that homemade backyard vermicompost was lower in microbial biomass, soil microbial activity, and yield of a species of ryegrass than municipal compost. it is rich in microbial life which converts nutrients already present in the soil into plant-available forms. unlike other compost, worm castings also contain worm mucus which helps prevent nutrients from washing away with the first watering and holds moisture better than plain soil. increases in the total nitrogen content in vermicompost, an increase in available nitrogen and phosphorus, a decrease in potassium, as well as the increased removal of heavy metals from sludge and soil have been reported. the reduction in the bioavailability of heavy metals has been observed in a number of studies. benefits soil improves soil aeration enriches soil with micro-organisms (adding enzymes such as phosphatase and cellulase) microbial activity in worm castings is 10 to 20 times higher than in the soil and organic matter that the worm ingests attracts deep-burrowing earthworms already present in the soil improves water holding capacity plant growth enhances germination, plant growth, and crop yield it helps in root and plant growth enriches soil organisms (adding plant hormones such as auxins and gibberellic acid) economic biowastes conversion reduces waste flow to landfills elimination of biowastes from the waste stream reduces contamination of other recyclables collected in a single bin (a common problem in communities practicing single-stream recycling) creates low-skill jobs at local level low capital investment and relatively simple technologies make vermicomposting practical for less-developed agricultural regions environmental helps to close the "metabolic gap" through recycling waste on-site large systems often use temperature control and mechanized harvesting, however other equipment is relatively simple and does not wear out quickly production reduces greenhouse gas emissions such as methane and nitric oxide (produced in landfills or incinerators when not composted). uses mid-scale worm bin (1 m x 2.5 m up to 1 m deep), freshly refilled with bedding soil conditioner vermicompost can be mixed directly into the soil, or mixed with water to make a liquid fertilizer known as worm tea. the light brown waste liquid, or leachate, that drains into the bottom of some vermicomposting systems is not to be confused with worm tea. it is an uncomposted byproduct from when water-rich foods break down and may contain pathogens and toxins. it is best discarded or applied back to the bin when added moisture is needed for further processing. the ph, nutrient, and microbial content of these fertilizers varies upon the inputs fed to worms. pulverized limestone, or calcium carbonate can be added to the system to raise the ph. operation and maintenance worms and fruit fly pupas under the lid of a home worm bin smells when closed, a well-maintained bin is odorless; when opened, it should have little smell—if any smell is present, it is earthy. the smell may also depend on the type of composted material added to the bin. an unhealthy worm bin may smell, potentially due to low oxygen conditions. worms require gaseous oxygen. oxygen can be provided by airholes in the bin, occasional stirring of bin contents, and removal of some bin contents if they become too deep or too wet. if decomposition becomes anaerobic from excess wet feedstock added to the bin, or the layers of food waste have become too deep, the bin will begin to smell of ammonia. moisture moisture must be maintained above 50%, as lower moisture content will not support worm respiration and can increase worm mortality. operating moisture-content range should be between 70 and 90%, with a suggested content of 70–80% for vermicomposting operations. if decomposition has become anaerobic, to restore healthy conditions and prevent the worms from dying, excess waste water must be reduced and the bin returned to a normal moisture level. to do this, first reduce addition of food scraps with a high moisture content and second, add fresh, dry bedding such as shredded newspaper to your bin, mixing it in well. pest species pests such as rodents and flies are attracted by certain materials and odors, usually from large amounts of kitchen waste, particularly meat. eliminating the use of meat or dairy product in a worm bin decreases the possibility of pests. predatory ants can be a problem in african countries. in warm weather, fruit and vinegar flies breed in the bins if fruit and vegetable waste is not thoroughly covered with bedding. this problem can be avoided by thoroughly covering the waste by at least 5 centimetres (2.0 in) of bedding. maintaining the correct ph (close to neutral) and water content of the bin (just enough water where squeezed bedding drips a couple of drops) can help avoid these pests as well. worms escaping worms generally stay in the bin, but may try to leave the bin when first introduced, or often after a rainstorm when the humidity outside is high. maintaining adequate conditions in the worm bin and putting a light over the bin when first introducing worms should eliminate this problem. nutrient levels commercial vermicomposters test and may amend their products to produce consistent quality and results. because the small-scale and home systems use a varied mix of feedstocks, the nitrogen, phosphorus, and potassium (npk) content of the resulting vermicompost will also be inconsistent. npk testing may be helpful before the vermicompost or tea is applied to the garden. in order to avoid over-fertilization issues, such as nitrogen burn, vermicompost can be diluted as a tea 50:50 with water, or as a solid can be mixed in 50:50 with potting soil. additionally, the mucous layer created by worms which surrounds their castings allows for a "time release" effect, meaning not all nutrients are released at once. this also reduces the risk of burning the plants, as is common with the use and overuse of commercial fertilizers. application examples vermicomposting is widely used in north america for on-site institutional processing of food scraps, such as in hospitals, universities, shopping malls, and correctional facilities. vermicomposting is used for medium-scale on-site institutional organic material recycling, such as for food scraps from universities and shopping malls. it is selected either as a more environmentally friendly choice than conventional disposal, or to reduce the cost of commercial waste removal. from 20 july 2020, state government of chhattisgarh india started buying cow dung under "godhan nyay yojana" scheme. cow dung procured under this scheme will be utilised for the production of vermicompost fertilizer.