The LTAR Cropland Common Experiment at the Gulf Atlantic Coastal Plain.

The Gulf Atlantic Coastal Plain (GACP) Long-Term Agroecosystem Research (LTAR) network site is characterized by hot and humid summers with low gradient stream channels surrounded by wetland forests and croplands. Beneath its sandy soils, a confining layer stifles recharge to the deeper aquifer system, so a substantial proportion of streamflow is driven by shallow subsurface baseflow. Agricultural practices in the area consist of forage and livestock production, forestry, and rotational cropping systems dominated by cotton (Gossypium hirsutum) and peanut (Arachis hypogaea). Certain factors impose challenges to the viability of GACP agricultural systems, like changing economics and demographics, as well as pest and disease pressures. The GACP communicates with stakeholders from various backgrounds, who provide their perspectives as agricultural research service scientists execute their research plans. The GACP LTAR common experiment (CE) is carried out via plot- and field-scale studies. The plot-scale CE compares prevailing practices, determined from regional data, with an alternative treatment including winter covers, such as the biofuel feedstock carinata (Brassica carinata, A. Braun), to provide both economic and environmental benefits. The field-scale CE is observational; key variables are monitored for two farms where management practices largely emulate the prevailing treatment. Data collection efforts quantify vegetation, hydrology, soils, and climate data to produce datasets for modeling and statistical analysis. Research teams quantify relationships between land management, environment, and socioeconomic benefits. Ultimately, the GACP LTAR site works to facilitate agricultural system health and wellbeing at local, regional, and national scales by providing long-term science-based solutions.