IMPORTANCE OF FARM MANURES
Of these two classes of manures the farmer should rely chiefly on the farm manures letting the commercial fertilizers take a secondary place because:
Farm manures are complete manures; that is they contain all the necessary elements of plant food.
Farm manures add to the soil large amounts of organic matter or humus.
The decay of organic matter produces carbonic acid which hastens the decay of mineral matter in the soil and so increases the amount of available plant food.
The organic matter changes the texture of the soil.
It makes sandy soils more compact and therefore more powerful to hold water and plant food.
It makes heavy clay soils more open and porous, giving them greater power to absorb moisture and plant food. This admits also of better circulation of the air in the soil, and prevents baking in dry weather.
Farm manures influence all of the conditions necessary for root growth while the commercial fertilizers influence mainly the plant food conditions.
The farm manures are good for all soils and crops.
They are lasting in their effects on the soil.
BARN OR STABLE MANURE
Barn or stable manure consists of the solid and liquid excrement of any of the farm animals mixed with the straw or other materials used as bedding for the comfort of the animals and to absorb the liquid parts.
The liquid parts should be saved, as they contain more than half of the nitrogen and potash in the manure.
The value of barn manure for improving the soil conditions necessary for root growth depends in a measure upon the plant food in it, but chiefly upon the very large proportion of organic matter which it contains when it is applied to the soil.
These factors are influenced somewhat: by the kind of animal that produces the manure; by the kind of food the animal receives; by the kind and amount of litter or bedding used; but they depend particularly on the way the manure is cared for after it is produced.
LOSS OF VALUE
Improper care of the manure may cause it to diminish in value very much.
Loss by leaching.
If the manure is piled against the side of the stable where water from the roof can drip on it, as is often the case, or if it is piled in an exposed place where heavy rain can beat on it, the rain water in leaching through the manure washes out of it nitrogen and potash, which pass off in the dark brown liquid that oozes from the base of the pile.
Loss by heating or fermenting
When barn manure is thrown into piles it soon heats and throws off more or less steam and gas. This heating of the manure is caused by fermentation or the breaking down of the materials composing the manure and the forming of new compounds. This fermentation is produced by very small or microscopic plants called bacteria.
The fermentation of the manure is influenced by the following conditions:
A certain amount of heat is necessary to start the work of the bacteria. After they have once started they keep up and increase the temperature of the pile until it gets so hot that sometimes a part of the manure is reduced to ashes. The higher the temperature the more rapid the fermentation. This can be seen particularly in piles of horse manure.
The bacteria which produce the most rapid fermentation in manure need plenty of air with its oxygen. Therefore fermentation will be more or less rapid according as the manure is piled loosely or in a close compact mass.
A certain amount of moisture is necessary for the fermentation to take place, but if the manure is made quite wet the temperature is lowered and the fermentation is checked. The water also checks the fermentation by limiting the supply of air that can enter the pile.
The composition of the manure influences the fermentation. The presence of considerable amounts of soluble nitrogen hastens the rapidity of the fermentation.
Now when the manure ferments a large part of the organic matter in it is broken down and changed into gases. The gas formed most abundantly by the fermentation is carbonic acid gas, which is produced by the union of oxygen with carbon of the organic matter. The formation of this gas means a loss of humus. This loss can be noticed by the fact that the pile gradually becomes smaller.
The next most abundant product of the fermentation is water vapor which can often be seen passing off in clouds of steam.
When manure ferments rapidly the nitrogen in it is changed largely into ammonia. This ammonia combines with part of the carbonic acid gas and forms carbonate of ammonia, a very volatile salt which rapidly changes to a vapor and is lost in the atmosphere. This causes a great loss of nitrogen during the rapid decomposition of the manure. This loss can be detected by the well known odor of the ammonia which is particularly noticeable about horse stables and piles of horse manure.
Besides these gases a number of compounds of nitrogen, potash, etc., are formed which are soluble in water. It is these that form the dark brown liquid that sometimes oozes out from the base of the manure heap.
APPLYING THE MANURE TO THE SOIL
From ten to twenty tons per acre is considered a sufficient application of barn manure for most farm crops. Larger amounts are sometimes applied to the soil for truck and market garden crops.
Barn manures are applied to the soil by these methods:
The manure is sometimes hauled out from the barn and placed in a large pile in the field or in many small piles where it remains for some time before being spread and plowed or harrowed in.
