Note: This dataset is superseded by version 2: https://doi.org/10.15482/USDA.ADC/1524724

As part of a study identifying relationships between environmental variables and insect distributions within a bioenergy crop, giant miscanthus (Miscanthus x giganteus) samples were collected in October 2016 at 33 locations within a field in southeast Georgia, USA. At each location, one plant sample was collected every meter along a 5-m transect, resulting in 5 replicates per sampling location. The plant samples were separated into leaves and stems, air-dried, weighed, and ground. This dataset describes the chemical composition of giant miscanthus leaves and stems including the total carbon (TC) and nitrogen (TN) content, total macro- and micronutrients (aluminum, arsenic, boron, calcium, cadmium, cobalt, chromium, copper, iron, potassium, magnesium, manganese, molybdenum, sodium, nickel, phosphorus, lead, sulfur, selenium, silicon, titanium, vanadium, and zinc), and the characterization of the water extractable organic matter (WEOM). The TC and TN content was determined directly on ground plant samples using a Vario EL III combustion C-N analyzer. For the quantitation of the total macro- and micronutrient content, the plant material was first digested in trace metal grade nitric acid in a microwave digestion system. The digestate was then analyzed using Inductively Coupled Plasma with Optical Emission Spectroscopy (ICP-OES) on a ThermoFisher Scientific iCAP 7400 Duo. For the characterization of the leaf and stem WEOM, the plant material was extracted in water and the extract was filtered and analyzed using UV-Visible and Fluorescence Excitation Emission Matrix (EEM) spectroscopy on a Horiba Scientific Aqualog spectrofluorometer. The optical data obtained from the EEM scans were used to calculate several indices representative of WEOM quality including the absorbance at 254nm, the absorbance ratios at 254 to 365nm and 280 to 465nm, the slope ratio, the fluorescence index, the humification index, the biological index, and the freshness index. The fluorescence intensity of 5 common fluorescence peaks (peaks A, C, M, B, and T) is also reported. This dataset includes an analytically diverse set of measurements that describe the chemical composition of giant miscanthus leaf and stem tissues. This dataset will be useful for those wishing to identify relationships between the chemical composition of giant miscanthus and pest distributions within a bioenergy crop field.