• Journal of Environmental Policy
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• v.8 no.1
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• pp.73-95
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• 2009

The fact that soil loss causing to increase muddy water and devastate an ecosystem has been appearing upon a hot social and environmental issues which should be solved. Soil losses are occurring in most agricultural areas with rainfall-induced runoff. It makes hydraulic structure unstable, causing environmental and economical problems because muddy water destroys ecosystem and causes intake water deterioration. One of three severe muddy water source areas in Soyanggang-dam watershed is Jawoon-ri region, located in Hongcheon county. In this area, many cash-crops are planted at illegally cultivated agricultural fields, which were virgin forest areas. The purpose of this study is to estimate soil loss with current land uses(including illegal cash-crop cultivation) and soil loss reduction with land use conversion from illegal cultivation back to forest. In this study, the Sediment Assessment Tool for Effective Erosion Control(SATEEC) ArcView GIS was utilized to assess soil erosion. If the illegally cultivated agricultural areas are converted back to forest, it would be expected to 17.42% reduction in soil loss. At the Jawoon-ri region, illegally cultivated agricultural areas located at over 30% and 15% slopes take 47.48 ha(30.83%) and 103.64 ha(67.29%) of illegally cultivated agricultural fields respectively. If all illegally cultivated agricultural fields are converted back to forest, it would be expected that 17.41% of soil erosion and sediment reduction, 10.86% reduction with forest conversion from 30% sloping illegally agricultural fields, and 16.15% reduction with forest conversion from 15% sloping illegally agricultural fields. Therefore, illegally cultivated agricultural fields located at these sloping areas need to be first converted back to forest to maximize reductions in soil loss reduction and muddy water outflow from the Jawoon-ri regions.

• Korean Journal of Soil Science and Fertilizer
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• v.40 no.2
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• pp.118-130
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• 2007

The steep-sloped agricultural land was severely damaged by rainfall events during July and August every year. The objective of this study was to investigate an effects of intensive rainfall to the soil properties of the steep-sloped agricultural land. Survey sites including the Sacheon myeon area were located in Gangneung, those were severely damaged from a forest fire in April 2000. Surveys were taken at these sites after two years of forest fire and severe rainfall events in August 2002, which included an event that poured with 870 mm of rainfall in a day. After this storm, soil erosion, burying, and flooding were observed. Severe soil loss was found at lower soil-depths, greater slopes, longer slope lengths, and concave landscapes. Soil loss and land slides were often found at areas with having a coarser textures, higher bulk densities, lower water holding capacity, and lower rates of soil aggregation. Crop growth stagnation was found at the site of crop restoration because of low soil fertility and poor drainage caused by the abrupt textural changes. In conclusion, it is necessary to manage the steep-slope agricultural land based on environmental impact assessment data of macro morphological and physical characteristics by intensive rainfall.

• 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 Environmental Agriculture
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• v.41 no.4
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• pp.230-235
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• 2022

BACKGROUND: Ammonia gas emitted from nitrogen fertilizers applied in agricultural land is an environmental pollutant that catalyzes the formation of fine particulate matter (PM2.5). A significant portion (12-18%) of nitrogen fertilizer input for crop cultivation is emitted to the atmosphere as ammonia gas, a loss form of nitrogen fertilizer in agricultural land. The widely practiced method for fertilizer use in agricultural fields involves spraying the fertilizers on the surface of farmlands and mixing those with the soils through such means as rotary work. To test the potential reduction of ammonia emission by nitrogen fertilizers from the soil surface, we have added N, P, and K at 2 g each to the glass greenhouse soil, and the ammonia emission was analyzed. METHODS AND RESULTS: The treatment consisted of non-fertilization, surface spray (conventional fertilization), and soil depth spray at 10, 15, 20, 25, and 30 cm. Ammonia was collected using a self-manufactured vertical wind tunnel chamber, and it was quantified by the indophenol-blue method. As a result of analyzing ammonia emission after fertilizer treatments by soil depth, ammonia was emitted by the surface spray treatment immediately after spraying the fertilizer in the paddy soil, with no ammonia emission occurring at a soil depth of 10 cm to 30 cm. In the upland soil, ammonia was emitted by the surface spray treatment after 2 days of treatment, and there was no ammonia emission at a soil depth of 15 cm to 30 cm. Lettuce and Chinese cabbage treated with fertilizer at depths of 20 cm and 30 cm showed increases of fresh weight and nutrient and potassium contents. CONCLUSION(S): In conclusion, rather than the current fertilization method of spraying and mixing the fertilizers on the soil surface, deep placement of the nitrogen fertilizer in the soil at 10 cm or more in paddy fields and 15 cm or more in upland fields was considered as a better fertilization method to reduce ammonia emission.

