scholarly journals Effects of hypolimnetic aeration on the quantity and quality of settling material in a eutrophied dimictic lake

Hydrobiologia ◽  
2019 ◽  
Vol 847 (21) ◽  
pp. 4525-4537 ◽  
Author(s):  
Juha Niemistö ◽  
Soila Silvonen ◽  
Jukka Horppila
Keyword(s):  
Organic Matter ◽  
Thermal Stratification ◽  
Phosphorus Content ◽  
Absolute Amount ◽  
Sedimentation Rates ◽  
Sediment Focusing ◽  
Lake Bottom ◽  
C And N ◽  
Subsequent Regeneration

AbstractEffects of hypolimnetic aeration (pumping of epilimnetic water into the hypolimnion) on the quantity of settling material in eutrophied Lake Vesijärvi, Finland were studied by comparing spatially comprehensive gross sedimentation rates as dry and organic matter prior to aeration activity and during two aerated years. Possible changes in the organic matter (as loss on ignition, LOI), carbon (C) and nitrogen (N) contents and changes in the C/N ratio of the settling material and surface sediment were quantified. Thermal stratification broke up earlier due to aeration and was followed by sedimentation peaks. The absolute amount of dry and organic matter as well as C and N settling to the lake bottom were significantly higher in the aerated years. Increased sedimentation rates were especially pronounced in the deep zones indicating enhanced sediment focusing. Increased sedimentation of C and N reflected higher primary production during the aerated years, which most likely was associated with increased temperature and turbulence and the subsequent regeneration and recycling of nutrients in the water body. Aeration seemed to slightly enhance degradation, but contrary to its ultimate aim, it failed to decrease the phosphorus content of the water column and deposits of organic material in the deep zones of the lake.

scholarly journals Interactive effects of management practices on water-stable aggregation and organic matter of a Humic Gleysol

2001 ◽  
Vol 81 (5) ◽  
pp. 545-551 ◽  
Author(s):  
Nicole Bissonnette ◽  
Denis A. Angers ◽  
Régis R. Simard ◽  
Jean Lafond
Keyword(s):  
Alkaline Phosphatase ◽  
Organic Matter ◽  
Microbial Biomass ◽  
Management Practices ◽  
Surface Soil ◽  
Dairy Manure ◽  
Soil Aggregation ◽  
Silty Clay ◽  
C And N

In many soils, the content and quality of organic matter (OM) control water-stable aggregation, which in turn preserves soil surface integrity. The effects of management practices on soil OM and aggregation remain to be determined for certain soils and climatic conditions. We assessed the effects of eight management systems involving two crop sequences: [barley ( Hordeum vulgare L.) monoculture (M) and barley in rotation (R) with a forage mix of red clover ( Trifolium pratense L.) and timothy ( Phleum pratense L. ‘Champ’)], two fall tillage [moldboard plowing (MP) and chisel plowing (CP)] and two nutrient sources [liquid dairy manure (LDM) and mineral fertilizers (MIN)] on soil aggregation and OM fractions of a silty clay Humic Gleysol. Soil samples from the 0–7.5 cm layer were taken periodically during 7 yr, and the total C and N, microbial biomass C (MBC) and carbohydrate (AHC) contents, alkaline phosphatase activity (APA), and water-stable aggregation were determined. By the 7th yr, initial total C and N contents of the surface soil had increased by 35 and 45%, respectively, in R-CP-LDM. They were slightly increased in R-CP-MIN an d R-MP-LDM, whereas they decreased by an average of 19% in R-MP-MIN and all monoculture plots. Increases in C contents were attributed to higher annual C inputs from forage residues and LDM, less frequent tillage in the rotation, and shallower tillage with CP. The MBC, APA, AHC and aggregation generally responded faster and to a greater degree to conservation management practices than total C and N. Overall, conservation tillage and manure applications resulted in greater improvement in surface soil conditions when used in a rotation system rather than in a monoculture. The rapid rate of changes in soil properties suggests that the surface quality of this cold silty clay soil can be improved relatively quickly with selected management combinations. Key Words: Cropping systems, total soil C, microbial biomass, carbohydrate, alkaline phosphatase, soil aggregation, liquid dairy manure, reducted tillage, rotations

scholarly journals Land-Use Change Depletes Quantity and Quality of Soil Organic Matter Fractions in Ethiopian Highlands

