Local growers have been advised to use organic waste for their farms by turning it into fertiliser through vermicomposting.
Dr Saddar Siddiqui of the National Agriculture Research Centre told WealthPK during an interview that the easily available huge quantity of organic waste in Pakistan such as municipal solid waste, cattle manure and chicken manure could be made a substitute for chemical fertiliser through vermicomposting.
In the bio-oxidative process of vermicomposting, earthworms engage extensively with bacteria and other fauna in the decomposer community, speeding up the stability of organic matter and changing its physical and biochemical properties.
The action of earthworms can be both physical and mechanical. Physical involvement in the degradation of organic substrates causes fragmentation, which increases the surface area of action, turnover and aeration. Microorganisms, on the other hand, bring biochemical changes in the decomposition of organic matter by enzymatic digestion, nitrogen excretion enrichment and transport of inorganic and organic materials.
Dr Saddar said that animal excrement was a valuable resource for supplementing organic matter and improving soil conditions. The cattle of average size produce four to six tonnes of fresh manure every year. After producing bricks, a considerable portion of cattle dung is utilised as cooking and heating fuel in Pakistan and other developing countries.
He said that the burning of dung cakes put negative impacts on human health and the environment. “Indoor concentrations of particles rise when animal dung is burned for cooking. Smoke from animal dung-based cooking stoves contains high levels of carbon monoxide, fine particles, nitrogen dioxide and hydrocarbons, which are dangerous. Acute respiratory infections, chronic obstructive pulmonary disease and cancer have all been linked to long-term exposure to airborne particulate matter,” he added.
The expert said that selection of appropriate earthworm species for vermicomposting was a crucial part of the process. Only a few, out of millions of earthworm species, are suited for vermicomposting organic wastes. Earthworms of the epigeic species are commonly used for the vermicomposting of various organic wastes.
Due to its well-established capacity for vermicomposting biodegradable organic resources such as agricultural wastes and animal manures, Eisenia fetida is the most extensively employed earthworm species for vermicomposting.
“This procedure takes six to nine months. The dung is still unstable, attracting termites to the crops after it is applied. In rural areas, this practice is a major cause of odor and insect problems. Vermicomposting merely regulates the environment so that things disintegrate more quickly. Greater manure handling, improved soil tilth and fertility, and reduced environmental risk are all potential benefits of vermicomposting,” said Dr Saddar.
He said that vermicomposting is getting attention from farmers, waste generators, government authorities and environmentalists. Compost adds organic matter to crops, improves soil structure, reduces the requirement of fertiliser and decreases the risk of soil erosion.
“As compost is sometimes regarded as a waste product, its price varies greatly. Its prices range from Rs10 to Rs20 per kilogram. Its cost is determined by the local market, the quality of the compost, and the raw materials used in it,” said Dr Saddar.—INP