• Magazine of the Korean Society of Agricultural Engineers
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• v.32 no.E
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• pp.1-19
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• 1990

Abstract Over the last several decades, crop production in the United States increased largely due to the extensive use of animal waste and fertilizers as plant nutrient supplements, and pesticides for crops pests and weed control. Without the application of animal waste best management, the use of animal waste can result in nonpoint source pollution from agricultural land area. In order to increase nutrient levels and decrease contamination from agricultural lands, nonpoint source pollution is responsible for water quality degradation. Nonpoint source pollutants such as animal waste, ferilizers, and pesticides are transported primarily through runoff from agricultural areas. Nutrients, primarily nitrogen and phosphorus, can be a major water quality problem because they cause eutrophic algae growth. In 1985, it was presented that Watershed/Water Quality Monitoring for Evaluation BMP Effectiveness was implemented for Nomini Creek Watershed, located in Westmoreland County, Virginia. The watershed is predominantly agricultural and has an aerial extent of 1505 ha of land, with 43% under cropland, 54% under woodland, and 3% as homestead and roads. Rainfall data was collected at the watershed from raingages located at sites PNI through PN 7. Streams at stations QN I and QN2 were being measured with V-notch weirs. Water levels at the stream was measured using an FW-l Belfort (Friez FWl). The water quality monitoring system was designed to provide comprehensive assessment of the quality of storm runoff and baseflow as influenced by changes in landuse, agronomic, and cultural practices ill the watershed. As this study was concerned with the Nomini Creek Watershed, the separation of storm runoff and baseflow measured at QNI and QN2 was given by the master depletion curve method, and the loadings of baseflow and storm runoff for TN (Total Nitrogen) and TP (Total Phosphorus) were analyzed from 1987 through 1989. The results were studied for the best management practices to reduce contamination and loss of nutrients, (e.g., total nitrogen and total phosphorus) by nonpoint source pollution from agricultural lands.

• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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• 2008.10a
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• pp.153-161
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• 2008

Agriculture and forest are basis for livelihood in Nepal while both sectors constitute around 40 percent of the national product and over two-thirds of the economically active population is dependent on agriculture. However, radical changes in land use, depletion in crops production and food availability are major threats due to loss of soil fertilityand severe environmental degradation. In this study, we used time series data from 1986/87 to 2005/06 about food crop production and population published by Government of Nepal, Ministry of Agriculture and Cooperatives and Central Bureau of Statistics. Descriptive statistics and ArcGIS were used to assess and map the food security status of Nepalese Terai based on the local food demand and supply system. Food supply to demand ratio(FSDR) was the main idea of assessment. Our results showed that out of 20 districts, only 8 districts were categorised under secured food districts whereas 5 districts were still under food unsecured situation. The analysis further revealed that 7 districts had faced food deficit more than 8-16 times during the last 20 year periods. Data further showed that there was surplus food supply relative to the requirements dictated by FSDR. However, the average FSDR was less than 1.2(less than 20% surplus) exploring fact that most of the districts were not producing sufficient food to cope up the food shock and after 1995 it was relatively stagnant. Our prediction reveals that food supply in Terai even in the future would remain at almost the same level as now, and there will not more than 16-17% surplus by 2021 considering medium vibrant population growth. The findings thus, indicate that Terai may not be a food secure region in the future, even though the region is considered as a food storage house of Nepal. In addition, this paper suggests ways to make future comprehensive case studies more widely comparable in Terai, Nepal.

• Proceedings of the Korea Water Resources Association Conference
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• 2019.05a
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• pp.225-225
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• 2019

건물, 차량, 사회인프라시설과 달리 농작물이란 물리적인 시설이 아닌 농업경제 활동의 결과물로서 최종적으로 판매를 통해 수익을 창출하는 행위에서 재난으로 인하여 지장을 받게 되는 경제적 피해가 고려되어야 한다. 이를 위해 본 연구는 홍수로 인한 농작물 피해를 "생산비 매몰비용"과 "순수익 손해"를 농작물 피해추정의 척도로 하였다. 생산비 매몰비용이란 경작시작부터 피해발생까지 투입된 생산비의 회수불가에 따른 피해이며, 순수익 손해란 피해발생에 따른 기대 순수익 하락에 따른 피해를 의미한다. 다양한 작물 가운데 10종의 대표작물을 선택하고, 각 작물의 표준생산비와 표준순수익을 농업생산 및 수익과 관련한 통계자료로부터 결정하였다. 이로부터 생육경과율과 홍수 발생시기(6~9월)를 고려하여 월별 투입생산비 및 기대순수익을 결정하였다. 대상지역 내 재난에 노출된 작물정보를 정의하는 농작물 인벤토리는 농림축산식품부에서 제작된 스마트 팜 맵(농경지 전자지도)을 활용하였고, 다양한 작물이 혼재된 밭의 경우 농업면적조사 결과를 토대로 결정한 밭작물 재배현황비를 고려하였다. 홍수에 따른 취약성을 설명하는 농작물 손상함수는 영향인자는 침수심, 침수기간이며, 이를 기준으로 한 손상함수는 농림부의 농업재해피해조사요령과 일본 치수경제조사메뉴얼을 참고하여 제시하였다. 본 연구에서 제시한 농작물 피해 추정 방법은 기존 방법인 다차원 홍수피해산정법(MD-FDA)과 비교할 때 대표작물의 현실화, 국내 실정을 고려한 손상함수, 그리고 면적 기반의 원단위를 사용함으로써 실무적으로 명확하고 실용적으로 사용될 것으로 기대된다.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.5
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• pp.711-716
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• 2012

