The sorption-desorption behavior of dicyandiamide (DCD) is an important chemical process that affects DCD fate and mobility in soils. Therefore, this study quantified DCD sorption-desorption on a phaeozem (Mollisol), ...The sorption-desorption behavior of dicyandiamide (DCD) is an important chemical process that affects DCD fate and mobility in soils. Therefore, this study quantified DCD sorption-desorption on a phaeozem (Mollisol), a burozem (Alfisol), a soil with organic matter-removed and peat humus using the batch-equilibration procedure, and identified soil properties that influenced DCD sorption. The sorption on peat humus was higher than that on the phaeozem and the burozem, with much lower sorption observed on the soil with organic matter-removed, indicating that soil organic matter was the main carrier of DCD sorption. Due to its amphipathic property the DCD molecule sorption on the phaeozem and the burozem decreased as pH increased from about 2 to 5, but a further increase in pH led to a rise in DCD sorption.The DCD desorption hysteretic effect for peat humus was greater than that for the phaeozem and the burozem using 0.01 mol L-1 CaC12 as the background electrolyte, suggesting that the hydrophobic domains of organic matter may play an important role in DCD sorption.展开更多
In this study, tropical peat swamp soils from Giam Siak Kecil-Bukit Batu Biosphere Reserve (GSKBB) in Indonesia was evaluated to assess the impact of oil palm and rubber plantations on this unique organic soil through...In this study, tropical peat swamp soils from Giam Siak Kecil-Bukit Batu Biosphere Reserve (GSKBB) in Indonesia was evaluated to assess the impact of oil palm and rubber plantations on this unique organic soil through comparisons with soils from a natural forest using a polyphasic approach (chemical and molecular microbial assays). Changes in the ammonium, nitrate and phosphate concentration were observed in soils converted to agricultural use. Soil enzyme activities in plantation soils showed reduced β-glucosidase, cellobiohydrolase and acid phosphatase activities (50% - 55% decrease). PCR-DGGE based analysis showed that the soil bacterial community from agricultural soils exhibited the lowest similarity amongst the different microbial groups (fungi and Archaea) evaluated (34% similarity to the natural forest soil). Shannon Diversity index values showed that generally the conversion of tropical peatland natural forest to rubber plantation resulted in a greater impact on microbial diversity (ANOVA p < 0.05). Overall, this study indicated substantial shifts in the soil microbial activity and diversity upon conversion of natural peatland forest to agriculture, with a greater change being observed under rubber plantation compared to oil palm plantation. These findings provided important data for future peatland management by relating changes in the soil microbial community and activities associated to agricultural practices carried out on peatland.展开更多
We explored the potential use of combining wavelength-dispersive X-ray spectroscopy(WDX) and micromorphology of thin sections to identify minerals in peat soils. Peat soil minerals from three peats and swamps across G...We explored the potential use of combining wavelength-dispersive X-ray spectroscopy(WDX) and micromorphology of thin sections to identify minerals in peat soils. Peat soil minerals from three peats and swamps across Golestan Province in northern Iran were first characterized by micromorphological studies. Soils were composed mainly of quartz, muscovite, biotite, pyroxene,sericitized Fe-nodules, and iron-rich garnet. In addition,micromorphological results indicated that Galougah Coastal Swamp sections contained some inorganic residue with biological origin including oyster and limpet, which may be related to the swamp's location near Gorgan Gulf.In order to determine mineralogical properties of samples,twelve unknown grains were chosen for elemental concentration map studies. Quartz, garnet, ilmenite, calcite,and pyroxene in Suteh samples; epidote and Fe-nodule in Ghaleh-Ghafeh Peat Swamp; and barite, phyllosilicates,and calcite in Galougah were identified by WDX mapping of Si, Al, Fe, Ca, Mg, C, Ba, S, and Ti. Composition of the oysters' body was also analyzed by WDX for Si, Ca, Fe,and C. The results indicated that most of the minerals in all sections likely formed through weathering, inheriting their composition from the parent rock. This research suggests that merging micromorphology and SEM/WDX image techniques can be useful in confirming the presence of mineral particles in soil science.展开更多
