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ARS Home » Midwest Area » West Lafayette, Indiana » National Soil Erosion Research Laboratory » Research » Publications at this Location » Publication #260924

Title: Mineralizable soil organic carbon dynamics in corn-soybean rotations in glaciated derived landscapes of northern Indiana

Author
item LIBAHOVA, ZAMIER - Natural Resources Conservation Service (NRCS, USDA)
item Stott, Diane
item OWENS, PHILIP - Purdue University
item WINZLER, HANS - West Virginia University
item WILLS, SKYE - Natural Resources Conservation Service (NRCS, USDA)

Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: 12/12/2013
Publication Date: 5/15/2014
Citation: Libahova, Z., Stott, D.E., Owens, P.R., Winzler, H.E., Wills, S. 2014. Mineralizable soil organic carbon dynamics in corn-soybean rotations in glaciated derived landscapes of northern Indiana. In: Hardemink, A.E., McSweeney, K. (eds.) Soil Carbon. Cham, Zug:Springer International Publishing. p. 259-269.

Interpretive Summary: The concerns about climate change have increased interest in understanding differences in soil carbon pools and availability. The objective of this study was to assess the impact of landscape and certain diagnostic soil characteristics on not only soil carbon (SC) contents, but also on carbon availability based on long-term laboratory incubations. We collected 210 soil samples from the 0-25cm surface layer along 10-point transects following the soil catena. Soil samples were analyzed for SC by dry combustion and C pools were determined by incubation. There are a variety of terms used in the literature for various C pools: we adopted the following definitions: Cmin, C lost as CO2 during 0-28 days incubation at optimal laboratory conditions, Cact, C loss from 28-60 days; Cslw, C loss from 60-90 days. The Cslw pool size reported in this paper is an underestimate of this pool, as generally it is defined by incubations of over 365 days. Although this paper stops at reporting C loss at 90 days, incubations are continuing, with additional C pools being determined by incubation and chemical analysis. The spatial distribution of soil SC followed patterns related to soil wetness. Overall, the depression areas and the poorly- and very poorly-drained soils, which represented areas with water accumulating for longer time periods, stored between 50 and 141 Mg C ha-1or between 50 to 68 % more of SC when compared to the relatively drier areas. During the first 28 days of incubation (Cmin), depressions and poorly- and very poorly-drained soils released 1.2 Mg C ha-1, which was significantly more than the drier areas at 0.8 Mg ha-1. All areas had Cact and Cslw pools of about 0.6 and 1.1 Mg C ha-1, respectively. Relative to total SC, the drier areas evolved about 8.5% C as CO2 as compared to 5.0% in the wetter areas, indicating that proportionally less SC was available after 90 days from wetter areas. The mean daily rate of C-CO2 evolved decreased exponentially during the first 28 days from 1.5 to 0.2 µg g-1 h-1. Soils with high and relatively less decomposed organic matter represented by the Haplosaprist great group (organic soils such as bogs, peats, moors or mucks) with organic matter contents from had the highest amount of total SC, 141 Mg C ha-1, compared to Endo- and Argiaquolls great groups with 60 Mg C ha-1. The difference indicates the potential of Endo- and Argiaquolls, and wetter areas in general, to store C if land is converted to C accruing management practices. The management of these targeted areas can potentially increase the soil C stock for in arable lands. This information will be useful to those modeling soil C stock for global change calculations and to land managers developing systems that will sequester soil carbon.

Technical Abstract: The concerns about climate change have increased interest in understanding differences in soil carbon pools and availability. The objective of this study was to assess the spatial distribution and stability of soil carbon (SC) as controlled by slope position, in glaciated northern Indiana. We collected 210 soil samples from the 0-25cm surface layer along 10-point transects following the soil catena. Total SC was determined by dry combustion and C pools by incubation. The spatial distribution of soil SC followed patterns related to soil wetness. Overall, the depression areas and the poorly- and very poorly-drained soils, which represented areas with water accumulating for long time periods, stored between 50 and 141 Mg C ha-1or between 50 to 68 % more of SC when compared to the drier areas. After 28 days of incubation (Cmin), depressions and poorly- and very poorly-drained soils released 1.2 Mg C ha-1, which was significantly more than the drier areas at 0.8 Mg ha-1. All areas released about 0.6 and 1.1 Mg C ha-1 between day 28 to 60 (Cact)and 60 to 90 (Cslw), respectively, however, relative to total SC, the drier areas evolved about 8.5% C as CO2 compared to 5.0% in the wetter areas. The mean daily rate of C-CO2 evolved decreased exponentially during the first 28 days from 1.5 to 0.2 µg g-1 h-1. Soils with high and relatively less decomposed organic matter represented by Haplosaprist great group had the highest amount of total SC, 141 Mg C ha-1, compared to Endo- and Argiaquolls great groups with 60 Mg C ha-1. The difference indicates the potential of Endo- and Argiaquolls, and wetter areas in general, to store C if the land is converted to C accruing management practices. The management of these targeted areas can potentially increase the soil C stock for in arable lands. This information will be useful to those modeling soil C stock for global change calculations and to land managers developing systems that will sequester soil carbon.