• Journal of The Korean Society of Agricultural Engineers
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• v.48 no.2
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• pp.59-66
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• 2006

This study is performed to evaluate freezing and thawing properties of polypropylene fiber reinforced eco-concrete using soil, natural coarse aggregate, soil compound and polypropylene fiber. The mass loss ratio is decreased with increasing the content of natural coarse aggregate and soil compound, but it is increased with increasing the content of polypropylene fiber. The ultrasonic pulse velocity, dynamic modulus of elasticity and durability factor are increased with increasing the content of natural coarse aggregate and soil compound, but it is decreased with increasing the content of polypropylene fiber. The mass loss ratio, ultrasonic pulse velocity, dynamic modulus of elasticity and durability factor are $1.49{\sim}3.32%,\;1,870{\sim}2,465\;m/s,\;77X10^2{\sim}225X10^2\;MPa\;and\;84.6{\sim}92.8$ after freezing and thawing 300 cycles, respectively. These eco-concrete can be used for environment-friendly side walk and farm road.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.3
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• pp.361-367
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• 2011

Soil fertility of alpine soils in Gangwon-Do has been deteriorating because of heavy input of chemical fertilizers for intensive crop production. To reduce application of chemical fertilizers, use of livestock manure compost in alpine soils increases consistently. Soil loss and runoff due to heavy rainfall in alpine area cause nutrient loss from soil, and subsequently pollute stream water. Therefore, the objective of this study was to assess nutrient efficiency and loss in Chinese cabbage cultivated soil with different livestock manure composts in several slopes. As control, chemical fertilizer was applied at the rate of $250-78-168kg\;ha^{-1}$ for $N-P_2O_5-K_2O$. Each pig-and chicken manure compost was applied at the rate of $10MT\;ha^{-1}$. Chemical fertilizer + chicken manure compost was applied as same rate. Four treatments was practiced in 5, 20, and 35% filed slopes, respectively. We monitored the amounts of soil loss and runoff water after rainfalls, and we also analyzed the contents of nutrients in soil and runoff water through lysimeter installed in alpine agricultural institute in Gangwon-Do. T-N loss due to soil loss was much greater with increasing filed slops rather than different fertilizer treatments. T-N loss has positive relationship with field slopes, which showing soil loss (MT/ha) = 1.66 slopes (%) - 3.5 ($r^2$ = 0.99). Available phosphate and exchangeable cations showed similar tendency with increasing slopes. T-N and T-P losses caused by runoff water were highest in chemical fertilizer (NPK) + chicken manure compost treated plot, while lowest in chemical fertilizer treatment. T-N contents (2.13, 1.95%) in chinese cabbage treated either pig and chicken manure composts compared to that (2.65%) of chemical fertilizer were significantly less. This could be resulted from much greater T-N loss in soil treated with pig and chicken manure composts.

• Korean Journal of Soil Science and Fertilizer
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• v.38 no.2
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• pp.59-65
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• 2005

This study was performed to estimate the soil loss on a national scale and grade regions with the potential risk of soil erosion. Universal soil loss equation (USLE) for rainfall and runoff erosivity factors (R), cover management factors (C) and support practice factors (P) and revised USLE for soil erodibility factors (K) and topographic factors (LS) were used. To estimate the soil loss, the whole nation was divided into 21,337 groups according to city county, soil phase and land use type. The R factors were high in the southern coast of Gyeongnam and Jeonnam and part of the western coast of Gyeonggi and low in the inland and eastern coast of Gyeongbuk. The K factors were higher in the regions located on the lower streams of rivers and the plain lands of the western coast of Chungnam and Jeonbuk. The average slope of upland areas in Pyeongchang-gun was the steepest of 30.1%. The foot-slope areas from the Taebaek Mountains to the Sobaek Mountains had steep uplands. Total soil loss of Korea was estimated as $50{\times}10^6Mg$ in 2004. The potential risk of soil erosion in upland was the severest in Gyeongnam and the amount of soil erosion was the greatest in Jeonnam. The regions in which annual soil loss was estimated over $50Mg\;ha^{-1}$ were graded as "the very severe" and their acreage was $168{\times}10^3ha$ in 2004. The soil erosion maps of city/county of Korea were made based on digital soil maps with 1:25,000 scale.

