• Geomechanics and Engineering
• /
• 제23권2호
• /
• pp.103-113
• /
• 2020

Gypsiferous soils classified as problematic soils due to the dissolution of gypsum. Presence of gypsum in the soils texture subjected to steady flow can cause serious damages for the buildings, roads and water transmission canals. Therefore, researchers have conducted a series of physical, mechanical and microstructural laboratory tests to study the effect of gypsum leaching on the geotechnical properties of a lean clay containing 0%, 3%, 6%, 9%, 12%, and 15% raw gypsum. In addition, a combination of two nano-chemical stabilizers named Terrasil and Zycobond was used in equal proportions to stabilize the gypsiferous clayey samples. The results indicated that gypsum leaching considerably changed the physical and mechanical properties of gypsiferous soils. Further, adding the combination of Terrasil and Zycobond nano-polymeric stabilizers to the gypsiferous soil led to a remarkable reduction in the settlement drop, compressibility, and electrical conductivity (EC) of the water passing through the specimens, resulting in improving the engineering properties of the soil samples. The X-ray diffraction patterns indicate that stabilization by terrasil and zycobond causes formation of new peaks such as CSH and alteration of pure soil structure by adding raw gypsum. Scanning electron microscope (SEM) images show the denser texture of the soil samples due to chemical stabilization and decrease of Si/Al ratio which indicates by Energy dispersive X-ray (EDS) interpretation, proved the enhance of shear strength in stabilized samples.

• 농촌계획
• /
• 제5권2호
• /
• pp.24-29
• /
• 1999

The soil from constructed wetland system for sewage treatment was analyzed to examine physical and chemical characteristics. Clogging and lowered permeability were the physical matters of concern, and nutrient and salt accumulation were the chemical matters of concern. However, the soil properties of the constructed wetland system after 3 year operation demonstrated no degradation and still the soil works almost same as the initial stage. Encouragingly, no sludge accumulation was observed inside the system. Therefore, it implies that the wetland sewage treatment system can work continuously as long as it is operated and managed properly not to cause excessive pollutant loading.

• Journal of Forest and Environmental Science
• /
• 제31권1호
• /
• pp.14-23
• /
• 2015

In this study, we investigated the effects of three land uses on soil properties in two soil layers; surface soil (0~15 cm) and subsoil (15~30 cm). Soil samples were collected from planted forest, barren lands and cultivated lands from different areas in Chittagong Cox's Bazar and analyzed for some physical and chemical properties. Results showed that soil textural class varied from sandy clay loam in planted forest and barren land site to sandy loam in cultivated soils. Maximum water holding capacity was higher in forest followed by barren land and the lowest in cultivated lands. At both soil depths, soils of cultivated land showed the highest values of bulk density (1.42 to $1.50g\;cm^{-3}$), followed by barren lands (1.37 to $1.46g\;cm^{-3}$) and the least (1.32 to $1.45g\;cm^{-3}$) in forest soils. Total porosity decreased with depth ranging from 40.24% to 41.53% in subsoils and from 42.04 to 43.23% in surface soil of cultivated and of planted forest sites respectively. The result further revealed that organic carbon (OC) and total nitrogen (TN) contents were higher in the planted forest soil than in other two land uses. The soils of all land uses under study are acidic in nature and the lowest pH was found in both surface and subsoils of barren land. Cultivated soil contained the highest amount of available P, Ca, Mg and K in both surface soil and subsoils. In contrast, barren site had the lowest contents of available P, Ca, Mg and K in both layers. The soil organic carbon (SOC) and total N storage were higher in planted forest than in barren and cultivated land uses.

• Advances in environmental research
• /
• 제4권3호
• /
• pp.183-196
• /
• 2015

Migration of leachate generated through embankment of construction waste soil (CWS) in low-lying areas was studied through physical and chemical analysis. A leachate solution containing soluble cations from CWS was found to have a pH above 9.0. To determine the distribution coefficients in the alkali solution, column and migration tests were conducted in the laboratory. The physical and chemical properties of CWS satisfied environmental soil criteria; however, the pH was high. The effective diffusion coefficients for CWS ions fell within the range of $0.725-3.3{\times}10^{-6}cm^2/s$. Properties of pore water and the amount of undissolved gas in pore water influenced advection-diffusion behavior. Contaminants migrating from CWS exhibited time-dependent concentration profiles and an advective component of transport. Thus, the transport equations for CWS contaminant concentrations satisfied the differential equations in accordance with Fick's 2nd law. Therefore, the migration of the contaminant plume when the landfilling CWS reaches water table can be predicted based on pH using the effective diffusion coefficient determined in a laboratory test.

