Adsorption of Dissolved Organic Carbon and Nitrogen in Soils of a Weathering Chronosequence

Abstract

Adsorption of DOM by soil has been implicated as a very important factor in controlling the loss of DOM Leaching of dissolved organic matter (DOM) and the associated from ecosystems in stream water (McDowell and Wood, nutrient elements can be a significant form of loss from developing 1984; Nelson et al., 1993; Qualls et al., 2002). Several ecosystems. We studied how the adsorption of dissolved organic C (DOC) and N (DON) changes during soil development and deter-authors have found positive correlations between pamined which soil characteristics control adsorption. We sampled 77, rameters derived from DOC adsorption experiments 255, 616, and about 1200ϩ yr-old andesitic soils at five depths and and soil characteristics such as clay content, oxalate did adsorption isotherm experiments fit to a modified Langmuir equaextractable Al and Fe, dithionite-citrate-bicarbonate tion. We measured DOC and DON in soil solution at the 10-to 20-, (DCB) extractable Fe, and surface area (Donald et al., 40-, and 150-cm soil depths during the snowmelt period to compare 1993; Moore et al., 1992; Nelson et al., 1993). Few studies with adsorption experiments. Ability of the soils to adsorb DOM inexist, however, on the adsorption of DON (Kaiser and creased with soil age. Regression analyses were performed between Zech, 2000b) despite N being the limiting nutrient in adsorption capacity or the null point concentration of either DOC or most terrestrial ecosystems (Schlesinger, 1997). DON and the independent variables soil organic C (SOC), N, allo-While several authors have studied the adsorption of phane, oxalate extractable Fe, crystalline Fe, and specific surface area. The best relationships were found between adsorption capacity and DOC to ferrihydrite and aluminum hydroxides, much the allophane/SOC ratio (r 2 ϭ 0.88), and between the null point less is known about the adsorption of DOC to allophane, concentration of DOC or DON and the SOC/allophane ratio (DOC: an aluminosilicate. Allophanic soils are known to accur 2 ϭ 0.85; DON: r 2 ϭ 0.77). Stepwise multiple regression indicated mulate organic matter rapidly and this has been attribthat oxalate-extractable Fe and specific surface area contributed only uted to their large surface area and positive surface small increases in the multiple R 2. High correlations between the nullcharge (Wada, 1989; Parfitt, 1990). The short-rangepoint adsorption of DOC or DON and the DOC (r 2 ϭ 0.92) or DON order aluminosilicates, allophane, and imogolite strongly (r 2 ϭ 0.86) field soil solution concentrations indicated that results adsorb DOC (Parfitt et al., 1977; Yuan et al., 2000). obtained in laboratory experiments were applicable to field condi-Dahlgren and Marrett (1991) attributed the strong adtions. The cause of the increased ability of the soils to adsorb and sorption of DOC in the Bs horizon of a volcanic Spodoretain DOM during soil development appears to be an increase in allophane concentrations.

Spatial distribution of soils determines export of nitrogen and dissolved organic carbon from an intensively managed agricultural landscape

“…Actually, adsorption of dissolved organic matter depends on molecular weight, acidic group and aromatic structure (Kaiser and Zech, 2000). The adsorption of DOC and DON also depends on their respective concentrations in the draining water (Lilienfein et al, 2004). According to Lilienfein et al (2004), at low initial concentrations in soil solution, the soil releases potentially more dissolved organic matter (DOM) than at higher concentrations for which it is more likely to retain these substances.…”

“…The adsorption of DOC and DON also depends on their respective concentrations in the draining water (Lilienfein et al, 2004). According to Lilienfein et al (2004), at low initial concentrations in soil solution, the soil releases potentially more dissolved organic matter (DOM) than at higher concentrations for which it is more likely to retain these substances. Meanwhile, Lilienfein et al (2004) also state that adsorption mechanisms of both species are controlled by similar factors.…”

“…According to Lilienfein et al (2004), at low initial concentrations in soil solution, the soil releases potentially more dissolved organic matter (DOM) than at higher concentrations for which it is more likely to retain these substances. Meanwhile, Lilienfein et al (2004) also state that adsorption mechanisms of both species are controlled by similar factors. Nevertheless in other studies that compare the behaviour of these two DOM components, conclusions are drawn that the tendencies for adsorption and degradation probably differ between DOC and DON (Michalzik and Matzner, 1999;Kalbitz et al, 2000).…”

Leaching of dissolved organic carbon, dissolved organic nitrogen, and other solutes from coarse woody debris and litter in a mixed forest in New York State

“…If the affinity of soil particles for DOC (i.e., the partition coefficient) decreases as the concentration of sorbed DOC increases (i.e., a Langmuir adsorption isotherm [Sparks 1995]), higher concentrations of DOC in soil solutions would lead to proportionally less adsorption on soil. Though some studies on DOC adsorption have demonstrated a linear response of DOC sorption to increasing solution concentration, notably at much lower DOC concentrations than those in CWD leachate (Nodvin et al 1986;Kaiser et al 1996;Kaiser et al 2000), others have shown a Langmuir-type response (van Hees et al 2003;Lilienfein et al 2004). Microbial degradation of DOC may also be proportionally lower in soil with higher concentrations of DOC, due to a shift in limitation from C to N or some other element.…”

Stabilization of Soil Organic Matter: Association with Minerals or Chemical Recalcitrance?

“…Also in the field, their importance for long-term OM stabilization has been affirmed by correlations found between the contents of OC and mineral phase properties. For example, in andic soils, poorly crystalline aluminosilicates (allophane, imogolite-type minerals) were shown to account for the sorption and preservation of OM (Torn et al 1997;Lilienfein et al 2004). In temperate, non-allophanic soils of varying phyllosilicate composition, Wiseman and Pu¨ttmann (2005) observed that C storage was largely a function of the contents of Fe and Al (hydr)oxides.…”