Author
REICOSKY, DONALD | |
REEVES, DONALD | |
Prior, Stephen - Steve | |
RUNION, G - AUBURN UNIVERSITY | |
ROGERS JR, HUGO | |
RAPER, RANDY |
Submitted to: Soil & Tillage Research
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 7/30/1999 Publication Date: N/A Citation: N/A Interpretive Summary: The increase in the carbon dioxide in the atmosphere has attracted interest due to potential global warming and the prospects of using the soil as storage for carbon released by other human activity. The cumulative effect of tillage and many cropping rotations has been a 30-50% decrease in soil carbon that causes an undesirable change in soil physical, chemical and biological properties. This study determines the effect of traffic-induced soil compaction and residue management history on the short-term tillage-induced CO2 and H2O flux from a representative soil in the southeastern Coastal Plain(USA). Gas exchange measurements were made on both conventional tillage and no-tillage at various times associated with tillage and irrigation events. Tillage-induced CO2 and H20 fluxes immediately after operations were larger than corresponding fluxes from plots not tilled. Irrigation caused the CO2 fluxes to increase rapidly in both tillage treatments, suggesting that soil gas fluxes were initially limited by lack of water. Traffic had no significant effects on the magnitude of CO2 fluxes. These results show the immediate impact of intensive surface tillage of sandy soils on gaseous carbon loss. This information will be helpful to scientists around the world by demonstrating the impact of intensive tillage. These results illustrate the importance of improved conservation tillage systems with less soil disruption to maximize the retention of the soil carbon and minimize the impact on global climate change. These results are significant to farmers and policy makers because intensive tillage results in a substantial short-term gaseous loss of CO2. This information will be of direct benefit to the farmers to enable them to maintain crop production with minimal impact on the environment. Technical Abstract: Management of crop residues and soil organic matter is of primary importance for minimizing agricultural impact on environmental change. Our objective was to determine the effect of traffic-induced soil compaction and residue management history on the short-term tillage-induced CO2 and H2O flux in the southeastern Coastal Plain (USA). The study site was a Norfolk loamy sand cropped to a corn (Zea Mays L.)-soybean (Glycine max (L.) Merr) rotation with a crimson clover (Trifolium incarnatum L.) winter cover crop for the last eight years. Experimental treatments included conventional tillage(CT)(disk harrow twice, chisel plow, field cultivator) and no-tillage(NT) as they affected residue management with and without traffic in a split-plot design of four replicates. A wide-frame tractive vehicle enabled tillage without wheel traffic on zero-trafficked plots. Gas exchange measurements were made with a large portable chamber on both conventional tillage and no-tillage at various times associated with tillage and irrigation events. Tillage-induced CO2 and H2O fluxes immediately after operations were larger than corresponding fluxes from plots not tilled. Irrigation caused the CO2 fluxes to increase rapidly in both tillage treatments, suggesting that soil gas fluxes were initially limited by lack of water. Tillage-induced CO2 and H2O fluxes were consistently higher from conventional tillage plots. The cumulative CO2 flux from conventional tillage after 80-h was nearly three times larger than from no tillage while the corresponding H2O loss was 1.6 times larger as a result of surface soil disturbance. Traffic had no significant effects on the magnitude of CO2 fluxes. These results show the immediate impact of intensive surface tillage of sandy soils on gaseous carbon loss. |