A comprehensive<em> in vitro</em> study on single and sequential extraction methods for Cu exraction by different extractants of distinct chemical nature from some peat soils of Bangladesh was conducted to...A comprehensive<em> in vitro</em> study on single and sequential extraction methods for Cu exraction by different extractants of distinct chemical nature from some peat soils of Bangladesh was conducted to assess the pattern of metal-extractability in drying and wetting sequences. Samples were collected from peat basins of two different districts of Bangladesh (Gopalgonj and Bagerhat) and an incubation study was designed and conducted in which soils were incubated to three alternate drying and wetting cycles for 21 days. Single and sequentially extracted Cu ions in all three cycles and by all three selective extractants were compared. Maximum amount of Cu was extracted in drying days and 1M HCl extracted the largest proportion of Cu from all the soils in each incubation time. Conversely, 1M NH<sub>4</sub>Cl was the least effective extractant for extracting Cu by both single and sequential process in either day of incubation. Considerable amount of Cu was extracted by 0.005 M DTPA in dry periods. In general, single extraction was found to be more effective in extracting Cu in the alternate drying and wetting cycles from the peat soil samples except for 1M HCl in initial drying days.展开更多
Soil carbon is one of the essential elements for soil quality, holding soil nutrients for plant uptake, soil conservation, and overall the natural soil systems that are the fundamental requirements for the soil securi...Soil carbon is one of the essential elements for soil quality, holding soil nutrients for plant uptake, soil conservation, and overall the natural soil systems that are the fundamental requirements for the soil security, and food production. Moreover, Peat soils are the vital storehouses of organic carbon where there is a scope to use this carbon for mitigating climate change. In this study, we consider three major soil series of peat soils in Bangladesh: sapric peat, hemic peat, and fabric peat. Single study on the estimation of organic carbon stocks in the peat soils of Bangladesh was conducted in the 1970s. For understanding the carbon emission, we conducted the same peat soils up to 100 cm depths. The research shows that the organic carbon in peat soils in Bangladesh was about 0.12 Pg in 2018 whereas it was about 0.25 Pg during the 1970s. So, it has observed that soil organic carbon loss is alarming in the tropical country like Bangladesh and the half of the total organic carbon has already reduced by the last 50 years. These reduced carbons have huge impact on climate change and global warming. It has also found that the carbon storage percentage is higher with the increasing soil profile depth from the soil surface. So, the management should be considered not only the surface soils but also the sub-surface soils. Another relationship found between the bulk density and carbon storage is inversely proportional (r = −0.65) in the peats soils. These peat soils are losing their carbon due to the decrease of inundation level by climate change, intensive agricultural and even used as fuel for cooking purposes by the local stakeholders. There were no regulations, maintenances, laws, even the evaluation and assessment of carbon storage was not appropriately estimated in Bangladesh. By representing the carbon percentage data and their changes over times will help to develop and implement the proper mitigation action which may improve soil health, soil quality, food security, and mitigation of climate changes.展开更多
The Hula Valley was drained in 1957. The land use was modified from natural wetland and old shallow lake ecosystems to agricultural development. About half of the drained land area was utilized for aquaculture. Popula...The Hula Valley was drained in 1957. The land use was modified from natural wetland and old shallow lake ecosystems to agricultural development. About half of the drained land area was utilized for aquaculture. Population size was enhanced and the diary was developed intensively resulting in the enhancement of domestic and husbandry sewage production that increased as well. The natural intact Hula Valley-Lake Kinneret ecosystem was heavily anthropogenically interrupted: The Hula was drained and Kinneret became a national source for domestic water supply. Some aspects of the environmental and water quality protection policy of the system are presented. The causation and operational management implications for the reduction of Nitrogen and Phosphorus migration from the Hula Valley are discussed. Drastic (81%) restriction of aquaculture accompanied by sewage totally removed achieved a reasonable improvement in pollution control which was also supported by the Hula Project. The implications of anthropogenic intervention in the process of environmental management design are presented.展开更多