• Korean Journal of Soil Science and Fertilizer
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• v.33 no.6
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• pp.432-445
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• 2000

The objective of this study was to determine the effects of various kinds of composts on the change of nutrition loss in upland soils. Field experiments were conducted in the loam and sandy loam soils, while the clay loam and sandy loam soils were used for laboratory experiments. Various kinds of composts such as poultry manure compost(PMC), cow manure compost(CMC), human excrement sludge(HES), and food industrial sludge compost(FISC) were applied annually at rates of 0, 40, and $80mg\;ha^{-1}$ to soils grown with soybean and maize plants for 4 years during 1994 to 1997. The results of this study were as follows : The loss of nutrients in the form of cation and anion by run-off water increased with the increase of compost application rate. Compared with bare soils, maize cultivation decreased the nutrient loss by run-off from soils by 43% in anionic form and 32% in cationic form. Amount of cation loss were ordered $K^+$ > $Ca^{2+}$ > $Na^+$ > $Mg^{2+}$ > $NH_4{^+} $ and that of anion loss were ordered $SO_4{^{2-}}$ > $NO_3{^-}$ > $Cl^-$ > $PO_4{^{3-}}$. Nutrient loss of sand loam soil in the cation and anion by percolation water increased 1.7 times compared with loam soil. $NO_3{^-}-N$ contents in percolated water were high at the initial stage after compost application, and the amounts were higher in sandy loam soil than loam soil. The maize cultivation also decreased the $NO_3{^-}-N$ contents in percolated water by 82% in loam soil, and 58% in sand loam soil. Soil pH of composts determined by laboratory incubation test increased pH 6.1~6.8 application with poultry and cow manure compost but application with human excrement sludge decreased pH 4.5~4.7. Soil EC were increased initially composts application and decreased up to 2 weeks, thereafter kept a certain level. Nitrogen mineralization rates of composts determined by laboratory incubation test at $25^{\circ}C$ were 39~76% in sandy loam soil, and 16~48% in clay loam soil.

• Korean Journal of Soil Science and Fertilizer
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• v.38 no.3
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• pp.127-133
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• 2005

The measurement technique using laser distometer to estimate soil erosion on sloped upland was assessed for its possibility for application. This technique was practiced in lysimeter installed in Chuncheon and Pyeongchang in 2001. The lysimeter installed at Chuncheon has 12% slope, 10 m slope length, 2 m width, and soil texture was sandy loam, while the lysimeter installed at Pyeongchang showed 23% slope, 15 m slope length, 5 m width, and sandy loam soil. Change of surface soil height was monitored using laser distance meter before and after rainy season on same spots. The Investigated periods in Chuncheon and Pyeongchang were from 22 June to 22 September and from July to October, respectively. Precipitation in Chuncheon and Pyeongchang in this period was 892.2 and 931.9 mm, respectively. Rainfall over 60% of annual precipitation was concentrated on July and August in Chuncheon and September and October in Pyeongchang, respectively. By monitoring the change of surface soil height using laser distance meter before and after rainy season, eroded soil surface in up-down fallow field in Chuncheon was 0.874 cm, while eroded soil surface in slant furrow field in Pyeongchang was 1.127 cm, which correspond to 79.5 and $98.0MT\;ha^{-1}$. Soil erosion increased as furrow length increased. Amounts of estimated soil loss using laser distance meter was 0.98-1.18 times higher compared to the estimated values through Iysimeter experiment, which implies possibility for application to monitor soil loss particularly in up-down and slant furrowed field. However, in the lysimeter with contoured tillage, amount of estimated soil loss using laser distance meter was approximately a half compared to that from lysimeter experiment, which implies inadequacy of distance meter application in contour- tillage field. The great soil loss difference between distance meter and lysimeter might be caused by disruption of some of the contoured furrows in lysimeter. The measurement technique using distometer in this study could be useful to estimate soil loss especially in up-down and slant-tillage fields.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.224-231
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• 2005

The ground excavation causes the deformation of the ground where the neighborhood structure is located. The ground deformation result in the vertical settlement of the neighborhood structure as well as the horizontal displacement of the temporary earth retaining structures. The decreased volume of the soil due to the ground settlement is defined as 'the ground loss quantity' or 'the ground loss'. When excavation is performed nearby existing structures, retaining walls should be designed and constructed to minimize the ground loss. Among various methods for reducing the ground loss, this study introduces the pre-loading method which has been recently developed. The reduction effect of the ground loss by pre-loading has been found to be larger as using a wall with relatively smaller rigidity.

