Submitted to: Soil Science Society of America Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/24/2009
Publication Date: 6/1/2010
Citation: Watts, D.B., Torbert III, H.A., Prior, S.A., Huluka, G. 2010. Long-term tillage and poultry litter impacts soil carbon and nitrogen mineralization and fertility. Soil Science Society of America Journal. 74(4):1239-1247. Interpretive Summary: Tillage and manure management practices can impact soil quality. Our work evaluated soil nutrient status as affected by long-term tillage (>25 years) and manure use (>10 years) in the Sand Mountain region of Northeast Alabama. The tillage practices were no-till and conventional tillage and the manure type was poultry litter. No-tillage led to more available plant nutrients compare to conventional tillage and use of litter led to more nutrients compared to not using litter. The greatest increase in nutrients was when both no-tillage and litter application were used. Findings indicate that long-term conservation practices such as no-tillage with litter application can increase availability of plant nutrients from soil.
Technical Abstract: Long-term tillage and manure application are thought to alter the ability of the soil to sequester plant nutrients and mineralize carbon and nitrogen. Thus, a laboratory incubation study was conducted under aerobic conditions to evaluate the residual effect of long-term poultry litter (litter) application (>10 years) as affected by tillage. Soil chemical properties were also evaluated in order to assess the influences of management practices. Soil samples were collected at three depths (0-5, 5-10, and 10-20 cm) from continuous soybean and corn plots (with and without litter) under conventional tillage (CT) and no-tillage (NT) systems. The study area was located at the Sand Mountain Substation in the Appalachian Plateau region of Northeast Alabama on a Hartselle fine sandy loam. Long-term tillage management and litter application greatly affected the amount of plant nutrients retained in soil under NT with litter at the 0-5 cm depth. The NT with litter also had higher total organic carbon (TOC) concentration (2.25 and 1.83 g kg-1 C) for corn and soybean plots followed by NT without litter (1.73 and 1.11 g kg-1 C), respectively. Further, the amount of C mineralized was significantly higher at the 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 litter application had higher C and N mineralization rates compared to plots without litter. At greater depths more C and N mineralization occurred under CT conditions than under NT conditions; this is attributable to mixing of soil in the plow layer. These results indicate that long-term tillage management plays an important role in the amount of C and N mineralized and sequestered in soil.