WATER RETENTION OF PROCESSED PINE WOOD AND PINE BARK AND THEIR PARTICLE SIZE FRACTIONS^©

The wettability of a material intended for horticultural use is integral for high quality plant growth and performance. The ability of a substrate material (organic or inorganic) to capture and retain water (wettability) contributes to water-holding capacity and improved plant growth (Plaut et al., 1973). Many horticultural substrate materials, such as pine bark, experience hydrophobicity at low moisture levels (Beardsell and Nichols, 1982; Fonteno et al., 2013; Michel et al., 2001) which in turn has deleterious effects on irrigation efficiency and crop production. Further advantages of a substrate material being able to capture water include maintaining plant quality in post-production retail environments. Some research suggests that the variation in size and structure of milled pine bark particles may contribute to water holding (Airhart et al., 1978). The purpose of this study was to explore how processed pine wood, pine bark, and their resulting particle fractions capture and retain water using the wettability method described by Fields et al. (2014).