Effective biotechnological solutions for composting manure

Yurii Shulha, PhD in Agriculture, head of animal husbandry, LLC TD “BTU-Center”

Composting is one of the most widely used methods of animal waste disposal in agriculture. The ingredients of compost mixtures can be various organic components: waste from wood processing enterprises, food production, straw, sapropel, peat, and others. Currently, composting is considered the most environmentally friendly and economical technology for recycling animal and poultry waste in order to obtain high-quality organic fertilizers based on them.

One of the most popular methods of processing manure and litter is aerobic composting, which helps to reduce ammonia odor, preserve nitrogen, accelerate the decomposition of fiber and organic compounds, and increase the content of available nutrients.

The technology of compost production by aerobic method, in addition to process stages, includes the mandatory use of bacteria that participate in all biological stages of compost production. Diversity of microorganisms is the key to producing high-quality compost, as different species perform certain stages of the compost production cycle.

The company “BTU-Center”, Ladyzhyn, Vinnytsia region, has developed a universal bacterial preparation “Componaza” with a complex of effective microorganisms and enzymes designed for composting organic waste of industrial, agricultural and domestic origin. The effect of the preparation is aimed at stabilizing volatile ammonia compounds in the composting material with their further transformation into nitrates and nitrites, reducing unpleasant odors, converting decomposed organic matter particles into polymer chains to produce a humified substrate (humus), stabilizing compost without energy loss, reducing the number of pathogenic microorganisms, enriching the obtained compost with beneficial microflora, macro- and micronutrients.

The preparation contains viable effective bacteria and fungi: Bacillus subtilis, Rodex, Trichoderma, etc., not less than 1.0-109 CFU/cm3 (TU U 24.1-30165603-020:2010).

For more than one year, this preparation has been applied at ALLC “Agrofirma Korsun”, in Cherkasy region. This farm for a season lays in compost piles about 80 thousand tons of cattle manure, receiving the 32 thousand tons of high-quality organic fertilizer in 1.5-2.0 months .

Fig. 1. Aeration of piles at ALLC “Agrofirma Korsun”

Aerobic composting conditions are created by periodic aeration of the mixture with air. This promotes the activity of microorganisms involved in both decomposition and synthesis reactions. Thanks to this, the products are formed that have a high fertilizing value, namely, an increased content of mobile forms of nutrients (P2O5, K2O, N), a favorable pH level and sufficient to improve and maintain soil fertility with the necessary amount of agronomically valuable microflora.

The basis of the biological product “Componaza” is cellulose-decomposing microorganisms that decompose organic substances of manure and straw in a short period. This allows you to keep several times more nutrients in the resulting compost than with conventional composting. The compost maturation process is reduced to 1.5-2 months instead of 6-12 months. In this case, after a few days (7-10 days), the odor of ammonia reduces.

The use of natural endophytic and soil nitrogen-fixing bacteria and phosphorus- and potassium-mobilizing bacteria in the biopreparation “Componaza” contributed to the positive dynamics of the level of the major nutrients, determined on absolutely dry basis at different stages of composting. Thus, the amount of total nitrogen in the obtained compost increased by 15.3% and phosphorus and potassium - by 69.1 and 16.7%, respectively (Fig. 2). 

 

Fig. 2 Dynamics of major nutrients (%) in the process of composting manure of cttle

Composting is a biothermic process that results in mineralization and humification of organic components of compost mixtures. The process takes place under aerobic conditions under the influence of various microorganisms, mainly thermophilic. As a result of chemical reactions, carbon dioxide and water are released, and the organic components of the mixtures are heated to 60-65°C. This is harmful to larvae of flies, helminth eggs, pathogenic non-spore-forming microorganisms and weed seeds.

One of the components of the biological product "Componaza" is lactic acid bacteria, which are antagonists of most pathogenic microorganisms, including Pseudomonas aeruginosa, the pathogen of salmonellosis, Escherichia coli, etc.

