Olson said that aeration, drainage, tillage, disturbance, more intensive crop rotations, use of synthetic fertilizers, erosion and lack of cover crops can all result in reduced soil organic carbon stocks.
Because it would take 20 to 50 more years to design and run such a study, the team found a long-term study that had all the required soil property data collected for the root zone or to a depth of 1 or 2 meters from before the tillage treatments were applied and sampled frequently during and at the end of the study. This study is located at U of I's Dixon Springs Agricultural Center with tillage plots that are part of a North Central Region Soil Erosion and Productivity Committee study and located on a Grantsburg soil with a fragipan at 75 centimeters, moderately eroded, on 6 percent slopes and with six replications.
Olson said that the accuracy of determining soil organic carbon sequestration depends on the method used. "In this review, both the paired comparison method and the pre-treatment soil organic carbon method were tested using the same plots and experiment," he said.
The results of this comparison showed that the paired-method (no-till compared to moldboard) overestimated soil organic carbon sequestration as compared to pre-treatment method, where both no-till and moldboard compared to the same pre-treatment baseline. "Another flaw in the paired comparison method is that the results could not be validated where no pre-treatment baseline is available," Olson said.
The team of researchers recommend: (1) that researchers trying to determine and measure soil organic carbon sequestration
|Contact: Debra Levey Larson|
University of Illinois College of Agricultural, Consumer and Environmental Sciences