Growing Dedicated Energy Crops on Marginal Lands and Ecosystem Services

Marginal lands are candidates for growing dedicated energy crops such as perennial warm-season grasses (WSGs) and short-rotation woody crops (SRWCs), but actual field data on ecosystem services have not been widely discussed. This review (i) discusses potential marginal lands studied for energy crop production, (ii) considers the impacts of energy crops on ecosystem services, and (iii) underlines research needs. Some marginal or degraded lands studied for energy crops include highly erodible, flood-prone, compacted, saline, acid, contaminated, or sandy soils, reclaimed minesoils, urban marginal sites, and abandoned or degraded croplands. Field data are few but indicate that ecosystem services vary with the type of marginal land, management (i.e., fertilizer or amendment rates), and perennial species. Biomass yields can vary between 1 and 14 Mg ha(-1) yr(-1) under WSGs and between 0.5 and 9.5 Mg ha(-1) yr(-1) under SRWCs. Growing energy crops on marginal lands can reduce water and wind erosion, sequester soil C between 0.25 and 4 Mg C ha(-1) yr(-1), restore contaminated or compacted soils, and improve biodiversity. Fertilization or addition of organic amendments increases biomass yield and C sequestration on marginal lands. Future research on energy crops on marginal lands should evaluate (i) all ecosystem services, (ii) site-specific management strategies, (iii) species tolerant to adverse climatic, soil, and environmental conditions, and (vi) economic viability, among others. Overall, dedicated bioenergy crops can provide biofuel feedstocks and other ecosystem services, but more experimental data are needed to reduce the uncertainty regarding the performance of energy crops under different types of marginal or degraded lands.