Emission of CO2, CH4, and N2O From Soils Amended with Two Different Biochars and Its Relation to Soil Structure and Microbial Activity.

Charcoal formation and deposition in soils were reported to be a promising option to transfer easily decomposable biomass into refractory soil organic matter (SOM) pools in tropical agricultural soils. Biochar is a long lasting carbon storage medium and at the same it can be used as a soil amendment because of its high cation exchange capacity, adsorptive capacity, and ability to stabilize soil structure. Despite of the diverse benefits of biochar, there has been remarkably little research on the effects of biochar application in temperate soils. The objective of this study is to understand the changes in carbon dynamics of temperate agricultural soils amended with biochar by analyzing greenhouse gas emissions, microbial activity, and changes in particulate organic matter (POM). Biochar was produced from agricultural byproducts of barley and organic waste from livestock. Soil samples for incubation were collected in spring, 2010, from pasture(sandy loam) and rice paddy(loamy sand), Chungchung-Do, Korea. Treatments were the addition of organic waste char (OWC) and barley char (BC). Control (CON) and sterilized controls (S_OWC and S_BC) were also employed and compared with the treatments. Soils were incubated for 8 weeks in a septum jar at 28^oC adjusted at 60% WHC. Gas samples in the headspace were collected in 1, 2, 3, 4, 6, and 8 wks after the initiation of incubation and measured by a GC. CO₂ and N₂O emissions were not changed by addition of OWC and BC both in pasture and rice paddy soils, while CH₄ emission from the pasture soil amended with OWC and BC  significantly decreased. Microbial activity and the change in particulate organic matter (POM) content will be measured and compared with the patterns of gas emission