Some farmers spread it on the field and allow it to lie some time before plowing it in.
It is sometimes spread as soon as hauled to the field and is immediately plowed in or mixed with the soil. This last is the safest and most economical method so far as the manure alone is concerned.
When the manure is left in a large pile it suffers losses due to fermentation and leaching.
When distributed over the field in small piles and allowed to remain so for some time, losses from fermentation take place, and the rain washes plant food from the pile into the soil under and immediately about it. This results in an uneven distribution of plant food over the field, for when the manure is finally scattered and plowed in, part of the field is fertilized with washed out manure while the soil under and immediately about the location of the various piles is often so strongly fertilized that nothing can grow there unless it be rank, coarse weeds.
When the manure is spread on the surface and allowed to lie for some time it is apt to become dry and hard, and when finally plowed in, decays very slowly.
When the manure is plowed in or mixed with the soil as soon as applied to the field there results an even distribution of plant food in the soil, fermentation takes place gradually and all gases formed are absorbed by the soil, there is very little loss of valuable nitrogen and organic matter, and the fermentation taking place in the soil also aids in breaking down the mineral constituents of the soil and making available the plant food held by them.
Therefore it seems best to spread the manure and plow it in or mix it with the soil as soon as it is hauled to the field, when not prevented by bad weather and other more pressing work.
PROPER CONDITION OF MANURE WHEN APPLIED
A large part of the value of barn manure lies in the fact that it consists largely of organic matter, and therefore has an important influence on soil texture, and during its decay in the soil produces favorable chemical changes in the soil constituents. Therefore it will produce its greatest effect on the soil when applied fresh. For this reason it is generally best to haul the manure to the field and mix it with the soil as soon after it is produced as possible.
If coarse manures are mixed with light, sandy soils it is best to follow with the roller, otherwise the coarse manure may cause the soil to lie so loose and open that both soil and manure will lose moisture so rapidly that fermentation of the manure will be stopped and the soil will be unfit for planting.
If it is desired to apply manure directly to delicate rooted truck and vegetable crops it is best to let it stand for some time until the first rank fermentation has taken place and the manure has become rotten.
A good practice is to apply the manure in its fresh condition to coarse feeding crops like corn, and then follow the corn by a more delicate rooted crop which requires the manure to be in a more decomposed condition than is necessary for the corn. In this case the corn is satisfied and the remaining manure is in proper condition for the following crop when it is planted.
Another practice is to broadcast the coarse manure on grass land and then when the hay is harvested the sod and remaining manure are plowed under for the following crop.
A study of root development in Chapter II. tells us that most of the manure used for cultivated crops should be broadcasted and thoroughly mixed with the soil. A small amount may be placed in the drill or hill and thoroughly mixed with the soil for crops that are planted in rows or furrows in order to give the young plant a rapid start. For the vegetable garden and flower garden and lawns, it is best to apply only manure that has been piled for some time and has been turned over several times so that it is well rotted and broken up.
There may not be a single farm where it will be possible to carry out to the letter these principles applying to the treatment and application of barn manures.
This is because climate, crops and conditions vary in different parts of the country and on different farms. Therefore we should study carefully our conditions and the principles and make our practice so combine the two as to produce the best and most economical results under the circumstances.
If we can get manure out in the winter it will very much lessen the rush of spring work.
In some parts of the country on account of deep snows, heavy rainfall and hilly fields, it is not advisable to apply manure in the winter. This will necessitate storing the manure.
If conditions are such that we can get the manure on to the land as soon as it is made, it should be applied to land on which a crop is growing or land which is soon to be planted. If land is not intended for an immediate crop, put a cover crop on it.
Composts are collections of farm trash or rubbish, as leaves, potato tops, weeds, road and ditch scrapings, fish, slaughter-house refuse, etc., mixed in piles with lime, barn manure, woods-earth, swamp muck, peat and soil.
The object of composting these materials is to hasten their decay and render available the plant food in them.
There are certain disadvantages in composting, namely:
Expense of handling and carting on account of bulk.
Loss of organic matter by fermentation.
Compost heaps serve as homes for weed seeds, insects and plant diseases.
Nevertheless, all waste organic matter on the farm should be saved and made use of as manure. These materials when not too coarse may be spread on the surface of the soil and plowed under; they should never be burned unless too coarse and woody or foul with weed seeds, insects and disease.
This article was taken from,
The First Book of Farming
By CHARLES L. GOODRICH
Publication date: 1905