an ecofriendly approach to sustainable agriculture

VERMS & VERMITECHNOLOGY

PROFESSOR (DR.) ARVIND KUMAR Environmental Science Research Unit, Post Graduate Department of Zoology, S.K.M. University, Dumka - 814 101 (Jharkhand), India.

A.P.H. PUBLISHING CORPORATION 5, ANSARI ROAD, DARYA GANJ NEW DELHI-110 002

Published by S.B. Nangia A.P.H. Publishing Corporation 5. Ansari Road, Darya Ganj New Delhi-110 002  23274050

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2005

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CHAPTER 3

VERMICOMPOSTING: AN ECOFRIENDLY APPROACH TO SUSTAINABLE AGRICULTURE Y.C. Tripathi, P. Hazarika and B.K. Pandey Rain Forest Research Institute, Deovan, Sotai-Ali, Jorhat - 785001 (Assam) INDIA

ABSTRACT The ultimate aim of sustainable agriculture is to develop more productive, profitable and ecofriendly farming systems. Rapidly growing world population and detrimental impact of agricultural systems on the environment necessitates developing a sustainable form of food production. Long-term use of synthetic fertilizers has disturbed natural fertility of croplands and created a number of adverse ecological consequences. Alternative to these synthetic fertilizers are important to maintain a certain ecological stability. There is, therefore, a renewed interest in organic farming system using fertilizers of biological origin. It is widely recognized that larger crop yield can be achieved only by increasing the availability of nutrients for plants, strictly dependent on the biological cycles in the soil. Vermicompost is one such alternative to the conventional chemical fertilizers that has shown its promise in the area of ecofriendly agriculture system. Vermicomposting is a method of converting all the biodegradable wastes into nutrient rich vermicompost through the action of earthworms. It improves the composting and utilization process of available organic and inorganic wastes in the natural plant production cycle. Various aspects of vermicomposting and its potential in sustainable agriculture system are discussed.

INTRODUCTION Sustainable agriculture is the successful management of resources to satisfy the changing human needs, maintaining or enhancing the quality of environment and conserving natural resources at the same time. The ultimate aim of sustainable agriculture is to develop farming systems that are productive and profitable, conserve the natural resource base, protect the environment and enhance health and safety over the long term. Considering the rapidly growing world population and the cases of detrimental impact of agricultural systems on the environment, it is necessary to develop a sustainable form of food production. Many economic, environmental and social problems associated with conventional agriculture suggest that it is possible to develop practices that enhance agriculture and improve

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Verms & Vermitechnology

environmental quality by relying on ecologically sound principles. Long-term use of chemical fertilizers intensifies soil acidity, retarding nutrient cycling and restricting water in filtration and plant root development (Rasmussen, 1998). Furthermore, enhanced soil acidity accelerates the mobility of some heavy metals thus increasing the potential for surfacewater and groundwater contamination. Therefore, maintaining a safe status of soil is a priority for agriculture production. Alternative to the synthetic chemical fertilizers are important to maintain a certain ecological stability. It is widely recognized that larger crop yield can be achieved only by increasing the availability of nutrients for plants, strictly dependent on the biological cycles in the soil. Prior to the advent of new agricultural technologies, organic wastes were widely applied in the croplands to improve tillage, fertility and productivity. There is a renewed interest in use of organic wastes and residues to protect agricultural lands from desertification and to maintain and restore their productivity. Billions of tones of agricultural wastes are yearly produced around the world as residues of high yield crops. They are mainly destroyed by burning, burying or uncontrolled disposed in the environment. Therefore, a great part of what is produced by plant is getting to be irremediably lost. This huge biomass could be usefully recycled in agriculture as safe soil conditioners. Through vermicomposting process, such waste products can be converted into nutrient rich organic matter directly usable to soil for increasing its fertility. The ideal objectives of vermicomposting include upgradation of the value of the original waste material, production of upgraded materials in-situ and production of a final product free from chemical and biological pollutants Bouche (1979).

VERMICOMPOST In nature, earthworm cast consist of excreted masses of soil, mixed with residues of comminuted and digested plant residues. Casts obtained by vermiculture are usually called vermicompost. The vermicompost is a product rich in organic bioremediated matter that differs from the compost obtained, from the same matrix for its level of humification and the greater presence of microbial metabolites. These metabolites, i.e., growth regulators, polysaccharides are strongly responsible for the fertilizing value of casts. Composting of the organic waste materials on farms, in households and in rural and urban human habitats turns them into valuable agriculture inputs and minimizes environmental problems. In this context, vermicompost, organic manure produced due to the activity of earthworms is rich in essential plant nutrients than the ordinary compost. Vermicompost contains major and minor nutrients in plant-available forms; enzymes, vitamins and plant growth hormones like gibberlins and immobilized microflora. Nutrient constituents of vermifertilizer are Nitrogen 2.0-2.5%; Phosphorus 1.3-1.8%; Potash 1.8-2.5%; Calcium 1.0-1.2%; Magnesium 0.3-0.5%; Sulphur 0.80.5%; Iron 0.8-1.5%; Copper 120-36 ppm; Zinc 100-1000 ppm and Manganese 1000-2000 ppm (Rajkhowa, 2003). It is 5 times richer in N, 7 times in P, 11 times in K, 2 times in Mg, 2 times in Ca and 7 times in actinomyces than ordinary soil. The average nutrient content of vermicompost is much higher than mostly used farmyard manure (FYM). Its application in soil easily makes available the essential elements. The quantity of inorganic fertilizers can be reduced to about half the recommended dose by applying vermicompost as organic manure instead of FYM. Vermicompost holds promise to play a significant role in building up of soil fertility and improving soil health for sustainable agriculture. Organic gardeners, landscape artists, home gardeners and field farmers use vermicompost which when mixed with the soil offer nitrogen, phosphorus and potash to the plants without the fear of burning. Besides agriculture, forestry, horticulture and kitchen gardens, earthworms can be used for the development of wasteland area.

