This datatable is part of the Marginal Land Rainfall Exclusion Experiment dataset. This dataset contains data from the GLBRC Marginal Land Rainfall Exclusion Experiment established in 2018 to examine the effects of drought on switchgrass production and composition. Rainfall exclusion (rainout) shelters are deployed over the growing season in fertilized split plots of the Switchgrass treatment (G5) at all sites of the Marginal Land Experiment (MLE) and in the Switchgrass treatment (G5) plots of the Biofuel Cropping System Experiment (BCSE) at the KBS GLBRC Intensive Site, which serves as a reference for cropped soils with higher fertility. Rainout shelters are deployed in four G5 replicate plots of the BCSE (R2-R5) and of the MLE (R1-R4) at all sites except Wisconsin Central–Hancock (R2-R4), which has only three replicates.