Influence of No-till Practice on Soil Carbon Pools.

No-tillage has potential to increase or maintain soil organic matter depending on regional soil characteristics. In Northern Great Plains, adoption of no-tillage is limited. Soil organic C pools from paired growers’ field under long-term (>20 yr) chisel plough (CT) and no-till (NT) practices were compared for three paired on-farm fields in the southeast ND. Three soil profile samples (90 cm) and bulk soil samples (0-10 cm) were processed analyzed for soil organic carbon (SOC) and total nitrogen (N) using automated total CN analyzer. For 45 days, soil samples of 0-15 cm depth were incubated in quart jars at 50% water holding capacity at 25°C and soil CO₂ efflux was measured using gas chromatograph. Long-term no-tillage effect on soil BD and SOC pools varied among sites. Profile (120 cm) C under CT and NT were 244 and 266 Mg C ha^-1, 377 and 297 Mg C ha^-1, and 382 and 339 Mg C ha^-1, respectively for three sites. Two out of three sites showed an increase in sensitive C_a pool under CT than NT and same sites also showed higher Cr pools. Chisel plough increased the easily mineralizable active C pool. Besides conservation tillage, crop rotation and other management practices might have significant influence on SOC pools. Identification of sites responsive to NT practice will be helpful.