Distribution of Organic Matter in Sediment of Lakeside Belt in East Dongting Lake

2012 ◽  
Vol 518-523 ◽  
pp. 319-325
Author(s):  
Dian Qing Lu ◽  
Hong Wang ◽  
Xu Lei Hou ◽  
Xiao Mei Liu

Distribution of organic matter and effect of wetland types and pH on organic matter were studied in sediment of lakeside belt in east Dongting Lake according to taking 56 samples from surface to 20cm and 52 samples from 20cm to 40cm. The results showed that the average content of organic matter was 15.40g/kg from surface to 20cm and 12.02g/kg from 20cm to 40cm in sediment of lakeside belt in east Dongting Lake. Spatial distribution of organic matter could be expressed as middle variation. Wetland types were classed into silt beach, lake marsh beach and reed beach in Dongting Lake region and influenced distribution of organic matter because of difference variance on hydraulic dynamics condition and retarding effect of vegetation on water flow velocity. Order of organic matter content in sediment was the lake marsh beach > reed beach > silt beach in 0-20cm and 20-40cm layers in lakeside belt in east Dongting Lake. Organic matter contents decreased in turn from 0-20cm to 20-40cm in lake marsh and reed beaches and increased in silt beaches. Values of pH in sediment were slightly alkaline in whole studied region. Negative correlation was established between organic matter content and pH value. The results will provide base data and science reference for controlling and recovery of sediment pollution in east Dongting Lake.

2019 ◽  
Vol 178 ◽  
pp. 108669 ◽  
Author(s):  
Manuel Conde-Cid ◽  
Gustavo Ferreira-Coelho ◽  
Avelino Núñez-Delgado ◽  
David Fernández-Calviño ◽  
Manuel Arias-Estévez ◽  
...  

2020 ◽  
Vol 204 ◽  
pp. 01013
Author(s):  
Gang Li ◽  
Ruiqing Zhang ◽  
Ying Wang ◽  
Nan Lu ◽  
Yang Wei ◽  
...  

In order to understand the soil pH and main nutrient characteristics of newly added cultivated land in the eastern part of Guanzhong, and 160 soil samples were collected in 2016, the soil pH, organic matter, total nitrogen, available phosphorus and available potassium in Heyang County were studied The suitability distribution of the indicators, using stepwise regression and path analysis methods, analyzes the direct relationship between soil pH and soil nutrients, and provides a theoretical basis for improving the newly added cultivated land. The results showed that the soil pH in Heyang County varied from 8.42 to 9.67, the soil organic matter content varied from 3.46 to 17.93 g/kg, the soil total nitrogen content varied from 0.13 to 5.61 g/kg, and the soil available phosphorus changed The range is 1.73 ~ 63.06 mg/kg, and the soil available potassium range is 46.50 ~ 523.74. The newly added soil has a certain nutrient basis, but it should be further adjusted and improved during the cultivation process. The direct positive effect on soil pH value is mainly soil organic matter, and the direct negative effect is mainly soil available phosphorus. By adjusting the organic matter, total nitrogen, available phosphorus and available potassium in the soil, the pH value of the soil can be effectively improved, so that the newly cultivated soil is suitable for the growth of local crops.


Author(s):  
Biboss Maharjan ◽  
Anon Chaulagain ◽  
Parikrama Sapkota ◽  
Dhurva P. Gauchan ◽  
Janardan Lamichanne

 The aim of this study was to investigate the response of soil physical and chemical properties during the transition from conventional to organic farming system. Soil samples were collected from five different farms: “Hasera organic farm” under 10 years of organic farming, “Everything organic nursery” under 5 years of organic farming, “Grameen Krishi” under 3 years of transition from conventional to organic, “Gautamshree farm” under 1 years of transition from conventional to organic and “Kuntabeshi farm” under IPM practice as reference. Soil bulk density, moisture content, texture, NPK, CEC and soil organic matter was evaluated in soil samples collected at 0-15 cm. Soil organic matter (5.45%) was highest in Hasera farm, whereas lowest bulk density (1.02gcm-3) was also in Hasera farm. Lowest soil organic matter content was found in Gautamshree farm. Soils of all farms were under loam texture. Soil macronutrients were highest in Grameen Krishi farm. The overall pH value of all soil samples was slightly acidic to acidic.Kathmandu University Journal of Science, Engineering and TechnologyVol. 13, No. 1, 2017, Page: 76-84