Forests ◽  
2022 ◽  
Vol 13 (1) ◽  
pp. 69
Author(s):  
Iftekhar U. Ahmed ◽  
Dessie Assefa ◽  
Douglas L. Godbold
Keyword(s):  
Land Use ◽  
Organic Matter ◽  
Soil Organic Matter ◽  
Natural Forest ◽  
Grazing Land ◽  
Eucalyptus Plantation ◽  
C And N ◽  
C And N Pools ◽  
Recalcitrant C

The depletion of soil organic matter (SOM) reserve after deforestation and subsequent management practices are well documented, but the impacts of land-use change on the persistence and vulnerability of storage C and N remain uncertain. We investigated soil organic C (SOC) and N stocks in a landscape of chrono-sequence natural forest, grazing/crop lands and plantation forest in the highlands of North-West Ethiopia. We hypothesized that in addition to depleting total C and N pools, multiple conversions of natural forest significantly change the relative proportion of labile and recalcitrant C and N fractions in soils, and thus affect SOM quality. To examine this hypothesis, we estimated depletion of SOC and N stocks and labile (1 & 2) and recalcitrant (fraction 3) C and N pools in soil organic matter following the acid hydrolysis technique. Our studies showed the highest loss of C stock was in grazing land (58%) followed by cropland (50%) and eucalyptus plantation (47%), while on average ca. 57% N stock was depleted. Eucalyptus plantation exhibited potential for soil C recovery, although not for N, after 30 years. The fractionation of SOM revealed that depletions of labile 1 C stocks were similar in grazing and crop lands (36%), and loss of recalcitrant C was highest in grazing soil (56%). However, increases in relative concentrations of labile fraction 1 in grazing land and recalcitrant C and N in cropland suggest the quality of these pools might be influenced by management activities. Also, the C:N ratio of C fractions and recalcitrant indices (RIC and RIN) clearly demonstrated that land conversion from natural forest to managed systems changes the inherent quality of the fractions, which was obscured in whole soil analysis. These findings underscore the importance of considering the quality of SOM when evaluating disturbance impacts on SOC and N stocks.

scholarly journals A Comparison of Two-Stage and Traditional Co-Composting of Green Waste and Food Waste Amended with Phosphate Rock and Sawdust

2021 ◽  
Vol 13 (3) ◽  
pp. 1109
Author(s):  
Edgar Ricardo Oviedo-Ocaña ◽  
Angélica María Hernández-Gómez ◽  
Marcos Ríos ◽  
Anauribeth Portela ◽  
Viviana Sánchez-Torres ◽  
...  
Keyword(s):  
Organic Matter ◽  
Product Quality ◽  
Food Waste ◽  
Phosphate Rock ◽  
Pilot Scale ◽  
Two Stage ◽  
Green Waste ◽  
Wet Weight ◽  
Two Phases

The composting of green waste (GW) proceeds slowly due to the presence of slowly degradable compounds in that substrate. The introduction of amendments and bulking materials can improve organic matter degradation and end-product quality. However, additional strategies such as two-stage composting, can deal with the slow degradation of green waste. This paper evaluates the effect of two-stage composting on the process and end-product quality of the co-composting of green waste and food waste amended with sawdust and phosphate rock. A pilot-scale study was developed using two treatments (in triplicate each), one being a two-stage composting and the other being a traditional composting. The two treatments used the same mixture (wet weight): 46% green waste, 19% unprocessed food waste, 18% processed food waste, 13% sawdust, and 4% phosphate rock. The traditional composting observed a higher degradation rate of organic matter during the mesophilic and thermophilic phases and observed thermophilic temperatures were maintained for longer periods during these two phases compared to two-stage composting (i.e., six days). Nonetheless, during the cooling and maturation phases, the two treatments had similar behaviors with regard to temperature, pH, and electrical conductivity, and the end-products resulting from both treatments did not statistically differ. Therefore, from this study, it is concluded that other additional complementary strategies must be evaluated to further improve GW composting.

