Improvement of the Wettability Properties of Compost Using Seaweed

Abstract

Composting substrate components from a wide variety of organic materials are becoming more prevalent in ornamental growing medium mixes. Hazelnut husk (HH) and seaweed (HHSW) composts were investigated for their different hydro-physical roles in substrate dynamics. The water repellent material HH was composted either solely or mixed with seaweed (1:1 by volume) and the hydro-physical properties related to the water retention and wettability of the two composts were evaluated using the water drop penetration (WDPT) and molarity of ethanol droplet (MED) tests and contact angle (u) determination. The addition of seaweed to the HH compost mixture had positive effects on the water holding capacity, water conductivity, air porosity, and wettability characteristics compared to pure HH compost. Although both composts exhibited signs of hydrophobicity under dry conditions, the repellency rate was more severe in the pure HH compost. The wettability tests results indicate that seaweed improved the hydrophobicity of HH compost by at least two ranking classes, from severe hydrophobicity to moderate hydrophobicity. Also, the contact angle reduced from 107 to 103 by composting seaweed. Seaweed was found to have an influence on the hydrological properties when incorporated as a compost component with the HH substrate.