The night soil compost, produced commonly in homes around Lahaul in Himachal Pradesh, can best be used as soil conditioner and results in higher germination rates of both food and non-food crops, a new study has found.
Funded by the National Mission on Himalayan Studies, the study conducted by researchers from CSIR – Institute of Himalayan Bioresource Technology (IHBT), Palampur, was aimed at evaluating the quality of the night soil compost, its safety and microbiome quality.
Night soil compost is formed after human faeces is converted into a compost-like soil amendment in a dry toilet system that is traditionally used in several Himalayan regions.
Seen in the higher regions of Ladakh, Uttarakhand and Himachal Pradesh, the dry toilet facility is a two-storey structure. The upper section collects the human faecal matter and the lower section comprises the composting chamber for collecting night soil. The collected waste is covered with cow dung, saw dust, sand, agriculture waste, wood ash and other waste and left for several months before it turns to compost naturally.
“The final compost recovered from the dry toilets has high fertilising efficiency, as it is rich in nutrients and safe for human handling. It was free from toxicity to the plant as it showed a higher germination index,” IHBT scientist Rakshak Kumar said.
Published in ‘Waste Management’ journal, the study found pathogen levels in the compost that were within the acceptable range as per standards set by the US Environment Protection Agency, thus making it safe for handling and for use as soil amendments for food and non-food plants.
Due to harsh winters, this region faces severe water scarcity. Hence, soil moisture takes a hit and is often supplemented by mixing this homemade night soil compost for nourishment.
Though producing night soil compost has been done traditionally and is an indigenous way of using organic manure by farmers, the practice was found fast declining in recent years with locals abandoning these setups.
Among the many reasons for this, Kumar said, are the long degradation time (which can span from six to eight months), the associated foul odour, lack of labour force to dig compost etc. “This serious issue of declining traditional knowledge and unavailability of organic manure has led to the dependence of farmers on chemical fertilisers, thus deteriorating the soil further,” he added.
However, with the growing winter tourism and inflow of tourists in these high altitude regions in recent years, combined with awareness campaigns on the benefits of using organic manure over chemical fertilisers, the IHBT researchers said that locals were keen on returning to their roots and adopting practices to save the soil quality.