Lei, Cheyenne, Jiquan Chen, and G. Philip Robertson. "Climate cooling benefits of cellulosic bioenergy crops from elevated albedo." *GCB Bioenergy* 15.11 (2023): 1373-1386. https://doi.org/10.1111/gcbb.13098 Abstract
Changes in land surface albedo can alter ecosystem energy balance and potentially influence climate. We examined the albedo of six bioenergy cropping systems in southwest Michigan USA: monocultures of energy sorghum (*Sorghum bicolor*), switchgrass (*Panicum virgatum* L.), and giant miscanthus ( *Miscanthus* × *giganteus)*, and polycultures of native grasses, early successional vegetation, and restored prairie. Direct field measurements of surface albedo (*α*s) from May 2018 through December 2020 at half-hourly intervals in each system quantified the magnitudes and seasonal differences in albedo (∆*α*) and albedo-induced radiative forcing (RF∆*α*). We used a nearby forest as a historical native cover type to estimate reference albedo and RF∆*α* change upon original land use conversion, and a continuous no-till maize (*Zea mays L*.) system as a contemporary reference to estimate change upon conversion from annual row crops. Annually, *α*s differed significantly (*p* < 0.05) among crops in the order: early successional (0.288 ± 0.012SE) >> miscanthus (0.271 ± 0.009) ≈ energy sorghum (0.270 ± 0.010) ≥ switchgrass (0.265 ± 0.009) ≈ restored prairie (0.264 ± 0.012) > native grasses (0.259 ± 0.010) > maize (0.247 ± 0.010). Reference forest had the lowest annual *α*s (0.134 ± 0.003). Albedo differences among crops during the growing season were also statistically significant, with growing season *α*s in perennial crops and energy sorghum on average ~20% higher (0.206 ± 0.003) than in no-till maize (0.184 ± 0.002). Average non-growing season (NGS) *α*s (0.370 ± 0.020) was much higher than growing season *α*s (0.203 ± 0.003) but these NGS differences were not significant. Overall, the original conversion of reference forest and maize landscapes to perennials provided a cooling effect on the local climate (RF*αMAIZE*: −3.83 ± 1.00 W m−2; RF*αFOREST*: −16.75 ± 3.01 W m−2). Significant differences among cropping systems suggest an additional management intervention for maximizing the positive climate benefit of bioenergy crops, with cellulosic crops on average ~9.1% more reflective than no-till maize, which itself was about twice as reflective as the reference forest. -- You received this message because you are subscribed to the Google Groups "geoengineering" group. To unsubscribe from this group and stop receiving emails from it, send an email to geoengineering+unsubscr...@googlegroups.com. To view this discussion visit https://groups.google.com/d/msgid/geoengineering/CAHodn9_-yk%3Ds%3Du-8rPaM6CFOPwyvoGc%3DsJ33a0W4i%3DqYtGHf2A%40mail.gmail.com.
