Development and Field Testing of Agricultural Snowmelting Agents Made from Recycled Bio-waste Materials

In snow-covering region of Japan, the promotion of snowmelting with application of agricultural snowmelting agents ("Yusetsuzai" in Japanese) has been widely carried out by farmers at the snowmelting season. When black colored materials with albedo-lowering effect are spread on snow surface, absorption of solar radiation by snow is increased, the snowmelting is promoted and snow thawing date becomes earlier. As a result, the growing season of crop plants is extended. Existing agricultural snowmelting agents have been mostly made from industrial waste materials or industrial processed products due to requirement for the low cost of the raw materials. These agents may contain harmful heavy metal elements and may lead to environmental pollution. To solve these problems, we developed the new agricultural snowmelting agents made from recycled bio-waste materials generated from the fields of agriculture and fishery. The developed snowmelting agents were made from shells of Patinopecten yessoensis, fowl droppings and processed wastes of fish and shellfish, etc. Especially, the shells of Patinopecten yessoensis has problems due to generation of a huge quantity in Hokkaido. Therefore, the recycling-use of these waste materials was strongly requested and expected. The developed snowmelting agents were possible to spread efficiently and safely on the snow-surface without wide scattering by controlling the particle size within the range larger than 100 μm and smaller than 1180 μm. Results obtained from the field experiment showed that the albedo was decreased from 0.70 for natural snow to 0.20 and the promotion of snowmelting for 11 days was recognized when 100 kg 10a^-1 of developed agent was spread. The promoting ability of the developed agent was equivalent to those of the existing commercial snowmelting agents.