NPK analysis of vermicompost produced from banana waste, papaya waste and paper waste.
The rapid increase in the volume of waste is one aspect of the environment crisis, accompanying global development. Earthworms play an important role in the decomposition of organic matter and soil metabolism through feeding, fragmentation, aeration, turnover and dispersion. The type of substrates used and species of earthworms introduced plays a significant role in plant growth and yield. The waste to be stabilized should support an adequate biomass needed for effective processing. In the present study the vermicompost produced from banana as a substrate did not show a significant increase in NPK content from that of the control. On the other hand poultry waste and vegetable waste with goat dung showed significant increase in the NPK content. The enhancement of the vermicompost was probably due to mineralization of the organic matter containing proteins and conversion of ammonium nitrogen into nitrite. Mineralization and consequent mobilization of phosphorous by enhanced bacterial and phosphatase activities during vermicomposting leads to increase in Phosphorus. The earthworm processed waste materials contain high concentration of exchangeable potassium, due to enhanced microbial activity during the vermicomposting process, which accordingly enhanced the rate of mineralization. Vermicompost tends to hold more nutrients over larger periods without adverse effects on the environment.
- organic matter
Solid waste is one of the growing problems in both developed and developing countries. Due to the rapid growth in industrialization, most of the rural populations have shifted towards the urban area in search of employment. The rapid increase in the volume of waste is one aspect of the environment crisis, accompanying global development.
Earthworms play an important role in the decomposition of organic matter and soil metabolism through feeding, fragmentation, aeration, turnover and dispersion . Earthworms are involved in the recycling of nutrients, soil structure, soil productivity and agriculture, and their application in environment and organic waste management is well understood [2, 3]. They help in the degradation of substrate indirectly by affecting microbial population structure and dynamics and also directly since their gut is capable of undertaking cellulolytic activity. Thus products of cellulose hydrolysis are available as carbon and energy sources for other microbes that inhabit the environment in which cellulose is degraded and this availability forms the basis of many biological interactions.
There are about 3627 species of terrestrial earthworms in the world . Sixty three species of earthworm from Sri Lanka of which 47 are considered as zoogeographically important to the Asian region have been recorded . Vermiculture biotechnology promises to contribute in the ‘second green revolution’ by completely replacing the destructive agrochemicals which did more harm than good to both farmers and their farmland during the ‘first green revolution’ of the 1950–1960s.
Three major groups of earthworms based on ecological strategies have been recognized: the epigeics (Epiges), anecics (Aneciques) and endogeics (Endoges) . Epigeic earthworms live in the soil surface and are litter feeders. Anecic earthworms are top soil species, which predominantly form vertical burrows in the soil, feeding on the leaf litter mixed with the soil. Endogeic earthworms preferably make horizontal burrows and consume more soil than epigeic and anecic species, deriving their nourishment from humus.
Vermicomposting is a mesophilic procedure, using microorganism and earthworms that are dynamic at 10–32°C. Vermiculture provide for the use of earthworms as a natural bioreactor for cost effective and eco-friendly waste management. Earthworm fecundity is based on the rate of cocoon production, hatching success of cocoons and number of offspring’s emerging from each cocoons. The success of the composting depends upon the fecundity of the earthworm.
The type of substrate used and species of earthworms introduced plays a significant role in plant growth and yield. The waste to be stabilized should support an adequate biomass needed for effective processing. The time, cost and space requirements could compete economically with conventional methods of composting .
2. Substrates used for vermicomposting
2.1 Cow and goat dung
Vermicomposting of cattle and goat manure by
2.2 Poultry waste
Poultry litter is the mix of bedding material, manure and feathers that result from intensive poultry production. This includes litter from meat chickens (broilers), egg laying chickens (layers) kept under barn conditions, turkeys, ducks and quails.
Limited available data presents numerous challenges while vermicomposting poultry litter. High ammonical nitrogen concentration, auto heating, and high bulk density are some of the major concerns that need to be addressed while vermicomposting poultry litter . Poultry wastes contain significant amount of organic salts and ammonia that kill worms. So it is necessary to neutralize freshly deposited wastes by CaCO3.
2.3 Fruit waste
The Indian state of Tamil Nadu is the largest producer of bananas in the country cultivating around 9 million metric tons (MT) annually, but inefficient postharvest practices lead to massive waste every year. An average of 30% or 2.7 million MT of Tamil Nadu’s bananas currently goes to waste largely due to the absence of integrated cold chain infrastructure. Banana cultivation produces a huge amount of waste: approximately 30 tonnes of waste is generated per acre in one crop season from banana stem alone.
