Cation exchange properties of acid forest soils of the northeastern USA

Johnson, Chris

doi:10.1046/j.1365-2389.2002.00441.x

Cited by 80 publications

(74 citation statements)

References 33 publications

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“…This is especially true in the coarse-grained, claypoor soils found at the HBEF. Johnson (2002) reported highly significant correlations between CEC and organic carbon in organic (r = 0.61) and mineral (r = 0.73) horizons. Also, the intercept of the soil CEC vs. carbon content relationship is essentially zero, indicating that organic matter contributes virtually all of the CEC to the HBEF soils.…”

Section: The Nature Of Organic Carbonmentioning

confidence: 97%

The Biogeochemistry of Carbon at Hubbard Brook

et al. 2005

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Abstract. The biogeochemical behavior of carbon in the forested watersheds of the Hubbard Brook Experimental Forest (HBEF) was analyzed in long-term studies. The largest pools of C in the reference watershed (W6) reside in mineral soil organic matter (43% of total ecosystem C) and living biomass (40.5%), with the remainder in surface detritus (14.5%). Repeated sampling indicated that none of these pools was changing significantly in the late-1990s, although high spatial variability precluded the detection of small changes in the soil organic matter pools, which are large; hence, net ecosystem productivity (NEP) in this 2nd growth forest was near zero (± about 20 g C/m 2 -yr) and probably similar in magnitude to fluvial export of organic C. Aboveground net primary productivity (ANPP) of the forest declined by 24% between the late-1950s (462 g C/m 2 -yr) and the late-1990s (354 g C/m 2 -yr), illustrating age-related decline in forest NPP, effects of multiple stresses and unusual tree mortality, or both. Application of the simulation model PnET-II predicted 14% higher ANPP than was observed for 1996-1997, probably reflecting some unknown stresses. Fine litterfall flux (171 g C/m 2 -yr) has not changed much since the late-1960s. Because of high annual variation, C flux in woody litterfall (including tree mortality) was not tightly constrained but averaged about 90 g C/m 2 -yr. Carbon flux to soil organic matter in root turnover (128 g C/m 2 -yr) was only about half as large as aboveground detritus. Balancing the soil C budget requires that large amounts of C (80 g C/m 2 -yr) were transported from roots to rhizosphere carbon flux. Total soil respiration (TSR) ranged from 540 to 800 g C/m 2 -yr across eight stands and decreased with increasing elevation within the northern hardwood forest near W6. The watershedwide TSR was estimated as 660 g C/m 2 -yr. Empirical measurements indicated that 58% of TSR occurred in the surface organic horizons and that root respiration comprised about 40% of TSR, most of the rest being microbial. Carbon flux directly associated with other heterotrophs in the HBEF was minor; for example, we estimated respiration of soil microarthropods, rodents, birds and moose at about 3, 5, 1 and 0.8 g C/m 2 -yr, respectively, or in total less than 2% of NPP. Hence, the effects of other heterotrophs on C flux were primarily indirect, with the exception of occasional 2 -yr) were small, larger quantities of C were transported within the ecosystem and a more substantial fraction of dissolved C was transported from the soil as inorganic C and evaded from the stream as CO 2 (4.0 g C/m 2 -yr). Carbon pools and fluxes change rapidly in response to catastrophic disturbances such as forest harvest or major windthrow events. These changes are dominated by living vegetation and dead wood pools, including roots. If biomass removal does not accompany large-scale disturbance, the ecosystem is a large net source of C to the atmosphere (500-1200 g C/m 2 -yr) for about a decade following disturbance and becomes a net si...

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Section: The Nature Of Organic Carbonmentioning

confidence: 97%

The Biogeochemistry of Carbon at Hubbard Brook

et al. 2005

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“…Agronomic and horticultural soil test methods have been developed to serve the agricultural industry and are often regionally standardized. These methods are often not applicable for soil monitoring when done in forest soils that can be acidic, high in exchangeable Al, low in exchangeable base cations and high in organic carbon (e.g., Johnson 2002, Ross et al 2009). Forest soils are arguably more variable than agricultural soils, ranging more broadly in slope, rock content and chemical conditions.…”

Section: Introductionmentioning

confidence: 99%

Inter‐laboratory variation in the chemical analysis of acidic forest soil reference samples from eastern North America

Ross¹,

Bailey²,

Briggs³

et al. 2015

Ecosphere

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Abstract. Long-term forest soil monitoring and research often requires a comparison of laboratory data generated at different times and in different laboratories. Quantifying the uncertainty associated with these analyses is necessary to assess temporal changes in soil properties. Forest soil chemical properties, and methods to measure these properties, often differ from agronomic and horticultural soils. Soil proficiency programs do not generally include forest soil samples that are highly acidic, high in extractable Al, low in extractable Ca and often high in carbon. To determine the uncertainty associated with specific analytical methods for forest soils, we collected and distributed samples from two soil horizons (Oa and Bs) to 15 laboratories in the eastern United States and Canada. Soil properties measured included total organic carbon and nitrogen, pH and exchangeable cations. Overall, results were consistent despite some differences in methodology. We calculated the median absolute deviation (MAD) for each measurement and considered the acceptable range to be the median 6 2.5 3 MAD. Variability among laboratories was usually as low as the typical variability within a laboratory. A few areas of concern include a lack of consistency in the measurement and expression of results on a dry weight basis, relatively high variability in the C/N ratio in the Bs horizon, challenges associated with determining exchangeable cations at concentrations near the lower reporting range of some laboratories and the operationally defined nature of aluminum extractability. Recommendations include a continuation of reference forest soil exchange programs to quantify the uncertainty associated with these analyses in conjunction with ongoing efforts to review and standardize laboratory methods.

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“…Across the Georgia Basin, this condition would apply to 3.4% of the area; elsewhere, BS CL would be the more sensitive criterion. The approach presented here can undoubtedly be improved (i) by considering more detailed acid-base cation-exchange formulations, empirically and theoretically (Matschonat & Vogt 1998;Skyllberg et al 2001;Johnson 2002), and (ii) by revising the soil weathering calculations. Generally, Eqn 3 produced soil weathering rates similar in range and magnitude compared to those obtained through more detailed means (see, e.g., Hodson & Langan 1999; Akselsson et al 2004;Ouimet & Duchesne 2005;Mongeon et al 2010, this issue).…”

Section: Resultsmentioning

confidence: 99%

“…The objective was to place CL and exceedance calculations into the direct context of sustainable forest and soil management policies and practices by introducing 'no further change in soil base saturation' as the main CL criterion for soil acidification. While soil base saturation, by itself, is a poor indicator of soil acidity according to Skyllberg et al (2001) and Johnson (2002), it provides a means to track gains and losses in soil base cations through space and time in response to external inputs and stressors, be they related to atmospheric deposition, soil weathering, and land-use practices.…”

Section: Introductionmentioning

confidence: 99%