• Korean Chemical Engineering Research
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• 제52권1호
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• pp.126-132
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• 2014

본 연구에서는 높은 농도의 염류가 집적된 시설재배지 토양의 제염을 위해 전기동력학적(EK) 기술을 적용한 파일럿 규모($2{\times}3{\times}0.2m^3$, $W{\times}L{\times}D$)의 실증시험을 실시하였다. 실험 전 토양의 전기전도도(EC)는 약 9 dS/m였으며, 토양내 주요 염류는 $Ca^{2+}$, $Cl^-$, $SO_4^{2-}$ 이온이었다. 2주간의 EK 처리 후 토양의 EC는 실험 전에 비해서 52% 감소하였으며, 이 중 대부분은 초기 1주일 이내에 제거되었다(47%). 이는 주로 $Na^+$와 $Cl^-$의 제거에 의한 것으로 보이며, 주요 염류 이자 토양에 대해 높은 흡착능을 가지는 $Ca^{2+}$와 $SO_4^{2-}$이온은 상대적으로 제거율이 낮았다. EK 실험이 진행되는 동안 토양의 온도는 전류의 세기에 따라 증가하여 최대 $50^{\circ}C$까지 증가하였다. 따라서 작물이 재배 중인 토양의 원위치 EK 적용을 위해서는 토양의 온도 상승을 제한하기 위해 전류를 조절할 필요가 있다. 결론적으로 EK 기술을 이용하여 경작 중이거나 휴경 중인 시설재배지 토양의 원위치 염류 제거가 가능할 것으로 판단되며 효율적인 탈염을 위해서는 적절한 운전 전략이 요구된다.

• 한국토양비료학회지
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• 제31권1호
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• pp.9-15
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• 1998

우리나라 시설재배지 토양화학성분 함량을 파악하기 위하여 과채류(果菜類) 350점, 엽채류(葉菜類) 119점, 화분류(花奔類) 44점 계 513점의 토양시료를 전국에서 채취하여 분석한 결과는 다음과 같다. 시설재배지 표토의 토양화학성분 함량의 평균함량은 pH 6.0, 유기물 35g/kg, 유효인산 1.092mg/kg, 전기 전도도 2.94dS/m이고, 치환성칼리, 석회, 고토함략은 각각 1.27, 6.0, 2.Scmol+/kg이며, 질산태질소 함량은 155.1mg/kg이었다. 작물별로는 엽채류(葉菜類) > 과채류(果菜類) > 화분류(花奔類)재배지 순으로 토양화학성분 함량이 많았다. 심토의 토양화학성분 함량은 pH 6.0, 유기물 27g/kg, 유효인산 761mg/kg, 염농도는 1.83dS/m이고. 치환성칼리, 석회, 고토함량은 각각 0.93. 5.3. 1.7cmol+/kg이며, 질산태질소 함량은 93.4mg/kg으로 pH를 제외하고 대부분의 성분들이 표토보다 낮았다. 토양의 화학성이 작물생육에 적정한 범위보다 낮은토양의 분포비율은 pH 46.4% 유효인산 12.7, 치환성칼리 23.4, 치환성석회 29.8, 치환성고토 27.9%, 유기물은 20.7%이었고, 적정범위보다 많은 토양은 pH 26.8% 유효인산 79.9, 치환성칼리 70.6, 치환성석회 52.4, 치환성고토 53.2, 유기물은 54.8%이었다. 토양화학성분들과 전기전도도와의 상관관계에서 상관계수는 질산태질소> 치환성고토> 치환성칼리> 치환성석회 순으로 감소하였다. 시설 재배지 토양화학성분 함량에서 년차의 경과에 따른 변동은 pH,치환성석회, 치환성고토함량은 변동폭이 크지 않았으나, 유기물, 유효인산, 치환성칼리함량은 점차 높아지는 경향이었다.

• 한국토양비료학회지
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• 제49권5호
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• pp.572-576
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• 2016

Soil quality assessment is an important tool for environmental management in an agricultural field. It can be used to evaluate the health of the soils and to establish the basis for sustainable urban agriculture and soil management. For this study, the chemical properties of the soils used for urban agriculture were examined. Results of the soil analysis for chemical properties were applied to soil quality assessment system, which is composed of principal component analysis, application to scoring function and derivation of soil quality index (SQI). Soil pH, electrical conductivity (EC), organic matter (OM), total nitrogen (T-N) were determined for minimum data set (MDS) according to principal component analysis. Based on the results of scoring for four indicators (pH, EC, OM, T-N), soil pH was the indicator that needs the most urgent management. Results of SQI derivation showed that many of the urban farms appeared to be insufficient score in comprehensive soil quality assessment. In conclusion, soil management practices based on scores derived from soil chemical indicators need to be carried out to maintain sustainable urban agricultural soil environment and to provide easy-to-understand information to urban farmers.