India produces around 2300 tonnes of papaya annually. In the past decade, the area under papaya cultivation in India has hugely increased following the introduction of Taiwanese and Hawaiian varieties. The processing operation of fruits and vegetables produce significant wastes as by-products, which constitute about 25–30% of a whole commodity group. The waste is composed mainly of seed, skin, rind, and pomace, containing good sources of potentially valuable bioactive compounds, such as carotenoids, polyphenols, dietary fibers, vitamins, enzymes, and oils, among others.
2.4 Paper waste
The Indian paper industry accounts for about 1.6 per cent of the world’s production of paper and paper board. It is the 15th largest in the world and is one of the high priority industries having a bearing on the socio-economic development of the country.
India consumes almost 100 lakh tons of paper and paper boards. Paper Mills in the country are increasing their production and renovating their plants. By 2025, the demand for paper would increase to 2.5 crore metric tons. There is no effective collection mechanism for waste paper from offices and households. Newspapers are used for packaging. Muncipalities are not efficient in waste management network. There is lack of space for storage and sorting of waste paper. No proper co-ordination exists between the informal sector and the main supply chain of waste paper to paper industry (Tables 1 and 2).
|Samples||Banana waste||Papaya waste||Paper waste|
|Control 45 days||0.48 ± 0.03*||1170 ± 5.83*||23 ± 0.37*||0.42 ± 0.06*||787 ± 6.12*||21 ± 0.32*||0.53 ± 0.30*||211.23 ± 4.38*||628.50 ± 93.04NS|
|Treated 45 days||0.41 ± 0.07*||840 ± 2.55*||17.1 ± 0.32*||0.47 ± 0.05*||974 ± 9.08*||19.10 ± 0.28*||0.57 ± 0.09*||270.13 ± 21.92*||526 ± 149.66NS|
|Samples||Poultry waste||Cow dung and vegetable waste||Goat dung and vegetable waste|
|Control 45 days||1.08 ± 0.07NS||0.39 ± 0.05*||0.22 ± 0.02*||6.31 ± 469.077NS||846 ± 48.256*||16.89 ± 127.71NS||6.31 ± 469.077NS||846 ± 48.256*||16.89 ± 127.71NS|
|Treated 45 days||2.5 ± 0.1NS||0.67 ± 0.14NS||0.65 ± 9.11NS||6.14 ± 434.925NS||896 ± 40.329*||17.74 ± 80.233NS||6.84 ± 1104.70NS||1024 ± 25.292*||18.76 ± 83.66NS|
2.5 NPK analysis
In the present study different substrates have been used to culture earthworms and the nutrient content of the vermicompost produced by them has been analysed. The nitrogen content has significantly increased in papaya waste, paper waste, poultry litter and vegetable waste with goat dung. Phosphorus content has significantly increased in all the wastes except banana and levels of potassium have decreased in banana and paper waste. In the study the vermicompost produced from banana as a substrate did not show a significant increase in NPK content from that of the control. On the other hand poultry waste and vegetable waste with goat dung showed significant increase in the NPK content.
In vermicompost, a higher amount of organic carbon is used when compared to the normal compost as the earthworms have higher additional assimilating capacity besides microorganisms. Earthworms also modify the conditions which subsequently lead to increased carbon losses as CO2 due to microbial respiration in organic matter being converted to vermicompost .
The pH reduction may be due to the mineralization of nitrogen into nitrates/nitrites and phosphrous into orthophosphates as well as bioconversion of organic wastes into organic acids . Studies where
The enhancement of the vermicompost was probably due to mineralization of the organic matter containing proteins [15, 16] and conversion of ammonium nitrogen into nitrite [17, 18]. The final N content of the compost as well as the vermicompost depends on the initial content of N in the substrate and the extent of its decomposition [19, 20]. The earthworms can enhance N levels during vermicomposting through the digestion of substrate in their gut and simultaneous addition of nitrogenous excretory products, mucous, body fluid, enzymes; besides the decay of dead tissues of worms in vermicomposting system . This nitrogen content value could have been due to the nitrogenous metabolic products of earthworms which are returned to the vermicompost as casts.
