By Dr. Sabyasachi Majumdar & Dr. Ram Singh
The farmers, particularly the small holders, nowadays are caught in a vicious circle of higher use of agrochemicals to boost crop productivity for food security.Continuous and indiscriminate use of agrochemicalshas led to soil deterioration, nutrient imbalance, and environmental contamination. India consumes 32.93 million tonnes of synthetic chemical fertilizers (NPK) with fertiliser use intensity of 151 kg/ha and usage ratio of 9.3:3.5:1, that is nitrogen biased. The phosphatic and potassic fertiliser industry in India is still largely dependent on imports, and about 80% of the natural gas utilised in our nation’s urea manufacture is imported. The crops only use 30-50% of applied nitrogen, 15-25%phosphorus, and 50-60% potassium; the rest is lost through leaching, runoff, volatilisation, or soil fixation. Regarding fertilisers and raw materials, the recent conflict-like scenario in West Asia should not be interpreted as a temporary supply chain crisis. It should, however, be viewed as a clarion call to reconsider and realign our nation’s policies, research and development goals with Atmanirbharta (self-reliance) in fertilisers.Therefore, it is imperative to have alternate methods for increasing the nutrient use efficiency of crops and reducing reliance on chemical fertilisers alone.
Crop diversification towards pulses and oilseeds, recycling organic waste under our nation’s Waste-to-Wealth initiative, better composting methods, investigating the potential of soil microbiota, crop breeding for increased nutrient use efficiency (NUE), good agricultural practices involving precision nutrient management (4R-Stewardship), integrating fertilisers and organic manures, and increasing the use of biological sources are some of the technologies available with us. Scientists are now focusing on “green alternatives” that have a very low environmental footprintcompared to chemical fertilisers. Vermicompost, a superior quality compost produced with the help of epigeic earthworms, stands out among these options as a desirable replacement for conventional chemical fertilisers. Through the action of earthworms and mesophilic microbes, vermicomposting is a non-thermophilic process that turns organic waste into a valuableorganic gold for the farmers. As most of the farmers prefer burning crop leftovers as the simplest and least expensive way to dispose of them due to the lack of on-site management systems, a nation-wide emphasis should be given for recycling of the crop residues into a valuable vermicompost.
Turning Waste into Black Gold: Vermicomposting and its nutrient composition
Vermicompost is a fine-grained, odourless, pure, stable organic manure prepared out of the farm leftover that improves the physiological and biological characteristics of soil. The bacteria, actinomycetes, fungi, that break down cellulose are abundant in vermicompost. Typical well-made vermicompost has 0.5-1.6%N, 0.3-1.0%P₂O₅, 0.50-0.70% K₂O, about 2 to 3 times that of common compost. Vermicompost adds 10³-10⁶ CFU/g of N-fixers, P-solubilizers, and plant growth promoting rhizobacteria (PGPR). They unlock native soil P, fix N, and mineralize organic N faster.Vermicompost can safely substitute 25 to 30% of the recommended nitrogen (N) fertilizers in crop production without affecting yield, while often improving soil health and crop quality. Vermicompost usually has more stable organic compounds and a larger percentage of fulvic and humic acids compared to standard compost. This profusion of humified organic matter guarantees that nutrients are stored in forms that release more gradually, acting as a buffer against quick leaching and sustaining microbial activity over time.Moreover, this concept of recycling crop residues into valuable vermicompost aligns with the United Nations Sustainable Development Goals 1 (No poverty), 2 (No hunger), 3 (Good health), 5 (Gender equality), 13 (Protect the planet) and 15 (Life on land).
