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24401. 题目: N addition increased microbial residual carbon by altering soil P availability and microbial composition in a subtropical Castanopsis forest Microbial residual carbon (C) plays a crucial role in soil organic C (SOC) stabilization, and exogenous nutrients have frequently been observed to increase the proportion of microbial residual C in soils with limited nitrogen (N). However, how microbial residual C responds to N deposition and their mechanisms in subtropical forest soil with low phosphorus (P) availability remains poorly understood. To fill this knowledge gap, an experiment with 5.5 consecutive years of N addition (control, 40 and 80 kg N ha−1y−1) to a Castanopsis carlesii forest in Fujian, China was performed. Soil properties (e.g., soil C, N, P, and pH), amino sugars (biomarkers of microbial residual C), phospholipid fatty acids (PLFAs), and enzyme activities were investigated. We found that N application and soil depths had significant interactive effects on amino sugars, the PLFAs, and soil enzyme activities. N addition significantly increased the contents of amino sugars and their proportions to soil C in the 0–10 cm soil layer but not the 10–20 cm soil layer (P > 0.05). In addition, glucosamine (GluN), which was mostly derived from fungal cell walls, accounted for 64.9–73.9% of the total amino sugars across three treatments, and the proportion of GluN to total C also increased after N addition in the 0–10 cm layer. These results indicate that N addition elevated the contribution of amino sugars, especially GluN, to soil C sequestration of the 0–10 cm soil layer but not 10–20 cm soil layer. Moreover, N addition significantly enhanced the biomass of fungi and ectomycorrhizal fungi (EMF) and the activities of phosphatase (ACP), phosphodiesterase (PD), N-acetyl glucosaminidase (NAG), acid phenol oxidase (PhOx), and peroxidase (Perox), while it significantly decreased soil organic P (OP) in the 0–10 cm soil layer. These results implied that changes in N:P ratio caused by N addition contributed to the increases of EMF and fungi, which have high P acquisition ability, this in turn enhanced soil P availability. The increased microbial biomass of EMF and fungi likely attributed to the increased contribution of amino sugars to SOC accumulation in the studied forest soil. Our study revealed a novel mechanism of soil C sequestration in subtropical forest ecosystems with low soil P under ongoing N deposition. | |||||
24402. 题目: Occurrence, fate and environmental risk assessment of pharmaceutical compounds in soils amended with organic wastes One of the most common ways of getting rid of sewage sludge is land spreading on agricultural fields as a source of nutrients and organic matter. However, sewage sludge may be contaminated with pharmaceuticals and can represent a cause of environmental contamination. The objectives of this study was (i) to determine the occurrence and the fate of pharmaceuticals such as antibiotics belonging to different classes: antibiotics (sulfadiazine, sulfamethoxazole, sulfamethoxypyridazine, ciprofloxacin, norfloxacin, tylosin, trimethoprim), anti-inflammatories (diclofenac) and anticonvulsants (carbamazepine) in the soil after spreading stabilized sludge (composted, limed and digested) and solid digestat, (ii) to evaluate agronomic benefits and (iii) to determine the potential ecotoxicological consequences of pharmaceutical compounds on the environment using a risk quotient approach. For this purpose, four different types of sludge samples, coming from the same treatment plant but submitted to different stabilization processes, were incorporated into three soils with different physicochemical characteristics and pedogenetic factors. The obtained results highlighted that the sludge treatments have a great influence on sludge contamination. Once applied onto the soil, the agronomic benefits will depend on the soil's properties as well as the sludge's characteristics. The risks concerning the ecotoxicity of pharmaceuticals, found in the sludge, are low but not insignificant. | |||||
24403. 题目: CDOM in the source regions of the Yangtze and Yellow Rivers, China: optical properties, possible sources, and their relationships with environmental variables | |||||
24404. 题目: Pathways to persistence: plant root traits alter carbon accumulation in different soil carbon pools | |||||
