Organic Compost and Vermicomposting

Last Updated on June 11, 2020 by Sagar Aryal

Organic Compost definition

Organic compost can be defined as a mixture of decayed organic matter which can be added to soil to enhance the growth of different plants. Composting is a process by which heterogeneous organic compounds can go through decomposition and the process occurs due to the presence of a moist ward aerobic environment and a mixture of different microorganisms. In general decomposition of organic matter takes place in the environment naturally. However, as the environmental parameters are not selected, many different organic compounds may remain the same. The microbial population is also dependent upon the environmental parameters. Therefore, the preparation of a quality organic compost requires specific environmental conditions.

Organic Compost and Vermicomposting

Image Source: Garden Topsoil Direct and Planet Natural.

Process of composting

The most important part of making compost is the specially designed pits where all organic matters are collected. The organic matter includes crop residues, cattle dungs, farm wastes, etc.  These components are mixed together and exposed to air and adequate moisture content. The degradation process occurs in different steps, at first only the mesophilic organisms grow and start decomposing the organic matter. As time goes, heat is generated due to the decomposition process and the microbial population also changes according to the environmental factors of the system. During these steps, different organic compounds are degraded into simple forms. Generally, compost contains a mixture of pectin, hemicelluloses, cellulose, lignin, etc. The whole process requires around 6-8 months and the material becomes ready to use in farms.

Factors Affecting Composting

Microorganisms

Microorganisms play the most important role in the process of composting. The selection of specific microbes on the basis of compost environment (aerobic or anaerobic) and organic matter to be decomposed is essential to carry forward the whole process. There are different microbial species related to the decomposition of organic compounds. Examples of such organisms are Aspergillus, Trichoderma, Penicillium, Trichurus, Azotobacter, and several other phosphate solubilizers, nitrogen-fixing bacteria, etc. The microbial load is mostly dependent upon the carbon-nitrogen ratio of the organic matter.

Soil

Soil is a natural medium that promotes plant growth. It is a mixture of different minerals, organic matters, and living microorganisms. On the basis of the mineral content and organic compound present in the soil, the biological activities of the microorganisms took place. This contributes to texture and fertility.

Organic Matter

Organic compounds are mostly required by the plants. Hence, these compounds are directly linked to plant growth promotion. However, only a limited number of organic compounds are required by the plants. Therefore, complex organic compounds need to be decomposed adequately to improve plant growth promotion.

Role of Compost

The simplest form of organic matter is soluble nitrogen. Composting helps the soluble nitrogen to remain in the compost mixture, which otherwise can easily be washed into the water if added directly into land. Apart from that, compost mixture also contains phosphorus residues and restricts the phosphorus content from washing off into the water. Moreover, the application of compost is directly connected with plant growth promotion. Due to its organic nature, it is safer to use than chemical fertilizers. However, one major drawback of using compost is the time-consuming process. The compost making process is also developing with time. Along with the plant growth promotion, compost can also improve the aeration and water holding capacity of the soil.

Vermicomposting

Vermicomposting is the process of organic matter decomposing by the use of earthworms. Vermicompost can provide essential nutrients to different plants which can lead to 10-15% more crop yield. This technique was first applied in Ontario, Canada in 1970. In recent times, many countries have applied this process to develop organic fertilizers. According to several studies 1 Kg. An earthworm can consume 1 Kg organic matter in a day and secretes simple organic compounds consist of calcium, magnesium, potassium, nitrogen, and phosphorus. Apart from the nutritional factors, earthworms involve in aeration of soil which promotes the enzymatic activity of soil bacteria and actinomycetes. The most common members of the earthworm involve in vermicomposting include: Eisenia andrie, E. foetida, Dravida willsii, Perionyx excavates, etc.

Process of Vermicomposting

A tank or pit or wooden crate can be used to perform the process of vermicomposting. The typical dimension of the container can be 2x1x1 m3. The entry of extra water is needed to be restricted by placing the whole system under a shade. Inside the pit or tank, several layers need to be made. The bottom layer is made up of broken bricks and pebbles. On top of that coarse sand is placed which can provide drainage. This layer then covered by loamy soil which is inoculated with earthworms. On top of that, cattle dung is placed and finally, the cattle dung portion is covered by agricultural waste materials. Moisture content is maintained by adding a specific amount of water daily for 20-25 days. The final product is prepared within 40-45 days.

Reference

R.C. Dubey and D.K. Maheswari, 2016, A Textbook of Microbiology, S Chand & Company Pvt. Ltd.

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