Thus, according to the results of bacteriological studies of manure and compost, it was found that the level of pathogens in the obtained compost after two months of composting significantly decreased, and pathogens such as Salmonella and Escherichia coli were not detected (Fig.3). 

Fig. 3. Bacteriological indicators of manure and compost

Antagonistic relationships of microorganisms are characterized by the fact that one species in one way or another inhibits the vital activity of another. Antagonism is common among various groups of microorganisms. It is found among bacteria, actinomycetes, fungi, algae, etc. Fungi, in comparison with other microorganisms, have a wide range of antagonistic properties - hyperparasitism, that is a high level of competition for nutrition substrate, and they also produce antibiotics and other substances that inhibit the development of pathogens. With joint development on the same substrate, the fungus that has the highest growth rate will prevail.

The use of fungal antagonists of the genus Trichoderma, bacteria (Bacillus subtilis, Pseudomonas, etc.) and their products in the composition of the preparation “Componaza” significantly reduces the level of pathogenic fungi both in the compost and in soil after its application (table 1). 

Table 1. Number of fungi in samples of manure and compost

Sample No.	Option	Total, thousand/g of soil	Pathogenic species		Saprotrophic species
			thousand/g	%	thousand/g	%
1	Manure	172,4	30,0	17,4	142,4	82,6
2	Compost	206,9	3,6	1,4	203,3	98,6

According to the results of mycological studies, the total number of fungi in the samples varied from 172 to 206.9 thousand/g of organic mixture. The share of pathogenic fungi was 1.4-17.4%. It should be noted that the number of pathogenic fungi in the compost was 16% less.

This level of pathogens in the compost had a positive effect on soil contamination after its application; the difference between the control samples was 15.9% (table 2). 

 Table 2. Number of fungi in the soil samples

Date of sample collection	Option	Total, thousand/g of soil	Pathogenic species		Saprotrophic species
			thousand/g of soil	%	thousand/g of soil	%
3.09.18	Soil	180,0	79,6	44,2	100,4	55,8
12.11.18	Soil + compost	233,3	66,0	28,3	167,3	71,7

The application of organic fertilizers, in particular compost, is the main means of human influence on the cycle of nutrients in agriculture. It makes it possible not only to maintain, but also to increase their amount by improving the soil structure (loosening, increasing oxygen access); regulating biochemical processes and activating the vital activity of beneficial microorganisms in soil; creating a fertile layer (humus); restoring water and air regimes. All these factors are aimed at improving the quantitative and qualitative indicators of agricultural crops.

Composting in the fields of ALLC "Agrofirma Korsun" contributed to an increase in the yield of various field crops from 6.2 to 15.6% (table 3). 

Table 3. Compost effect on the crops yields

Control			Experiment
area, ha	gross harvest, t	yield, centner/ha	area, ha	gross harvest, t	yield, centner/ha	difference
Winter wheat, variety “Dostatok”
40,0	1,54	38,4	40,0	1,78	44,4	+6,0 centner/ha
Corn, variety “Cubus”
23,0	1,31	57,0	40,0	2,6	65,0	+8,0 centner/ha
Sugar beet, variety “Scorpion”
30,0	13,5	451,3	40,0	19,2	479,3	+28,0 centner/ha

The introduction of compost for sowing sugar beet in the amount of 7 t/ha increased the yield by 28.0 centner/ha.

The same amount of compost positively affected the yield of corn, the difference with the field where organic fertilizers were not applied was + 8.0 centner/ha.

The best result was obtained when growing winter wheat. Adding compost at the rate of 5 t/ha increased the yield of this crop by 6.0 centner/ha, and this, in turn, contributed to an additional profit of 1230.0 UAH/ha.

Consequently, the application of the biological product “Componaza” for composting organic animal waste at ALLC “Agrofirma Korsun” contributed to the acceleration of decomposition of organic waste, reducing its amount by 60%, obtaining high-quality organic fertilizer without odor and a significant number of pathogenic microorganisms, which positively affected the yield of various crops.