Vermicomposting : An Ecofriendly Approach….

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INVESTIGATIVE REPORTS Considerable work has so far been done on the beneficial aspects of vermicompost in augmenting crop yields. An increase of 4.63 times in wheat productivity has been found with the application of vermicastings of Pheretima posthuma and Eutyphoeus waltoni and 2.42 time increase in wheat grains by using castings of P. posthuma and E. waltoni in laboratory conditions (Nijhawan and Kanwar, 1957). Bano et al., (1984) and Girija et al., (1984) reported that the castings of Eudrilus eugeniae could be used as a suitable biofertilizer. However, Kale and Bano (1986) have found no increase in paddy crop production in the field condition by using castings of E. eugeniae but the shoot length of paddy was 1.36 more when the castings were used. Recently Singh and Dev (1991) have noticed an increase of 1.5 times in the production of Brassica oil seeds by using t he castings of P. posthuma and E. waltoni in the field. Studies carried out by Singh et al., (1999) revealed that the castings of P. posthuma increase the shoot length of wheat plants (Triticum aestivum) and lady finger (Hibiscus esculentus) by 1.13 and 1.50 times respectively. Similarly, this increase was 2.27 and 2.00 times for Z. angustifolia and P. drummondi respectively. Increases in plant development, crop yield and quality have often been reported in plants grown in the presence of earthworms or earthworm cast (Satchell, 1983; Lee, 1985). The beneficial effects have been related to an improvement of soil properties (Edwards and Lofty, 1980), greater availability of mineral nutrients (Lee and Ladd, 1984) to the influence of microbial hormone like substances (Nielson, 1965; Springett and Syer, 1979; Graff and Makeskin, 1980; Tomati et al., 1988) and to the presence of metal chelating agents which could enhance the plant uptake of metals involved as co-factors in several enzymatic activities (Tomati et al., 1996). Plant improvement is undoubtly the consequence of a synergic action of all those factors. Few reliable field studies support the thesis that plant growth and development depend on the effect of earthworm on soil structure (Logsdon and Linden, 1992). On the contrary, there is evidence that casts are able to influence plant metabolism, rooting, rooting initiation and development in controlled environments (Broom, 1980; Edwards, 1980; Edwards and Lofty, 1977; Springett and Syers, 1979; Grappelli et al., 1985; Tomati et al., 1990) and to stimulate plant growth in the open field (Tomati et al, 1985). Casts moreover, have been shown able to enhance protein synthesis in lettuce seedlings and in Agaricus bisporus primordial (Tomati et al., 1990; Galli et al., 1990). These effects could be related to the hormone-like properties of casts rather than the substrate structure or/and the nutrients supplied. Furthermore, the ability of some organic compounds, i.e. polysaccharides and humates, to chelate metals is another factor worthy to be considered to better understand the fertility value of casts (Tomati and Galli, 1995, Tomati et al., 1996). Casts have been shown effective in enhancing nitrogen metabolism in plants (Aldag and Graff, 1974; Atlavynite and Vanagas, 1982; Tomati et al., 1990; Tomati et al., 1996). This observation could be explained by the increase in polysaccharides and humic compounds to the soil, already reported by Parle (1963) and the increased population of tree living nitrogen fixers found in the earthworm gut and casts (Bhatanagar, 1975; Citernesi et al., 1977; Tomati and Galli, 1995). Tomati et al., (1996) observed an increase of metals especially for zinc, iron and molybdenum involved in metallo-enzyme proteins in casts. Molybdo-depending enzymes are involved in both nitrogenase(s) and nitrato reductase, which are respectively responsible for nitrogen fixation in soil and nitrate assimilation in plants (Dantzig et al., 1978). The increased availability of molybdenum could help to explain the improved nitrogen metabilism. The effect of earthworm on molybdenum availability in New Zealand soils was already reported. Little information is available on the effect of earthworms and their casts on metal availability, but this could be a promising field of investigation to improve fertility in metal deficient soils.

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Vermicompost, because of its high level of humification, microbial population present in it-free living nitrogen fixers constituting a consistent component (Bhatnagar, 1975; Citernesi et al., 1977; Kaplan and Hartenstein, 1977), the high concentration of hormone like compounds and microbial metabolites (Parle, 1963; Gabrilov, 1963; Dubash and Ganti, 1964; Tomati et al., 1988) is more effective when agriculture is required to produce in short time. Therefore, greenhouse activities are the most advisable field of application. Very promising results have been obtained in horticulture and related application either in regard of the final crop or in the nursery (Broom, 1980; Edwards, 1980; Edwards and Lofty, 1980; Springett and Syers, 1979; Grappelli et al., 1985; Tomati et al., 1988).

