Assessing Productivity in Prairie Biomass Feedstocks with Different Levels of Diversity

High-diversity mixtures of tallgrass prairie vegetation provide many ecosystem services and could be effective biomass feedstocks for marginal farmland in Iowa. In this study, we measured productivity in four prairie biomass feedstocks with different diversity: 1, 5, 16, and 32 species. Each feedstock was replicated four times on three soil types (48 research plots, 0.33 – 0.56 ha each). For the past seven years, we have monitored productivity in these feedstocks by harvesting tissue from randomly selected quadrats. In addition to continuing the productivity survey, we examined the efficacy of remote sensing (NDVI) and leaf area index (LAI) imaging for estimating productivity in 2015 and 2016. Across soil types, the 1-, 16-, and 32-species feedstocks are equally productive and outperform the 5-species feedstock. Regions with high LAI correspond with regions of high productivity at the plot- and quadrat-level. NDVI does not correspond with productivity at the plot- or quadrat-level. The low predictive power of our regressions suggests that neither metric is a suitable replacement for annual biomass harvest