Carbon Sequestration and Soil Characteristics In Louisiana Crawfish Ponds.

Carbon (C) sequestration is considered an effective method to mitigate climate change and improve soil quality. Due to the increasing crawfish industry in Louisiana and lack of research on this area, this study examined C sequestration in crawfish pond sediments and other soil characteristics. The study compared SOC (soil organic C) concentration and mass under crawfish ponds and adjacent agriculture fields in monocropping and rotational systems respectively. Other characteristics such as bulk density, nitrogen (N) concentration and mass, particle size, pH, and carbon to nitrogen ratio (C:N), were also examined. A significant difference (P<0.05) was found in the top layer of SOC concentration in crawfish monocropping systems (25.8 g kg^-1) compared to adjacent crop fields (20.8 g kg^-1). However, no significant differences were found in other soil/sediment layers for C concentration or C mass in both systems. Crawfish ponds did not appear to have an advantage over upland cropping systems with regard to soil C sequestration. In addition, 1) SOC concentration decreased significantly with pond soil depth; 2) the concentration of SOC did not increase with pond age but reach equilibrium according to numerous studies; and 3) the low input of crawfish culture and management practices in ponds did not favor C accumulation. Hence, C sequestration of Louisiana crawfish ponds might not be promising experimentally and theoretically.