The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Mark G Johnson - One of the best experts on this subject based on the ideXlab platform.
-
remediation of an acidic mine spoil miscanthus biochar and lime amendment affects metal availability plant growth and Soil Enzyme Activity
Chemosphere, 2018Co-Authors: J M Novak, J A Ippolito, Thomas F Ducey, D W Watts, Kurt A Spokas, Kristin M Trippe, Gilbert C Sigua, Mark G JohnsonAbstract:Biochar may be a tool for mine spoil remediation; however, its mechanisms for achieving this goal remain unclear. In this study, Miscanthus (Miscanthus giganteus) biochar was evaluated for its ability to reclaim acidic mine spoils (pH < 3) through reducing metal availability, improving Soil microbial enzymatic Activity, and initial growth of grass seedlings. Biochar was applied at 0, 1, 2.5 and 5% (w/w) along with lime/no lime and fertilizer additions. Blue Wildrye (Elymus glaucus cv. 'Elkton') was planted and later the shoots and roots were collected and metal concentrations determined. Afterwards, each pot was leached with deionized water, and the leachate analyzed for pH, electrical conductivity (EC), dissolved organic carbon (DOC) and soluble metal concentrations. After drying, the spoil was extracted with 0.01 M CaCl2 and Mehlich 3 (M3) to determine extractable Al, Cu, and Zn concentrations. Additionally, microbial Activity was measured using a fluorescent β-glucosidase and N-acetyl-β-d-glucosaminidase assay. Spoil treated with lime and biochar had significantly greater pH and EC values. Significantly greater β-glucosidase Activity occurred only in the 5% biochar plus lime treatment, while N-acetyl-β-d-glucosaminidase activities were not altered. Metal concentrations in rye shoot and roots were mixed. Lime additions significantly reduced extractable metal concentrations. Increasing biochar rates alone significantly reduced leachate DOC concentrations, and subsequently reduced leachable metal concentrations. Surprisingly, miscanthus biochar, by itself, was limited at mitigation, but when combined with lime, the combination was capable of further reducing extractable metal concentrations and improving β-glucosidase Enzyme Activity.
-
remediation of an acidic mine spoil miscanthus biochar and lime amendment affects metal availability plant growth and Soil Enzyme Activity
Chemosphere, 2018Co-Authors: J M Novak, J A Ippolito, Thomas F Ducey, D W Watts, Kurt A Spokas, Kristin M Trippe, Gilbert C Sigua, Mark G JohnsonAbstract:Abstract Biochar may be a tool for mine spoil remediation; however, its mechanisms for achieving this goal remain unclear. In this study, Miscanthus (Miscanthus giganteus) biochar was evaluated for its ability to reclaim acidic mine spoils (pH d -glucosaminidase assay. Spoil treated with lime and biochar had significantly greater pH and EC values. Significantly greater β-glucosidase Activity occurred only in the 5% biochar plus lime treatment, while N-acetyl-β- d -glucosaminidase activities were not altered. Metal concentrations in rye shoot and roots were mixed. Lime additions significantly reduced extractable metal concentrations. Increasing biochar rates alone significantly reduced leachate DOC concentrations, and subsequently reduced leachable metal concentrations. Surprisingly, miscanthus biochar, by itself, was limited at mitigation, but when combined with lime, the combination was capable of further reducing extractable metal concentrations and improving β-glucosidase Enzyme Activity.
Wei Zhou - One of the best experts on this subject based on the ideXlab platform.
-
distinct responses of Soil bacterial and fungal communities to changes in fertilization regime and crop rotation
Geoderma, 2018Co-Authors: Shuiqing Zhang, Wei Zhou, Xin Zhang, Doudou Guo, Shaomin HuangAbstract:Abstract Nutrient availability and plant diversity are two important factors determining crop productivity in agricultural ecosystems, but little is known about the underlying mechanisms shaping microbial communities and their regulatory roles in Soil biological Activity and function. Here, we explored the impacts of fertilization regimes and crop rotations on Soil physicochemical properties, crop yield and bacterial and fungal community structures in a 26-year field experiment. The critical determinants for regulating Soil Enzyme Activity profiles involved in carbon (C), nitrogen (N) and phosphorus (P) cycling were identified by the partial least squares path model (PLS-PM). Long-term inorganic or organic fertilization significantly increased Soil total N by 27%–77% and crop yield by 237%–419% and decreased Soil pH by an average of 0.4 units when compared with non-fertilized control. Soil bacteria were more sensitive than fungi to the fertilization practices. Nutrient additions enriched copiotrophic taxa affiliated to the Pseudomonadaceae and Cytophagaceae bacterial families, but reduced some Acidobacteria such as subgroup 4 RB41, which was the most sensitive biomarker responding to no fertilization. Conversely, fungi were more active in response to crop conversion from wheat-maize to wheat-soybean rotation, leading to a 3-fold enhancement of an unclassified Sordariomycetes family in soybean-based rotation. PLS-PM revealed that fertilization-induced increases in Soil Enzyme activities were regulated by the bacterial community, while plant-driven alterations in yield, organic C input and Soil aggregate-size distribution played an important role for fungal development, which, however, had no significant link to Soil Enzyme Activity profiles. Our results suggest that different response patterns of Soil bacteria and fungi to agricultural practices might have consequences for ecosystem function.
