Sunday, 5 February 2006

This presentation is part of: Soils Posters

Long-Term Effects of Tillage and Manure Application on Soil Carbon and Nitrogen Mineralization.

Dexter Watts, H. Allen Torbert, and Steven Prior. USDA-ARS National Soil Dynamics Laboratory, 411 S. Donahue Drive, Auburn, AL 36832

Long-term tillage and manure application are thought to alter the ability of the soil to sequester and mineralize carbon and nitrogen. Thus, a laboratory incubation study was conducted under aerobic conditions to evaluate the residual effect of long-term manure application (>10 years) as affected by tillage. Soil samples were collected at three depths (0-5, 5-10, and 10-20 cm) from continuous soybean and corn plots with and without manure under conventional (CT) and no-tillage (NT) systems at the Sand Mountain Substation in the Appalachian Plateau region of Northeast Alabama on a Hartselle fine sandy loam. The NT with manure had the higher total C (TOC) concentration (2.25 and 1.83 g kg-1 C) for corn and soybean plots followed by NT without manure (1.73 and 1.11 g kg-1 C) at the 0-5 cm depth, respectively. Further, the amount of C mineralized was significantly higher at 0-5 cm depth for NT and CT compared to the other depths; similar patterns were observed for N mineralization. Plots subjected to long-term manure application had a higher C and N mineralization rate compared to plots without manure. The deeper depths showed higher C and N mineralization occurring under CT conditions relative NT conditions, which is attributed to mixing of soil in the plow layer. These results indicate that long-term tillage management will limit the amount of C and N mineralized and sequestered in soil, but will be true for NT systems.


See more of Soils Posters
See more of The ASA Southern Regional Branch (February 5-7, 2006)