals fed on the farm, and to the drainings from the manure-heap, which, in place of being returned to it, are allowed to flow away, and collected in tanks, from which they are distributed by a watering-cart, or according to the method recently introduced in Ayrshire, and since adopted in other places, by pipes laid under-ground in the fields, and through which the manure is either pumped by steam-power, or, where the necessary inclination can be obtained, is distributed by gravitation. That liquid manure must necessarily be valuable, is an inference which maybe at once drawn from the analyses of the urine of different animals already given, and of which it chiefly consists. In addition to the urine, however, it contains also the soluble organic and mineral matters of the dung, as well as a quantity of solid matters in suspension, among which phosphates are found, and thus it possesses a supply of an element which would be almost entirely deficient if it were composed of urine alone. In the following analyses by Professor Johnston, No. 1 is the drainings of the manure-heap when exposed to rain; and No. 2 the same, when moistened with cows' urine pumped over it, the results being expressed in grains per gallon:—

No. 1.No. 2.
Ammonia9·621·5
Organic matter200·877·6
Ash268·8518·4
————
Total solids in a gallon479·2617·5

The ash contained—

Alkaline salts207·8420·4
Phosphates25·144·5
Carbonate of lime18·231·1
Carbonate of magnesia, and loss4·33·4
Silica and alumina13·419·0
————
268·8518·4

More elaborate analyses of the same fluid have since been made by Dr. Voelcker, with the subjoined results per gallon:—

1.2.3.
Organic matters and ammoniacal salts263·80250·6370·121
Silica2·499·981·154
Oxide of iron0·700·68...
Lime5·3425·1813·011
Magnesia2·9615·331·660
Potash103·23112·2613·411
Chloride of potassium72·0077·387·712
Chloride of sodium17·1846·0317·258
Phosphoric acid2·709·512·304
Sulphuric acid22·3137·603·408
Carbonic acid, and loss33·9027·9514·025
—————————
Total solids526·61612·53144·064
Ammonia114·1622·3126·647