• Journal of Ecology and Environment
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• 제46권4호
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• pp.282-291
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• 2022

Background: The Arctic permafrost stores enormous amount of carbon (C), about one third of global C stocks. However, drastically increasing temperature in the Arctic makes the stable frozen C stock vulnerable to microbial decomposition. The released carbon dioxide from permafrost can cause accelerating C feedback to the atmosphere. Soil organic matter (SOM) composition would be the basic information to project the trajectory of C under rapidly changing climate. However, not many studies on SOM characterization have been done compared to quantification of SOM stocks. Thus, the purpose of our study is to determine soil properties and molecular compositions of SOM in four different Arctic regions. We collected soils in different soil layers from 1) Cambridge Bay, Canada, 2) Council, Alaska, USA, 3) Svalbard, Norway, and 4) Zackenberg, Greenland. The basic soil properties were measured, and the molecular composition of SOM was analyzed through pyrolysis-gas chromatography/mass spectrometry (py-GC/MS). Results: The Oi layer of soil in Council, Alaska showed the lowest soil pH and the highest electrical conductivity (EC) and SOM content. All soils in each site showed increasing pH and decreasing SOC and EC values with soil depth. Since the Council site was moist acidic tundra compared to other three dry tundra sites, soil properties were distinct from the others: high SOM and EC, and low pH. Through the py-GC/MS analysis, a total of 117 pyrolysis products were detected from 32 soil samples of four different Arctic soils. The first two-axis of the PCA explained 38% of sample variation. While short- and mid-hydrocarbons were associated with mineral layers, lignins and polysaccharides were linked to organic layers of Alaska and Cambridge Bay soil. Conclusions: We conclude that the py-GC/MS results separated soil samples mainly based on the origin of SOM (plants- or microbially-derived). This molecular characteristics of SOM can play a role of controlling SOM degradation to warming. Thus, it should be further investigated how the SOM molecular characteristics have impacts on SOM dynamics through additional laboratory incubation studies and microbial decomposition measurements in the field.

• 농업과학연구
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• 제49권2호
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• pp.239-247
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• 2022

The physico-chemical properties of agricultural soil are factors that affect crop productivity and soil fertility. In Korea, agricultural environment change surveys have been conducted every four years since 1999. The purpose of this study is to investigate the status and changes in the physico-chemical properties of agricultural soil in Chungcheongnam-do. Samples were collected from the exact location of the aforementioned environment survey, and environmental variables (land use, type of crop cultivated) were investigated in relation to the samples. Soil collection was conducted using a core sampler and a single gouge auger. The bulk density of the soil generally increased up to a depth of sampling of 40 cm but decreased thereafter to a depth of 60 cm. Additionally, the bulk density was highest in the upland soil case and stood at 1.59 g·cm^-3, while the lowest value of 1.52 g·cm^-3 was obtained from orchard soil samples. Conversely, the porosity and moisture gradually decreased at soil depths of 0 - 40 cm and increased at depths of 40 - 60 cm. Most of the soil chemical properties generally decreased with an increase the soil depth from 0 to 70 cm, but electrical conductivity (EC) increased up to a depth of 40 cm. Therefore, it is judged that it is necessary to lower the bulk density by supplying organic matter for agricultural land in Chungcheongnam-do.

• 한국환경복원기술학회지
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• 제18권1호
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• pp.13-23
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• 2015

This study was performed to compare the effects of different drainage layers on tree growth at the exposed sites of Saemangeum sea dike. 4 types of drainage layers including control(dredged soil), specially prepared bark, gravel, and wood chip were set in 150~165cm depth of soil. Pinus thunbergii and Celtis sinensis were planted after 9 months of soil treatment. Electrical conductivity(EC) of soil in all treated plots were decreased under $4dS{\cdot}m^{-1}$, and NaCl(%) was decreased under 0.05% after 1 year from soil treatment. Soil moisture at the 120cm depth of the bark treated plot was higher than that of the 180cm soil depth, below the drainage layer. It is considered that vertical mobility of water was inhibited. Organic matter(OM) at the 120cm soil depth increased at bark and wood chip treated plots. Survival rates after 4 years of P. thunbergii and C. sinensis were 100% in all treatments. The height of P. thunbergii was not significantly different among the treatments while the height of C. sinensis was significantly different among the treatments and it was highest at the bark treated plot.

