• Korean Journal of Soil Science and Fertilizer
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• v.11 no.3
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• pp.145-160
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• 1979

The effects of organic material application on soil physical properties were reviewed in relation to soil productivity. The organic matter contents and soil physical properties of the cultivated land in Korea were summarized and the effects of organic matter were compared in terms of land uses and soil types. Soil physical properties related to crop yield potential, such as soil aggregation, permeability, water holding capacity, erodibility, and compactibility, were used in evaluating the effects of organic materials as a soil physical amendment. The benefical effects of organic matter addition on soil physical conditions include (1) better aeration and increased infiltration in silty and clayey soils, (2) increased water holding capacity and moisture availability in sandy soils, (3) decreased soil erodibility, and (4) increased resistance to compaction. It is, therefore, concluded that continuous application of organic materials could greatly improve the various soil physical properties and favor the growth and yield of crops. A high rate of organic matter addition could contribute to reducing not only the soil erosion on sloping land, but also the possible detrimental effect of farm mechanization. In general, the effects of organic matter on soil physical improvement were estimated to be much higher in upland than in paddy. Organic matter would have a more pronounced effect on low productive lands such as heavy clayey or sandy soils and newly reclaimed soil. The optimum level of soil organic matter content was estimated to be about 3.0 to 3.5% for the best soil physical condition. Since the organic matter contents of the cultivated lands in Korea are much lower than optimum level, it would be desiable to use more organic materials to soil for the increase of soil productivity, continuation of stabilized high productivity and soil erosion control.

• Korean Journal of Soil Science and Fertilizer
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• v.32 no.2
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• pp.95-108
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• 1999

Field experiments were conducted in the 101 tobacco fields(51 fields in 1985 and 50 fields in 1986) of chief tobacco producing counties of Chungbuk province(Jincheon, Eumseong, Goesan, and Joongweon counties), Chungnam province(Cheonweon county), and Kyongbuk province (Cheongdo, Seongju, and Andong counties) for two years from 1985 to 1986 in order to evaluate soil fertility using chemical properties and soil map database. Pot experiments also on the same soils were conducted and the results were compared to those of field experiments. The yield of tobacco in the plots of no fertilization was considered as a basic factor representing the soil fertility and was evaluated by nineteen independent variables, that was 9 chemical properties and 10 soil map databases. These independent variables were classified into two groups, 11 quantitative indexes and 9 qualitative indexes, and were analyzed by multiple linear regression(MLR) of SAS by REG and GLM models. The yield of tobacco in the plot of no fertilization showed high variations, e.g. the difference between minimum and maximum yields was about 5.0-5.5 times in the pot experiment and 8.2-14.9 times in the field experiment. The indexes indicating close link between yield of tobacco and soil chemical indexes, was selected but it was not well matched by the years or between pot and field experiments. Also, the standardized partial regression coefficients of quantitative indexes for the yield of field were less than 1.0, suggesting that it is difficult to develop an available single index for the evaluation of soil fertility. Evaluation for the soil fertility of field by MLR was better than that of single regression and it was gradually improved by adding chemical properties, quantitative indexes, and qualitative indexes of soil map. For example, the coefficient of determination ($R^2$) of MLR for the yield of 1985 was increased to 0.422 with chemical indexes, 0.503 by addition of quantitative indexes, and 0.633 by the additional adding of qualitative indexes of soil map, compared to 0.244 of single index, $NO_3-N$ content of soil. Consequently, it is assumed that this approach by MLR with quantitative and qualitative indexes including chemical properties and soil map databases was available as an evaluation model of soil fertility for tobacco field.

• Proceedings of the Korea Water Resources Association Conference
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• 2021.06a
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• pp.70-70
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• 2021