scholarly journals Chemical and Phytocoenological Characteristics of Two Different Slovak Peatlands

Plants ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1290
Author(s):  
Danica Fazekašová ◽  
Gabriela Barančíková ◽  
Juraj Fazekaš ◽  
Lenka Štofejová ◽  
Ján Halas ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Profile ◽  
Agricultural Land ◽  
Nitrogen Supply ◽  
Point Of View ◽  
Statistical Testing ◽  
Plant Residues ◽  
Soil Reaction ◽  
Chemical Parameters

This paper presents the results of pedological and phytocoenological research focused on the detailed research of chemical parameters (pH, organic carbon, and nutrients), risk elements (As-metalloid, Cd, Co, Cr, Cu, Ni, Pb, and Zn), and species composition of the vegetation of two different peatlands on the territory of Slovakia—Belianske Lúky (a fen) and Rudné (a bog). Sampling points were selected to characterize the profile of the organosol within the peatland, the soil profile between the peatland and the agricultural land, and the soil profile of the outlying agricultural land, which is used as permanent grassland. Based on phytocoenological records, a semi-quantitative analysis of taxa in accordance with the Braun–Blanquet scale was performed. The study revealed that the thickness of the peat horizon of the fen in comparison with the bog is very low. In terms of the quality of organic matter, the monitored peatlands are dominated by fresh plant residues such as cellulose and lignin. Differences between individual types of peatlands were also found in the soil reaction and the supply of nitrogen to the organic matter of peat. The values of the soil exchange reaction were neutral on the fen, as well as slightly alkaline but extremely low on the bog. A significantly higher nitrogen supply was found in the organic matter of the fen in contrast to the bog. At the same time, extremely low content of accessible P and an above-limit content of As in the surface horizons were also found on the fen. From the phytocoenological point of view, 22 plant species were identified on the fen, while only five species were identified on the bog, which also affected the higher diversity (H’) and equitability (e). The results of the statistical testing confirmed the diversity of the studied peatlands and the different impact of environmental variables on plant diversity.

scholarly journals Assessment of the Content of Dry Matter and Dry Organic Matter in Compost with Neural Modelling Methods

Agriculture ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 307
Author(s):  
Dawid Wojcieszak ◽  
Maciej Zaborowicz ◽  
Jacek Przybył ◽  
Piotr Boniecki ◽  
Aleksander Jędruś
Keyword(s):  
Image Analysis ◽  
Organic Matter ◽  
Dry Matter ◽  
Neural Model ◽  
Original Method ◽  
Neural Models ◽  
Test Error ◽  
Effective Assessment ◽  
Modelling Methods

Neural image analysis is commonly used to solve scientific problems of biosystems and mechanical engineering. The method has been applied, for example, to assess the quality of foodstuffs such as fruit and vegetables, cereal grains, and meat. The method can also be used to analyse composting processes. The scientific problem lets us formulate the research hypothesis: it is possible to identify representative traits of the image of composted material that are necessary to create a neural model supporting the process of assessment of the content of dry matter and dry organic matter in composted material. The effect of the research is the identification of selected features of the composted material and the methods of neural image analysis resulted in a new original method enabling effective assessment of the content of dry matter and dry organic matter. The content of dry matter and dry organic matter can be analysed by means of parameters specifying the colour of compost. The best developed neural models for the assessment of the content of dry matter and dry organic matter in compost are: in visible light RBF 19:19-2-1:1 (test error 0.0922) and MLP 14:14-14-11-1:1 (test error 0.1722), in mixed light RBF 30:30-8-1:1 (test error 0.0764) and MLP 7:7-9-7-1:1 (test error 0.1795). The neural models generated for the compost images taken in mixed light had better qualitative characteristics.

