Data supporting research on temporal and biophysical drivers of Net Ecosystem Carbon Balance of Grazing Lands across the continental United States, 2013-2024

This dataset supports research on the relationships between phenology metrics, biophysical drivers, and carbon flux dynamics in U.S. grazing lands. Data were compiled from eddy covariance towers located across seventeen pastures at eight Long-Term Agroecosystem Research (LTAR) network sites, spanning multiple growing seasons.
The dataset includes multi-year carbon flux measurements — net ecosystem productivity (NEP), ecosystem respiration (ER), and gross primary productivity (GPP) — alongside ancillary environmental variables: precipitation (P), air temperature (TA), incoming solar radiation (Rg), and soil water content (SWC). Drought conditions are represented through the Palmer Drought Severity Index (PDSI), sourced from the National Centers for Environmental Information. Vegetation dynamics are captured via the Enhanced Vegetation Index (EVI) and Normalized Difference Vegetation Index (NDVI) derived from the Harmonized Landsat-Sentinel (HLS) dataset. Phenological indicators — start of growing season (SOS), end of growing season (EOS), and growing season length (GSL) — were derived annually using a 50% maximum daily GPP threshold.
These data are intended to facilitate investigation of how temporal and biophysical factors influence carbon flux at both annual and monthly timescales across diverse grazed agroecosystems. The dataset is suitable for analyses examining linear and non-linear relationships between ecosystem productivity, carbon balance, and drivers such as climate variability, soil moisture, and vegetation phenology in managed grassland systems.