Characteristics of earthworm species commonly used for vermicomposting
Based on their deedingand burrowing habits, at least 4400 species of earthworms are divided into three ecological niches: epigeic, endogeic, and anecic. Epigeic earthworms, also known as compost earthworms or surface-dwelling earthworms are the weak burrowers, who prefer to live among loose organic materials and topsoil. Endogeic earthworms prefer to literally dwell inside the earth, burrowing beneath the top soil layers and seldom rising to the surface. Although some will burrow deep into the soil, they are most frequently found in the topmost soil layers, where they form horizontal, semi-permanent tunnels or beneath rocks and logs. They usually only appear on the ground when it rains a lot because the additional moisture keeps them from drying out. Anecic earthworms are relatively large and live in vertical burrows from which they collect dead organic matter on the surface at night. Epigeic species are most suited for vermicompostingbecause of their strong affinity for the organic substrate, high rates of consumption and digestion, short life cycles, high rates of reproduction, and ease of culture. Of the many species of earthworms tested for mass culture all over the world, Eisenia foetida, Pherritima elongate, Eudriluseugeniae, andPerionyxexcavatusare in the order of preference for their ability to compost organic wastes. Vermicompost can be prepared within a short period of 3 monthsin a pit size of 3m x 1m x 1m with paddy straw, weed biomass, banana pseudo stem, cowshed leftover, etc.as substrate and releasing Eisenia foetida earthworms @ 1500 worms/pit. Now a days low-cost readymade vermicomposting poly bags are also available.
Impact of vermicompost on soil health
Vermicompost use in sustainable agriculture not only increases the activity of beneficial soil organisms like mycorrhizal fungi and phosphate-solubilizing microbes, but also contributes significantly to the provision of vital nutrients in plant-available forms, such as nitrogen, phosphorus, and potassium. Because of its porous texture, vermicompost encourages drainage, aeration, porosity, cation exchange capacity and high water-holding capacity of soil. It produces micropores, which are home to nutrients, water, and roots. This supports a varied microbial community that includes bacteria, fungus, and actinomycetes, creating the optimum conditions for plant growth. The fulvic and humic acids in vermicompost have the ability to dissolve mineral nutrients that are trapped in organic matter (OM), making them accessible to plants and enhancing their ability to withstand stress. Additionally, humic substances in vermicompost enhance soil stability, prevent nitrogen leaching, and reduce erosion. Vermicompost also alleviates the negative effects of salinity by stimulating enzymatic activity, protein synthesis, and physiological processes.
Vermicompost as apart of climate resilient agriculture
Vermicomposting may have a greater environmental footprint compared to other waste-related industries like recycling or municipal composting. Vermicomposting contributes to environmental preservation. Vermicompost promotes resilience by improving soil structure and carbon sequestration, mitigating drought effects, and reducing reliance on chemical fertilizers. The organic composition of earthworm droppings promotes water and air flow through the soil. Consequently, soil becomes a healthier habitat for both plants and the organisms that make up the soil food web. Additionally, it is less likely to erode and compress. Thus, rather than becoming unusable due to erosion or compaction, the soil’s resources are used to their fullest potential. Around 34% of the total waste across the world is made up of paper and paperboard products, 25% is made up of food scraps and yard trimmings, and 0.06% is made up of wood waste (by weight). These materials can be recycled, composted, or vermi-composted rather than dumped in landfills. The current urban organic waste problem can be solved with vermicomposting technology, which uses earthworms to expedite humification of organic waste at a lower cost compared to other available technologies. Using vermicompost technology, municipal garbage is transformed into high-quality humus, a highly valued substance that meets plants’ primary nutritional needs. Moreover, India produces more than 500 million tonnes (Mt) of crop leftovers annually, according to the Indian Ministry of New and Renewable Energy (MNRE). According to this assessment, there is still a surplus of 140 Mt, of which 92 Mt are burnt annually, even after the majority of crop leftovers are used as fuel and feed for various residential and industrial uses. Crop residue burning has been a major environmental concern as it affects human and animal health through deterioration of air quality. To reduce the negative consequence of crop residue burning on soil-plant-human-animal continuum, the vermicomposting should be considered as an ideal ecofriendly alternative.