24405. 题目: Microbial community composition turnover and function in the mesophilic phase predetermine chicken manure composting efficiency The aim of this work was to study the influence of inoculation with microbial inoculants (MI) or mature compost (MC) by comparing the resultant composting efficiency with that in a noninoculated (CK) treatment. MI and MC application both accelerated the composting process according to fluorescence excitation-emission matrix (EEM) detection and germination index testing. Bacterial and fungal community composition both differed significantly over the composting period. However, the turnover of the initial bacterial community played a significant role in the composting process, and the key operational taxonomic units (OTUs) of MI (OTU_26, Thermicanus) and MC (OTU_48, Tepidimicrobium) showed significant explanatory power for the formation of humic acid-like and fulvic acid-like substances, respectively, during the stage of composting. Thus, our results indicate that microbial inoculation accelerates the composting process by stimulating key resident microbes in the initial stage. | |||||
24406. 题目: Microbial extracellular polymeric substances (EPS) acted as a potential reservoir in responding to high concentrations of sulfonamides shocks during biological wastewater treatment Extracellular polymeric substances (EPS), one of the main components of activated sludge, could complex with pollutants and thus influence their fate in wastewater treatment system. In this work, the roles of EPS in resisting sulfamethazine (SMZ) shocks were investigated in a continuous flow membrane bioreactor. Results show that SMZ could be intercepted in the EPS of activated sludge during the lag phase of biodegradation. EPS acted as a potential reservoir against SMZ shocks, guaranteeing undetectable SMZ in the effluent. The increased production of EPS in responding to SMZ shocks improved the binding capability of EPS to SMZ. The critical roles of microbial EPS in removing bio-refractory contaminants such as sulfonamides are probably underestimated previously. | |||||
24407. 题目: Adsorption of toluene on various natural soils: Influences of soil properties, mechanisms, and model This study investigated toluene adsorption on natural soils. The linear partition model was found to represent the adsorption isotherm well (R2 = 0.958–0.994), compared with the Freundlich model (R2 = 0.901–0.991). Therefore, the coefficient, Kd, of the linear model indicated the adsorption capacity of soils A to F. Traditionally, Kd and the total organic carbon (TOC) content have a good linear relationship. However, this relationship was weak (correlation coefficient (r) = 0.689) when TOC values (8.43–12.9 mg/g) were low and close. To correct this deviation, this study investigated the influences of physicochemical properties, such as special surface area, mineral composition, functional groups, pH, and potentials. As soils B and C consisted of a large amount of active clayey minerals (69.4% kaolinite and 79.3% nacrite, respectively) and rich functional groups, they demonstrated the strongest adsorption capacity. Additionally, the r for pH-Kd, zeta potential-Kd, and redox potential-Kd were high, at 0.806, 0.914, and 0.932, respectively. To explore adsorption mechanisms, the adsorption thermodynamic parameter (enthalpy) was used initially to determine the forces. Combined with the analysis of soil properties, the mechanisms identified were hydrophobic interaction and hydrogen-pi bonding, involving co-adsorption with water molecules. Based on all studies, the properties were quantified and simplified by the plastic limit (PL), and TOC was simplified by soil organic matter (SOM). Then, PL and SOM were weighted by the entropy-weight method to obtain the determination factor, DF, a logarithmic parameter to replace TOC. Finally, a new model describing toluene adsorption on natural soils was established and expressed as Kd = 4.80 + 3.53DF. This new model had significantly improved the correlation between Kd and TOC (r = 0.933) and expanded the engineering adaptability. | |||||
24408. 题目: Biochar mitigates the negative effect of chloropicrin fumigation on beneficial soil microorganisms Chloropicrin (CP) is the most commonly used soil fumigant worldwide. Although CP effectively controls soilborne pathogens, it is also detrimental to beneficial soil microorganisms unless measures can be put in place to protect them from the effects of fumigation. In this study, we evaluated the ability of biochar made from the invasive weed Eupatorium adenophorum to mitigate the effects of CP fumigation on beneficial species. Our results showed that the addition of biochar to the soil effectively reduced the detrimental effects of CP on beneficial species and their ecological functions. Biochar added to CP-fumigated soil shortened the time to 28–84 days for microbial diversity and nitrogen cycle functions to be restored to unfumigated levels. At the same time, the inorganic nitrogen (NH4+-N, NO3−-N) content and N2O production potential level in CP-fumigated soil returned to unfumigated levels relatively quickly, which showed that nitrogen metabolism improved with the addition of biochar. The mitigation effect of biochar in CP-fumigated soil was more evident at higher biochar amendment rates. Our results suggest that the addition of biochar to CP-fumigated soil significantly reduced the impact of CP on beneficial species and their ecological functions, and significantly shortened the time for beneficial species to recover to pre-fumigation levels. Field research is required to determine biochar's ability to mitigate the impact of CP and other fumigants on beneficial species and to quantify its benefits on crop quality and yield. | |||||