SELECTION AND MASS MULTIPLICATION OF WORMS All the worm species use to consume the organic wastes. But, their action on organic waste consumptions, rate of degradation and some other physiological characters are variable. Therefore, selection of suitable worms is must for efficient production of vermicompost. The earthworm species that capable of adaptation to high percentage of organic materials have high adaptability with respect to environmental factors, with high fecundity rate and low incubation period, small interval between hatching and maturity, high growth, consumption, digestion and assimilation rate and minimal vermistabilization are considered to be efficient for production of vermicompost. Julka (1986) reported a list of 20 Indian worms, which could be possible to use as agent for vermicomposting. In a comparative account of the vermicultureal characteristics of the some Indian worms are Eisenia foetida, Lumbricus rubellus, Amyanthas diffringens, Eudrillus eugineae, Perionyx escavatus, Lampito mauritii, Drawida nepalensis, Pontocolex corethrurus, Gordiodrilus elegans etc. are a few earthworm species widely and efficiently used in vermicompost production. For Indian condition, worms like Dichogaster bolaui, Drawida willsi, Lampito mauritii and Perionyx excavatus are found efficient (Dash and Senapati, 1986). The African worm Eudrilus euginiae is being tried at different centers and is giving encouraging results (Kale, 1986). However, it is better to look for endemic species, because exotic species might carry fungal and other pathogens, which may create additional problems for our crop. The methods of vermicomposting have already been standardized in Indian conditions and can simply be started wooden box or earthen tubs. Although many species of earthworms are suitable for waste processing, two species have been taken into consideration for vermicomposting; Eisenia fetida and Eudrilus eugeniae. Their growth, productivity and ability to transform organic wastes, agricultural residues, urban wastes and sludge were widely reviewed (Lee, 1985; Edwards, 1998). Earthworms can be multiplied in 1:1 mixture of cow dung and decaying leaves taken in a cement tank or wooden box or plastic bucket with proper drainage facilities. The nucleus culture of earthworms is introduced into the above mixture at the rate of 50 numbers per 10 kg of organic wastes and properly mulched with dried grass, straw or wet gunny bag. The unit should be kept in shade and sufficient moisture level should be maintained by occasional sprinkling of water. Within 1-2 months, the earthworms multiply 300 times, which can be used for large-scale composting. Worms can also be successfully cultured in a 50 X 25 X 15 cm wooden box and filled with one fourth soil and a layer of small gravel at the base, one fourth with saw dust, rice burn, straw or sieved organic garbage, one fourth with dry cow dung or any suitable nitrogenous waste and rest left as empty space (Senapati and Dash, 1984). Hundred adult worms of selected species are added in that mixture and after six month the culture will multiply up to 150 –200 times. The culture should be kept at 15-20 % of soil moisture and at temperature around 25-280C (Senapati and Dash, 1985).


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Major Steps in Vermicomposting The ideal objectives of vermicomposting are to upgrade the value of the original waste material to produce upgraded materials in situ and obtain a final product free of chemical and biological pollutants (Bouche, 1979). The overall vermicomposting process involve following major steps: Collection and Processing of Waste Organic wastes such as residues of crop, vegetables, agricultural and agro-industrial byproducts, weeds such as Water Hyacinth, Ipomoea, Eupatorium, etc. and municipal wastes are the major source of raw materials for compost making by earthworms (Rajkhowa, 2003). During collection of agro-industrial and municipal wastes certain process like shredding, mechanical separation of metal, glass, ceramic, plastics are needed. Shredding is the process through which wastes materials are being crashed into small parts or particles to the volume reduced to 50-70%. Raw organic wastes are generally pilled and kept as such for 7-10 days. Cow dung slurry are applied over the pilled wastes during this period maintaining suitable time gap for 2-3 times. Vermicompost suitably produces in concrete tub/ tank of the size 3´x 2´ x 6´ or length can be maintained as per volume of the organic wastes (Rajkhowa, 2003). Lowermost layer of the compost tub or tank must be filler in thin layer (1-2//) sand or powdered soil. The 2nd layer must be filled with half decomposed cattle dung of 1-2 inches thickness. After that organic waste and half decomposed dung can be filled in alternate layer. Total height of the compost mixture should be restricted to 1.5 - 2//. There should be remained unfilled a volume of 6// on the upper side of the tub or tank. Composting by Earthworms During this process earthworms convert the organic waste into vermicompost. To the mixture selected species of earthworm cocoon or adult to be added. In general, 2-3 kg of adult worms is required to get vermicompost after 45-60 days (Rajkhowa, 2003). Byproduct of biogas plant can also be used in the earthworm beds for production of vermicompost. A handy earthworm beds for households use can be prepared with a concrete lining or in wooden boxes. After adding the earthworm, the tub/tank filled with mixture should kept in cover with gunny begs or rice thresh. Light watering is required to maintain 60-80% humidity depending upon the whether condition. Proper care should be taken so as to keep the compost tubs/tanks in shed. To prevent the attack/infection of harmful pests such as white ants and ants etc. regulatory measure can be taken by applying burn mobile, liquid paraffin or any other suitable material just outside the tubs/tanks as or when required (Rajkhowa, 2003). Screening and Sorting Composting process can be marked as complete by the earthworms when the waste mixture turns in to brown or dark brown (Rajkhowa, 2003). Now the vermicompost can be collected in layer by layer so as to separate the intermingled earthworms without making more injure or harm. Screening and sorting is done to separate the undecomposed waste, which can be used for land filling or reprocessing. Earthworms can be separated from the compost by a dynamic separation method involving a sieve and a photo/thermal stimulus (Dash and Senapati, 1985).