Impact of vermicompost on growth and yield of crops
Vermicompost plays an important role in sustainable agriculture. The homogeneity, high porosity, high water-holding capacity, stability, low C:N ratio, and nutrient-rich, environmentally benign nature of vermicompost are the qualities that make it an effective organic fertilizer. The vermicompost is usually applied at 1.0-4.0 t/ha for field crop, 1.0 t/acre or 2-4 kg per tree for fruit crops, 2-3 t/acre for vegetables, and 100-250 g/square feet for flower/potted plants. Use of vermicompost, on an average, increases commercial yield of crops by 26%, total biomass by 13%, shoot biomass by 78%, and root biomass by 57%.Yield improvement in different grain crops ranges from 6 to 51%. Application of vermicompost increased fruit yield of tomato by 74%, along with improvements in fruit quality indicators, including vitamin C content (47%) and soluble sugar concentration (71%). On an average, application of vermicompost usually increased the yield by 10-30% in cereals, 30-50% in pulses, 15-40% in oilseeds, 20-50% in fruits and vegetables, 10-20% in sugarcane and 10-15% in cotton.Several studies have also confirmed the economic viability of vermicompost application in grain crop production with B:C ratio in the range of 1.4 to 3.2.Combining vermicompost, microalgae and chemical fertilisersis the cheapest option for rice production, butvermicompost alone was more expensive than chemical fertilisers. Vermicompost can substitute 25% of the recommended nitrogen (N) in any Integrated Nutrient Management (INM) option.
Wiggling Way to Wealth: Vermicomposting as a Rural Income Booster and Bio-entrepreneurship
India has a large young population and must find a profitable way to engage its idle youngsters. The unemployment rate among roughly 27% of people are between the ages of 15 and 24, and biggest obstacle in obtaining sustainable livelihoods of youth are lack of opportunities, financial support, appropriate mentoring, and skills. Simultaneously, there is a growing recognition that chemical-driven agriculture, which harms the environment, needs to change to ecologically friendly and sustainable methods. Vermicomposting, in this situation, offers a creative way to meet the twin goals of youth empowerment and sustainable agriculture. A vermicomposting unit can be set up in any convenient scale according to the availability of resources and can be easily adopted by the small and marginal farmers of the North Eastern Hill (NEH) Region of India.
On an average, in a year, 2.25 tonnes of vermicompost can be produced from a vermi tank of dimension 3m x 1m x 1m, assuming three numbers of harvest in a year, with the average cost of production of Rs. 4.2 per kg. If the price of the vermicompost is assumed as Rs 20 per kg, then a profit of Rs 3,59, 855 can be earned annually, considering at least 500 adult worms can be sold.However, it is advisable to fix the price of vermicompost competitively. It will help the farmers to obtain a healthy profit even if the price drops because the production costs are relatively cheap. The government of India provides financial support to the farmers for production of quality composts from various organic residues through different schemes. National Mission for Sustainable Agriculture (NMSA) is one of the eight missions under National Action Plan on Climate Change (NAPCC). For vermicomposting unit, the NMSA incurs 50% of the cost subject to a limit Rs. 5000/- per ha and Rs. 10,000/- per beneficiary. Under Paramparagat Krishi Vikas Yojana (PKVY), assistances are provided to the cluster member at a minimal charge of Rs. 5000 for setting up a vermicomposting unit and the time frame for implementation is 3 years in a cluster basis.
Vermicomposting, which creates superior manure for crop cultivation, is an efficient method of recycling organic waste from households, farms, and rural and industrial locations, thus ought to be viewed as an inexpensive and environmentally beneficial business venture for enhancing the standard of living and nutritional security of small and marginal farmers. It is a practical example of how a simpleorganic technology can deliver environmental restoration, economic opportunity, and social inclusion simultaneously.Growing consumer demand for organic goods and the use of sustainable farming methods are driving the compound annual growth rate (CAGR) of global vermicompost market to 15.56% by 2030.However, the main barriers to vermicomposting are farmers’ lack of access to efficient earthworm strains, technical know-how, and their poor communication with extension staff. Therefore, for vermicomposting technology to be widely adopted by resource-poor farmers for effective crop waste recycling and sustainable soil health management, a comprehensive approach in terms of technical support and scientific knowledge must be communicated.
(The writers are attached with the College of Agriculture, Kyrdemkulai, Meghalaya, CAU, Imphal)
