Tuesday, November 14, 2006

Towards the Carbon Credit and Trading Schemes: Estimation of Soil Carbon Storage as Influenced by Alternative Cropping Systems Using the EPIC Model.

Hillarius Kludze and Dave Archer. North Central Soil Conservation Res, 803 Iowa Ave, Morris, MN 56267

Model-based approaches to quantifying, monitoring, and verifying soil carbon sequestration (SCS) have the advantages of being low-cost and convenient, and the ability to provide information on long-term soil C dynamics resulting from different management practices. Using the EPIC Model, we examined the differences in the capabilities of five different within-field soil series to sequester carbon under a wide range of cropping system treatments including two types of systems: conventional and organic, two tillage treatments: conventional and strip tillage, two crop rotations: corn-soybean and corn-soybean-spring wheat/alfalfa-alfalfa, and two levels of fertility management: fertilizer/manure and no fertilizer/manure. At 0.2 m sampling depth, EPIC Model results for the field treatments show that carbon sequestration would be maximized either in an organic cropping system by using strip tillage and the corn-soybean rotation with a rye cover crop and using manure for fertility, or in a conventional system by using strip tillage and the four-year rotation. At 1.5 m sampling depth, the organic cropping system with strip tillage, four-year rotation, and manure fertilized treatments became dominant in sequestering soil C. The ‘business as usual’ conventional system of using conventional tillage and two-year corn-soybean rotation with chemical fertilizer enhanced C losses. Sequestration occurred mostly within 10-15 years and declined thereafter. At the farm scale, adoption of a single cropping system for potential maximum SCS, irrespective of within-field soil heterogeneity, still appears feasible. This could be important to many stakeholders in implementing site-specific management for optimum SCS, and in helping to determine how much C is sequestered to warrant payments in carbon credit and trading schemes. 

Handout (.pdf format, 71.0 kb)