Greenhouse Gas Emissions and the Interrelation of Urban and Forest Sectors in Reclaiming One Hectare of Land in the Pacific Northwest

Abstract

The interrelation between urban areas and land use options for greenhouse gas mitigation was evaluated by assessing the utility of urban residuals for soil reclamation. Long-term impacts on soil C storage for mine lands restored with urban organic residuals were quantified by sampling historic sites reclaimed both conventionally and with residuals-based amendments. Use of amendments resulted in greater C storage compared to conventional practices for all sites sampled, with increases ranging from 14.2 Mg C ha(-1) in a coalmine in WA to 38.4 Mg C ha(-1) for a copper mine in British Columbia. Expressed as Mg C per Mg amendment, effective C increases ranged from 0.03 to 0.31 Mg C per Mg amendment. Results were applied to three alternative land-use scenarios to model the net GHG balance for a site restored to forest or low-density development. The model included construction of 3.9 243 m(2)-homes, typical of urban sprawl. Emissions for home and road construction and use over a 30-year period resulted in net emissions of 1269 Mg CO2. In contrast, conventional reclamation to forestland or reclamation with 100 Mg of residuals resulted in net GHG reductions of -293 and -475 Mg CO2. Construction of an equivalent number of smaller homes in an urban core coupled with restoration of 1 ha with amendments was close to carbon neutral. These results indicate that targeted use of urban residuals for forest reclamation, coupled with high-density development, can increase GHG mitigation across both sectors.

Soil Carbon and Nitrogen Fraction Accumulation with Long‐Term Biosolids Applications

“…2). This is a higher rate of soil C retention of land applied biosolids than the 25 Mg CO 2 per 100 Mg dry biosolids previously observed and modeled (Brown et al, 2010), but lower than the 140 Mg CO2e per 100 Mg dry biosolids estimated by Trlica and Brown (2013). If only stable C, as represented by nonhydrolyzable C, is credited for C sequestration, then the 0.34 Mg C in soil per Mg of added C in biosolids (0.07 Mg C per Mg dry biosolids; 25 Mg CO 2 e per 100 Mg dry biosolids) rate of C accumulation should be used, a value that is in accordance with Brown et al (2010).…”

Chemical soil attributes of Cerrado areas under different recovery managements or conservation levels

“…Calgaro et al (2008) observed an increase in chemical attributes (OM, P, pH, K, SB, CEC, and V %) when E. crassipes was applied. The use of this or other residues have been reported to be beneficial for degraded areas as organic or microbial fertilizers supporting revegetation (Trlica and Brown, 2013). Pavinato and Rosolem (2008) noticed that residues from vegetation improve the Ca, Mg and K content.…”

Use of Amendments to Restore Ecosystem Function to Metal Mining-Impacted Sites: Tools to Evaluate Efficacy

“…As the importance of and potential for establishing these sites as functional ecosystems is increasingly recognized, it is likely that traditional measures of soil fertility, quality, and productivity will be included in tools to evaluate amendment mixtures and remedial options. Long-term sites where disturbance rather than metal contamination was the primary factor limiting plant growth (e.g., coal mine sites) have shown that amendments are sufficient to reestablish productivity [19,45]. It is likely that similar results will be seen with the appropriate use of amendments.…”

“…Many of these benefits have been realized at disturbed noncontaminated sites restored with residuals. For example, high rates of carbon sequestration have been observed on sites reclaimed with organic residuals in comparison to sites restored with topsoil or fertilizer [19,45,77]. US EPA sampled contaminated sites restored with amendments to quantify soil carbon restoration [76].…”