Submitted to: Agronomy Abstracts
Publication Type: Abstract only
Publication Acceptance Date: 6/25/2008
Publication Date: 10/7/2008
Citation: Mikha, M.M., Vigil, M.F., Calderon, F.J. 2008. Gas Flux in Tillage Field That Have Been in No-Tillage for 12 Years. Agronomy Abstract. Presented at the International American Society of Agronomy meetings, Crop Science Society of America and Soil Science Society of America (ASA/CSSA/SSSA) annual meetings. Oct. 5-9, 2008. Houston, TX. Interpretive Summary:
Technical Abstract: No-tillage (NT) systems have many benefits. These benefits include increased surface soil organic matter (SOM), improved soil aggregation, improved soil water conservation, decreased risks of soil erosion, and reduced greenhouse gas emissions (especially carbon dioxide, CO2). Long-term NT has disadvantages as well. These are poor weed control of weeds resistant to herbicides and with surface phosphorous (P) buildup (nutrient stratification) from repeated surface applications of P fertilizers. Some studies suggest that one or a few tillage operations might be necessary to mitigate these disadvantages. In this report we are concerned primarily with the changes that a single tillage operation after many years of NT has on CO2 gas flux and soil water content. In 2004, the CO2 flux experiment was initiated on a farmer’s field that has been under no-till management for 12 years. The treatments include: (i) No-tillage, (ii) conventional tillage (CT) for 3 growing seasons; (iii) NT for the first season and CT for the next 2 growing seasons; and (iv) NT for 2 growing seasons and CT for one growing seasons. In 2004, the CO2 flux was 70% grater with the 1st time tillage than with no-tillage especially during the first 2 seconds after running a v-blade sweep in the surface 10 cm of soil. While the CO2 flux was only 40% greater than NT with the treatment that was tilled for the second year (in 2005). After 1 hour of tillage, CO2 flux with both tillage treatments (1st and 2nd year tillage) was almost the same and it was greater than NT by 55%. At the 24 hour to 4 week period, the CO2 flux was positively affected by soil water content (SWC). Greater SWC after 2 weeks of tillage increase CO2 flux by more than 37% with tillage treatments compare with NT. This increase could be due to SOM decomposition which was promoted by tillage practice. No-tillage showed 80% less CO2 flux and 11% greater SWC compared with both tillage treatments even after 4 weeks of measurement.