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VERMICOMPOST FROM ORGANIC WASTES Conversion of selected garbage components by earthworms into compost and the multiplication of earthworm are simple process and can be easily handled by any layman in the village (KAU, 2002). Followings are the process for preparation of vermicomposts from different organic wastes: Vermicompost from Farm Wastes Pits of size 2.5 m length, 1 m breadth and 0.3 m depth are taken in thatched sheds with sides left open. The bottom and sides of the pit are made hard by compacting with a wooden mallet. At the bottom of the pit, a layer of coconut husk is spread with the concave side upward to ensure drainage of excess water and for proper aeration. The husk is moistened and above this, biowaste mixed with cowdung in the ratio of 8:1 is spread up to a height of 30 cm above the ground level and water is sprinkled daily. After the partial decomposition of wastes for 7 to 10 days, the worms are introduced @ 500 to 1000 numbers per pit. The pit is covered with coconut fronds. Moisture is maintained at 40 to 50 per cent. When the compost is ready, it is removed from the pit along with the worms and heaped in shade with ample light. The worms will move to bottom of the heap. After one or two days the compost from the top of the heap is removed. Put back the un-decomposed residues and worms to the pit for further composting as described above. The vermicompost produced has an average nutrient status of 1.5%, N, 0.4% P2O5 and 1.8% K2O with pH ranging from 7.0 to 8.0. The nutrient level will vary with the type of material used for composting. The composting area should be provided with sufficient shade to protect from direct sunlight. Adequate moisture level should be maintained by sprinkling water whenever necessary. Preventive measures should be taken to ward off predatory birds, ants or rats. Depending on the extent of weathering of leaves used for composting, 70 per cent of the material will be composted within a period of 60-75 days. At this stage, watering should be stopped to facilitate separation of worms from the compost. Compost can be collected from the top layers, which can be sieved and dried under shade. Earthworms aggregated at the bottom layers can be collected and used for further vermicomposting. Vermicompost from Coconut Leaves Weathered coconut leaves can be converted into good quality vermicompost in a period of three months with help of earthworm, Eudrillus sp. On an average, 6-8 tones of leaves will be available from a well-managed coconut garden, which will yield 4-5 tones of vermicompost with about 1.2, 0.1 and 0.5% N, P2O5, K2O respectively. Vermicompost from Household Wastes A wooden box of 45 x 30 x 45 cm size or an earthen/plastic container with broad base and drainage holes containing plastic sheet with small holes towards the bottom is used for this purpose. In this box, soil and coconut fibre are placed in layers of thickness 3 cm and 5 cm respectively. Then a thin layer of compost and worms is added above it. About 250 worms are sufficient for the box. Vegetable wastes are spreaded daily in layers and top of the box is covered with a piece of sac to provide dim light inside the box. When the box is full, the box is kept for a week without disturbance. When the compost is ready, the box is kept outside in the open for 2-3 hours so that the worms come down to the lower fibre layer. Compost is removed from the top, and then dried and sieved. The vermicompost thus produced has been found to have average nutrient status of 1.8 % N, 1.9 % P2O5 and 1.6 % K2O, but composition may vary with the substrate used.


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PREPARATION OF VERMIWASH Two methods are generally used for preparation of Vermiwash.

