• Journal of The Korean Society of Agricultural Engineers
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• v.54 no.1
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• pp.11-18
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• 2012

This study was investigated agricultural water supply system of major agricultural waterway for Gimje canal, Jeongeup canal, Dongjin river conduit of Dongjin river basin. Furthermore, this result will be used for water resources and agricultural demand in Saemangeum reclaimed arable land. Annual precipitation for 5 years in Dongjin river basin was 1,311.7mm. The average discharges in Dongjin river basin was $1,390{\times}10^6\;m^3$ and $1,516{\times}10^6\;m^3$ and $744{\times}10^6\;m^3$ for 2,007 and 2008, respectively. Also, annual average amount of water resources was 1,861${\times}10^6\;m^3$ and $2,279{\times}10^6\;m^3$ and $1,227{\times}10^6\;m^3$ for 2,007 and 2008, respectively. Dongjin river basin water system for the analysis of agricultural water in water resources, runoff, agricultural water demand and usage surveys were analyzed, resulting in the total amount of water due to precipitation of the watershed of the $12.3{\times}10^9\;m^3$ ~$22.8{\times}10^9\;m^3$ and Dongjin River basin in waters flowing discharge is $7.4{\times}10^9\;m^3$~$16.1{\times}10^9\;m^3$, agricultural water demand and usage of each of $6.8{\times}10^9\;m^3$~$6.9{\times}10^9\;m^3$ and $4.9{\times}10^9\;m^3$~$7.1{\times}10^9\;m^3$ compared to the agricultural water demand was more likely. Agricultural water supply system in Dongjin river basin is complex because of devided branches to the main canal and branch canal. In this process, accurately assessment of water usage is very difficult. Therefore, systematic management of water resources and supply of agricultural water supply system to use the terms of the complexity and diversity by considering the appropriate level of agricultural water management systems will be needed. As a result of this study, it can be used water resources assessment in quantity, rational usefulness and basic planning of water resources development for water distribution.

• Korean Journal of Soil Science and Fertilizer
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• v.49 no.2
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• pp.168-180
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• 2016

Various researches on the effects of fertilization levels on functional metabolites in crop have been conducted. This review summarizes the previous studies on the relation between fertilization supply and accumulation of metabolites (phenolics, carotenoids, ascorbic acid and glucosinolates) which function as antioxidants in crop. The accumulation of phenolic compounds is related to the activation of phenylalanine ammonia lyase (PAL) in phenylpropanoid pathway. Most of the previous studies discuss that low nitrogen (N) supply activates PAL, thereby increasing the synthesis of phenolics. Similarly, high N supply leads to a decrease in ascorbic acid because of the shading effect derived from the accelerated vegetative growth under high N level. Unlike the phenolics and ascorbic acid, carotenoids are accumulated with increasing N supply. In this regard, the previous studies explain that N is a main element closely associated with formation of key enzyme for the synthesis of carotenoids. Glucosinolates are generally increased under decreasing N supply and increasing S supply. Although the previous studies show similar trends about the accumulation of metabolites by nutrient level, they also suggest that many other factors including crop types, cultivars, cultural environment (water, temperature, light, etc.) influence the accumulation of functional metabolites in crop.

• Journal of The Korean Society of Agricultural Engineers
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• v.65 no.2
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• pp.21-33
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• 2023

While the main purpose of irrigation reservoirs is to supply agricultural water, the needs of environmental flow and flood control has been expanded. The agricultural reservoirs have been operated in the form of carry-over system until now. Therefore, the supply of agricultural water is difficult when the storage rate is not sufficiently secured after large volume of irrigation. In addition, there are regulation of the upper storage rate for some large reservoirs during the flood season, but lower storage rate is not regulated. Accordingly, this study aims to evaluate the capacity of agricultural water and environmental flow supply by setting the management lower storage rate of reservoir. The changes in the supply of agricultural and environmental flow was simulated according to the three different regulating lower storage rate scenarios. As a result, it was judged effective in terms of water supply managing the lower storage rate up to 30% when the initial storage rate of farming period is above annual average for the Naju reservoir considering existing water management practice. If the lower storage rate would have been controlled above 30%, the supply of agricultural water might be increased and non-effective discharge amount would be decreased compared to other scenarios during dry period of 2016-2018.

• Journal of The Korean Society of Agricultural Engineers
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• v.63 no.3
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• pp.1-12
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• 2021

Optimal water management is to efficiently and equally supply an appropriate amount of water by using irrigation facilities. Therefore, it is necessary to evaluate water supply capacity through distribution simulation between the designed distribution rate and re-distributed rate according to the changed farming conditions. In this study, we recalculated the agricultural water supply amount of Geumcheon main canal, which beneficiary area was reduced due to the development of Gwangju-Jeonnam innovation city, and we constructed a canal network using the SWMM model to simulate the change in supply rate of each main canal according to the re-distributed rate. Even though the supply amount of the Geumcheon main canal was reduced from 1.20 m³/s to 0.90 m³/s, it showed a similar supply rate to the current, and the reduced quantity could be supplied to the rest of the main canal. As a result, the arrival time at the ends of all main canal, except for the Geumcheon main canal, decreased from 1 to 3 hours, and the supply rate increased from 4 to 17.0% at the main canal located at the end of the beneficiary area of Naju reservoir.

