Changes in Forest Soil Carbon and Nitrogen after a Thirty‐Year Interval

Abstract

Increases in atmospheric C have resulted in concerns about global warming and interest in finding the means to sequester atmospheric C through land management strategies. The purposes of this study were to: (i) compare changes in mineral soil C after a 30‐yr interval, and (ii) examine the potential roles of soil N, soil texture, and topography in these changes. The Camp Branch watershed is a second‐growth, oak‐dominated, mixed hardwood forest on the Cumberland Plateau in central Tennessee. In July 1976, soil samples were collected at permanently identified points and archived. These points were resampled in July 2006 and both the archived and new samples of the 0‐ to 10‐cm increment of the mineral soil were analyzed for C and N. Comparisons revealed that the changes in C and N were distinct to each of the eight soil series occurring on the site. Comparison of 2006 samples to 1976 samples indicated that changes in C concentration ranged from −13.1 to 12.0%. Changes in C mass ranged from −11.3 to 8.3%. Increases in C were most closely associated with increases in the C/total N ratio. The change in C was positively correlated with the change in exchangeable inorganic N (r2 = 0.31, P < 0.0001). An overstory inventory indicated a decline in oak domination and site‐specific changes in basal area, density, and stand age. Since regression analysis revealed that the change in C was not predicted by topographic factors or soil texture, we speculate that changes in forest cover influenced the changes in mineral soil C.

Soil Organic Carbon and Total Nitrogen Gains in an Old Growth Deciduous Forest in Germany

“…Similarly, increases in OC were positively correlated to increases of the OC-to-TN ratio, a relation that was also observed in the repeated forest soil inventory conducted by Kiser et al [30].…”

Controls of litter quality on the carbon sink in soils through partitioning the products of decomposing litter in a forest succession series in South China

“…If considering the same duration of 1978-2008, the rate would be 67 ± 5 g C m −2 yr −1 (y = 67.2x − 146262, R 2 = 0.81, n = 19, p < 0.0001). This phenomenon has been globally noted (Richter et al, 1999;Paul et al, 2002;Resh et al, 2002;Hooker and Compton, 2003;Johnson et al, 2003;Mendoza-Vega et al, 2003;Zhou et al, 2006a;Bush, 2008;Don et al, 2009;Kiser et al, 2009).…”

“…Some studies have revealed that pioneer and transition forests have limited effects on soil organic carbon (SOC) accumulation even if the aboveground biomass accumulates rapidly and has attained a high level (Richter et al, 1999;Paul et al, 2002;Hooker and Compton, 2003;Johnson et al, 2003;Zhou et al, 2006a;Don et al, 2009), especially for pine forests (Richter et al, 1999;Paul et al, 2002;Zhou et al, 2006a). On the contrary, other evidences showed that broadleaved forests or those with nitrogenfixing trees may allocate a higher fraction of NPP into soils (Paul et al, 2002;Resh et al, 2002;Mendoza-Vega et al, 2003;Bush, 2008;Kiser et al, 2009). A few studies even reported high organic carbon accumulation rate in mineral soils (Zhou et al, 2006b) or the whole ecosystem (Knohl et al, 2003) of matured broadleaved forest.…”

“…A few studies even reported high organic carbon accumulation rate in mineral soils (Zhou et al, 2006b) or the whole ecosystem (Knohl et al, 2003) of matured broadleaved forest. Kiser et al (2009) speculated that changes in forest species and cover influenced changes in mineral soil carbon. All these reports and findings have implied that chemical components of forest biomass may have deep impacts on SOC accumulation and thus 0378-1127/$ -see front matter © 2010 Elsevier B.V. All rights reserved.…”

Dynamics of soil organic carbon and dissolved organic carbon in Robina pseudoacacia forests

“…SOC increases by up to 52% after a change from crop to secondary forest (Guo et al, 2002). Forests with nitrogen-fixing trees may also allocate a higher fraction of their net primary production to soil (e.g., Bush, 2008;Kiser et al, 2009). However, the results of soil carbon stock change in forest chronosequence are likely to be different.…”