• 한국지하수토양환경학회지:지하수토양환경
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• 제26권6호
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• pp.27-35
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• 2021

This study examined the possibility of reutilization of soil reclaimed from contaminated sites after completing remediation. The current status of soil remediation methods in Korea was reviewed and physicochemical properties of soil before and after remediation processes were examined to access the recycling possibility of reclaimed soils based on Recycling Aggregate Quality Standard. The most commonly practiced soil remediation techniques are soil washing, land farming, and thermal desorption. These techniques tend to deteriorate various soil properties including electrical conductivity(EC), organic matter content(OM), available P₂O₅, and cation exchange capacity(CEC). Evaluation of the properties of soil retrieved after each remediation process indicated soil washing may yield the most suitable soil for use as a filling, covering, back-filling, road pavement, and blocking materials, In addition, the soils reclaimed from land farming and thermal desorption have potential utility as a filling, covering and road pavement materials.

• 농업과학연구
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• 제50권4호
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• pp.713-721
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• 2023

Soil acidification challenges global food security by adversely influences soil fertility and agricultural productivity. Carbonized agricultural residues present a sustainable and ecofriendly way to recycle agricultural waste and mitigate soil acidification. We evaluated the effects of organic amendments on lettuce growth and soil chemical properties in two soils with different pH levels. Carbonized rice husk was produced at 600℃ for 30 min and rice husk was treated at 1% (w·w^-1). Carbonized rice husk increased soil pH, electrical conductivity, total carbon content, and nitrogen content compared with untreated and rice husk treatments. Furthermore, this study found that lettuce growth positively correlated with soil pH, with increasing soil pH up to pH 6.34 resulting in improved lettuce growth parameters. Statistical correlation analysis also supported the relationship between soil pH and lettuce growth parameters. The study findings showed that the use of carbonized rice husk increased the constituent elements of lettuce, such as carbon, nitrogen, and phosphate content. The potassium content of lettuce followed a similar trend; however, was higher in acidic soil than that in non-acidic soil. Therefore, improving the pH of acidic soil is essential to enhance agricultural productivity. It is considered advantageous to use agricultural residues following pyrolysis to improve soil pH and agricultural productivity.

• 농업과학연구
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• 제46권1호
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• pp.103-111
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• 2019

Gray mold caused by Botrytis cinerea on strawberry plants is an economically significant disease in Korea. The rates for diseased fruits are high during the strawberry harvesting period from December to February, especially in hydroponic cultivation. This study assessed the effect of the nitrogen type in the soil culture and the electrical conductivity (EC) of the nutrient solution in a hydroponic culture on the gray mold incidence in 'Seolhyang' strawberry plants. The nitrogen sources assayed included calcium nitrate tetrahydrate (CN4), calcium nitrate decahydrate (CN10), ammonium sulfate (AS), and commercial fertilizer 213 (213). The effect of the EC was tested at 0.5, 0.8, 1.0, and $1.5dS{\cdot}m^{-1}$. The occurrence of gray mold varied according to the nitrogen type. The disease incidence and nitrogen content for the main nitrogen type were higher compared to the non-treated control. The AS treatment showed the highest occurrence of tipburn and gray mold. The incidence of gray mold as well as the nitrogen and phosphorus content of the leaves increased as the EC level was increased. These results indicate that the incidence of gray mold in strawberry plants is related to the nitrogen content of the leaf and the EC of the nutrient solution.

• 한국토양비료학회지
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• 제47권2호
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• pp.100-106
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• 2014

The present study investigated variations in soil microbial communities by fatty acid methyl ester (FAME) and the chemical properties at 24 sites of upland soils in Gyeongnam Province. The electrical conductivity of the soil under potato cultivation was significantly higher than those of the red pepper and soybean soils (p < 0.05). The gram-negative bacteria community in potato soil was significantly lower than those in the garlic and soybean soils (p < 0.05). The communities of actinomycetes and arbuscular mycorrhizal fungi in the red pepper soil were significantly higher than those in the potato soil (p < 0.05). In addition, the cy17:0 to 16:$1{\omega}7c$ ratio was significantly lower in red pepper, soybean, and garlic soils compared with potato soil, indicating that microbial stress decreased. Consequently, differences in soil microbial community were highly associated with cultivated crop species, and this might be resulted from the difference in soil chemical properties.