• Korean Journal of Environmental Agriculture
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• v.22 no.4
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• pp.241-245
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• 2003

This study was carried out to evaluate the status of the groundwater quality for paddy fields irrigation in Korea. Water samples were collected at 130 sites throughout the country. Samples were collected at three seasons - April, July and October - in 2000. According to our survey, the groundwater was found to be suitable for irrigation purpose. Average EC was shown 0.286 dS/m. Nitrate-nitrogen and $Cl^-$ concentration was 5.6 mg/L, 32.95 mg/L which satisfied the Korean Standards for Irrigation Water. Nitrate-nitrogen concentration in each province was shown as following orders: Jeju (11.17 mg/L) > Chungnam (8.16 mg/L) > Gyeongbuk (6.64 mg/L) > Gyounggi (5.91 mg/L) > Chungnam (4.95 mg/L) > Gyeongnam (3.91 mg/L) > Jeonbuk (3.50 mg/L) > Jeonnam (3.27 mg/L) > Gangwon (2.91 mg/L). The concentration by sampling seasons were October (6.62 mg/L) > July (5.88 mg/L) > April (4.78 mg/L). As the soil of Jeju Province is usually derived from volcanic ash soils mainly used for upland drops, it may influence the nitrate-nitrogen concentration of groundwater. The amount of rainfall also influence the water quality. But the $COD_{Cr}$ were shown April (3.17 mg/L) > July (2.91 mg/L) > October (2.40 mg/L), it is highly related in the basal dose of organic matter fertilizers. This study demonstrated that groundwater quality was suitable for irrigation, but continuous monitoring is recommended for agricultural policy and developing OECD agricultural environment indicators.

• Journal of Korean Society of Rural Planning
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• v.19 no.3
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• pp.25-36
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• 2013

This study aims to perform the economic analysis to the use of solar power facilities in rural villages considering the climate change scenario. IPCC climate change scenarios in the recently adopted the RCP scenarios (RCP8.5, RCP6.5, RCP4.5, RCP2.6) was used. By RCP scenarios, solar radiation, depending on the scenario in 2100, respectively, 3.6%, 2.5%, 1.9%, 1.1% was assumed to increase. From the economic analysis(payback period is 25 year) on 8 points of each province, in all cases of normal data and four RCP scenarios, at all points analyzed were NPV indicate a negative, BC ratio less than 1.0, respectively. In the case of Mokpo, Chunnam RCP8.5, BC ratio were found to be up to a 0.92, followed by 0.89 in the case of RCP8.5 in Jinju, Kyungnam shows, while the minimum was in Jeju. BC ratio is 1.0 or bigger, in order for the normal solar radiation data in Mokpo, Chonnam was the minimum that it takes 37 years. Similarly, in the case of RCP scenarios, 30 years in Mokpo, Chonnam RCP8.5 and 31 years in the cases of Jinju, Kyungnam and Jeonju, Cheonbuk RCP8.5 were analyzed. It was analyzed that RCP8.5 has the highest value. BC analysis models for each of the factors, the results of the sensitivity analysis, the initial installation costs, electricity sales price, discount rate in the order of economy showed higher sensitivity, and the rest factors showed lower changes. Although there are some differences of solar radiation by region, but in Korea most facilities in rural areas, the use of solar power was considered to be economical enough, considering change of several factors with high sensitivity, such as increasing of government subsidies for the solar power installation of the facility, rising oil prices due to a rise in electricity sales price, and a change in discount rate. In particular, when considering climate change scenarios, the use of solar energy for rural areas of the judgment that there was more economical.

• Korean Journal of Soil Science and Fertilizer
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• v.48 no.5
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• pp.509-514
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• 2015

Indicators of environmental conditions qualitatively and quantitatively describe the state of the environment and natural resources, and the OECD (Organization for Economic Cooperation and Development) has initiated and suggested AEIs (Agri-Environmental Indicators) to assess trends over time of the effects of agriculture on the environment and the effectiveness and efficiency of agricultural and environmental policy measures since 1990's. This study aims to develop the state indicators of water quality for agricultural water, surface and groundwater, to evaluate the environmental impacts of agricultural activities and policies by qualifying the environmental levels of a nation. Status indicators were calculated according to the agricultural water quality standards of OECD and Korea, and their trends were analyzed over time. Particularly, nitrate ($NO_3{^-}$) status indicators of ground water in 2013 were significantly lower than the ones in 2000. Overall, the water quality indicators of surface water in 2013 were higher than the ones in 2012, except for pH and DO. The groundwater quality indicators in 2013 were lower than those of previous years. The optimal management indicators were calculated to assess agricultural surface water and groundwater quality. The findings of this study indicated that the state indicators could play a significant role to establish policies and procedures for managing and conserving water resources. This study also discussed water pollution caused by agricultural and industrial effluents.