Wetland stores substantial amount of carbon and may contribute greatly to global climate change debate. However, few researches have focused on the effects of global climate change on carbon mineralization in Zoig...Wetland stores substantial amount of carbon and may contribute greatly to global climate change debate. However, few researches have focused on the effects of global climate change on carbon mineralization in Zoigê al-pine wetland, Qinghai-Tibet Plateau, which is one of the most important peatlands in China. Through incubation ex-periment, this paper studied the effects of temperature, soil moisture, soil type (marsh soil and peat soil) and their in-teractions on CO2 and CH4 emission rates in Zoigê alpine wetland. Results show that when the temperature rises from 5℃ to 35℃, CO2 emission rates increase by 3.3-3.7 times and 2.4-2.6 times under non-inundation treatment, and by 2.2-2.3 times and 4.1-4.3 times under inundation treatment in marsh soil and peat soil, respectively. Compared with non-inundation treatment, CO2 emission rates decrease by 6%-44%, 20%-60% in marsh soil and peat soil, respec-tively, under inundation treatment. CO2 emission rate is significantly affected by the combined effects of the tempera-ture and soil type (p < 0.001), and soil moisture and soil type (p < 0.001), and CH4 emission rate was significantly af-fected by the interaction of the temperature and soil moisture (p < 0.001). Q10 values for CO2 emission rate are higher at the range of 5℃-25℃ than 25℃-35℃, indicating that carbon mineralization is more sensitive at low temperature in Zoigê alpine wetland.展开更多
Field surveys indicate lateral variation in peat humification levels （von Post） in dominantly occurring fibric,fibric to hemic,sapric and hemie to sapric peats across a gradient from the margin towards the centre of...Field surveys indicate lateral variation in peat humification levels （von Post） in dominantly occurring fibric,fibric to hemic,sapric and hemie to sapric peats across a gradient from the margin towards the centre of tropical lowland peat domes.Cement-peat stabilisation can be enhanced by adding mineral soil fillers （silt,clays and fine sands） obtained from Quaternary floodplain deposits and residual soil （weathered schist）.The unconfined compressive strength （UCS） of the stabilised cement-mineral soil fifler-peat mix increases with the increased addition of selected mineral soil filler.Lateral variation in the stabilised peat strength （UCS） in the top 0 to 0.5 m layer was found from the margin towards the centre of the tropical lowland peat dome.The variations in the UCS of stabilised tropical lowland peats along a gradient from the periphery towards the centre of the peat dome are most likely caused by a combination of factors due to variations in the mineral soil or ash content of the peat and horizontal zonation or lateral variation in the dominant species of the plant assemblages （due to successive vegetation zonation of the peat swamp forest from the periphery towards the centre of the tropical lowland peat dome）.展开更多
基金Project supported by the National High Technology Research and Development Program of China (863 Program) (No. 2004AA246020) the National Natural Science Foundation for Distinguished Young Scholars, China(No. 20225722).
文摘The sorption-desorption behavior of dicyandiamide (DCD) is an important chemical process that affects DCD fate and mobility in soils. Therefore, this study quantified DCD sorption-desorption on a phaeozem (Mollisol), a burozem (Alfisol), a soil with organic matter-removed and peat humus using the batch-equilibration procedure, and identified soil properties that influenced DCD sorption. The sorption on peat humus was higher than that on the phaeozem and the burozem, with much lower sorption observed on the soil with organic matter-removed, indicating that soil organic matter was the main carrier of DCD sorption. Due to its amphipathic property the DCD molecule sorption on the phaeozem and the burozem decreased as pH increased from about 2 to 5, but a further increase in pH led to a rise in DCD sorption.The DCD desorption hysteretic effect for peat humus was greater than that for the phaeozem and the burozem using 0.01 mol L-1 CaC12 as the background electrolyte, suggesting that the hydrophobic domains of organic matter may play an important role in DCD sorption.