Method – 1 The system consists of a plastic basin having a capacity of 20 L, a plastic perforated waste-paper basket and a PVC pipe of 5 cm diameter and 30 cm length. The waste-paper basket is covered with nylon net and placed at the centre of the basin upside down. A hole is made at the bottom of the waste paper basket so that a PVC pipe of 5 cm diameter can be placed into the basin through the hole in such away that one end of it touches the basin. The PVC pipe is perforated so that the leachate from the basin seeps through the waste-paper basket and collects in the PVC pipe, which can be siphoned out by a kerosene pump. In the basin outside the waste-paper basket, a layer of brick pieces are placed and a layer of coconut fibre of 2-3 cm placed above it. After moistening this, 2 kg worms (about 2000) are introduced into it and 4 kg kitchen-waste is spread over it. After one week the kitchen-waste turns into black well-decomposed compost. Two litres of water is sprinkled over the compost containing worms. After 24 hours, the leachate collected in the PVC pipe is removed by siphoning. The collected leachate is called vermiwash, which is actually an extract of compost containing worms. This is used for soil application and foliar spray in different crops. Vermiwash is honey-brown in colour with a pH of 8.5 and N, P2O5 and K2O content 200, 70 and 1000 ppm respectively. For large-scale collection of vermiwash, a cement tank of size 80 x 80 x 80 cm is constructed. A layer of small brick pieces or gravel is placed at the bottom of the tank. Above it a layer of fibre of 3-4 cm thickness in placed. A definite quantity of biowaste (4kg) is added to the system along with 2 kg of earthworms. After two weeks, the entire mass of biowaste will turn to brownish black compost. Then add 2 litre of water. Vermiwash is collected through the side tap after 24 hours. Again biowaste s added to the system and the process is repeated. Method - 2 This is a simple and economical technique to collect vermiwash. The system consists of an earthen pot of 10 kg capacity, which is filled, with pieces of stone up to 10 cm height from the bottom. Above this, a plastic net is placed and spread out. Then a thick layer of coir fibre along with humus containing 1500-2000 worms of species Eudrillus euginae or Isenia foetidae is laid down. The hole situated at the bottom of the pot is fixed with a water tap through which vermiwash is collected. Every day, the kitchen waste is put into the container. The composting process is allowed to continue for one week or more till brownish black mask of compost is obtained. Occasionally, two or three tablespoons of fresh cowdung slurry are poured on the humus as feed for the worms. After the formation of compost, the entire mask id soaked with 2 litre of water. After 24 hours, about 1.5 litre of vermiwash can be collected. This process can be continued for one or two weeks till the brown colour of wash disappears. The less enriched compost that remains in the pot can be collected and used as fertilizer. Later, the pot can be emptied and set up again to continue the process. The potential of vermiwash as a biocide either simply or when mixed with botanical pesticides can be very well exploited for household vegetable cultivation.

SPENT COMPOST About 50% of the compost applied is usually remains as spent compost. The lignocellulose residues that remain as wastes after crop harvesting are a potential raw substrate for edible mushroom cultivation. The recycle of this huge biomass is beneficial to

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human welfare since it increases food supply and reduces environmental pollution. The utilization of crop residues for mushroom cultivation does not lead to a complete decomposition. Due to their activity on lignin, the while-rot fungi transform the substrate into a soil ameliorant, rich in humic and fulvic fractions and in plant nutrients. The spent compost has high nitrogen content. About 80% is bound to high molecular weight fraction of lignin and humic fractions (Grabbe, 1982) so it slowly released and kept available for plant requirement. The spent compost has been used as a soil-improving agent especially in protected agriculture and nursery (Sochtig and Grabbe, 1995; Chang, 1982). The spent compost is generally used in small quantities in horticulture and landscape gardening. However, at least on a limited scale, it can contribute to increase soil fertility especially in developing countries where mushroom cultivation is a common practice at family level.

DEVELOPMENTS IN VERMICOMPOSTING Different approaches are being used to process large volumes of organic residuals with earthworms, ranging from relatively simple land and labor-intensive techniques to fully automated high-tech systems Types of systems include windrows, beds, bins, and reactors. The largest vermicomposting facilities rely on tipping fees for feedstocks and accept a wide variety of organic materials. Smaller facilities usually have to purchase feedstocks or pay for transportation of materials. Commercial in-vessel vermicomposting systems first appeared on the market in the United States in the early 1990s.The first mid-scale vermicomposting system was the Worm Wigwam, which was introduced in the Pacific Northwest by John GormanSauvage. About the same time, Al Eggen, owner of Original Vermitechnology Toronto, Canada developed an automated, larger-scale vermicomposting system (Sherman-Huntoon, 2000). .

Operating mid-to-large-scale systems poses temperature control challenges that are seldom experienced with smaller operations. Larger systems generate more heat from decomposing organic materials and hold heat longer than smaller units. Operators also have to be concerned with solar gain in or around the system. Methods of lowering system temperatures include adding water, activating fans in or near the unit, and reducing the amount of feedstock applied. Factors that may be considered for selecting the appropriate vermicomposting technology for a project include; amount of feedstock to be processed; funding available; site and space restrictions; climate and weather; state and local regulatory restrictions; facilities and equipment in hand and availability of low-cost labour.

Windrow Windrows are extensively being used both in the open and under cover, but require either a lot of land or large buildings. It is difficult to harvest the vermicompost without earthworms being included, so a mechanical harvester is commonly used with these operations. American Resource Recovery (ARR) in Westley, California operates the largest vermicomposting facility in the United States. The vermiculture operation was begun in 1993 to build an earthworm inventory; four years later, ARR began processing and selling vermicompost. Currently, an estimated 500,000 pounds of earthworms process 75,000 tons of materials annually on 70 of ARR’s 320 acres. The worms are fed paper pulp generated from recycled cardboard, tomato residuals, manure, and green waste in three-foot wide windrows, some of which are a quarter mile long. During its busiest season, ARR ships up to 100 tons of vermicompost per week. In 1998, they began selling earthworms throughout the United States, and expanded to foreign markets in 1999. From 1994 until 1999, at the Crow Worm Farms in Cleburne, Texas, vermicomposting windrows occupied ten of the 200 acres. About 20,000 pounds of dairy manure were applied


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to windrows each week using a side discharge feed wagon pulled by a tractor. The hot, humid summers and cool winters posed challenges to survival of temperature-sensitive red worms. Misting houses on top of the windrows were used in summer and winter to protect worms from temperature fluctuations. In summer, windrows were kept moist by running the hoses twice daily for 15 minutes, or a third time if the temperatures soared above 100° Fahrenheit. Water was also used to protect the worms when freezing temperatures were expected. In addition to being susceptible to overheating, worms are sensitive to vibrations, and thunderstorms that can cause them to leave their beds. Spacing the windrows 20 ft apart to allow worms that left their beds to reach another bed safely may solve the problem. About 10 tones of vermicompost were harvested from the windrows each week at roughly 40 %t moisture level.