강수의 변동성 중 특히 가뭄과 홍수의 급격한 연간 변화는 기후변화로 인하여 근래에 많이 발생하고 있다. 가뭄이 발생한 이후 홍수가 발생하거나 그와 반대의 현상이 발생하는 것을 날씨 편달(weather whiplash)라고 한다. 이러한 현상은 토양에 매설되어 수분을 저감하는 배수시설로 인하여 토양 수분 변동 및 무기질소 손실에 지배적은 영향을 준다. 이러한 질소 손실은 부영양화를 일으켜 생태계에 막대한 영향을 미치게 된다. 하지만, 토양 무기질소는 토양에서 체류시간이 길기 때문에 강우 변동성에 의해 발생하는 상호작용을 특정하고 분석하기에는 많은 어려움이 따른다. 이 문제를 해결하고자 이번 연구에서는 생태수문모형과 생물지질모형을 결함한 3차원 모델인 Dhara를 이용하여 토양 배수시설에서 유출되는 무기 질소의 농도 및 나이를 분석하였다. 여기서 나이란 화합물이 발생 하여 다른 형태로 변화하는데 걸리는 시간을 의미한다. 집중적으로 관리되는 경작지에 Dhara 모형을 적용하여 본 연구를 수행하였다. 토양 수분과 질소의 나이를 분석한 결과 반응 화합물인 질소의 경우 토양 수분(비반응 화합물)과 비교하여 이전의 강우상태에 많은 영향을 받는 것으로 분석이 되었다. 가뭄이후 홍수가 발생할 때 배수시설에서 발생하는 질소의 유출이 그 반대 기상 환경인 홍수 이후 가뭄이 발생할 때 보다 더 많이 발생한 것으로 나타났다. 하지만 배수 흐름의 경우 질소의 거동과 반대하는 현상을 보였다. 이러한 결과는 질소유출 저감하여 강 및 바다에서 부영양화를 감소하기 위해 강수의 변동성과 연계하여 분석한다면 새로운 질소유출 저감 대책을 수립할 수 있는 가능성을 보여주었다.

• Journal of the Korean GEO-environmental Society
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• v.11 no.2
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• pp.5-11
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• 2010

Abandoned mines release acid mine drainage and cause the contamination of soil and crops around the mine area. The objective of current study is to evaluate effect of mine on the soil and crop contamination. Soils, water, and crops were collected and analyzed, and the heavy metal data were classified into types of the soil, types of crops, and distance from the minehead. Surface soils of the mine area were highly contaminated with heavy metals, especially with zinc and lead. Tailings and cultivated paddy soils were also highly contaminated. Heavy metal concentrations upon distance from minehead decrease steadily as the distance from the minehead increase. The correlation between heavy metals was extracted from soils and the content in the rice samples showed a positive relation for arsenic and cadmium but not a meaningful relation for other metals.

• Korean Journal of Remote Sensing
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• v.19 no.2
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• pp.107-115
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• 2003

This research investigated the 2001 spring drought on croplands in South Korea using satellite imagery. South Korea has suffered from spring droughts almost every year. Meteorological indices have been used for monitoring droughts, however they don't tell the local severity of drought. Therefore, this research aimed at detecting the local, spatial pattern of drought severity at a cropland level. This research analyzed the agricultural drought using the wetness of remotely sensed pixels that affects the growth of early crops significantly in the spring. This research, specifically, analyzed the spatial distribution and severity of drought using the tasseled cap transformation and topographical factors. The wetness index from the tasseled cap transformation of Landsat 7 ETM/sub ＋/ imagery was very useful for detecting the 2001 spring drought susceptibility in agricultural croplands. Especially, the wetness values smaller than -0.2 were identified as the croplands that were suffering from serious water deficit. Using the water deficit pixels, drought severity was modeled finally.

• Economic and Environmental Geology
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• v.38 no.3 s.172
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• pp.207-219
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• 2005

The physical and chemical characteristics of soils in a small watershed were investigated and the effect of geology and land use on soil quality were examined by using multivariate statistical methods, principal components analysis and discriminant analysis. The soil developed from andesite had finer texture and higher contents of water extractable inorganic components, clay, and mafic minerals than the soil developed from granite. It is considered that the accumulation of salts in the farmland soils indicated by electrical conductivity, contents of cations and anions and pH was caused by fertilizer input during cultivation. The low contents of organic matter in the farmland soils was due to the enhanced oxidation of organic matter by tillage and by the harvest of crops. The contents of inorganic components are increased as following order: upland > orchard > paddy field > forest. The high contents of water soluble $SO_4\;^{2-}$ of paddy soils is due to the oxidation of sulfides mineral formed during the flooding period during the air-dry and extraction. The results of principal components analysis show the difference of soil quality was controlled by geology and land use. PCI indicate the input of fertilizer, mineral weathering and ion exchange reaction by application of nitrogenous fertilizers. The results of two discriminant analyses using water extractable inorganic components and their ratios by land use were also clearly classified by discriminant function 1 and 2. In discriminant analysis by components, discriminant function 1 indicated the effect of fertilizer application and increased as following order: upland > orchard > paddy field > forest soil. The investigated and predicted data for land use from discriminant analysis showed similar results. The discriminant analysis can be used as a useful method certifying the change of land use.

