Potential of Vermicompost for Sustainable Crop Production and Soil Health Improvement in Mung Bean

One of the key Kharif pulse crops is green gram [Vigna radiata (L.), often known as mung bean and golden gramme. In regions with irregular rainfall, Greengram can be cultivated on well-drained loamy to sandy loam soils and is drought-tolerant. With an excellent yield and a contribution to maintaining soil fertility, green gramme requires less irrigation than many field crops.

Green gram production can be greatly increased by expanding the area under cultivation, boosting the crop's productivity, spreading organic manures (FYM/compost/vermicompost), fertilising the soil in a balanced manner, and maintaining soil fertility. In many regions of the nation, zinc (Zn) is regarded as the third-most important nutrient for plants, behind phosphorus and nitrogen. Metal maintains the structural integrity of biological membranes and directly contributes to protein synthesis, two fundamental functions of metal in biological systems. Tryptophan, which is a component of zinc, is a precursor of the hormone auxin. Furthermore, as soil pH increases, zinc availability declines. Zn is a crucial component of both man-made and organically occurring complexes in plants.

Vermicompost increases soil biodiversity by encouraging beneficial microbes, which in turn promotes plant growth directly by producing substances that regulate plant growth (hormones and enzymes) and indirectly by preventing the spread of plant pathogens, nematodes, and other pests that live in the north-eastern hills, improving plant health and reducing yield loss. Vermicompost's micro and macro elements, vitamins, enzymes, hormones, and other components can have a major impact on the growth and production of plants. With the aforementioned in mind, this study was conducted to provide an effective nutrient management strategy for raising green gram productivity, enhancing soil health, and bringing sustainability to the pulse production system.

Utilizing vermicompost and zinc enhances the soil's physico-chemical characteristics by creating sufficient pore space, BD, PD, and water holding capacity. Vermicompost enhances microbial activity in the soil, which increases soil porosity. Neutral to alkaline soil with a high organic content and low to moderate levels of nitrogen-containing macronutrients are favourable conditions for the growth of green grains. The soil has a moderate amount of zinc, potassium, and phosphorus. Farmers must maintain the nutrient quality of the soil, use appropriate management techniques, and give the soil the right nourishment to support the growth of green gramme. Utilizing zinc with vermicompost improves the production and quality of green gram.

Over the past few decades, experts from all over the world have become interested in the role that vermicompost plays in feeding agricultural crops. Vermicomposting is the process of turning organic waste into nutrient-rich compost by utilising earthworms. The casting of the earthworms is a nutrient-rich organic manure that is high in humus, NPK, micronutrients, advantageous microorganisms, antibiotics, enzymes, growth hormones, etc. Vermicompost incorporated into soil has been shown in numerous instances in the literature to have positive benefits. Vermicompost application as organic manure improved nutritional status, increased cation exchange capacity, microbial activities, microbial biomass carbon, and enzymatic activities. It also built up organic carbon in the soil. Castings from earthworms are also pest-repellent. In addition, vermicompost enhances soil structure, soil aggregation, and water retention. Since the green revolution, chemical fertilisers have been used much more frequently, which has led to a strong reliance on them in traditional agricultural systems.

Chemical fertilisers have undoubtedly greatly increased crop output, but their constant and uneven use has also had negative impacts on the health of the soil, which has caused a stagnation in crop yields over the past few decades. The long-term fertiliser experimental studies showed that continuous sole application of chemical fertiliser in an unbalanced manner produces negative effects on soil physical, chemical, and biological properties further, inducing secondary and micronutrient deficiencies in soil, unbalanced nutrient levels in soil and plants, environmental hazards, and a decrease in total factor productivity. Due to the uneven application of fertiliser, the microbial community in the soil has also been negatively impacted. In addition, overuse of fertiliser is endangering the ecosystem and contaminating surface and subsurface water bodies, particularly through nitrate leaching (Pimentel, 1996), which in turn poses major risks to human and animal health. Therefore, in the current environment, it is imperative to implement climate resilient integrated crop management modules in order to maintain soil health and crop productivity for a longer period of time. Recycling organic wastes could be one of the possibilities in the scenario above to lessen the need of chemical fertilisers. Because vermicompost organic manure has a considerable positive impact on soil characteristics and the microbial population, using it in crop production is a superior option for enhancing soil health, crop productivity, and quality.