24409. 题目: Bioavailability of organic phosphorus in the water level fluctuation zone soil and the effects of ultraviolet irradiation on it in the Three Gorges Reservoir, China Ultraviolet (UV) irradiation is an abiotic pathway for the transformation of complex phosphorus (P) components into inorganic P in ecosystems. To explore the effect of UV irradiation on organic P (OP) bioavailability in the water level fluctuation zone (WLFZ) soil, we collected representative soil samples from WLFZ of the Pengxi River, a tributary of the TGR, China. We determined the contents of different forms of OP in the WLFZ soil through sequential extraction. The bioavailability of different forms of OP and the effect of UV light were characterised using a combination of enzymatic hydrolysis and UV irradiation. The OP contents of the different extracts (Po) were ranked as NaOH-Po > NaHCO3-Po > H2O-Po, whereas those of enzymatically hydrolysable organic P (EHP) were ranked as NaOH-EHP > NaHCO3-EHP > H2O-EHP. UV irradiation was found to improve OP bioavailability, as demonstrated by increased levels of UV-sensitive P (UV-P) and EHP in the extracts after irradiation. The total contents of bioavailable Po in extracts were 5.6–35.3% higher after UV irradiation than before irradiation. Thus, the effect of UV irradiation on the OP bioavailability and release activity cannot be neglected in TGR WLFZ soil. | |||||
24410. 题目: Distribution of chemical forms of mercury in sediments from abandoned ponds created during former gold mining operations in Colombia Total mercury (THg) and methylmercury (MeHg) were studied in sediments from 27 abandoned gold mining ponds (AGMPs) through small-scale artisanal gold mining in the district of San Juan in Chocó region of Colombia. The AGMPs were abandoned in the last century (1997) and were grouped into three distinct groups (2–6; 7–12; 13–20 years). Overall concentration (in ng g−1) pattern of THg in sediments varied from 39.06 to 1271.32 (avg. 209.57) with 174.81 (13–20 years), 205.56 (7–12 years) and 248.33 (2–6 yrs) respectively. MeHg concentrations accounted for 3.3–10.9% (avg. 6.5%) of THg and were significantly correlated with THg during all periods. Correlations between organic matter (OM) vs MeHg and THg were negative in the oldest pools, signifying a dilution effect or natural burial of THg and MeHg. Results for sequential extraction indicate that the fraction of elemental Hg (Hg-e) and organo chelated Hg (Hg-o) represent the main chemical forms of Hg in the sediments, regardless of the abandonment period, whereas the bioavailable fraction was only 0.12–1.65% of THg. The significant statistical relationship between MeHg, THg and OM suggests that these parameters control the distribution, mobility, toxicity and bioavailability of Hg in the sediments of these abandoned ponds. Evaluation of THg with sediment quality guidelines indicates that the values are on the higher side for Threshold effect concentration and Upper continental crust. Comparing of MeHg with many other regions outside Colombia is a worrying factor and needs immediate attention to protect the human health. | |||||
24411. 题目: Processes of chromium (VI) migration and transformation in chromate production site: A case study from the middle of China The migration and redox transformation processes of toxic Cr(VI) in the upper and deep soil of chromate-polluted site are of great importance for the environmental risk control and soil remediation. In this study, soils from surface to deep (around 30–60 m) and the groundwater in a typical abandoned chromate production plant site which has experienced decades of contamination were both sampled and analyzed. The results show that the soil in the leaching workshop of Cr(VI), dichromate transformation workshop and chromium slag dumping ground exhibits severe contamination of chromium and the pollution has extended to the groundwater, causing serious pollution in groundwater too. The vertical migration and transformation of Cr(VI) in the soil layer are mainly affected by the soil permeability, organic matter content and the amount of water passing through the soil layer. During the downward migration, Cr(VI) tends to be retained by the clay layer and further accumulates around the depth of 5–10 m where the concentrations of both hexavalent and total Cr reach maximum values, and then continues to diffuse from the accumulation layer towards the deeper soil. Accompanying with the reduction of Cr(VI) by organic matter in the soil, the Cr(III) exists at various depths. When the depth is below the groundwater level of saturated aquifer, the distribution of chromium in the soil and groundwater reaches leaching and redox equilibrium due to the long-term interaction between the soil and groundwater. | |||||