• 아시안잔디학회지
• /
• 제5권2호
• /
• pp.81-86
• /
• 1991

The sludge, a waste of brewery industries, was examined for potentials as a natural organic fertilizer (or soil conditioner) for lawn. Trial products were measured for changes of physical, chemical properties in laboratory and seed germination and seedling growth in green house were also tested. The results are as the following:1The sludge from distilled liquor brewery contained high quantity of organic matter which had proper physical and chemical properties for lawn fertilizer (natural organic fertilizer, soil conditioner, top-dressing mix) . It showed good characteristics in handling and capabilities to be developed as commercial products for golf courses. 2.Sludge from beer company needs proper treatment to improve physical properties for futher degradiation. It is because aggregation of the sludge particles prevented microbial activities and changing to soluble form. 3.Green carbon can be used as carbon source for organic fertilizer production using brewery sludge, but it should not contain wood extract which inhibit seed germination and seedling growth.

• 한국토양비료학회지
• /
• 제34권2호
• /
• pp.110-116
• /
• 2001

벼 2모작 재배시 보릿짚시용후 질소시용량별 토양의 이화학적 변화와 수도체의 양분흡수량, 질소이용효율을 조사하기 위하여 2년간('97~'98) 전북통에서 시험한 결과는 다음과 같다. 보릿짚시용으로 경도, 용적밀도, 고상율이 낮아졌고 공극율과 기상율이 증가하여 토양의 물리성이 개선되었다. 보릿짚시용으로 벼 재배후 토양의 pH, OM, T-C, $SiO_2$, K, CEC가 증가한 반면 $P_2O_5$이 감소되었다. 보릿짚시용후 벼 재배시 토양중 $Fe^{+{+}}$함량은 분얼기~유수형성기까지 높은 함량을 보였으나 출수기에는 낮아졌고 $Mn^{+{+}}$함량은 증가되었다. 보릿짚시용시 수도체로의 시비질소 흡수량은 질소시용량 $126kg\;ha^{-1}$ 시용구까지는 증가하였으나 질소 $144kg\;ha^{-1}$ 시용구에서는 감소되었다. 또 질소시용량이 적을수록 보릿짚시용구에서 무시용구보다 시비질소 흡수기간이 길었다. 수도체로의 질소이용율은 분얼기에는 1% 전후였지만 최고분얼기부터 크게 증가하였고 보릿짚시용구에서 낮았다. 수도체로의 인산흡수량은 보릿짚시용구에서 질소시용량에 관계없이 모두 높았으나 칼리함량은 낮았다.

• 한국토양비료학회지
• /
• 제45권1호
• /
• pp.98-102
• /
• 2012

Organic farming has rapidly increased in Gangwon province, but there is a concern about nutrient accumulation and nutrient imbalance in the soil of organic farming. This study was conducted to investigate the impact of continuous application of organic amendments on growth and yield of red pepper and soil characteristics compared with chemical fertilizers application for four years. Treatments of organic amendments including oil cake, rice straw compost, amino acid compost, rice bran compost, and mushroom media (spent substrate) compost resulted in comparable growth and yield of pepper to chemical fertilizers. Organic amendments improved soil physical and chemical characteristics. Especially, rice bran compost and oil cake significantly increased soil organic matter compared with chemical fertilizer application and mushroom media compost and rice straw compost significantly improved soil aggregate stability. On the other hand, available phosphate level in the soil amended with rice bran compost or mushroom media compost was relatively high compared with the other treatments due to relatively high phosphate levels in the composts. It is not easy to adjust nutrient composition in the organic materials. Therefore, the results obtained from the study imply that nutrient imbalance needs to be carefully considered in organic farming without use of chemical fertilizers.