Vermicomposting is the process of turning organic waste into nutrient-rich compost by utilising earthworms. The vital function of soil earthworms in agriculture is the decomposition of dead organic waste through consumption and release as castings. By releasing minerals in forms that plants can easily absorb, earthworms speed up the breakdown of organic matter and plant litter and increase soil fertility. The majority of minerals found in vermicompost, including nitrates, phosphates, exchangeable calcium, and soluble potassium, are available to plants. The physical, chemical, and biological aspects of organic matter and soil are altered by the earthworms' feeding, burrowing, and casting behaviours, which are necessary for plant growth and nutrient uptake. Vermicompost provides numerous micro-sites for nutrient retention and exchange as well as a microbial activity because of its vast surface area. Vermicompost often contains a wide variety of microbial species, especially fungus, bacteria, and actinomycetes. The earthworm-produced compost contains a variety of enzymes, hormones, vitamins, antibiotics, and other vital nutrients required for plant growth. It also plays a significant role in enhancing soil structure and water-holding capacity, which in turn boosts crop output and quality. High porosity, aeration, drainage, water holding capacity, and microbial activity define vermicompost.

Vermicompost might have various physical, chemical, and chemical characteristics as a whole as a result of their various manufacturing procedures, which varied the ways in which plant growth and general morphology were influenced. Thus, adding vermicompost as organic manure to soil improved nutritional status, increased cation exchange capacity, increased microbial activities, increased microbial biomass carbon, and increased enzymatic activities. Raw materials for vermicomposting, including earthworms Although there are more than 3000 different species of earthworms in the soil, only 8–10 species have been determined to be suitable for making vermicompost. Earthworms that live in organic horizons and are classified as epigaeic species, including Eisenia fetida and Eudrilus eugeniae, are the ideal types for vermiculture and vermicomposting. These worm species create richer casts than those that feed on plain soil because they tend to settle on top soil and prefer to eat organic leftovers like vegetable waste, compost, and organic bedding. These worms are known as the kind of worms that can consume up to half of their body weight each day. They effectively decompose and degrade natural residues, converting the leftovers into top-notch organic compost.

Additionally, the aforementioned earthworm species are resilient to changes in humidity and temperature. These species also proliferate quickly, are active all year long, breakdown organic matter quickly (rapid casting), and aid in the quicker preparation of vermicompost. Other varieties of red worms or red wigglers include Eisenia andreii, Perionyx excavatus, Lumbricus rubellus, and Perionyx sansibaricus  could potentially be productively utilised to produce vermicompost Any material that can decompose readily, such as weeds, wastes (leaves and rind) of vegetables and fruits, crop residue, roughage of the animals, as well as municipal wastes of organic origin, could be used for vermicompost preparation. Cattle dung or farm yard manure (FYM) is used as the raw material for vermicomposting. Earthworms physically break down the organic waste they consume in the gizzard, where it is then exposed to several enzymes, including protease, cellulose, lipase, chitinase, and amylase, which are secreted into the lumen by the gut wall and accompanying bacteria. Complex macromolecules are broken down into simpler ones by the aforementioned enzymes. Vermicompost's structural stability is provided by mucus secretions from the gut wall. Only 5-10% of the ingested material is absorbed by earthworms for their growth and remaining is excreted as casting.

Selection of site for vermicomposting

In general, earthworms prefer to reside in damp, shaded areas because these environments facilitate their rapid reproduction. For the worms, high temperatures and dry environments are more restricting than low temperatures and a water-rich habitat. Because earthworms cannot survive in standing water, make sure the vermicomposting unit has enough drainage. The ideal temperature range for the earthworms' quickest multiplication and growth is between 20 and 30 oC. As a result, compost of outstanding quality can be generated quickly and at room temperature employing the right type of earthworms Before creating a vermicompost unit, the following things should be taken into consideration: Choose a damp, shaded area, preferably beneath a tree or a shed with ventilation. Make sure the vermicompost bed or unit has enough drainage, and the supply of water should be close to the unit. It needs to be far from the biogas plant because otherwise earthworms will eat the biogas' carbon and slow down the breakdown of the material.