• Korean Journal of Soil Science and Fertilizer
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• v.42 no.spc
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• pp.47-50
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• 2009

Nutrient losses, especially nitrogen and phosphorus, in agricultural runoff can contaminate surface and ground water, leading to eutrophication. Thus, erosion control is crucial to minimizing nutrient losses from agricultural land. Assessments of various erosion control practices were carried out under various cropping system, soil management practices, and slope conditions by means of a lysimeter study and under artificial rainfall. Soil and nutrient losses were monitored in a small agricultural field to evaluate the soil conservation practices. Nutrient losses occur in runoff and leachate (dissolved nutrient) and in sediments (particulate nutrient). Dissolved nitrates accounted for the majority (about 90%) of nitrate transport within the soil. Particulate phosphate in sediments represented the majority (60% to 67%) of phosphate transport. Recently, engineering and agronomic erosion-control practices haver been used to reduce erosion problems in fields on slopes. These practices reduced soil loss, runoff, and nutrient loss to 1/6, 1/2,and 1/3 their original levels, respectively. Bioavailable particulate phosphate in sediments represents a variable but longterm source of phosphate for algae. Dissolved nitrate and phosphate are immediately available for algal uptake, so reducing fluxes of these nutrients should also reduce the risk of eutrophication.

• Journal of Korean Society of Rural Planning
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• v.11 no.2 s.27
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• pp.51-57
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• 2005

It has been well known that soil erosion and sediments from alpine agricultural fields are causing severe water quality and turbidity problems in receiving waters. Also these result in the loss of money because farmers have to buy top soils to provide enough root zone in the following year. Thus, there have been needs to reduce soil erosion and sediment discharge into the stream networks. To accomplish this end, an effective erosion control plans should be developed based on scientific research, not by rule of thumb. The Universal Soil Loss Equation (USLE) has been widely used to estimate the soil erosion in many countries over the years. In this study, the USLE was used to estimate soil erosion potential under different cropping scenarios in HongCheon County, Kangwon. The soil erosion potential for continuous corn cropping was the highest compared with those from continuous potato find average cropping scenarios. This indicates the soil erosion plans need to be established considering cropping system in the field. The Unit Stream Power Erosion-Deposition (USPED) was applied for HongCheon County to estimate soil erosion and deposition areas. The USPED estimated results can be used to complement USLE results in developing effective erosion control plans.

• Korean Journal of Soil Science and Fertilizer
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• v.16 no.2
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• pp.112-118
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• 1983

Rainfall factor (R-factor), which is an index for the prediction of soil erosion in the Universal Soil Loss Equation (USLE), was computed from 21 years rainfall data at 51 locations in Korea. The values of R-factor are from 200 to 300 in the eastern part, and 300 to 700 in the western and southern part of the peninsula. Curvilinear regressions exist between annual rainfall and annual R-factor or between monthly rainfall and monthly R-factor. The R-factor can be estimated from the regression equation as a function of the amount of rainfall. According to the comparison between the actual soil loss measured by lysimeter and the soil loss predicted by the USLE, EI 30 for R-factor was recognized as a suitable factor for the USLE in korea.

• Journal of Korean Society on Water Environment
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• v.31 no.4
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• pp.407-417
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• 2015

Soil loss is one of the significant disasters which have threatened human community and ecosystem. Particularly, Korea has high vulnerability of soil loss because rainfall is concentrated during summer and mountainous regions take more than 70% of total land resources. Accordingly, the sediment control management plan are required to prevent the loss of soil resources and to improve water quality in the receiving waterbodies. In this regard, the objectives of this study are 1) to quantify the effect of the Vegetative Filter Strip (VFS) on sediment runoff reduction and 2) to analyze the relationship of rainfall intensity and sediment runoff. For this, SATEEC and VFSMOD were used to estimate sediment runoff according to rainfall intensity and to quantify the effect of VFS on sediment runoff reduction, respectively. In this study, the VFS has higher impact on sediment reduction for lower maximum rainfall intensity, which means that the maximum rainfall intensity is one of significant factors to control sediment runoff. Also, the sediment with VFS considered was highly correlated with maximum rainfall intensity. For these results, this study will contribute to extend the applicability of VFS in establishing eco-friendly sediment control plans.