One of the "food losses" that has been regarded as a problem in recent years is the residue (leftover food) in school lunch.It is estimated that the amount of school lunch residue is 1 kg per child / student per year and 17.2 tons in Japan as a whole (results of a 5 survey by the Ministry of the Environment), and most of it is incinerated and discharged in the process. Carbon dioxide is also a factor in deteriorating the global environment.
To solve this problem, a group at Osaka Prefecture University focused on vermicomposting technology using school lunch residues.Whether it is possible to make compost from school lunch residues by utilizing the ability of earthworms to decompose organic substances in the body and contribute to soil fertilization, with the cooperation of the Osaka Prefectural Education Agency, Osaka Prefectural Fujiidera Support School as a model school I verified it.
In the experiment, Eisenia fetida was used to make compost from discarded food residue and paper waste (cut with a shredder, for adjusting the amount of water) in a compost making device installed in the schoolyard. Eighteen weeks later, when the chemical composition of the compost was analyzed, the C / N ratio (ratio of carbon content and nitrogen content) showing the properties of the compost was about the same as that of general compost.On the other hand, in addition to nitrate nitrogen, minerals such as potassium and magnesium were found to be more abundant than ordinary compost that does not use earthworms.
Subsequently, when a germination test of Komatsuna was conducted using this vermicompost, the germination index indicating the goodness of germination was about twice that of normal compost.Furthermore, analysis of the bacterial flora in compost confirmed that the proportion of bacterial groups with plant growth promotion and disease control functions was increasing.
From the above, it was demonstrated that in addition to the fact that earthworm compost can be produced from the food residue that has not been used so far, the compost is more useful than ordinary compost.
This study suggests that the use of vermicompost in various food loss situations, not limited to the recycling of food residue, may lead to the construction of a new resource-recycling society.
Paper information:[Japan Agricultural Research Quarterly] Chemical and Microbiological Evaluation of Vermicompost Made from School Food Waste in Japan