• Journal of The Korean Society of Agricultural Engineers
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• v.59 no.4
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• pp.27-42
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• 2017

The global rise in atmospheric $CO_2$ concentration and its associated climate change have significant effects on agricultural productivity and hydrological cycle. For food security and agricultural water resources planning, it is critical to investigate the impact of climate change on changes in agricultural productivity and water consumption. APEX-Paddy model, which is the modified version of APEX (Agricultural Policy/Environmental eXtender) model for paddy ecosystem, was used to evaluate rice productivity and evapotranspiration based on climate change scenario. Two study areas (Gimjae, Icheon) were selected and the input dataset was obtained from the literature. RCP (Representitive Concentration Pathways) based climate change scenarios were provided by KMA (Korean Meteorological Administration). Rice yield data from 1997 to 2015 were used to validate APEX-Paddy model. The effects of climate change were evaluated at a 30-year interval, such as the 1990s (historical, 1976~2005), the 2025s (2011~2040), the 2055s (2041~2070), and the 2085s (2071~2100). Climate change scenarios showed that the overall evapotranspiration in the 2085s reduced from 10.5 % to 16.3 %. The evaporations were reduced from 15.6 % to 21.7 % due to shortend growth period, the transpirations were reduced from 0.0% to 24.2 % due to increased $CO_2$ concentration and shortend growth period. In case of rice yield, in the 2085s were reduced from 6.0% to 25.0 % compared with the ones in the 1990s. The findings of this study would play a significant role as the basics for evaluating the vulnerability of paddy rice productivity and water management plan against climate change.

• Journal of The Korean Society of Agricultural Engineers
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• v.63 no.4
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• pp.55-64
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• 2021

The expansion of upland crop cultivation in rice paddy fields is recommended by the Korean government to solve the problem of falling rice price and reduction of rice farmer's income due to oversupply of rice. However, water use efficiency is significantly influenced by the land use change from paddy field to upland. Therefore, this study aimed to evaluate the water budget of soybean grown in using APEX (Agricultural Policy and Environmental eXtender) model. The amount of runoff was measured in a test bed located in Iksan, Jeollabu-do and used to calibrate and validate the simulated runoff by APEX model. From 2019 to 2020, the water budget of soybean grown in uplands were estimated and compared with the one grown in paddy fields. The calibration result of AP EX model for runoff showed that R² (Coefficient of determination) and NSE (Nash-Sutcliffe efficiency) were 0.90 and 0.89, respectively. In addition, the validated results of R² and NSE were 0.81 and 0.62, respectively. The comparative study of each component in water budget showed that the amounts of evapotranspiration and percolation estimated by APEX model were 549.1 mm and 375.8mm, respectively. The direct runoff amount from upland was 390.1 mm, which was less than that from paddy fields. The average amount of irrigation water was 28.7 mm, which was very small compared to the one from paddy fields.

• Journal of the Korea Organic Resources Recycling Association
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• v.18 no.2
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• pp.55-61
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• 2010

This study was carried out to analyze national and regional distribution of the organic wastes generation and build their distribution maps including food wastes, paper and wood wastes, wastewater and slaughterhouse wastes. The information for the annual waste production was modified using statistics from Ministry of Environment (MOE). Based on waste generation resources data, we established database architecture table about waste generation. The distribution maps for food wastes were built up in both national and regional scales and distribution maps for paper and wood wastes, wastewater and slaughterhouse wastes were also produced, respectively. The distribution maps of waste generation graphically provide the information regarding biomass resources to policy-makers, farmers, general users and it is highly expected to be utilized for policy-making of environmental-friendly agriculture and bioenergy.