2021 ◽  
Author(s):  
Emily Dazé ◽  
Eunji Byun ◽  
Sarah A Finkelstein

Abstract Wetlands that develop peat are a globally significant pool of soil carbon. While some wetland types such as bogs and fens are well characterized by the consistent development of carbon-rich peat, swamps soils are more variable both in terms of their carbon densities and accretion rates. Subcategorizing swamps by forest type may be a useful way of understanding this variability. Here we provide a case study of carbon accumulation in two distinct forest stands of Greenock Swamp located in the Great Lakes – St Lawrence mixed forest region in Bruce County, Ontario, Canada: an Acer - Fraxinus (maple-ash) dominant stand (i.e., broad-leaved swamp) and a Thuja occidentalis (cedar) dominant stand (i.e., needle-leaved swamp). Organic matter and organic carbon contents were analyzed among seven Acer - Fraxinus soil cores and one Thuja occidentalis core collected from Greenock Swamp. The Acer - Fraxinus cores had peat depths ranging from 18-60 cm with a mean organic matter content of 54% and an organic carbon content of 34% of dry mass. The Thuja occidentalis swamp core had at least 4 m of almost homogeneous peat with a mean organic matter content of 89%. Radiocarbon dating indicates that the Acer - Fraxinus swamp accumulates peat episodically whereas the Thuja occidentalis swamp showed continuous peat accumulation since the Middle Holocene. Overall, both broad-leaved and needle-leaved swamps have important soil carbon stocks, and are prevalent wetland types in middle latitudes. Both need to be considered to fully represent the carbon pools and potential sink of temperate wetlands.


2012 ◽  
Vol 518-523 ◽  
pp. 201-204
Author(s):  
Yue Jin Zhang ◽  
Juan Wang

The five surface soil samples were collected in along zhonghuan road of Jiaxing city. According to different solubility in acid and alkali solution, the soil organic matters were divided into different kinds of components such as fulvic acid, humic acid and Humin. Both humic acid and minerals were extracted by sequence and the images were displayed in assistance of scanning electron microscope. Different extraction time and extraction conditions were optimized and the methods were established in the last. Correlations between organic matter content, pH value and contents of HA were fitted and a linear relationship was found between OM and HA. On the help of SEM, different structure of HA and minerals were found that images of HA were columnar and that of mineral were Massive. It is just the reason that why the OM has great sorption ability than the minerals.


2021 ◽  
pp. geochem2021-024
Author(s):  
Yuriy Vodyanitskii ◽  
Tatiana Minkina ◽  
Tatiana Bauer

In recent years, an increase in the input of lanthanides (Ln), an important group of heavy metals (HMs), has been observed in the environment throughout the world (in particular soil). Anthropogenic Ln sources are mainly connected to phosphogypsum, Ln-bearing microfertilizer and micronutrients, and mine waste. Therefore, assessment of hazards associated with the presence of Ln in the soil is an urgent issue. Hazardousness, depending strongly upon the buffer capacity of a specified soil, is determined by the organic matter content, the pH value and other soil properties. For a standard soil (containing 10% organic matter and 25% clay), the discrepancy of the hazardousness of HMs can be estimated based on the maximum permissible concentration (MPC) values proposed by ecologists in the Netherlands. Low levels of Ln contamination in the soil are found, making it possible to classify them in the group of moderately and weakly acting pollutants. The MPC value proposed for cerium (Ce) in the standard soil is 44 mg/kg. Approximate MPC values for several other lanthanides (Ln, Pr, Nd, Sm, Gd and Dy) in soils were proposed based on MPC values for freshwater sediments in the Netherlands. According to the MPC value, Ln falls into the group of moderate- and low-hazardous heavy metals.


2012 ◽  
Vol 50 (No. 3) ◽  
pp. 117-122 ◽  
Author(s):  
T. Włodarczyk ◽  
J. Gliński ◽  
U. Kotowska

Increasing deposition of N-compounds cause environmental problems such as leaching of nitrate or enhanced emission of N<sub>2</sub>O. Most N<sub>2</sub>O is formed from dissimilatory reduction of nitrate in oxygen deficient environment, although it can also be produced from chemolitotrophic and heterotrophic nitrification and assimilatory reduction of nitrate in aerobic conditions. N<sub>2</sub>O production is affected by many physical and biochemical factors, such as: the nature and amount of organic matter available as energy sources to the denitrifiers and heterotrophic nitrifiers, the aeration/moisture status of the soil, the soil nitrate concentration, soil pH, and the soil texture. These factors interact in a complicated manner with microorganisms on a microscale level in the soil, creating the large spatial and temporal variability in denitrification and and influenced on N<sub>2</sub>O/N ratio. The N<sub>2</sub>O emission increased linearly with NO<sub>3</sub><sup>&ndash;</sup> reduction and curvilinearly with organic matter content, dehydrogenase activity and pH value and decreased curvilinearly with oxygen content.


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