24412. 题目: Organic composition in feed solution of forward osmosis membrane systems has no impact on the boron and water flux but reduces scaling This study aimed to characterize the impact of organic and inorganic compounds in the feed solution on the membrane fouling and the boron flux in a forward osmosis (FO) membrane system. Lab-scale FO membrane systems were operated in batch mode, with a solution containing organic compounds (humic acid (HA), bovine serum albumin (BSA), sodium alginate (SA)), scaling constituents (calcium chloride, sodium sulfate), and boric acid as feed solution, and with concentrated sodium chloride as draw solution. Preparations of membrane sample for scanning electron microscopy and energy dispersed spectroscopy (SEM-EDX) by freeze- and by oven-drying showed different results and can therefore not be considered as suitable for the evaluation of the samples. Results showed that the organic fouling layer did not have an impact on water and boron fluxes, but reverse salt flux was reduced in the presence of BSA and HA. The molar flux ratio between water and boron was roughly 105, regardless of the presence of the fouling. The hydrophobicity and surface charge of the fouling layer were not related to the boron transport rate. A thicker and more uniform organic fouling layer, as observed, caused a reduced RSF. The organic compounds in the feed solution impeded the crystallisation of gypsum, which can lead to reduce scaling. | |||||
24413. 题目: Point bars retained particulate organic carbon within a meandering river corridor in Zoige Basin of the Tibetan Plateau Carbon retention within river corridors influences ecosystem processes of catchments and regulates regional to global carbon budgets. Previous studies lack focus of carbon retention associated with meandering river migration. To fill the gap, this study concentrated on particulate organic carbon (POC) retention by point bars that built via hydrogeomorphic processes within meandering river corridors. We selected a typical meandering river (White River) in Zoige Basin of the Tibetan Plateau to conduct field works in the growing seasons of 2016, 2018, and 2019. We found (i) concentration of POC retained within point bars was 0.17%-2.52%, three to five times significantly lower than on general areas of floodplain, and did not show downstream trends; (ii) POC was homogeneously distributed within individual point bars, whereas the positions pioneer plants invaded had significantly higher concentrations; (iii) the order for POC concentration within the river corridor was: positions of bars without plants (1.08%) < positions of bars with pioneer plants (2.96%) < general area of floodplain (5.65%); (iv) the frequency of pioneer plants invasion increased downstream by advantage of the widened channel. Hydrogeomorphic processes through building point bars exerted an intense influence in modifying the POC concentration within the meandering river corridor. | |||||
24414. 题目: Arctic amplification of global warming strengthened by sunlight oxidation of permafrost carbon to CO2 Once thawed, up to 15% of the ∼1,000 Pg of organic carbon (C) in arctic permafrost soils may be oxidized to carbon dioxide (CO2) by 2100, amplifying climate change. However, predictions of this amplification strength ignore the oxidation of permafrost C to CO2 in surface waters (photomineralization). We characterized the wavelength dependence of permafrost dissolved organic carbon (DOC) photomineralization and demonstrate that iron catalyzes photomineralization of old DOC (4,000‐6,300 a BP) derived from soil lignin and tannin. Rates of CO2 production from photomineralization of permafrost DOC are two‐fold higher than for modern DOC. Given that model predictions of future net loss of ecosystem C from thawing permafrost do not include the loss of CO2 to the atmosphere from DOC photomineralization, current predictions of an average of 208 Pg C loss by 2299 may be too low by ~14%. | |||||
24415. 题目: Composition characterization and biotransformation of dissolved, particulate and algae organic phosphorus in eutrophic lakes Characteristics and transformation of organic phosphorus in water are vital to biogeochemical cycling of phosphorus and support of blooms of phytoplankton and cyanobacteria. Using solution 31P nuclear magnetic resonance (NMR), combined with field surveys and lab analyses, composition and structural characteristics of dissolved phosphorus (DP), particulate phosphorus (PP) and organic P in algae were studied in two eutrophic lakes in China, Tai Lake and Chao Lake. Factors influencing migration and transformation of these constituents in lake ecosystems were also investigated. A method was developed to extract, flocculate and concentrate DP and PP from lake water samples. Results showed that orthophosphate (Ortho-P) constituted 32.4%–81.3% of DP and 43.7%–54.9% of