-
maize biochar addition rate influences Soil Enzyme Activity and microbial community composition in a fluvo aquic Soil
Applied Soil Ecology, 2015Co-Authors: Xiubin Wang, Guoqing Liang, Dali Song, Qian Zhang, Wei ZhouAbstract:Abstract Biochar addition to Soil has been proposed as a strategy to enhance Soil quality and crop productivity, which may also affect microbial Activity. However, the response of Soil Enzymes and microbial community composition to biochar addition and the main factors that drive their consequent behavior have rarely been studied. Therefore, to investigate the combined effect of different amounts of biochar (0, 0.5, 1.0, 2.5 and 5.0% by mass) and urea application on Soil nutrients, enzymatic activities and microbial community in a fluvo-aquic Soil, we conducted a 90-day laboratory study. Increased maize biochar addition led to significantly increased Soil organic carbon (SOC), total N, and exchangeable K and reduced Soil exchangeable Ca. Soil total N and exchangeable Ca were dominant factors affecting Soil Enzyme activities. Activities of Soil extracellular Enzymes involved in C and S cycling (except β-xylosidase) suggested lower amounts of biochar addition (0.5% by mass) could increase Soil Enzyme activities, while higher amounts of biochar addition reduce Soil Enzyme activities. However, the activities of l -leucine aminopeptidase and urease, both of which are involved in N cycling, increased with the increase of biochar addition rate. Total phospholipid fatty acid content and the relative abundance of bacteria were significantly reduced with increasing biochar addition rate. The relative abundance of fungi in the urea-amended Soil was significantly higher than that in the other treated Soils, and abundance of actinomycetes did not show a clear response to biochar addition. The changes in the microbial community composition were mainly related to SOC and total N contents, with a significant negative correlation. We concluded that the effect of biochar addition on Soil Enzymes and microbial community composition was highly variable. There is an urgent need to further estimate both the positive and negative long-term effects of biochar on the Soil quality and crop productivity in this region.
-
the alleviation of acid Soil stress in rice by inorganic or organic ameliorants is associated with changes in Soil Enzyme Activity and microbial community composition
Biology and Fertility of Soils, 2015Co-Authors: Guoqing Liang, Jingwen Sun, Shuanhu Tang, Shaohai Yang, Wei Zhou, Xiubin WangAbstract:The effects of calcium-magnesium phosphate, rock phosphate, lime, fly ash, and animal manure as liming agents on the microbial community composition, Enzyme activities involved in C, N, P, and S cycling and rice yields of acid sulfate Soils were studied in a three-year field trial. Significant increases in Soil pH caused by five ameliorants, particularly lime and fly ash, were observed after 3 years. Both Soil exchangeable Al3+ and H+ were significantly (P < 0.05) and negatively correlated with Soil pH. Increased pH led to 61–102 % increase in rice yield after 2 and 3 years but not after 1 year. Soil phospholipid fatty acid (PLFA) profiles and Enzyme activities were significantly changed after 3 years of application of the Soil amendments. Enzyme activities increased along gradients of Soil pH, indicating that the influences of inorganic or organic ameliorants on Soil Enzyme activities were mainly due to the effect on Soil pH value. PLFA analysis showed that this pH effect played a more important role in shaping microbial community composition than specific effects of organic and inorganic amendments. All rice yield-associated Enzymes and PLFA biomarkers (e.g., gram-negative bacteria and actinomycetes) were regulated by Soil pH after 3 years. These results revealed that pH-induced changes in Soil Enzyme Activity and microbial composition might be an important mechanism in alleviating acid stress in Soil cropped to rice by various ameliorants.
Jared L Deforest - One of the best experts on this subject based on the ideXlab platform.