Steps involved in vermicompost production

Composting is a great way to lessen environmental risks and create a healthy, natural soil addition. Vermicompost is actually a fantastic substitute that enables composting with no regard for room. Vermicomposting has been a hot topic practically everywhere because to its simplicity and adaptability to different scales. Vermicomposting from raw waste demands a thorough understanding of the procedure. The following describes each process in the creation of vermicompost: After deciding on a location for the preparation of vermicompost, level the surface. Make a bed out of bricks that is roughly 10 x 3 x 3 feet (L x B x H). However, depending on the amount of material available and the necessity, the size of the bed may be reduced or enlarged. Sprinkle water on the bed's surface to moisten it. Spread a layer of dried leaves, paddy straw, or another material 2-3 inches thick at the base of the bed. Once more, add some water to the layer of dry material. Over the layer of leaves or straw, evenly distribute a layer of farmyard manure or cow dung, and spray water to sufficiently moisten it. Cow dung shouldn't be too recently dumped. Fresh cow dung produces a lot of heat and can kill earthworms, so it should be at least 10 to 15 days old. Similarly, cow dung shouldn't be too old because it has started to degrade and won't provide any food for earthworms. Add the kitchen waste now by breaking it up into little bits, such as vegetable leaves, fruit rinds and/or grasses, animal roughages, etc. Once more, evenly distribute a layer of cow dung about 1-1.5 feet thick. Sprinkle with an adequate amount of water. Spread around 1 kilogramme of vermiculture (which contains 800–1000 earthworms) over the cow manure layer. Once more, evenly distribute a 2-3 inch layer of green leaves and other vegetation over the layer of FYM. Now use jute or gunny bags to cover the vermicompost bed. Sprinkle water over the gunny bags on a daily basis to keep the vermicompost bed at the ideal moisture and temperature level. The moisture content and temperature in the bed should be around 35–40% and 15–30°C, respectively. To ensure the best circumstances for earthworm growth and operation, sprinkle water often. Provide a shed or roof over the vermicomposting unit if it is set up in an open area so that it can be kept in a shaded environment and earthworms may be protected from the sun's rays and raindrops. Vermicompost can be made by following the above processes in 8 to 10 weeks. When mature, the vermicompost is granular, dark brown in colour, extremely porous, and odourless.

Nutritional value of vermicompost

The waste material or base substrate used to prepare the vermicompost generally affects how many nutrients are present. The type of earthworms employed in vermicomposting may also have an impact on the compost's quality. The average percentages of N, P2O5, and K2O in vermicompost made from banana wastes (leaves, pseudostems) and cattle manure were 1.5, 0.4, and 1.8 percent, respectively. Similar to this, vermicompost made from various organic materials like sugarcane waste, ipomea, parthenium, neem leaves, and banana peduncles is incredibly nutrient-dense, increasing rice productivity and soil fertility. Therefore, the foundation substrate utilised to produce vermicompost has a significant impact on its nutritional content. However, average nutrient concentration in the vermicompost is given in

Table.1 Nutrient concentration in the vermicompost

Table.2 Comparison between the nutritive value of vermicompost and farmyard manure

Source: Punjab State Council for Science and Technology (2010). Online: http://agri.and.nic.in/vermi_culture.htm

Benefits of vermicompost

The nutrients nitrogen, phosphorus, potassium, calcium, magnesium, and micronutrients like iron, zinc, copper, and manganese are all present in sufficient amounts in vermicompost, making it a high-quality manure that helps crops grow more productively and with better quality. Vermicompost application enhances the soil's physical, chemical, and biological qualities. Because of the improved soil structure, soil is more porous and permeable to both soil and water. A sufficient number of vitamins, amino acids, antibiotics, enzymes, and hormones that are beneficial to plant growth and development can be found in vermicompost. Vermicompost gives plants a full diet and builds their resistance against pests, illnesses, and insects. Vermicompost improves the soil's capacity to store water and reduces the need for irrigation. Additionally, it lowers the expense of expensive chemical fertiliser inputs, lowering the overall cost of production. Several weeds that are damaging to crops, including Lantana, Ageratum, Parthenium, and Eupatorium, can be used to produce vermicompost.

Effects of vermicompost on crop growth and productivity

A possible input for sustainable agriculture is vermicompost. Vermicompost application in soil has been shown to have positive impacts in numerous studies. Studies have shown that because vermicompost has a high quantity of nutrients, humic acids, and humates, plants react to its application like they would to hormonally triggered activity. Even though plants already receive the best nourishment possible, several studies have seen increased plant growth after adding vermicompost. Vermicompost encourages the growth of roots and shoots, which benefits vegetative growth as well. Vermicompost spraying also alters the morphology of crop plants, resulting in increased leaf area, root branching, and enhanced flowering, as well as an increase in flower quantity and biomass and overall fruit output. Application of vermicompost reliably increased seed germination, increased plant productivity and improved seedling growth. In comparison to without adding any vermicompost, the mungbean (Vigna radiate L.) exhibited greater rates of germination (93 percent), growth, and yield (84 percent ). Similar to treatments without vermicompost, treatments with vermicompost embedded registered earlier and greater germination. In comparison to applying only N, P, and K chemical fertilisers, the application of 10 t ha-1 of vermicompost coupled with the necessary quantities of N, P, and K nutrients produced the highest pea yield. While working on tomato, similar discoveries were also made. They emphasised that tomato yields were higher when vermicompost (5 t ha-1) was incorporated into the soil together with the appropriate applications of N, P, and K fertiliser. However, according to some researchers, vermicompost contains growth-promoting hormones generated by earthworms, including auxins, cytokinins, and gibberellins.

