Effectiveness of ground bamboo mulching in suppressing weeds and enhancing rice production: a microcosm experiment

Abstract

Bamboos have expanded their distribution in Japan in recent decades due to the abandonment of forest management practices following depopulation and aging in rural communities. Developing effective uses for bamboo biomass resources is highly desirable. In this study, we tested the effectiveness of ground bamboo as a new organic mulching material for agrochemical-free rice farming. Specifically, we tested whether ground culms and leaves with or without refrigeration/fermentation treatments influenced rice production differently. Using plastic tubs (0.31 m2), we conducted a field experiment comprising five treatments with five replicates deployed in a randomized block design: (1) control, (2) fermented ground bamboo culm application, (3) refrigerated ground bamboo culm application, (4) fermented ground bamboo leaf application and (5) refrigerated ground bamboo leaf application. Ground bamboo application successfully suppressed the coverage of the most dominant aquatic weed, Monochoria vaginalis (Pontederiaceae). Tiller numbers and soil plant analysis development values of rice plants were significantly higher in most ground bamboo treatments (relative to controls) regardless of differences in bamboo organ source or refrigeration/fermentation treatment. Through enhancement of rice plant growth and suppression of aquatic weeds, rice yields were 1.76–2.06 times higher in the four ground bamboo treatments relative to controls. Application of ground bamboo did not noticeably reduce rice grain quality. Thus, the use of ground bamboo mulch has considerable potential in increasing the yield of high-quality rice, at least on a small scale.