PP, respectively; while monoester phosphorus (Mono-P) was 13.2%–54.0% of DP and 32.9%–43.7% of PP, respectively. Phosphorus in algae was mostly organic P, especially Mono-P, which was ≥50% of TP. Environmental factors and water quality parameters such as temperature (T), electrical conductivity (EC), pH, secchi depth (SD), dissolved oxygen (DO), chemical oxygen demand (CODcr), chlorophyll-a (Chl-a), affected the absolute and relative concentrations of various P components in the two lakes. Increased temperature promoted bioavailable P (Ortho-P and Mono-P) release to the lake waters. The results can provide an important theoretical basis for the mutual conversion process of organic P components between various media in the lake water environment. | |||||
24416. 题目: Nitrogen induced DOC and heavy metals leaching: Effects of nitrogen forms, deposition loads and liming Atmospheric nitrogen (N) deposition is believed to accelerate dissolved organic carbon (DOC) production and could lead to increased heavy metal mobility into water resources. We sampled intact soil cores from the Isle of Skye with low background N deposition history and having Serpentine rock known for its higher heavy metal concentrations including zinc (Zn), copper (Cu), nickel (Ni) and lead (Pb). The effects of 16 (16kgN) and 32 kg N ha−1 year−1 (32kgN), and liming with 32kgN (32kgN + Lime) on soil solution chemistry and heavy metal mobilization were investigated over the 15-month study. Nitrogen in deposition load was added at five ammonium (NH4+) to nitrate (NO3−) ratios of 9:1, 5:1, 1:1, 1:5 and 1:9 along NO3−dominance. We found significant effects of load on Cu and NH4+/NO3− ratio on pH, DOC and Zn in soil solution. However, under lime and ratio experimental factors, liming significantly influenced pH, DOC, Cu and Pb, and NH4+/NO3− ratio pH, DOC, Ni and Zn whereas interactions between lime and ratio was significant for Ni and Cu. pH and DOC increased with N load, liming and NO3− dominance, and both correlated significantly positively. Liming under NH4+ dominance enhanced DOC production due to supply of base cations in lime. Mobilization of Cu, Ni and Pb was driven by DOC concentrations and, therefore, increased with load, liming and NO3− dominance in deposition. However, in contrast, low pH and high NH4+ dominance was associated with Zn mobilization in soil solution. On the contrary, despite of some patterns, heavy metals in soil HNO3 extracts were devoid of any load, lime and NH4+/NO3− ratio effects. Our study suggests that the effects of N load and forms in deposition on sites with high accumulated loads of metals need to be better quantified through soil solution partitioning models. | |||||
24417. 题目: What is the impact of pasture reform on organic carbon compartments and CO2 emissions in the Brazilian Cerrado? The emission of CO2 from the soil in agricultural areas is the result of the interaction of several factors, including soil and crop management practices and local edaphoclimatic conditions. The dynamics of organic carbon (OC), in the midst of reform processes in agricultural areas, can be used as an indicator of chemical soil quality because carbon loss is directly related to its lability, quality, or decomposition capacity. This study aimed to evaluate the impact of the reform of degraded pastures in the soil organic matter compartment and its effect on mitigating CO2 emissions. The study was carried out in the municipality of Selvíria, Mato Grosso do Sul, Brazil, in two areas destined for extensive beef cattle grazing, subsidized by the forage plant Urochloa brizantha cv. Marandu. Geostatistical meshes were installed in the areas, and soil samples of deformed and undeformed structures were taken to evaluate the physical and chemical attributes of the soil. The results indicated that soil management practices, followed by the cultivation of sorghum intercropped with U. brizantha, increased the total OC (TOC) stocks through the stable fraction (OC associated with the mineral fraction) and consequent reduction in CO2 emissions from the soil. This highlights the spatial variability in CO2 emissions and how soil attributes affect the flow of CO2 into the atmosphere. The use of multivariate geostatistics has made it possible to forecast CO2 emissions from the soil. This small-scale study provides a theoretical basis for the large-scale spatial monitoring of biogeochemical processes that control CO2 emissions in agricultural ecosystems, particularly in degraded pasture areas. | |||||
