Carbon Legacy Effects of Agricultural Soil Erosion Research Collaboration

Overview

This research program investigates the legacy effects of agricultural soil erosion on the carbon cycle, addressing a critical gap in understanding how eroded soil carbon is redistributed across landscapes. Conventional agriculture has accelerated soil erosion rates by 10-to-100-fold since 1900, yet the fate of eroded soil carbon remains incompletely understood. The research posits that carbon transported from upland farms is deposited in low-lying, less-oxidizing environments such as river valleys and lakes, where it forms longer-term carbon reservoirs that partially offset soil carbon losses from agricultural lands.

Findings from the Tennessee River Valley near Huntsville, Alabama demonstrate that carbon storage times in floodplain sediments ranged from 1,000-900 years during 500-1350 AD, decreasing to 800-900 years during 1350-1800 AD. These shifts coincided with carbon isotope enrichment indicating expansion of C4 grass and corn agriculture. The research aims to establish historical baselines for carbon storage that can inform modern assessments of agricultural sustainability and climate mitigation strategies.

Technical specifications

Key methodologies:

• Radiocarbon dating (14C) to determine carbon age and differentiate it from actual carbon storage time in sediments
• Optically stimulated luminescence dating to establish sediment deposition timelines
• Carbon isotope analysis (δ13C) to track shifts in vegetation cover and crop selection through time
• Floodplain and lake sediment analysis across the Mississippi River basin, one of the largest agricultural regions globally
• Sedimentation rate measurements correlated with historical agricultural practices

Research scope:

• Focus on lower Tennessee and Red River valleys where an existing data base supports expansion
• Investigation of over 1,500 floodplain lakes in the lower Mississippi alluvial valley, ranging from 50 to 10,000 years in age
• Assessment of how mechanized agriculture post-1800 AD affected carbon erosion and storage dynamics
• Evaluation of anoxic preservation conditions in depositional centers

Technology readiness level

This is an active research program at the foundational and observational stage. Initial validation has been completed in the Tennessee River Valley, establishing proof-of-concept for the dating methodology and carbon storage time measurements. Future validation will expand the geographic scope to the Mississippi River basin to assess how agricultural practices have affected landscape-scale carbon storage times over the past several centuries. The research seeks collaborators interested in agricultural sustainability, soil carbon dynamics, and climate change mitigation through improved understanding of terrestrial carbon reservoirs.