1,721,010 research outputs found
Keep oxygen in check: Contrasting effects of short-term aeration on hydrolytic versus oxidative enzymes in paddy soils
No full textPlant-mediated CH4 transport and contribution of photosynthates to methanogenesis at a boreal mire: a C-14 pulse-labeling study
No full textPlant-mediated methane (CH4) transport and the contribution of recent photosynthates to methanogenesis were studied on two dominating vascular plant species - Eriophorum vaginatum and Scheuchzeria palustris - at three types of microrelief forms (hummocks - E. hummocks, lawns - E. lawns and hollows - S. hollows) of a boreal natural minerogenic, oligotrophic fen in Eastern Finland. C-14-pulse labeling of mesocosms with shoots isolated from entire belowground peat under controlled conditions allowed estimation of plant-mediated CH4 flux and contribution of recent (C-14) photosynthates to total CH4. The results showed (i) CH4 flux increased in the order E. hummocks <= E. lawns < S. hollows corresponding to the increasing water table level at the relief microforms as adjusted to field conditions. (ii) Plant-mediated CH4 flux accounted for 38, 31 and 51% of total CH4 at E. hummocks, E. lawns and S. hollows, respectively. (iii) Contribution of recent photosynthates to methanogenesis accounted for 0.03% for E. hummocks, 0.06% for E. lawns and 0.13% for S. hollows of assimilated C-14. Thus, microsites with S. palustris were characterized by higher rates of transported CH4 from the peat column to the atmosphere when compared to E. vaginatum of drier lawns and hummocks. Contribution of recent photosynthates to methanogenesis was dependent on the plant biomass within-species level (E. vaginatum at hummocks and lawns) but was not observed between species: smaller S. palustris had higher flux of (CH4)-C-14 as compared to larger E. vaginatum. Therefore, for the assessment of CH4 dynamics over meso-and macroscale as well as for the implication and development of the modeling of CH4 fluxes, it is necessary to account for plant species-specific differences in CH4 production, consumption and transport and the attribution of those species to topographic forms of microrelief.DFG [Wi 2680/2-1]; Alexander von Humboldt Foundatio
Improved water and rice residue managements reduce greenhouse gas emissions from paddy soil and increase rice yields
No full textMicrobial strategies for phosphorus acquisition in rice paddies under contrasting water regimes: Multiple source tracing by 32P and 33P
No full texthttp://dx.doi.org/10.13039/501100001659 German Research Foundatio
Effects of nitrate and sulfate on greenhouse gas emission potentials from microform-derived peats of a boreal peatland: A C-13 tracer study
No full textIncreasing natural and anthropogenic deposition of nitrate (NO3-) and sulfate (Sail to peatlands may modify CH4 oxidation, CO2 and N2O production, thereby affecting the balance of greenhouse gases (GHG) globally. Among environmental factors controlling these biogeochemical processes, effects of peatland microrelief are poorly understood. Fluxes of CO2, CH4 and N2O were measured before and after incubation with NO3- and Sair-for peat samples collected from various microrelief positions,of a boreal oligotrophic mire in Eastern Finland. Soil was spiked with (CH4)-C-13 to understand the processes of CH4 oxidation, its microbial utilization and incorporation into soil organic matter (SOM). We hypothesized that the addition of NO3- and SO42- would 1) stimulate CO2 and N2O production (nutritional effect), but 2) decrease CH4 oxidation due to acceleration of other more energetically favorable processes (e.g., denitrification), and 3) these patterns should follow the naturally established aerobic zone of a microform type and decrease with depth. Microbial biomass (MB) at 50 cm below all microforms was 9-15 folds higher than in the topsoil. MB controlled the GHG dynamics and was related to specific depth-dependent environmental conditions, rather than oxygen availability. Indeed, production of CO2 and N2O, and oxidation potentials of CH4 revealed no clear linkage with the naturally established aeration zone of the peatland's microforms. Following NO3- and SO42- addition, production of CO2 decreased by 20-65% compared to the control, with the greatest reduction in CO2 emission occurring in the topsoil of hollows. In turn, CH4 oxidation was suppressed by 20-94% with NO3- addition at 50 cm in lawns and with both NO3- and SO42- at 50 cm in hollows. The N2O production was increased up to 180-240 times under NO3- treatment at 50 cm in hollows and lawns. In conclusion, human-induced deposition of NO3- and SO4- may suppress CO2 emissions from and CH4 oxidation by boreal oligotrophic mires especially under the conditions of deposition increase. Finally, the deposition of inorganic compounds is strongly important to be considered in the estimation of ecosystem C and N balances. (C) 2016 Elsevier Ltd. All rights reserved
Evaluation of the CALPUFF model performance for the estimation of the urban ecosystem CO2 flux
No full textC and N urban soil budget and its spatial differentiation in comparison with natural areas in the Wroclaw region of Poland
No full textAn assessment of C and N balance in urban soil compared to the natural environment was carried out to evaluate the influence of biological processes along with human-induced forcing. Soil C and N stocks were quantified on the samples (n=18) collected at 5 - 10 cm depth from dominated green areas and arable lands in the city of Wroclaw (Poland) and the relatively natural grassland located ca. 36 km south-west. Higher soil carbon and nitrogen levels (C/N ratio = 11.8) and greater microbial biomass C and N values (MBC = 95.3, MBN = 14.4 mg N kg -1 ) were measured in natural grassland compared with the citywide lawn sites (C/N ratio = 15.17, MBC = 84.3 mg C kg-1, MBN = 11.9 mg N kg -1 ), respectively. In contrast to the natural areas, the higher C and N concentration was measured in urban grass dominated soils (C = 2.7 % and N = 0.18 % of dry mass), which can be explained mainly due to the high soil bulk density and water holding capacity (13.8 % clay content). The limited availability of soil C and N content was seen under the arable soil (C = 1.23 %, N = 0.13 %) than in the studied grasslands. In fact, the significantly increased C/N ratios in urban grasslands are largely associated with land conversion and demonstrate that urban soils have the potential to be an important reservoir of C
Oxygen matters: Short- and medium-term effects of aeration on hydrolytic enzymes in a paddy soil
No full textEffect of plant communities on aggregate composition and organic matter stabilisation in young soils
No full textCarbon (C) content in pools of very young soils that developed during 45 years from loess was analysed in relation to vegetation: deciduous and coniferous forests and cropland. We hypothesised that variations in the amount of particulate organic matter (POM) can explain the C accumulation and also affects the C bound to mineral surfaces in soil under various vegetation. Soil samples were collected under three vegetation types of a 45-year-old experiment focused on initial soil development. Aggregate and density fractionations were combined to analyse C accumulation in large and small macro- and microaggregates as well as in free and occluded POM and mineral factions. Deciduous forest soil accumulated the highest C content in the 0-5 cm layer (43 g C kg(-1)), whereas values in coniferous forest and arable soils were lower (30 and 12 g C kg(-1), respectively). The highest portion of C in arable soil was accumulated in the mineral fraction (80 %), whereas 50-60 % of the C in forest soils were in POM. More C was associated with minerals in deciduous forest soil (16 g C kg(-1) soil) than under coniferous forest and arable land (8-10 g C kg(-1) soil). Particulate organic matter explains most of the differences in organic C accumulation in soils developed during 45 years under the three vegetation types on identical parent material. The C content of the mineral soil fraction was controlled by plant cover and contributed the most to differences in C accumulation in soils developed under similar vegetation type (forest).DAA
An improved Amplex Red‐based fluorometric assay of phenol oxidases and peroxidases activity: A case study on Haplic Chernozem
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