LINKAGE BETWEEN SOIL MOVEMENT AND CARBON DYANAMICS IN AGRICULTURAL LANDSCAPES

Authors: McCarty, Gregory; Venteris, Erik; Ritchie, Jerry

Submitted to: Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 12/1/2003
Publication Date: 3/4/2004
Citation: McCarty, G.W., Venteris, E.R., Ritchie, J.C. 2004. Linkage between soil movement and carbon dyanamics in agricultural landscapes. In: Proceedings of the International Workshop on: Identification of Current Status and Needs of GIS and Databases Technology in the Agricultural Sector - GIS for Analysis and Monitoring of Land Use and Land/Water Quality, March 4-6, 2004, Pulawy, Poland. IV:1-6.

Interpretive Summary: It is well established that the introduction of agriculture to a watershed generally results in loss of soil carbon in the production fields. The influence of soil erosion and redistribution on terrestrial C storage is poorly understood. Landscape processes have important impact on distribution of soil carbon in fields and near streams, and soil redistribution by water and tillage is a major process affecting distribution of soil carbon within agricultural ecosystems. It has been assumed that erosion results in loss of carbon from the ecosystem, but recent models indicate that soil erosion/ deposition can stimulate sequestration due to the perturbation of soil forming processes. Most studies of erosion/ soil carbon interactions have occurred at the field scale, but such studies cannot encompass the full range of variability due to land cover, agricultural management, and topographic setting. Space and time records of soil movement in landscapes have been obtained from a series of naturally occurring radioactive tracers that cover different time spans from about 50 years to over 20,000 years. Distribution patterns of soil organic carbon and redistribution of soil sediment can be correlated to the shape of the landscape. New technologies promise to provide better measure of landscape shape over the different scales of interest. This should help modeling water and soil movement within watersheds.

Technical Abstract: Landscape processes have important impact on distribution of soil properties, and soil redistribution by water and tillage is a major process affecting distribution of soil carbon within agricultural ecosystems. It has been assumed that erosion results in loss of carbon from the ecosystem, but recent models indicate that soil erosion/ deposition can stimulate sequestration due to the perturbation of soil forming processes. Most studies of erosion/ soil carbon interactions have occurred at the field scale, but such studies cannot encompass the full range of variability due to land cover, agricultural management, and topographic setting. Spatio-temporal records of sedimentary redistribution have been obtained from radiometric tracers such as 137Cs (45 y span) and 210Pb (150 y span) covering the period of agricultural practice with many geographic regions of the United States as well as from the 14C content of soil organic matter (span >20,000 y). Distribution patterns of soil organic carbon and redistribution of soil sediment can be correlated to terrain parameters. Technologies such as synthetic aperture radar provide great promise for economical generation of high quality field and regional scale digital elevation models (DEMs) that are needed in terrain modeling of soil properties as well as understanding movement of water in agricultural landscapes.