文摘In this study, tropical peat swamp soils from Giam Siak Kecil-Bukit Batu Biosphere Reserve (GSKBB) in Indonesia was evaluated to assess the impact of oil palm and rubber plantations on this unique organic soil through comparisons with soils from a natural forest using a polyphasic approach (chemical and molecular microbial assays). Changes in the ammonium, nitrate and phosphate concentration were observed in soils converted to agricultural use. Soil enzyme activities in plantation soils showed reduced β-glucosidase, cellobiohydrolase and acid phosphatase activities (50% - 55% decrease). PCR-DGGE based analysis showed that the soil bacterial community from agricultural soils exhibited the lowest similarity amongst the different microbial groups (fungi and Archaea) evaluated (34% similarity to the natural forest soil). Shannon Diversity index values showed that generally the conversion of tropical peatland natural forest to rubber plantation resulted in a greater impact on microbial diversity (ANOVA p < 0.05). Overall, this study indicated substantial shifts in the soil microbial activity and diversity upon conversion of natural peatland forest to agriculture, with a greater change being observed under rubber plantation compared to oil palm plantation. These findings provided important data for future peatland management by relating changes in the soil microbial community and activities associated to agricultural practices carried out on peatland.
文摘We explored the potential use of combining wavelength-dispersive X-ray spectroscopy(WDX) and micromorphology of thin sections to identify minerals in peat soils. Peat soil minerals from three peats and swamps across Golestan Province in northern Iran were first characterized by micromorphological studies. Soils were composed mainly of quartz, muscovite, biotite, pyroxene,sericitized Fe-nodules, and iron-rich garnet. In addition,micromorphological results indicated that Galougah Coastal Swamp sections contained some inorganic residue with biological origin including oyster and limpet, which may be related to the swamp's location near Gorgan Gulf.In order to determine mineralogical properties of samples,twelve unknown grains were chosen for elemental concentration map studies. Quartz, garnet, ilmenite, calcite,and pyroxene in Suteh samples; epidote and Fe-nodule in Ghaleh-Ghafeh Peat Swamp; and barite, phyllosilicates,and calcite in Galougah were identified by WDX mapping of Si, Al, Fe, Ca, Mg, C, Ba, S, and Ti. Composition of the oysters' body was also analyzed by WDX for Si, Ca, Fe,and C. The results indicated that most of the minerals in all sections likely formed through weathering, inheriting their composition from the parent rock. This research suggests that merging micromorphology and SEM/WDX image techniques can be useful in confirming the presence of mineral particles in soil science.
文摘A comprehensive<em> in vitro</em> study on single and sequential extraction methods for Cu exraction by different extractants of distinct chemical nature from some peat soils of Bangladesh was conducted to assess the pattern of metal-extractability in drying and wetting sequences. Samples were collected from peat basins of two different districts of Bangladesh (Gopalgonj and Bagerhat) and an incubation study was designed and conducted in which soils were incubated to three alternate drying and wetting cycles for 21 days. Single and sequentially extracted Cu ions in all three cycles and by all three selective extractants were compared. Maximum amount of Cu was extracted in drying days and 1M HCl extracted the largest proportion of Cu from all the soils in each incubation time. Conversely, 1M NH<sub>4</sub>Cl was the least effective extractant for extracting Cu by both single and sequential process in either day of incubation. Considerable amount of Cu was extracted by 0.005 M DTPA in dry periods. In general, single extraction was found to be more effective in extracting Cu in the alternate drying and wetting cycles from the peat soil samples except for 1M HCl in initial drying days.
文摘Soil carbon is one of the essential elements for soil quality, holding soil nutrients for plant uptake, soil conservation, and overall the natural soil systems that are the fundamental requirements for the soil security, and food production. Moreover, Peat soils are the vital storehouses of organic carbon where there is a scope to use this carbon for mitigating climate change. In this study, we consider three major soil series of peat soils in Bangladesh: sapric peat, hemic peat, and fabric peat. Single study on the estimation of organic carbon stocks in the peat soils of Bangladesh was conducted in the 1970s. For understanding the carbon emission, we conducted the same peat soils up to 100 cm depths. The research shows that the organic carbon in peat soils in Bangladesh was about 0.12 Pg in 2018 whereas it was about 0.25 Pg during the 1970s. So, it has observed that soil organic carbon loss is alarming in the tropical country like Bangladesh and the half of the total organic carbon has already reduced by the last 50 years. These reduced carbons have huge impact on climate change and global warming. It has also found that the carbon storage percentage is higher with the increasing soil profile depth from the soil surface. So, the management should be considered not only the surface soils but also the sub-surface soils. Another relationship found between the bulk density and carbon storage is inversely proportional (r = −0.65) in the peats soils. These peat soils are losing their carbon due to the decrease of inundation level by climate change, intensive agricultural and even used as fuel for cooking purposes by the local stakeholders. There were no regulations, maintenances, laws, even the evaluation and assessment of carbon storage was not appropriately estimated in Bangladesh. By representing the carbon percentage data and their changes over times will help to develop and implement the proper mitigation action which may improve soil health, soil quality, food security, and mitigation of climate changes.