Therefore, adding hormone-rich vermicompost to the soil improved plant growth and development overall. Significantly longer plemule lengths were observed in maize seedlings after vermicompost application, showing the presence of hormones that promote plant growth in vermicompost. Vermicompost incorporated into soil has been shown to stimulate the germination of green gramme, tomato, and petunia seeds, respectively. Crops including tomato, potato, rapeseed, groundnut, blackgram, paddy, mulberry, and marigold tend to produce more when vermicompost is combined with inorganic fertilisers. Vermicompost addition in crop production has been shown in studies to promote plant development. Vermicompost encourages the beginning of new roots, boosts root biomass, improves plant growth, and modifies general plant shape. The conclusions of the aforementioned researchers are supported by the fact that the addition of vermicompost greatly affected the vegetative growth of paddy, as measured by shoot weight, root weight, root and shoot length, and in comparison to the sole application of chemical fertilisers.

Vermicompost mixed with the necessary amounts of NPK nutrients increased rice yield by 30% compared to chemical fertiliser applications alone. Since vermicompost contains nutrients in plant-available form that may be readily absorbed by crop plants, adding it to soil before sowing actually has immediate effects. Application of 2.5 t ha-1 of vermicompost considerably boosted rice's gramme and straw yields while using up to 50% less of the recommended NPK fertiliser rates for upland rice. The cast of earthworms (vermicompost) was discovered to be a better source for improved plant growth, dry matter production, and productivity. It also suggested the possibility of replacing the prescribed quantity of N with 50 kg N ha-1. Utilizing vermicompost decreased the need for expensive fertiliser input and increased the net returns from rice production. Increased biomass and grain yield in various crops have been seen in several experiments after careful application of vermicompost and chemical fertilisers. Wheat flour's quality has improved as a result of treatments using vermicompost that have more gluten. Along with the results already mentioned, there are numerous cases in the literature that show how adding vermicompost, an immediate source of nutrients, led to improved growth in a variety of plant species.

Effects of vermicompost on soil properties

Compacted soils are rejuvenated and have better water penetration when earthworms are present in the soil. The feeding, burrowing, and casting behaviours of earthworms change the biological, chemical, and physical characteristics of soil and organic materials. As was previously said, vermicompost typically has a greater nutrient profile than conventional compost. Vermicompost actually has the ability to physically, chemically, and biologically improve soil fertility. Physically, soils with added vermicompost have better porosity, aeration, bulk density, and water retention. Due to the application of vermicompost, the chemical characteristics of the soil—such as pH, electrical conductivity, organic matter, and nutrient status—significantly improved, resulting in greater plant growth and output. Additionally, during casting, earthworms release a number of hormones, enzymes, and vitamins that encourage the activity of other advantageous bacteria in the soil, ultimately enhancing soil health. Humus makes up a large portion of the castings of earthworms. The ability of humus to aggregate soil particles leads to improved porosity, which enhances soil aeration and water retention capacity. Additionally, the humic acid in humus acts as binding sites for a number of plant nutrients, including calcium, iron, potassium, phosphorus, and sulphur. When the plants need them, these nutrients are released from the humic acid where they are kept in the form of easily accessible nutrients. Because new castings have a higher moisture content and more readily available nutrients, soil consumed by earthworms may produce an environment that is even more favourable for plant growth. The infiltration, water retention, and erosion resistance of soil are all improved by earthworm casts, which are typically credited with healthy soil structure. Soils that have been modified with vermicompost have the capacity to enhance soil structure and hold onto more moisture. Earthworm casts are chemically and biologically rich, as was previously mentioned. As a result, soils imbedded with vermicompost display higher cation exchange capacity, a higher rate of plant growth hormones and humic acids, higher microbial population and activity, less root pathogens or soil-borne diseases, and an overall improvement in plant growth and yield. This suggests that microorganisms in the worm casts may fix atmospheric N in such quantities that are significant for the earthworm.

In contrast to nearby soils, soils consumed by earthworm casts frequently have substantially higher levels of soil organic carbon and nutrients. Vermicompost was added to soil, which improved soil organic carbon status, lowered bulk density, increased soil porosity and water holding capacity, raised microbial populations, and increased dehydrogenase activity in the soils, according to the research that were conducted. According to research, the average values for organic matter in worm casts and surface soil, respectively, were 48.2 and 11.9 g kg-1. Additionally, earthworms increased the availability of N for plants by contributing 3 to 60 kg ha-1 year-1 to N turnover in farmed soils.

Authors Detail

^1*Udiyata Kumari and ²Uttam Kumar

Department of Soil Science and Agricultural Chemistry

Naini Agricultural Institute,

Sam Higginbottom University of Agriculture, Technology and Sciences

Prayagraj, UP, India

Email:-udiyatachoudhary12@gmail.com