Manure

MANURE, excrement and urine of animals mixed with the bedding on which the livestock stands. Accordingly, straw manure, peat manure, and others are distinguished. Manure is a valuable fertilizer in agriculture. In cities and other places, manure can pollute the soil, water, and air. The same can happen in rural-type locations where careless storage and untimely removal of manure are observed. In the black-earth belt of the USSR, manure is also used as fuel, which is now considered irrational due to the loss of valuable fertilizing substances contained in manure. The quantity of manure fluctuates depending on the method of stable construction, the amount of bedding used, the frequency of stall cleaning, and the animals' feed. The "Rules for Cleaning Settlements with Sparse Development from Waste in the Absence of Sewerage," approved by the II All-Union Water Supply Sanitary-Technical Congress (1927), provide the following norms for manure accumulation per head of livestock per day (together with bedding): cow—from 0.040 to 0.080 m³, horse—from 0.030 to 0.055 m³, pig—about 0.010 m³, sheep, goat—about 0.007 m³. For approximate calculations, one can assume an accumulation of 1 m³ per head of livestock per month. In agricultural terms, cow manure is considered the best, as it contains more water and decomposes slowly in the soil. Horse manure is drier, its decomposition proceeds faster, and it heats up quickly, which is why it is called "hot" manure. Manure from pigs and sheep has the least value. The fertilizing properties of manure depend on its composition, which contains substances valuable for plants: nitrogen, phosphorus, and potassium.

Another main property of manure, which makes it a valuable product for agriculture, is its ability to restore the structure of depleted soils. Tillage destroys the cloddy structure of the soil, turning its upper layers into a dusty mass. Manure restores this structure by gluing soil particles into small clods, which is very important from the point of view of the water and air regime of the soil. Finally, manure, by coloring the soil black, contributes to its better warming, and through its bacterial environment, increases the number of nitrifying bacteria in the soil. The sanitary significance of manure is determined by three factors. First, manure can pollute the soil and water bodies with organic substances. This occurs with poor construction of stables and manure storage facilities, and when dumping manure near wells, along riverbanks, etc. The method of reinforcing dams with the help of manure deserves full condemnation. Second, manure can be a medium in which pathogenic microorganisms are preserved. Diseases of humans and animals in the spread of which manure can play a role include tetanus, anthrax, glanders, and other livestock diseases. Furthermore, in view of the frequent use of stables as latrines in our rural conditions, manure can contribute to diseases such as typhoid fever, cholera, dysentery, and other gastrointestinal diseases. Manure can also play a significant role in the development of helminthic invasions by contaminating pastures for livestock, water bodies, and garden crops with helminth eggs. Third, manure is a favorite place for fly breeding, and in the matter of fly control, the method of storage, processing, and removal of manure is of paramount importance. To eliminate the harmful influence of manure, the following measures should be carried out: proper construction of stables and stables; a floor impermeable to liquid (the simplest method for this is laying a layer of compacted clay under the wooden flooring); and ensuring the drainage of urine through impermeable gutters or channels into an impermeable receiver (a urine or liquid manure collector). Cesspools must be strictly prohibited. No less important is the timely removal of manure to specially equipped manure storage facilities. The latter are constructed either as an above-ground type or recessed into the ground. Figure 1 shows a sample of an above-ground manure storage facility in the form of a wooden box made of tongue-and-groove and tarred boards. The dimensions of the box depend on the number of livestock and the cleaning schedule. In general, it must be said that above-ground manure storage facilities are suitable only for the temporary storage of manure with the expectation of its further removal to the place of use, which is why they can be recommended in cities and urban-type settlements. In Fig. 1, the dimensions are given as 2x2x0.89 m (calculated for 10 head of large livestock, provided weekly cleaning). The storage facility is covered from above with a wooden shield (for the purpose of protection from flies). The box is installed on skids to avoid soil contamination. For the same purposes, the place where the manure storage facility is installed must be paved, or a special platform made of compacted clay should be arranged for it. In agricultural farms, storage facilities for manure are usually built recessed into the ground. These can be receivers made of concrete or brick. As a simplest type, the structure shown in Figure 2 can be recommended. Finally, in large farms, special fermenters for manure are built, in which the loss of the fertilizing properties of manure is reduced to a minimum. Their type is shown in Fig. 3.

Figure 2.

Figure 3.

Figure 2. Manure storage with a well for liquid manure. The bottom and sides of the pit are compacted with clay. The bottom is made sloping toward the well. Figure 3. One of the simplest types of open fermenter. The method of open manure storage in the form of compost heaps is also used. When setting them up, from a sanitary point of view, one should take care to protect the soil from contamination by equipping an impermeable platform and a similar receiver for liquid (the latter, collected in liquid receivers, is used for watering the heap). Both from a sanitary and agronomic point of view, the German method of obtaining so-called "noble manure" (Edelmist) deserves the greatest attention. This method consists of the following. Manure is stacked in heaps in very loose layers, due to which a high temperature (up to 70°) quickly develops in it thanks to the vital activity of aerobic bacteria. After 3-4 days, the manure is strongly compacted by treading it down. The displacement of air stops the processes of manure decomposition, the temperature inside it drops; the manure remains in a semi-decomposed state until it is taken out to the field, which helps to preserve nitrogen reserves, which, upon complete decomposition due to the vital activity of denitrifying bacteria, would have escaped into the air or been washed away by rains. It is not difficult to see that all methods of improved manure storage also contribute to sanitary goals, since the heating of manure in heaps, manure pits, fermenters, etc., causes the death of pathogenic microbes, helminth eggs, and fly larvae. Sometimes it is necessary to resort to treating manure with chemical substances. For this, one can recommend chlorinated lime (10% solution), tar in alkaline solutions, and iron sulfate (5% solution). However, these substances do not protect humans from roundworm eggs, since the shells of the latter do not allow salts, alkalis, or acids to pass through. To combat them, hot water or steam can be used. In large livestock farms, where the concern for protecting livestock from diseases, including helminths, is paramount, the most radical measures should be taken to disinfect manure. In ordinary agricultural conditions, one has to be limited to daily cleaning of manure from stalls and the rationalization of its storage, as indicated above, i.e., to implement those measures which, at the lowest cost, give the greatest effect in terms of obtaining fertilizer and disinfecting manure.