Possibilities of the application of food wastes to agriculture:Effect of coffee grounds extract on the growth of Japanese mustard spinach

Many food wastes dispose from mainly developed countries including Japan, on the other hand a drain of phosphatic fertilizer is an issue of sustainable agriculture. Here we investigated effective utilization of the food wastes for agriculture, and focused on coffee grounds which is disposed of in a large quantity and difficult to reuse. It is difficult to use the coffee grounds for agricultural materials (ex; fertilizer, soil conditioner), because the coffee grounds are high carbon to nitrogen (C/N) ratio and contains a kind of plant growth inhibitor. Hence, the water (coffee grounds extract) stained out coffee grounds was used. Japanese mustard spinach (Brassica rapa var. prviridis) growth (fresh weight, dry weight and shoot length) was enhanced by applying the coffee grounds extract, and the growth ratio was almost same as plants applied commercial liquid fertilizer. We therefore suggest that the coffee grounds extract may use fertilizer in agriculture.