24418. 题目: Contrasting impacts of manure and inorganic fertilizer applications for nine years on soil organic carbon and its labile fractions in bulk soil and soil aggregates Careful nutrient management to increase soil organic carbon (SOC) content is important in increasing agricultural productivity and maintaining ecosystem health. A field experiment was conducted for nine years to investigate the effects of manure (M) and inorganic fertilizer (NPK) on SOC and its labile fractions within the bulk soil and in soil aggregates in a wheat-maize rotation on the North China Plain. Nine treatments were included: control (CK) with no fertilization, cattle manure (M, applied at rates of 3000, 6000, 9000, and 12,000 kg ha−1 crop−1), and inorganic NPK fertilizer applied to give equivalent rates of N, P and K. Straw was returned to all plots. Results showed that fertilization significantly increased SOC sequestration and the concentrations of SOC and labile SOC fractions (cold water - extractable SOC, hot water-extractable SOC, microbial biomass C, and dissolved organic C within the bulk soil and soil aggregates). The values increased with increasing application rate of manure but not with increasing NPK fertilizer rate. The differences between manure and NPK fertilizer were apparent at rates equivalent to 9000 and 12,000 kg manure ha−1. Labile SOC fractions were linearly correlated with SOC within the bulk soil and aggregates and hot water-extractable C was the labile C fraction most sensitive to changes in SOC content. Aggregate stability was significantly positively correlated with SOC content and its labile fractions in both bulk soil and aggregates. The results indicate that straw return and/or combined application of fertilizers and manures may be feasible in achieving the '4 per 1000' initiative, with manure application particularly effective. Manure application at a rate of 9000 kg ha−1 crop−1 may be the optimum strategy to sequester C and maintain high crop productivity. Periodic high application rates of manures should be integrated with appropriate inorganic fertilizer application rates to optimize nutrient management strategies on calcareous soils. | |||||
24419. 题目: Effects of Biochar on Microalgal Growth: Difference between Dissolved and Undissolved Fractions | |||||
24420. 题目: Organo-mineral interactions and soil carbon mineralizability with variable saturation cycle frequency The response of mineral-stabilized soil organic carbon (SOC) to environmental change is a source of uncertainty in the understanding of SOC cycling. Fluctuating wet-dry cycles and associated redox changes in otherwise well-drained soils may drive mineral dissolution, organic carbon (OC) mobilization, and subsequent OC mineralization. However, the extent to which rapid fluctuations between water-saturated and unsaturated conditions (i.e., flashy conditions) result in long-term changes in mineral composition and organo-mineral interactions is not well understood. In this study, the effect of variable saturation frequency on soil mineral composition, mineral-associated OC, and OC mineralizability was tested using selective dissolution, bulk spectroscopy, microscale imaging, and aerobic-anaerobic incubation experiments. Previous water table fluctuation measurements and diagnostic profile characteristics at Hubbard Brook Experimental Forest (NH) were used to identify soils with high, medium, and low saturation frequency regimes (defined by historical water table cycling frequency; i.e., water table presence and recession in the upper B horizon). We found the amount of OC released during extractions targeting non-crystalline minerals was of similar magnitude as extracted iron (Fe) in lower saturation frequency soils. However, the magnitude of extracted OC was 2.5 times greater than Fe but more similar to extractable aluminum (Al) in higher saturation frequency soils. Bulk soil Fe was spatially more strongly correlated to soil organic matter (SOM) in lower saturation frequency soils (Spearman Rank rs = 0.62, p < 0.005), whereas strong correlations between Al and SOM were observed in higher saturation frequency soils (rs = 0.88, p < 0.005) using nanoscale secondary ion mass spectrometry (NanoSIMS) imaging. Characterization of bulk soil Fe with X-ray absorption spectroscopy showed 1.2-fold greater Fe(II) and 1-fold lower contribution of Fe-organic bonding in soils with high saturation frequency. Fe(III) interactions with carboxylic and aromatic C were identified with 13C nuclear magnetic resonance (NMR) spectroscopy Fe(III) interference experiments. Additionally, carboxylic acid enrichment in high saturation frequency soils quantified by C K-edge X-ray absorption spectroscopy point towards the role of carboxylic functional groups in Al-organic in addition to Fe-organic interactions. In our incubation experiments, a doubling in short-term CO2 evolution (per unit total soil C) was detected for high relative to low saturation frequency soils. Further, an order of magnitude increase in CO2 evolution (per unit water-extractable OC) following anaerobic incubation was only detected in high saturation frequency soils. The observed shift towards Al-dominated SOC interactions and higher OC mineralizability highlights the need to describe C stabilization in soils with flashy wet-dry cycling separately from soils with low saturation frequency or persistent saturation. | |||||
