Soil Organic Carbon

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Carbon inputs to the 10 cropping systems (Kong et al., 2005).

The amount of carbon inputs and resulting carbon sequestration in the main plots at Russell Ranch is closedly monitored. This information will hopefully allow Russell Ranch to identify ways of sequestering carbon and delivering carbon credit payments to farmers who adopt conservation practices.

The 10 cropping systems received different amounts of carbon input in the form of crop residues, manures and cover crops (Figure 1). The organic corn/tomato rotation (OMT) received the most carbon inputs and the unfertilized, rainfed wheat/fallow (RWC) received the least.

Changes in the average amount of carbon accumulated or lost over the ten-year period from 1994 to 2003 are represented in Figure 2 for all the cropping systems. The OMT system had the largest increase in soil organic carbon (SOC). The RWC system showed a decline in SOC while SOC in the other wheat systems was not significantly different. This information is important for assessing the potential for carbon sequestration in California soils.

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Rate of soil organic sequestration (Kong et al, 2005).