Author
 |
Reicosky, Donald |
|
Submitted to: Australian/New Zealand National Soils Conference
Publication Type: Proceedings Publication Acceptance Date: 4/29/1998 Publication Date: N/A Citation: N/A Interpretive Summary: Man's activity in agricultural production associated with tillage may have a significant influence on atmospheric composition and the greenhouse effect. Minimizing agriculture's impact on the global increase in carbon dioxide requires that we sequester carbon and maintain high levels of soil organic matter. Maintenance of soil organic matter is critical for erosion control, soil fertility, and crop nutrition that can have significant economic impact. Information is needed on variation and magnitude of carbon loss from soils and the interaction of different tillage tools. This work showed a large loss of carbon dioxide immediately after moldboard plowing and small losses after strip tillage tools. The magnitude of this short-term gaseous carbon loss helps explain the long-term decrease in soil organic matter as a result of plowing. There was significant variation in carbon dioxide loss related to tillage tool type. The carbon dioxide loss was proportional to the volume of soil disturbed. This information will be of direct benefit to scientists making recommendations for herbicide application rates and conservation tillage methods. The potential contribution of agriculture to global climate change as a result of carbon dioxide loss from plowing can be reduced with improved strip tillage methods. These results contribute to our understanding of conservation tillage methods that minimize soil disruption and maximize carbon sequestration in agricultural production systems. Technical Abstract: Concern for soil quality and related environmental issues requires new knowledge to minimize agriculture's impact on the environment. The impact of broad area tillage on soil carbon and carbon dioxide loss suggests possible improvements with mulch between the rows and less intensive strip tillage to prepare a narrow seedbed. The objective was to quantify short-term tillage-induced CO2 loss after strip tillage tools. Various strip tillage tools, spaced at 76 cm, were used and gas exchange measured with a large portable chamber. Gas exchange was measured regularly for six hours and then at 24 and 48 hours. No-till had the lowest CO2 flux during the study and moldboard plow had the highest immediately after tillage that declined as the soil dried. Other forms of strip tillage had an initial flush related to tillage intensity that was intermediate between these extremes, with both the 5- and 24-hour cumulative losses related to soil volume disturbed by the tillage tool. Reducing the volume of soil disturbed by tillage should enhance soil and air quality by increasing soil carbon content. These results suggest soil and environmental benefits of strip tillage be considered in soil management decisions. |