• Proceedings of the Korea Water Resources Association Conference
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• 2010.05a
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• pp.1486-1490
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• 2010

본 연구는 강원도 횡성군의 남한강 제1지류인 섬강의 횡성댐 상류 계천에 위치한 시험유역으로 남한강 상류 산지지형 시험유역으로 이유역의 운영을 통하여 신뢰성 있는 고품질의 산간유역 수문자료의 지속적 확보이다. 2001년부터 10년 동안 시험유역이 운영되어오면서 강우관측소 3곳, 수위 관측소 3곳(농거리, 매일, 소군), 지하수 및 토양수분 측정소 5곳의 자료를 구축하고 있다. 유역의 토양 이용 현황은 삼림이 90 %, 경작지 10 %로 이루어져 있으며, 면적 $164.81km^2$, 유로연장 22.4km, 평균경사 5.97%를 지니고 있다. 고품질을 보장하고 좋은 데이터를 얻기 위하여 불확실도 분석을 실시하고, 개발된 수위-유량곡선을 통하여 시계열 수위를 유량으로 환산하였다. 아울러 수문순환 성분의 분석을 위하여 토양수분 및 지하수위를 측정하여 강우-유출해석, 수문특성 분석 등을 실시하였다. 측정된 자료는 웹사이트와 CD로 제공된다. 구축된 각종 자료는 수문 및 수리의 정량적 순환구조의 이해와 모델개발의 검정 및 검증 기반의 자료를 구축하여 산간유역의 폭 넓은 물 순환해석을 위한 기초자료로 활용될 것이다.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2001.11a
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• pp.71-73
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• 2001

W3와 W4는 질산성 질소의 농도가 자연 토양의 농도 범위에 있고 질산성 질소의 기여율도 토양이 각각 찔.8과 75%로 질산성 질소에 의한 오염이 없다고 볼 수 있다. Sl의 경우 토지 이용이 주거지와 상류에 밭 경작지가 있어서 생활 하수와 화학비료의 영향을 받고 있음을 알 수 있다. S2와 W6의 경우는 생활 하수와 화학비료의 영향이 48.1%와 48.2%로 거의 유사하게 영향을 주고 있음을 알 수 있다. Wl, W2 그리고 W7은 각각 73.2%, 82.7% 그리고 48.8%의 화학비료의 기여율로 보아 주로 화학비료의 영향을 받고 있다고 사료된다.

• The Korean Journal of Mycology
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• v.2 no.1
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• pp.15-19
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• 1974

A severe ginseng root rot disease was occurred and became widespraed in 1973 affecting the ginseng cultivating plot around Kangwha and Gimpo-Gun of Kyunggi province. Soil samples were collected from the area of Wolgot-Myun, Gimpo-Gun, Kuunggi-Do, 1974. We examined general fungi and Fusarium sp. in soil layers and also in different kinds of soil of respective diseased, uncultivated and healthy areas, and found the following results. 1. In the diseased and uncultivated area, the content of moisture, organic matter and silt was greater than in the healthy area. 2. Contray to the above, the healthy area contained a greater amount of inorganic elements such as $P_2O_5$, K,Ca and of soil particle such as Cs and Fs. The degree of pH and content of Mg were even in the three types of soils. 3. General fungi were found in abundance in the diseased and uncultivated soils. It was observed that in all types of areas, general fungi reside in abundance in the rhizosphere, i.e., 10-15cm layers and that the closer the surface, the greater the numbers of fungi. 4. A great number of Fusarium sp. was found in the uncultivated area, and followed diseased and healthy areas. It was observed that in all types of areas, Fusarium sp. distributed in abundance in rhizosphere and that the closer the surface, the greater the numbers of Fusarium sp., with the numbers decreasing as the soil layers increase.

• Journal of Korean Society of Environmental Engineers
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• v.36 no.1
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• pp.13-19
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• 2014

The management of non point sources was marked by the need for clean water environments. It was proposed the fundamentals to promote the reasonable land management in this study. We monitored rainfall events at two non point sources with different crop cultivations such as a sweet potato and a cherry tree for three years. Because the most important factor was rainfall, the rainfall runoff and pollutant loads were generated 100% in the case of rainfall ranges with 50 < rainfall (mm). However the frequency of rainfall runoff was interacted with the crop cultivation and soil characteristics in the case of rainfall ranges such as 30 < rainfall (mm) ${\leq}50^a$ and 10 < rainfall (mm) ${\leq}30^b$. The frequency of rainfall runoff was a : 60% and b : 5% in the cherry tree cultivation with growing significantly and pollutant loads were lower than that of the sweet potato cultivation. Meanwhile the frequency of rainfall runoff was a : 60% and b : 5% in the sweet potato cultivation.