文摘The Hula Valley was drained in 1957. The land use was modified from natural wetland and old shallow lake ecosystems to agricultural development. About half of the drained land area was utilized for aquaculture. Population size was enhanced and the diary was developed intensively resulting in the enhancement of domestic and husbandry sewage production that increased as well. The natural intact Hula Valley-Lake Kinneret ecosystem was heavily anthropogenically interrupted: The Hula was drained and Kinneret became a national source for domestic water supply. Some aspects of the environmental and water quality protection policy of the system are presented. The causation and operational management implications for the reduction of Nitrogen and Phosphorus migration from the Hula Valley are discussed. Drastic (81%) restriction of aquaculture accompanied by sewage totally removed achieved a reasonable improvement in pollution control which was also supported by the Hula Project. The implications of anthropogenic intervention in the process of environmental management design are presented.
基金Under the auspices of Fundamental Research Funds for the Central Universities (No. BLYX200932)National Natural Science Foundation of China (No. 30700108, 41071329)Forestry Commonweal Program (No. 200804005)
文摘Wetland stores substantial amount of carbon and may contribute greatly to global climate change debate. However, few researches have focused on the effects of global climate change on carbon mineralization in Zoigê al-pine wetland, Qinghai-Tibet Plateau, which is one of the most important peatlands in China. Through incubation ex-periment, this paper studied the effects of temperature, soil moisture, soil type (marsh soil and peat soil) and their in-teractions on CO2 and CH4 emission rates in Zoigê alpine wetland. Results show that when the temperature rises from 5℃ to 35℃, CO2 emission rates increase by 3.3-3.7 times and 2.4-2.6 times under non-inundation treatment, and by 2.2-2.3 times and 4.1-4.3 times under inundation treatment in marsh soil and peat soil, respectively. Compared with non-inundation treatment, CO2 emission rates decrease by 6%-44%, 20%-60% in marsh soil and peat soil, respec-tively, under inundation treatment. CO2 emission rate is significantly affected by the combined effects of the tempera-ture and soil type (p < 0.001), and soil moisture and soil type (p < 0.001), and CH4 emission rate was significantly af-fected by the interaction of the temperature and soil moisture (p < 0.001). Q10 values for CO2 emission rate are higher at the range of 5℃-25℃ than 25℃-35℃, indicating that carbon mineralization is more sensitive at low temperature in Zoigê alpine wetland.
基金the IPPP grant PV018-2011A for financial support from the University of Malaya
文摘Field surveys indicate lateral variation in peat humification levels （von Post） in dominantly occurring fibric,fibric to hemic,sapric and hemie to sapric peats across a gradient from the margin towards the centre of tropical lowland peat domes.Cement-peat stabilisation can be enhanced by adding mineral soil fillers （silt,clays and fine sands） obtained from Quaternary floodplain deposits and residual soil （weathered schist）.The unconfined compressive strength （UCS） of the stabilised cement-mineral soil fifler-peat mix increases with the increased addition of selected mineral soil filler.Lateral variation in the stabilised peat strength （UCS） in the top 0 to 0.5 m layer was found from the margin towards the centre of the tropical lowland peat dome.The variations in the UCS of stabilised tropical lowland peats along a gradient from the periphery towards the centre of the peat dome are most likely caused by a combination of factors due to variations in the mineral soil or ash content of the peat and horizontal zonation or lateral variation in the dominant species of the plant assemblages （due to successive vegetation zonation of the peat swamp forest from the periphery towards the centre of the tropical lowland peat dome）.