Wedge System This modified windrow system maximizes space and simplifies harvesting because there is no need to separate worms from vermicompost. Organic materials are applied in layers against a finished windrow at a 45-degree angle. The piles can be inside a structure or outdoors if they are covered with a tarp or compost cover to prevent leaching of nutrients. A front-end loader is used to establish a windrow four to ten feet wide by whatever length is appropriate. Spreading a 12 to 18-inch layer of organic materials the length of one end of available space starts the windrow. Up to one pound of red worms is added per square foot of windrow surface area. Subsequent layers of two to three inches of organics are added weekly, although three to six inch layers can be added in colder weather. After the windrow reaches two to three feet deep, it can be extended sideways by adding the next layers at an angle against the first windrow. Worms in the first windrow will eventually migrate toward the fresh feed. Fresh manure is added to the second pile until it reaches the depth of the first one, and then a new windrow is started. Worms will continue to move laterally through the windrows. After two to six months, the first windrow and each subsequent pile can be harvested. The wedge system is one of the processes used on the Yelm Earthworm and Castings Farm, located near Yelm, Washington. The 10-year old worm farm is among the largest in North America, with 30,000 square feet of enclosed space in addition to production areas outdoors. About 15 tons of redworms are used to process a variety of feedstocks, including animal manures, wood chips, leaves, spoiled hay/straw, grass clippings, yard debris, produce, food scraps, waxed cardboard, soiled paper, and corrugated cardboard.

Bed & Bin Systems Beds and bins have been used extensively throughout the industry to varying degrees, from home enthusiasts to part-time worm growers to large operations. Outdoor large-scale systems usually require some type of cover to keep out direct sunlight or rain. It’s a laborintensive process to harvest worms and vermicompost by hand. One advantage of this system is that if the worm beds get too hot, worms can burrow deeper into the bed where the temperature remains below 75° F. Another advantage is the system can be left alone for up to three days, as compared to automated reactors that need to be checked daily for moisture and temperature levels. A disadvantage is that the worms and castings must be separated manually. Migrant workers use pitchforks to remove the top 4-inches of the beds for use in starting new beds. Pitchforks and flat shovels are used to harvest the finished castings, which are then run through a trammel screen to separate the worms. Castings are sold to several markets, either in bulk or in 50-pound bags.

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The bin system was chosen for use at the Broad River Correctional Institution in Columbia, South Carolina. In May 1998, Larry Martin of Orange Lake, Florida installed a vermicomposting unit. Measuring 34-feet long by seven-feet wide by 20-inches high, the wooden bin with insulated panels has a center divider for ease of feeding and harvesting. A screen was laid down first to keep out moles, and greenhouse mesh suspended by metal poles was added overhead for shading. Kitchen scraps are placed in a pile for composting, then every two to three weeks about 800 to 1,000 pounds of shredded food scraps are added in four- to six-inch layers in the worm bin. About thirteen 55-gallon barrels of castings are harvested from the bin two or three times a year.

Plastic Bins Simple plastic bins are by far the most common type of vermicomposting bin. Their use is fairly simple. Bins are filled at least three-quarters full of damp bedding and compost worms are added, and then organic waste buried. The occasional addition of bedding material is also helpful. When a significant portion of the material in the bin has been converted into vermicompost (usually 3-6 months), then it’s time to harvest. As many first-time vermicomposters know, even a simple plastic tub with well-placed aeration holes can work just fine as a worm bin. Additional modifications, however, make it easier to keep the bin from having some of the problems typical of this type of bin. Most commercially available worm bins incorporate multiple ventilation holes on the sides and top of the bin, a catchment basin or tray for excess liquid or a drain spigot. The simple plastic bins have a tendency to develop anaerobic pockets. Aeration holes or vents should be abundant. It’s good to have them placed within an inch or two of the bottom and the very top of the bin, to promote good circulation throughout the composting mass. If lot of condensation on the sides and top of the bin are seen and worms are moving to those areas, that indicates a probable deficit of oxygen in the composting mass Better aeration is the answer. Plastic traps water and water vapour, which is released in great quantities by decomposing organic matter- and particularly by food waste. The less moisture escapes through vents, the more likely it will be that water will pool in the bottom of the bin. Better aeration, a drain spout or a perforated bottom and catch tray will help to prevent swamp.