• Journal of Soil and Groundwater Environment
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• v.24 no.2
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• pp.23-37
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• 2019

To evaluate the available groundwater supply to the agricultural water demand in the future with the climate change scenarios for 40 sub-regions in Jeju Island, groundwater recharge and the available groundwater supply were estimated using water balance analysis method. Groundwater recharge was calculated by subtracting the actual evapotranspiration and direct runoff from the total amount of water resources and available groundwater supply was set at 43.6% from the ratio of the sustainable groundwater capacity to the groundwater recharge. According to the RCP 4.5 scenario, the available groundwater supply to the agricultural water demand is estimated to be insufficient in 2020 and 2025, especially in the western and eastern regions of the island. However, such a water shortage problem is alleviated in 2030. When applying the RCP 8.5 scenario, available groundwater supply can't meet the water demand over the entire decade.

• Journal of The Korean Society of Agricultural Engineers
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• v.55 no.3
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• pp.41-49
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• 2013

Drought risk assessment is usually performed qualitatively and quantitatively depending on the definition a drought. The meteorological drought indices have a limit of not being able to consider the hydrological components such as evapotranspiration, soil moisture and runoff, because it does not consider the water demand in paddies and water supply in reservoirs. Agricultural drought was defined as the reservoir storage shortage state that cannot satisfy water requirement from the paddy fields. The objectives of this study were to suggest improved agricultural drought risk assessment in order to evaluate of regional drought vulnerability and severity studied by using Reservoir Drought Index (RDI). The RDI is designed to simulate daily water balance between available water from agricultural reservoir and water requirement in paddies and is calculated with a frequency analysis of monthly water deficit based on water demand and water supply condition. The results indicated that RDI can be used to assess regional drought risk in agricultural perspective by comparing with the historical records of drought in 2012. It can be concluded that the RDI obtained good performance to reflect the historical drought events for both spatially and temporally. In addition, RDI is expected to contribute to determine the exact situation on the current drought condition for evaluating regional drought risk and to assist the effective drought-related decision making.

• Journal of Korean Society of Water and Wastewater
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• v.36 no.5
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• pp.289-296
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• 2022

Mangyeong River and Dongjin River are highly dependent on external regions for domestic and agricultural water, and the agricultural water supply and use system of those rivers are very complicated. For smooth water supply, rivers are used as a supply system. Of the total river water use permits (as of 2019), agricultural water accounts for 97.5%, 80.4% in Mangyeong River and Dongjin River, respectively. The excessive intake of river water as agricultural purpose is causing the stream to dry out and to deteriorate the ecological health of the river. It is necessary to minimize the water use system that takes in and utilizes river water. In both rivers, the flow rate of agricultural drainage and the load of major water quality items that flowing into the main stream are similar to or higher than those of the major tributaries, indicating that management is necessary to improve the water quality of the river. It is necessary to understand the effect of agricultural drainage on river water quality by establishing a continuous monitoring system for the form of agricultural drainage.

• Journal of The Korean Society of Agricultural Engineers
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• v.54 no.1
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• pp.93-97
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• 2012

Agricultural water reservoirs upstream of the intake on the basis of the intaking water volume is being made. Therefore, the supply capacity of reservoirs are not considered when the water balance analysis, storm water reservoirs are based on agriculture and further secured by the reservoir water is not used to using natural river water analysis. To overcome these problems can supply reservoirs are available to permit analysis of how much the quantity of water balance analysis, it should be reflected in the line to help. In this study, the natural daily flow data and apply the dimensions of the reservoir, and for more than 30 years of the long-term water balance analysis conducted by Date Youngsan river basin can supply reservoirs are large quantity of permits available is presented.

• Korean Journal of Agricultural Science
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• v.50 no.3
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• pp.489-498
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• 2023

Cabbage, which is one of the main materials of kimchi, normally has an unstable supply due to cultivation and climate conditions. This unstable supply negatively affects the profitability of kimchi processors in Korea. Thus, kimchi processors found a better method for acquiring a consistent cabbage supply with long-term storage of over 3 months. However, a consensus regarding the best method for the stable and economical acquisition of cabbage remains controversial. This study aimed to analyze the current issue concerning cabbage acquisition by kimchi processors and evaluate the economic feasibility of kimchi storage. Findings obtained through survey and economic analyses using theoretical methodology were as follows: First, A survey conducted on kimchi processors in Korea revealed that even though they recognize the importance of kimchi storage, they struggle to store adequate amounts of cabbage. This is particularly evident with summer cabbage, which experiences the highest supply volatility and thus requires greater attention from kimchi processors in terms of storage. Second, the price analyses using the coefficient of variation show that cabbage in Korea has a high level of price instability, which suggests more storage of cabbage. Third, the evaluation of the economic feasibility of cabbage storage indicated that kimchi processors should consider storing a greater amount of cabbage, particularly during the summer season. This approach can help reduce the overall cost associated with kimchi processing.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2003.10a
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• pp.423-426
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• 2003

The purpose of this paper is to estimate Agricultural water demand at irrigation area of sumjin reservoir, the Dongjin River basin, which consist of multi-wide water supply system and complicated irrigation channel and supplementary irrigation facilities.