Fabrication of Fertilizer-Impregnated Boards from Low Quality Thinned logs using the High-Pressure Steam Method

抄録

Thinned logs from plantations in Japan are usually left in the forest due to their low quality and market values. In order to utilize these biological resources effectively, the high-pressure steam and mechanical pressing method was used to fabricate chipboards from low quality thinned Sugi (Crpytomeria Japonica D. Don) logs. Knowing that the nutrient content of wood is naturally low, urea was impregnated into some of the chips with the purpose of fabricating urea-impregnated boards. By using these two types of boards as mulches, field experiments were conducted on a maize plot on the campus of Gifu University. The results obtained indicate that the total biomass yield on an area of 1.44 m^2 were 2.1 kg for the plot mulched with urea-impregnated boards, 1.7 kg for chipboard mulched plot and 1.4 kg for the bare plot. Weed weight (dry matter) after one month of cultivation was found to be highest for the bare plot (71 g), while very low figures of 12 g and 8 g were obtained for the urea-impregnated board mulches and chipboard mulches respectively. These findings suggest that impregnating boards with fertilizer and using them as mulches will not only reduce soil moisture loss but also serve as a means of effectively supplying nitrogen to crops. Furthermore, the use of such mulches in small-scale farming systems can have both economic and environmental benefits by increasing agricultural production, eliminating the cost of weeding and the need to apply weedicides.