Reactor System Reactor systems have raised beds with mesh bottoms. Feedstocks are added daily in layers on top of the mesh or grate. Finished vermicompost is harvested by scraping a thin layer from just above the grate and then it falls into a chamber below. These systems can be relatively simple and manually operated or fully automated with temperature and moisture controls. For maximum efficiency, they should be under cover. According to Ohio State University professor Clive Edwards, construction and operation costs of flow-through reactor facilities compare favorably with similar sized conventional thermophilic composting operations. Edwards estimates that a 1,000 T/Y vermicomposting facility would cost approximately $100,000. The smallest flow-through reactor in the market is the Worm Wigwam, which is now manufactured by EPM, Inc. of Cottage Grove, Oregon. This system has a proven record of efficiency with few problems and is being used at correctional facilities, schools, universities and colleges, office buildings, military bases, and hospitals throughout North America. The Wigwam consists of a recycled plastic shell and lid that stands three-feet high and is three-


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feet in diameter. Inside is a galvanized steel grate about 16 inches off the ground, leaving an 18-inch vermicomposting chamber above and a storage area below for the finished product. A hand-operated crank pulls a bar across and just above the grill, scraping off a thin layer of finished vermicompost that falls through the widely spaced bars to the chamber below. The bin is heated and insulated for optimum year round use. The Worm Wigwam uses up to 35-40 pounds (35,000 to 40,000) of worms, and can process up to 8,000 pounds of organics per year, depending on the material. Reactors are often used in groups to increase capacity to handle feedstocks. Since July 1999, the Medical University of South Carolina has been using a Vermitech system to process 100 pounds of cafeteria food residuals daily. The vermicomposting unit consists of two, eight-foot modular beds with a two-foot section containing hydraulic equipment and an air conditioner. Feedstock is delivered to the bin via a conveyor belt connected to a Vermitech shredder/mixer. Every two to four weeks, the hydraulic system is activated to scrape off the bottom layer of vermicompost. About 500 pounds are collected each month and used by the campus grounds department. Pacific Garden Company in Ferndale, Washington, uses a continuous-flow reactor to process separated solids from a dairy farm. The 120-foot by eight-foot bed, constructed from existing equipment used in the dairy industry, was designed to handle 6,000 pounds of organic materials per day. Layers of waste are applied by a moving gantry feeder on rails above the earthworm bed. A moving breaker bar expels the finished vermicompost through the suspended mesh floor and a hydraulically driven series of scraper bars remove the vermicompost from beneath the bed to a collection point.

BENEFITS OF VERMICOMPOSTING Unlike chemical fertilizers vermicompost is economic and cost effective. It is very potential input for sustainable agriculture and can also be an important component of Integrated Plant Nutrition System (IPNS). Application of chemical fertilizers alongwith vermicompost can go a long way in sustaining yields without deteriorating soil quality. Vermicomposting facilities employ four times more people on a per-ton basis than landfills. It creates new full-time jobs, replicable, and will demonstrate economic feasibility of commercial food discard composting and vermicomposting. Some farmers raise worms as a source to supply bait dealers or create their own bait routes. The worms business is flexible allowing the farmer to raise only worms, or worms in addition to other farm animals and equipment. Many rabbitries and other livestock farms implement the use of worms to reduce the manure stock. There are many facets to the worm industry and vermiculture. For instance, by contacting local grocery stores, produce vendors, schools, or restaurants or any company having food or paper waste, another opportunity can be created. The worm farmer introduces this waste stream to the worms, keeps the beds moist, and while the worms multiply and grow, they are creating yet another valuable commodity, the worm castings. Farm operations that produce a lot of waste matter, particularly manures from cattle, sheep, pig, horse, rabbit and poultry operations which utilize feedlots, need to find a way of disposing of that waste. Hitherto manures have been regarded mainly as a waste product but not as a resource. The economics of vermiculture depends in part on how effective the end product (vermicast) is compared with alternative fertilizers, as most livestock breeders would be looking to apply the vermicast for their own broad acre uses. Alternatively, farmers using compost worms to treat manures may aim to sell their vermicast.

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DEMAND AND MARKET POTENTIAL Compost is a historically low priced commodity. Worms have a way of improving the nutritive value of compost for plants and vermicompost command a premium price. Many operators further minimize investment in composting and sell inferior, typically un-finished materials. These poor products compound market disinterest in compost. Utilizing food with urban plant debris may produce a finished product with more nutritional value than yard trash compost. There are many worm breeders whose main or only product is solid and/or liquid vermicast. A lot of attention has been given to developing the market for recycled waste materials that can be sold to the horticulture industry and for broadacre applications. Much less focus has been given to the market potential for worms, particularly so-called compost worms of the Red, Tiger and Blue varieties. In some cases, the market for compost worms is derived from the vermicast demand. Compost worms are being sold as breeding stock to other growers who produce solid and liquid vermicast as a stand-alone operation. The demand for compost worms from this source depends on the size of the market for vermicast and mixtures containing vermicast. Compost worms can be sold to the farmers for on-farm waste management. Farm operations that produce a lot of waste matter, particularly manures from cattle, sheep, pig, horse, rabbit and poultry operations which utilise feedlots, need to find a way of disposing of that waste. Hitherto manures have been regarded mainly as a waste product but not as a resource. The economics of vermiculture depends in part on how effective the end product (vermicast) is compared with alternative fertilizers, as most livestock breeders would be looking to apply the vermicast for their own broadacre uses (Huang, 1999). Alternatively, farmers using compost worms to treat manures may aim to sell their vermicast. The information regarding true state of supply and demand in the vermiculture industry is either non-existent or unreliable. Any idea regarding how many worm farmers is currently in operation, what stock of worms they have, their costs of operation, and what quantity of vermicast they are producing is lacking. All these informations need to be place together in a broad picture of the potential market.