2.7 Total phosphorous
Mineralization and consequent mobilization of phosphorous by enhanced bacterial and phosphatase activities during vermicomposting leads to increase in P . An increase of 25% P in paper waste sludge after the activities of earthworms was reported . They further suggested that the consequent increase in P after the earthworm’s activities may be due to the direct action of worm gut enzymes and due to enhanced microbial activity in the vermicompost. Increase in P content in vermicompost could be due to enhanced mineralization and mobilization of phosphorous as a result of increased bacterial and fecal phosphatase activity of earthworms .
Plant litter was found to contain more available P after ingestion by earthworms, which may be due to the physical breakdown of the plant materials by worms. An increase of 25% in P in paper waste sludge after worm activity was observed. They attributed this increase in P to the direct action of worm gut enzymes and indirectly by stimulation of the microflora .
The increased phosphorous level was due to mineralization of phosphorous. The release of phosphorous in the available form is performed partly by earthworm gut phosphatases and further release of phosphorous might be assigned to the phosphorous solubilizing microbes present in vermicast. The earthworm affects phosphorous mineralization in wastes during passing organic matter through its gut.
2.8 Total potassium
Decrease in potassium content in the vermicompost may be due to the leaching of this soluble element through the action of excess water draining through the mass . The rate of nutrient loss was directly related to the initial concentrations . The selective feeding of earthworms on organically rich substances which breakdown during the passage through the gut, biological grinding, together with enzymatic influence on finer soil particles, were lightly responsible for increasing the different forms of K . The increase of soil organic matter resulted in decrease K fixation and subsequent increase K availability .
The available micro-nutrients like potassium (K) are required for assimilation by earthworms during the vermicomposting, although the quantity required is very low as compared to the initial content present in the parent feed material. The production of acids by the microorganisms and enhanced mineralization rate through increased microbial activity during the vermicomposting process play a key role in the solubilizing of insoluble potassium [28, 29].
The increase of potassium in the treated might be due to changes in the distribution of potassium between exchangeable and non-exchangeable forms. The earthworm processed waste materials contain high concentration of exchangeable potassium, due to enhanced microbial activity during the vermicomposting process, which accordingly enhanced the rate of mineralization.
When organic matter passes through the gut of earthworm, unavailable potassium is transformed to more soluble forms with enhanced rate of mineralization. Decomposition of organic material by microorganisms produces acid products that increase the available soluble potassium. On the other hand, the gut of earthworm has a big population of microflora that could enhance potassium content in the vermicompost.
Vermicomposting has many applications such as increasing water holding capacity, crop growth and yield, improves the physical, chemical and biological properties of the soil. It increases the production of plant growth regulators. Vermicompost is pollution free and cost effective. The texture of vermicompost is homogenous, contains many plant growth hormones and soil enzymes and tends to hold more nutrients over larger periods without adverse effects on the environment.
The author would like to thank the Department of Biotechnology, Government of India, for strengthening Life Sciences and for initiating Research Projects at the under graduate level.
Conflicts of interest
There is no conflict of interest.
Singh D, Suthar S. Vermicomposting of herbal pharmaceutical industry solid wastes. Ecological Engineering. 2012; 39:1-6
Ansari AA, Ismail SA. Role of earthworm in vermitechnology. Journal of Agricultural Technology. 2008; 8(2):403-415
Ansari AA, Sukhraj K. Effect of vermiwash and vermicompost on soil parameters and productivity of okra ( Abelmoschus esculentus) in Guyana. Journal of Agriculture and Environmental Sciences. 2010; 8(6):666-671
Reynolds J. Earthworms of the world. Global Biodiversity. 1994; 4:11-16
Stephenson J. The Fauna of British India Including Ceylon and Burma. London: Taylor and Francis; 1923. p. 518
