P1. Whole-profile soil carbon change after 25-years along an agricultural management gradient.
Main question: Can we find soil organic carbon gains after 25 years of different agricultural management and agroecosystems (ranging from conventional agricultural corn-soybean rotations, perennials, and forest fields) in LTER-KBS plots?
P2. Root-to-shoot ratios and contributions to soil carbon by perennial bioenergy crops in the Upper Midwest US.
Main question: Are bioenergy crops carbon neutral if included in Midwestern cropping systems?
P3. Root sampling of bioenergy crops methodological comparison pit vs. deep soil cores;
Main question: How close can a deep soil core estimate bioenergy crops' roots compare to a pit excavation?
P4. Switchgrass morphological developmental differences among varieties;
Main question: Can we explain changes in Mean Stage Count simply by shifts in the relative maturity of tillers present in the population?
P5. Associative nitrogen fixation rate variability among high-yielding switchgrass varieties.
Main question: How does associative nitrogen fixation rate vary among high-yielding switchgrass such as Cave-in-Rock and Kanlow?