TRENDS AND FUTURE PROSPECTS For the past decade, several large-scale vermicomposting systems have been used with varying success. Given the time frame and the number of failed attempts, large-scale vermicomposting perhaps is still in a developmental phase. This indicates the need for ongoing assessment of factors that contribute to the success of large-scale systems. Problems that plague the industry include poor management, undercapitalization, misrepresentations of facts, difficulties with regulatory agencies, unstable markets and emerging technology that still needs to be perfected. Some system designers who were eager to introduce their units on the market didn’t have all of the bugs worked out in some cases and in others they failed to provide thorough training, resulting in poor management. Many regulatory agencies don’t know whether to classify vermicomposting as composting or create a new category with different rules. Yet, most of these challenges can be overcome through dissemination of information and training. Marketing vermicompost continues to pose a challenge due to potential users’ unfamiliarity with the product. However, making research data available in an accessible form and educating retailers, nursery workers and the public can overcome these problems. Tremendous opportunities lie in two trends: Blending vermicompost with compost to give it a competitive edge; and vermicompost tea which is drawing interest from farmers as well as gardeners.


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OVERCOMING OBSTACLES - INNOVATIVE WAYS Harvesting Worm Castings Harvesting of worm casting without disturbing the worms while they actively work with the materials, is a difficult process. Use of a specialized castings extractor that allows worm castings to be removed from the system without harvesting worms may overcome this challenge and at the same time it will increase operational efficiency. The process may also result in increased aeration of the worm beds.

Odor Suppression Odor has been the primary cause of composting operation failure. Current research indicates that the majority of odor is produced during the first two weeks of composting. To avoid odor generation, the specialized aeration equipment (such as innovative turners and a modified passive/active aerated static pile), mobile small-scale in-vessel composting systems, and vermicomposting are essential. On-site composting could also have a significant impact on odor reduction. Additional potential benefits of onsite composting include: reduction in the weight and volume of materials that need to be managed, increased stability of materials that must be handled, and more cost-effective transportation of residue.

Quality Assurance Compost quality need to be ascertained by testing finished product for quality, including nutrient analysis, compost maturity, problem metals and pathogens. produce compost from municipally generated organic discards need to follow the stringent norms environmentally oriented groups. Both the overall approach and system components apply novel approaches and new technologies to overcome obstacles to effectively manage food discards.

Collection Infrastructure The major obstacles to waste management are the limitation on collection infrastructure and failure of integrated collection strategies. There is a need to implement an innovative collection system for collecting compostable discards focusing on transportation efficiencies, their evaluation at the site (origin), and transportation of partially composted materials. Source separated composting has been limited by lack of knowledge about recipe formation. Recipes are the proportional combination of several materials to make a mixture of materials that has the chemical and physical characteristics to promote optimal decomposition by aerobic organisms and to avoid malodorous emissions. Areas of innovation include demonstration of new composting recipes using food discards and urban plant debris, implementation of original management strategies, and use of non- traditional carbon sources.

CONCLUSION Sustainable agriculture, in a correct social development that can ensure the sustainability of resources and human health; since it guarantees the conservation of environmental equilibria and assures the productivity on adurable basis in the respect for safety of both farmers and consumers and economical sustainability, since it assures convenient productions and profit, especially in the poorest areas of the world. Organic farming is a whole-system approach that works to optimize the natural fertility resources of the farm. This is accomplished through traditional practices of recycling farm-produced

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livestock manures, composting, crop rotation, green manuring, and crop residue management. Organic agriculture looks to local waste products i.e., manures from confinement feeding, food processing wastes, etc. to supplement soil fertility economically. Many organic operations achieve a high degree of sustainability using these methods, innate nutritional deficits in regional soils, pest management abuses, and high productivity demands commonly require the farmer to purchase additional fertilizers or amendments from specialty suppliers (Sampson et al., 2002). Rapid increase in the human population beyond the limit and of the urbanization, total agricultural land is decreasing day by day which are directly affecting the crop production. Although due to the usage of various chemical fertilizers and pesticides crop production has increased many fold; but their excessive and imbalance usages causing tremendous alterations in natural soil environment. Vermicomposting, although it has been around long enough to attract worldwide attention, is in many ways, still in a stage of infancy. Programmes aimed to investigate the possibility of large-scale vermicomposting; its economic and environmental potential however did not achieve the targeted goals. A dedicated corps of individuals continues in its efforts to bring the good news of vermicomposting to those concerned about organic waste management and to those interested in soil fertility. Before the full potential of the compost worm can be realized, there needs to be further development of vermiculture technologies and systems and better data to gauge the potential supply and demand.

ACKNOWLEDGEMENT Authors are grateful to the Director, RFRI, Jorhat for the encouragement and necessary facilities. Literature collection work done by Shri R.C. Dutta, Smt. Rupjyoto Baruah and Shri Bhuban Kachari, Research Assistants of C.F. & E. Division is also acknowledged.

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