-
the influence of time storage temperature and substrate age on potential Soil Enzyme Activity in acidic forest Soils using mub linked substrates and l dopa
Soil Biology & Biochemistry, 2009Co-Authors: Jared L DeforestAbstract:Abstract The purpose of this experiment was to evaluate whether Soil storage and processing methods significantly influence measurements of potential in situ Enzyme Activity in acidic forest Soils. More specifically, the objectives were to determine if: (1) duration and temperature of Soil storage; (2) duration of Soil slurry in buffer; and (3) age of model substrates significantly influence the Activity of six commonly measured Soil extracellular Enzymes using methylumbelliferone (MUB)-linked substrates and l -dihydroxyphenylalanine ( l -DOPA). Soil collected and analyzed for Enzyme Activity within 2 h was considered the best measure of potential in situ Enzyme Activity and the benchmark for all statistical comparisons. Sub-samples of the same Soil were stored at either 4 °C or −20 °C. In addition to the temperature manipulation, Soils experienced two more experimental treatments. First, Enzyme Activity was analyzed 2, 7, 14, and 21 days after collection. Second, MUB-linked substrate was added immediately (i.e.
-
the influence of time storage temperature and substrate age on potential Soil Enzyme Activity in acidic forest Soils using mub linked substrates and l dopa
Soil Biology & Biochemistry, 2009Co-Authors: Jared L DeforestAbstract:The purpose of this experiment was to evaluate whether Soil storage and processing methods significantly influence measurements of potential in situ Enzyme Activity in acidic forest Soils. More specifically, the objectives were to determine if: (1) duration and temperature of Soil storage; (2) duration of Soil slurry in buffer; and (3) age of model substrates significantly influence the Activity of six commonly measured Soil extracellular Enzymes using methylumbelliferone (MUB)-linked substrates and l-dihydroxyphenylalanine (l-DOPA). Soil collected and analyzed for Enzyme Activity within 2 h was considered the best measure of potential in situ Enzyme Activity and the benchmark for all statistical comparisons. Sub-samples of the same Soil were stored at either 4 °C or −20 °C. In addition to the temperature manipulation, Soils experienced two more experimental treatments. First, Enzyme Activity was analyzed 2, 7, 14, and 21 days after collection. Second, MUB-linked substrate was added immediately (i.e. <20 min) or 2 h after mixing Soil with buffer. Enzyme Activity of Soil stored at 4 °C was not significantly different from Soil stored at −20 °C. The duration of Soil storage was minimal for β-glucosidase, β-xylosidase, and peroxidase Activity. N-acetyl-glucosaminidase (NAGase), phosphatase, and phenol oxidase Activity appeared to change the most when compared to fresh Soils, but the direction of change varied. Likewise, the activities of these Enzymes were most sensitive to extended time in buffer. Fluorometric MUB and MUB-linked substrates generally had a 3-day shelf life before they start to significantly suppress reported activities when kept at 4 °C. These findings suggest that the manner in which acidic forest Soils are stored and processed are site and Enzyme specific and should not initially be trivialized when conducting Enzyme assays focusing on NAGase, phosphatase, and phenol oxidase. The activities of β-glucosidase, β-xylosidase, and peroxidase are insensitive to storage and processing methods.
Ralph E J Boerner - One of the best experts on this subject based on the ideXlab platform.
-
initial effects of fire and mechanical thinning on Soil Enzyme Activity and nitrogen transformations in eight north american forest ecosystems
Soil Biology & Biochemistry, 2008Co-Authors: Ralph E J Boerner, Carla Giai, Jianjun Huang, Jessica R MieselAbstract:This study assessed the first-year effect of three ecosystem restoration treatments (prescribed fire, mechanical thinning, and their combination) on Soil Enzyme Activity, Soil N transformations, and C:N ratios of Soil organic matter and mineral Soil in eight North American forested ecosystems. The ecosystems we studied were part of the larger Fire and Fire Surrogate (FFS) network, and all had a history of frequent fire that has been altered by almost a century of organized fire suppression. Across all eight sites there were no statistically significant effects of the three manipulative treatments on phosphatase Activity or chitinase Activity; in contrast, at the network-scale phenol oxidase Activity was reduced by fire alone, relative to the control. There was no significant network-scale effect of the three treatments on net N mineralization or net nitrification. Soil C:N ratio increased modestly after mechanical thinning, but not after prescribed fire or the combination of fire and thinning. There was a statistically significant reduction in forest floor C:N ratio as a result of all three treatments. Ordination of the differences between the treated and control areas indicated that fire alone resulted in greater changes in phenol oxidase Activity and net nitrification than did the other two treatments. Large-scale restoration treatments such as those utilized in this study produce modest proximate effects on Soil microbial Activity and N transformations.