Bouché MB. Relations entre les structures spatiales et fonctionelles des écosystemes, illustrées par le rôle pédobiologique des vers de terre. In: Pesson P, editor. La Vie dans les Sols, Aspects Nouveaux, Études Experimentales. Paris: Gauthier-Villars; 1971. pp. 187-209
Haimi J, Huhta V. Capacity of various residues to support adequate earthworm biomass for vermicomosting. Biology and Fertility of Soils. 1986; 2:23-27
Loh TC, Lee YC, Linang JBT. Vermicomposting of cattle and goat manure by Eisenia fetidaand their growth reproduction performance. Bioresource Technology. 2005; 96(1):111-114
Mupondi LT, Mnkeni PNS, Brutsch MO. The Effects of Goat Manure, Sewage Sludge and Effective Microorganisms on the Composting of Pine Bark. Compost Science and Utilization. 2006; 14(3):201-210
Natarajan N, Gajendran M. Vermiconversion of paper mill sludge for recycling the nutrients using earthworm Eudrilus eugeniae. International organization of scientific research. Journal of Environmental Science, Toxicology and Food Technology. 2014; 8(9):06
Aira M, Monroy F, Dominguez J. Eisenia fetida(Oligochaeta: Lumbricidae) modifies the structure and physiological capabilities of microbial communities improving carbon mineralization during vermicomposting of pig manure. Microbial Ecology. 2007a; 54:662-671
Ndegwa PM, Thompson SA, Das KC. Effects of stocking density and feeding rate on vermicomposting of biosolids. Bioresource Technology. 2000; 71:5-12
Jyotsana P, Vijayalakshmi K, Prasanna ND, Shaheen SK. Isolation and characterization of cellulase producing Lysinibacillus sphaericusfrom gut of Eisenia foetida. The Bioscan. 2010; 6(2):325-327
Edwards CA, Bohlen PJ. Biology and Ecology of Earthworms. London: Chapman and Hall; 1996. p. 456
Bansal S, Kapoor KK. Vermicomposting of crop residues and cattle dung with Eisenia fetida. Bioresource Technology. 2000; 73:95-98
Kaushik P, Garg VK. Vermicomposting of mixed solid textile mill sludge and cow dung with the epigeic earthworm Eisenia foetida. Bioresource Technology. 2003; 90(3):311-316
Suthar S, Singh S. Feasibility of vermicomposting in biostabilization of sludge from distillary industry. Science of the Total Environment. 2008; 394:237-243
Atiyeh RM, Dominguez J, Subler S, Edwards C. Changes in biochemical properties of cow manure during processing by earthworms ( Eisenia andrei bouche) and the effects on seedling growth. Pedobiologia. 2000; 44:709-724
Crawford JH. Review of composting. Process Biochemistry. 1983; 18:14-15
Gaur AC, Singh G. Recycling of rural and urban waste through environmental and vermicomposting. In: Tandan HLS, editor. Recycling of Crop, Animal, Human and Industrial Waste in Agriculture, Fertilizer. New Delhi: Development and consultation organization; 1995. pp. 31-44
Suthar S. Vermicomposting potential of Perionyx Sansibaricus(Perrier) In different waste materials. Bioresource Technology. 2007; 98:1231-1237
Edwards CA, Lofty JR. Biology of Earthworms. London: Chapman and Hall; 1972
Satchel JE, Martin K. Phosphatase activity in earthworm faeces. Soil Biology and Biochemistry. 1984; 16:191-194
Tahir TA, Hamid FS. Vermicomposting of two types of coconut wastes employing Eudrillus eugeniae: A comparative study. International Journal of Recycling of Organic Waste in Agriculture. 2010; 1(7):1-6
Das D, Powell M, Bhattacharya P, Banik P. Changes of carbon, nitrogen, phosphorous and potassium content during storage of vermicomposts prepared from different substrates. Environmental Monitoring and Assessment. 2014; 186:8827
Rao S, Subba Reo A, Takkar PN. Changes in different forms of K under earthworm activity. In: National Seminar on Organic Farming and Sustainable Agriculture; India: 1996; pp. 9-11
Olk DC, Cassman KG. Reduction of potassium fixation by organic matter in vermiculitis soils. In: Soil Organic Matter Dynamics and Sustainability of Tropical Agriculture. (In Agris). USA: John Wiley and sons Ltd; 1993. pp. 307-315
Kaviraj, Sharma S. Municipal solid waste management through vermicomposting employing exotic and local species of earthworms. Bioresource Technology. 2003; 90:169-173
Khwairakpam M, Bhargava R. Vermitechnology for sewage sludge recycling. Journal of Hazardous Materials. 2009; 161(2–3):948-954
Joseph PV. Microbiological and physicochemical analysis of vermicompost of fruit waste by Eudrilus eugeniae. International Journal of Science and Research Methodology. 2018; 8(4):77-93
Joseph PV. NPK ratio of paper waste degradation through vermicomposting in an Institutional setup. In: National Seminar on Eco-Waste Management NS Nanobiology; 2016