Coir Fiber and Bamboo Vinegar Improve the Quality of Composted Green Waste as a Growing Medium for Peacock Arrowroot

Abstract

Composting is considered an environmentally sound and economically viable alternative for the management of organic residues. Although compost product may be used as a peat substitute in soilless culture, it generally has poor physical structure, low nutrient content, high pH, and high salt content. This study chose the coir fiber (CF) produced from coconut (Cocos nucifera) and bamboo vinegar (BV) produced from mottled bamboo (Phyllostachys bambusoides) as the media amendments, and evaluated the effects of CF (at 0%, 15%, and 25%) and/or BV (at 0%, 0.5%, and 1.0%) on the physical, chemical, and microbiological properties of composted green waste (CGW) and on the growth of peacock arrowroot (Calathea makoyana). The highest quality growing medium and the best growth of peacock arrowroot were obtained when CGW was amended with the combination of 15% CF and 0.5% BV; the lowest quality medium and the least plant growth were obtained with nonamended CGW. The optimal combination not only improved particle-size distribution and adjusted bulk density (BD), porosity, and water-holding capacity (WHC) into ideal ranges, but it also decreased pH and electrical conductivity (EC) and increased microbial numbers, enzyme activities, and macro- and micronutrient contents in the CGW. Relative to the nonamended CGW, the optimal CGW reduced the BD from 0.58 g·cm−3 to 0.34 g·cm−3 and the pH from 8.05 to 5.61, and increased the total porosity (TPS) from 48.1% to 77.0% and the WHC from 57.4% to 75.5%; the optimal CGW increased shoot fresh weight, shoot dry weight, root fresh weight, root dry weight, plant height, crown breadth, number of leaves, and total root length by 83.9%, 77.8%, 66.1%, 65.1%, 63.6%, 73.8%, 55.6%, and 65.2%, respectively.