Effect of Organic and Mineral Mulches on Soil Properties and Growth of Red Maple

Abstract

Five mineral mulches (crushed red brick, pea gravel, lava rock, carmel rock, and river rock) and three organic mulches (finely screened pine bark, wood chips, and shredded hardwood bark) were evaluated over 2 years to determine their influence on soil temperature, moisture, and pH, and to quantify their effect on growth of Fairview Flame® red maple (Acer rubrum L.). Mulch treatments (2.3-m2 plots of eight mulches and a non-mulched control) were randomly applied to trees in five blocks. Organic mulches were placed directly on bare ground, while mineral mulches were underlaid with a woven polypropylene fabric. Soil temperature was highest and soil moisture lowest under the mineral mulches and non-mulched control. Soil pH was highest under shredded bark (6.82) and wood chips (6.81), and lowest in the non-mulched control (6.03). Despite such differences in the root-zone environments, there were no significant differences in stem caliper or tree height, but leaf dry mass was greatest for trees treated with mineral mulches.