• Journal of The Korean Society of Agricultural Engineers
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• v.62 no.5
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• pp.47-62
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• 2020

Rice paddy accounts for approximately 52.5% of all farmlands in South Korea, and it is closely related to the water environment. Climate change is expected to affect not only agricultural productivity also the water and the nutrient circulation. Therefore this study was aimed to evaluate changes of nitrogen load from rice paddy considering climate change scenario uncertainty. APEX-Paddy model which reflect rice paddy environment by modifying APEX (Agricultural Policy and Environmental eXtender) model was used. Using the AIMS (APCC Integrated Modeling Solution) offered by the APEC Climate Center, bias correction was conducted for 9 GCMs using non-parametric quantile mapping. Bias corrected climate change scenarios were applied to the APEX-Paddy model. The changes and uncertainty in runoff and nitrogen load were evaluated using multi-model ensemble. Paddy runoff showed a change of 23.1% for RCP4.5 scenario and 45.5% for RCP8.5 scenario compared the 2085s (2071 to 2100) against the base period (1976 to 2005). The nitrogen load was found to be increased as 43.9% for RCP4.5 scenario and 76.0% for RCP8.5 scenario. The uncertainty analysis showed that the annual standard deviation of nitrogen loads increased in the future, and the maximum entropy indicated an increasing tendency. And Duncan's analysis showed significant differences among GCMs as the future progressed. The result of this study seems to be used as a basis for mid- and long-term policies for water resources and water system environment considering climate change.

• Journal of Environmental Policy
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• v.4 no.1
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• pp.93-111
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• 2005

Defining soil quality in scopes and applications is one of the prerequisite for the sustainable management of soil environment to orient researches, strategies and policies. However, definition of soil quality is controversial depending upon a viewpoint of soil science or soil environment. Soil quality can be, irrespective of the disciplines, defined as the capacity of a soil to function within ecosystem boundaries to sustain biological productivity, maintain environmental quality and promote plant and animal health. Common to all of the soil quality concepts can be summarized as the capacity of soil to function effectively at present and in the future. The OECD includes soil quality as one of the agri-environment indicators. This article intends to i) summarize the current soil quality research, and ii) provide information on protocol of soil quality assessment. A framework for soil quality was divided into three steps: indicator selection as minimum data set (MDS), scoring of the selected indicators, and integration of scores into soil quality index. Korean government suggested possible physical and chemical indicators such as bulk density and organic matter for paddy and upland soils to OECD. The framework of soil quality assessment is not yet implemented in Korea. Countries such as USA, Canada and New Zealand have constructed the framework on soil quality assessment and developed a user-friendly version of soil quality assessment tools to evaluate the integrated effects of various soil management practices. The protocol provided in this review might help policymakers, scientists, and administrators improve awareness about soil quality and understand the way of soil environment management.

• Korean Journal of Environmental Agriculture
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• v.40 no.4
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• pp.279-289
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• 2021

BACKGROUND: Recently, the golden apple snail, Pomacea canaliculata has been used as an environmentally-friendly weed-control agent in rice farming. Although effective for this particular style of farming, P. canaliculata can be destructive to other crops. The objective of this study was to identify overwintering as well as regional and seasonal distribution characteristics of P. canaliculata. Notably, winter is typically fatal for P. canaliculata. However, owing to increasing average global temperatures, we assessed the ability of P. canaliculata to survive through uncharacteristically warm winters. METHODS AND RESULTS: To examine the distribution and overwintering regions of P. canaliculata, We conducted a survey from April 2020 to May 2021 on environmentally-friendly rice fields, agricultural waterways, and streams in 23 cities belonging to 8 provinces. In addition, because air temperature may influence the distribution density of P. canaliculata, we analyzed the winter temperature data (http://weather.rda.go.kr). CONCLUSION(S): In 2021, overwintering of P. canaliculata (1-3 individuals/m²) was observed in the Goheung and Yeongam regions in Jeonnam. Overwintering of P. canaliculata was observed in fewer regions in 2021 than in 2020; this fact may be attributed to the lower minimum temperatures measured in 2021 (approximately 8℃ lower) than those in 2020. Our results suggest that overwintering occurs as long as overnight temperatures are ≥ -15℃, but can take place if temperatures are as low as -19℃.