Due to the climate change in South Korea the annual total precipitation will increase by 17 percent by 2100. Rainfall is concentrated during the summer in South Korea and the landslide of farmland by heavy rain is expected to increase. Because regional torrential rains accompanied by a storm continue to cause the damage in farmland urgent establishment of adaptation plant for minimizing the damage is in need. In this study we assessed vulnerability of landslide of farmland by heavy rain for local governments. Temporal resolution is 2000 year and the future 2020 year, 2050 year, 2100 year via A1B scenario. Vulnerability of local government were evaluated by three indices such as climate exposure, sensitivity, adaptive capacity and each index is calculated by selected alternative variable. Collected data was normalized and then multiplied by weight value that was elicited in delphi investigation. Current vulnerability is concentrated in Jeju island and Gyeongsangnam-do, however, it is postulated that Kangwon-do will be vulnerable in the future. Through this study, local governments can use the data to establish adaptation plans for farmland landslide by climate change.

• The Korean Journal of Pesticide Science
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• v.19 no.2
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• pp.113-118
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• 2015

This study was carried out to develop the economic thresholds for powdery mildew on pepper. To investigate the relationship between powdery mildew incidence degree and yield, experimental plots with ten treatments as initial disease degree were established. Disease intensity exhibited negative and significant correlation with fruit characters like fruit length, fruit diameter, fruit weight. The adverse effect of the disease on these characteristics was low yield, exhibiting significant negative correlation with disease intensity. There existed close correlation between rate of infected leaf area and yields in the plastic house (Chonhatongil: Y = -3.44X+291.09 $R^2=0.73$, Buchon: Y = -2.14X+327.9 $R^2=0.78$). There existed close correlation between rate of infected leaf area and yield loss in the plastic house (Chonhatongil: Y = 2.14X+15.45 $R^2=0.76$ $r=0.87^{**}$, Buchon: Y = 3.44X+114.21 $R^2=0.73$ $r=0.85^{**}$). Control thresholds diseased rate on powdery mildew of pepper was below 3.2 to 7.3% rate of infected leaf area per plant in the plastic house. The economic thresholds for powdery mildew of pepper was below 3.8 to 6.2% rate of infected leaf area per plant in the plastic house.

• Korean Journal of Soil Science and Fertilizer
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• v.33 no.2
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• pp.61-70
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• 2000

Soil erosion in the hilly and mountainous uplands in the Daekwanryong area, Kangwon-Do, were investigated through a field plot experiment. The plot size was 15m long and 2.5m wide with the average slope of 12.5 percents. Soil erodibility factor (K), surface coverage (SC), soil aggregate percentage and wind erodibility (I) were evaluated in the mountainous soils under different management practices for corn and potato cultivations. Soil erodibility factor (K) was greater in upper part than in lower part of the plots. Surface coverage (SC) values ranged from 0.01 to 0.84 depending on the amounts of crop residues. Soils having a greater crop residue in surface were less subjected to soil erosion. SC values after corn harvest were 0.4 to 0.8, while those after potato harvest were 0.4 to 0.5, indicating potato might be better than corn for erosion control. Soil aggregate percentages of the experimental plots ranged from 49.7 to 79.8%. Those were higher in potato-cultivated plots with higher surface coverage, organic fertilizer treatment and contour tillage. Soil aggregate percentage of potato-cultivated plots was significantly correlated to crop residue coverage after harvest. The dried soil aggregate percentage, showing the ranges of 26.4 to 56.4%, were higher in the plots with the increased crop residue incorporation. Wind erodibility (I) of the soil was decreased with increasing surface coverage. When soil had 26.4% of the dried aggregate percentage, wind erodibility was estimated to be $183Mgha^{-1}$ which was equivalent to soil loss of $0.5Mg\ha^{-1}day^{-1}$.