Post-thinning soil organic matter evolution and soil CO2 effluxes in temperate radiata pine plantations: impacts of moderate thinning regimes on the forest C cycle

2012 ◽  
Vol 42 (11) ◽  
pp. 1953-1964 ◽  
Author(s):  
Irene Fernandez ◽  
Juan Gabriel Álvarez-González ◽  
Beatríz Carrasco ◽  
Ana Daría Ruíz-González ◽  
Ana Cabaneiro
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Radiata Pine ◽  
Soil Samples ◽  
Mitigation Strategies ◽  
Change Scenario ◽  
Soil C ◽  
C Storage ◽  
C Cycle ◽  
C And N

Forest ecosystems can act as C sinks, thus absorbing a high percentage of atmospheric CO2. Appropriate silvicultural regimes can therefore be applied as useful tools in climate change mitigation strategies. The present study analyzed the temporal changes in the effects of thinning on soil organic matter (SOM) dynamics and on soil CO2 emissions in radiata pine ( Pinus radiata D. Don) forests. Soil C effluxes were monitored over a period of 2 years in thinned and unthinned plots. In addition, soil samples from the plots were analyzed by solid-state 13C-NMR to determine the post-thinning SOM composition and fresh soil samples were incubated under laboratory conditions to determine their biodegradability. The results indicate that the potential soil C mineralization largely depends on the proportion of alkyl-C and N-alkyl-C functional groups in the SOM and on the microbial accessibility of the recalcitrant organic pool. Soil CO2 effluxes varied widely between seasons and increased exponentially with soil heating. Thinning led to decreased soil respiration and attenuation of the seasonal fluctuations. These effects were observed for up to 20 months after thinning, although they disappeared thereafter. Thus, moderate thinning caused enduring changes to the SOM composition and appeared to have temporary effects on the C storage capacity of forest soils, which is a critical aspect under the current climatic change scenario.

Methyl mercury in zooplankton—the role of size, habitat, and food quality

2002 ◽  
Vol 59 (10) ◽  
pp. 1606-1615 ◽  
Author(s):  
Martin Kainz ◽  
Marc Lucotte ◽  
Christopher C Parrish
Keyword(s):  
Organic Matter ◽  
Fatty Acid ◽  
Body Size ◽  
Methyl Mercury ◽  
Size Fraction ◽  
Food Sources ◽  
Calanoid Copepods ◽  
Bacterial Food

Pathways of methyl mercury (MeHg) accumulation in zooplankton include ingestion of organic matter (OM). We analyzed fatty acid (FA) biomarkers in zooplankton to (i) investigate the effect of allochthonous and autochthonous OM ingestion on MeHg concentrations ([MeHg]) in zooplankton and (ii) examine how algal and bacterial food sources affect MeHg bioaccumulation. We partitioned bulk zooplankton samples (i.e., >500, 202, 100, and 53 μm) from Lake Lusignan (Québec) and measured [MeHg] and [FA] in each fraction. [MeHg] increased with increasing body size and was significantly higher in pelagic than in littoral macrozooplankton (>500 μm). The amount of the ingested terrestrial FA biomarker 24:0 indicated that less than 1% of the total FA in zooplankton was derived from allochthonous sources. More than 60% of the ingested FA originated from algal biomarkers and <10% from bacterial biomarkers. Relative amounts of algal-derived essential FA and bacterial FA were not associated with [MeHg] in any size fraction. In pelagic zones, the amount of MeHg in zooplankton related positively to the number of large organisms such as Calanoid copepods and Daphnia. We propose that the accumulation of MeHg in lacustrine zooplankton depends on the zooplankton habitat rather than on the quality of ingested food.

Sign in / Sign up

Export Citation Format

Share Document