-
fire frequency and Soil Enzyme Activity in southern ohio oak hickory forests
Applied Soil Ecology, 2003Co-Authors: Ralph E J Boerner, Jennifer A BrinkmanAbstract:Abstract As part of a larger study of the efficacy of prescribed fire for restoration of structure and function in deciduous forests subjected to fire suppression and chronic atmospheric deposition, this study examined the effects of annual and periodic fire on Soil organic C and the Activity rates of four Soil Enzymes (acid phosphatase, β-glucosidase, chitinase, and phenol oxidase) over a 5-year period. Two study areas in southern Ohio were divided into watershed-scale treatment units of 90–120 ha. One unit in each site was burned annually between 1996 and 1999, a second burned periodically (1996 and 1999) and a third left as an unburned control. Relative to the unburned control, acid phosphatase and β-glucosidase activities decreased in the burned plots, by 15–50% and 5–50%, respectively. Phenol oxidase Activity increased 20–80% following burning, depending on site. Chitinase Activity changed little. Taken together these changes indicate a shift in these ecosystems back to a condition characterized by relatively slow nutrient recycling, low microbial Activity and recalcitrant organic matter, much like what is believed to have existed prior to a century of atmospheric deposition and fire suppression. These results suggest that prescribed fire can be a significant aid in restoring mixed oak forests to pre-settlement conditions.
-
prescribed burning effects on Soil Enzyme Activity in a southern ohio hardwood forest a landscape scale analysis
Soil Biology & Biochemistry, 2000Co-Authors: Ralph E J Boerner, Kelly L M Decker, Elaine Kennedy SutherlandAbstract:We assessed the effect of a single, dormant season prescribed fire on Soil Enzyme Activity in oak-hickory (Quercus-Carya) forests in southern Ohio, USA. Four Enzymes specific for different C sources were chosen for monitoring: acid phosphatase, β-glucosidase, chitinase and phenol oxidase. Postfire acid phosphatase Activity was generally reduced by burning and decreased with increasing longterm Soil water potential. Postfire β-glucosidase differed little between control and burned plots. Chitinase Activity increased after fire in proportion to fire intensity. Phenol oxidase Activity was highly variable and did not correlate well with either fire or Soil water potential. Enzyme activities tended to vary more between samples taken upslope vs. downslope of a given tree than as the result of fire or landscape position. Overall Enzymes whose activities are controlled by microclimatic or edaphic factors were affected more than those controlled primarily by substrate availability. Single, dormant season fires may consume a large proportion of the forest floor and change the apparent character of the surface organic matter complex without having major effects on Soil Enzyme Activity.
Diana R Nemergut - One of the best experts on this subject based on the ideXlab platform.
-
fire severity shapes plant colonization effects on bacterial community structure microbial biomass and Soil Enzyme Activity in secondary succession of a burned forest
Soil Biology & Biochemistry, 2015Co-Authors: Joseph E Knelman, Emily B Graham, Nicole A Trahan, Steven K Schmidt, Diana R NemergutAbstract:Abstract The increasing frequency and severity of wildfires has led to growing attention to the effects of fire disturbance on Soil microbial communities and biogeochemical cycling. While many studies have examined fire impacts on plant communities, and a growing body of research is detailing the effects of fire on Soil microbial communities, little attention has been paid to the interaction between plant recolonization and shifts in Soil properties and microbial community structure and function. In this study, we examined the effect of a common post-fire colonizer plant species, Corydalis aurea, on Soil chemistry, microbial biomass, Soil Enzyme Activity and bacterial community structure one year after a major forest wildfire in Colorado, USA, in severely burned and lightly burned Soils. Consistent with past research, we find significant differences in Soil edaphic and biotic properties between severe and light burn Soils. Further, our work suggests an important interaction between fire severity and plant effects by demonstrating that the recolonization of Soils by C. aurea plants only has a significant effect on Soil bacterial communities and biogeochemistry in severely burned Soils, resulting in increases in percent nitrogen, extractable organic carbon, microbial biomass, β-glucosidase Enzyme Activity and shifts in bacterial community diversity. This work propounds the important role of plant colonization in succession by demonstrating a clear connection between plant colonization and bacterial community structure as well as the cycling of carbon in a post-fire landscape. This study conveys how the strength of plant–microbe interactions in secondary succession may shift based on an abiotic context, where plant effects are accentuated in harsher abiotic conditions of severe burn Soils, with implications for bacterial community structure and Enzyme Activity.