Senthilkumar, S., A.N. Kravchenko, X. Huang, G.P. Robertson, and A.J.M. Smucker.
Presented at the All Scientist Poster Reception (2006-05-09 )
Quantitative assessment of soil carbon has gained increased interest in the recent past, owing to its importance for carbon sequestration studies and its potential impact on global climate change. Soil carbon management is a key issue in many sustainable agriculture programs and global climate change studies. However, accuracy in estimating soil C to determine best management practices is hindered by the inherent variability of soil properties that is widespread in soils across all scales. Soil carbon content varies across fields as a result of complex interactions among factors such as soil properties, tillage practices, and terrain attributes. Our objective is to study the effect of topography on spatial variability of the total soil carbon, content under different management systems. The studied topographical features include relative elevation terrain slope, curvature, aspect and soil wetness index. The three studied management systems are treatments from the RCBD experiment with six replications at the Long Term Ecological Research site at Kellogg Biological Station, Michigan. We studied two systems with conventional chemical inputs (chisel plow and no-till) and a certified organic chisel plowed system with a winter leguminous cover crop and no manure or compost inputs. The elevation measurements at a 2 m interval were collected with a 12-channel Leica SR530 real time kinematic DGPS receiver. Terrain derivatives were obtained from the elevation data using surface and hydrologic analysis of ARCMAP spatial analyst. From each of 18 sampled 1-ha experimental plots we collected approximately 100 soil samples at 0-5 cm depth for total soil C measurements. The data were analyzed using multiple regression and analysis of covariance. Relationships between total carbon and topographical features observed in the 18 1-ha plots of the three studied systems will be presented and discussed.
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