Early accumulation of active fraction soil carbon in newly established cellulosic biofuel systems

We examined relative changes in soil C pools shortly after the establishment of six perennial and two annual bioenergy cropping systems that differed in diversity (monoculture vs. polyculture). Perennial systems included two monocultures (switchgrass, Panicum virgatum; and miscanthus, Miscanthus × giganteus) and four polycultures including hybrid poplar (Populus sp.) + herbaceous understory; mixed native grasses, successional vegetation, and restored prairie. Two annual systems included no-till continuous corn (Zea mays) and rotational corn (corn-soybean (Glycine max)-canola (Brassica napus)). Each crop was planted in a full factorial design at both a moderate fertility Alfisol and a high fertility Mollisol site. Relative differences in active, slow, and passive C pools in surface soils, where C changes are most likely to be detected early, were evaluated with 322-day laboratory incubations followed by acid hydrolysis to infer different pools from exponential decay curves. Five years po...

本研究针对6种多年生与2种一年生生物能源种植系统建立初期的土壤碳库相对变化展开调查，这些系统在种植多样性上存在差异（单作vs.混作）。多年生系统包含2种单作体系（柳枝稷（Panicum virgatum）与芒草（Miscanthus × giganteus））以及4种混作体系，具体为杂交杨（Populus sp.）+ 草本下层植被、本土混合草本群落、演替植被以及恢复草原。2种一年生系统则涵盖免耕连作玉米（Zea mays）与轮作玉米体系（玉米-大豆（Glycine max）-油菜（Brassica napus））。所有种植体系均在中度肥力淋溶土（Alfisol）与高肥力软土（Mollisol）两个试验点采用完全因子设计开展种植。针对碳变化最易被早期检测到的表层土壤，本研究通过322天室内培养试验结合酸水解法，基于指数衰减曲线推算活性、缓效与惰性碳库的相对差异。种植五年后……