Effects of Torrefied Wood Chips and Vermicompost on Tree Growth and Weed Biomass: Implications for the Sustainable Management of Salt-Affected Reclaimed Lands

Abstract

A harsh environment, slow tree growth, nutrient deficiencies, and competition between trees and weeds can impede forest establishment on reclaimed lands. We investigated the effects of torrefied wood chips (TWC) and vermicompost (VC) soil amendments on the growth of Populus euramericana Guinier, weed biomass, and soil chemical properties on reclaimed land in Saemangeum. The 2.5 Mg ha−1 and 5.0 Mg ha−1 TWC had a similar effect on tree diameter and height growth (i.e., 2.5 = 5.0 > 0 TWC) and tended to have similar, higher effect on the total biomass of P. euramericana than the 0 Mg ha−1. The 2.5 Mg ha−1 TWC resulted in a significantly larger root biomass than the 5.0 Mg ha−1 TWC. The weed biomass was significantly larger at the 2.7 Mg ha−1 VC (i.e., 730.5–810.5 g m−2) than the control (605.1–610.6 g m−2), but VC alone was not effective for tree growth and soil amelioration. The TWC had no effect on weed biomass. Thus, the TWC and VC had contrasting effects on tree growth and weed biomass when they were used as soil amendments on salt-affected reclaimed land. VC application may promote weed proliferation, whereas TWC application may potentially increase the growth of P. euramericana and control weed growth on reclaimed lands. Our results enhance the existing knowledge on tree and weed responses to torrefied wood chips and vermicompost amendments for the sustainable management of salt-affected reclaimed lands.