• 환경생물
• /
• 제18권3호
• /
• pp.299-305
• /
• 2000

본 연구는 울릉도 성인봉 주변에 생육하고 있는 너도밤나무군락의 섬조릿대하위군락, 전형하위군락, 일색고사리하위군락에 대한 토양단면 및 토양의 이화학적 특성을 조사하여 울릉도 산림토양의 기초자료를 제공하고, 하위군락별 토양특성의 차이를 조사하기 위해 실시되었다. 하위군락별 토양단면의 형태는 하위군락간에 큰 차이를 보이지 않았다. 하위군락간 토양의 이화학적 요인분석에 있어서 0-10cm 토양 깊이에서 Ca함량에서만 유의적인 차이가 나타났을 뿐, 다른 요인들은 하위군락 간에 큰 차이가 없는 것으로 나타났다. 울릉도 성인봉 주변의 토양특성 중 유기물함량은 0-10cm 토양 깊이에서 평균 21.6%로 매우 높게 나타났으며, 전질소함량도 0-10cm 토양 깊이에서 평균 0.74%로 높게 나타났다. 가비중은 0.43g/cm로 매우 낮게 나타났으며, pH는 평균 4.4로 강한 산성토양의 특성을 나타내어 우리나라의 일반 산림 토양과는 매우 다른 특성을 가지고 있는 것으로 나타났다.

• 아시안잔디학회지
• /
• 제23권2호
• /
• pp.271-278
• /
• 2009

본 연구는 골프장의 상토조성 시 사용되는 토양개량제의 적절한 활용과 이해를 위해 입경과 화학적 특성이 비슷한 무기성 토양개량제의 3종의 혼합비율에 따른 모래상토의 물리 화학적 특성변화를 조사하였다. 토양개량제의 혼합비율에 따라 상토의 물리 화학성을 조사한 결과는 다음과 같다. A와 C가 pH가 95% 수준에서 상관성을 나타내었고, C의 양이온치환용량이 95% 수준에서 상관성을 보여 토양개량제의 특성에 따라 상토의 토양화학성에 영향을 주었다. 상토의 토양물리성 결과를 통해 USGA 기준으로 평가할 때, 최적의 혼합비율은 토양개량제 A와 B에서는 3%였고, C는 7~10% 였다. 각 토양개량제들의 혼합에 따른 토양물리성변화에 가장 큰 영향을 미치는 물리적 요인은 총공극량이었다. 토양개량제의 혼합비율에 따른 토양개선효과 를 비교할 때, B는 모세관공극과 비모세관공극에서, C는 모세관공극, 총공극 및 수리전도 도에서 고도의 상관성을 나타내었다(P<0.05). 이들 결과를 통해 골프코스의 상토조성에 사용되는 무기성 토양개량제는 그 종류와 혼합비율이 USGA 상토의 뿌리층 개량의 토양 이화학성에 영향을 미치고 있음을 알 수 있었다.

• 한국초지조사료학회지
• /
• 제20권2호
• /
• pp.139-146
• /
• 2000

A trial was carried out to investigate the effect of fermented saw-dust pig manure (FSP) and N fertilizer application on physical, chemical properties and microbial population of soil on Cheju brown volcanic ash pasture during the period from September, 1997 to January, 1999. Average soil N contents during 3 different periods, August and October, 1998, and January, 1999 were 0.39, 0.41 and 0.39% for fertilizer N level 0, 150 and 300kg/ha, respectively. Soil N contents determined in January, 1999, was significantly increased by an increase of fertilizer N. Nitrogen contents in the soil applied with 0, 3, 6 and 12 tons 1 ha of FSP were 0.43, 0.40, 0.38 and 0.38%, respectively, showing decreasing tendency of soil with increasing levels of FSP application. Soil N contents determined in August, 1998 and January, 1999, were significantly decreased by increasing levels of FSP application. Organic matter contents of the soil applied with N 0, 150 and 300 kg/ha was 8.04, 8.37, and 9.08%. Soil organic matters determined on the 1st and 2nd period trended to increase with increasing level of fertilizer N. FSP application significantly decreased organic matter contents of pasture soil, (9.14, 8.79, 8.28 and 7.78% OM in soil applied with FSP 0, 3, 6 and 12 tonlha of FSP), respectively. Soil OM determined in October, 1998, also showed a significant decrease with increasing level of FSP. Soil pH, available phosphorus, exchangeable K, Ca, Mg and Na in soil studied were not influenced by fertilizer N or FSP application during all three periods. N application tended to increase soil bacteria count, ($27.0\;{\times}\;10^4\;cfu/g,\;29.4\;{\times}\;1-^4\;cfu/g$ and $53.6\;10^4\;cfu/g$ in the soil applied with 0, 150 and 300 kg N/ha, respectively). The number of colonies of soil bacteria and fungi determined in June and October, 1998 was not increased remarkably by FSP application, but the number of colonies of bacteria determined in March, 1998 showed a significant increase with increasing level of FSP application. In conclusion, N contents and OM of soil increased with increasing level of N application, but decreased with increasing level of FSP application.