Submitted to: American Society of Agronomy Branch Meeting
Publication Type: Abstract Only
Publication Acceptance Date: February 5, 2006
Publication Date: February 5, 2006
Citation: Watts, D.B., Torbert III, H.A., Prior, S.A. 2006. Long-term effects of tillage and manure application on soil carbon and nitrogen mineralization [abstract]. American Society of Agronomy Branch Meeting. CDROM Technical Abstract: 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.