• KCID journal
• /
• v.18 no.1
• /
• pp.94-102
• /
• 2011

The aim of this study was to evaluate the load of non-point sources pollutant at a paddy plot located at the valley watershed during irrigation period. Irrigation, runoff and water quality data in the paddy plot were analyzed periodically from June 1 to October 31 in 2005. The observed amount of precipitation, irrigation, runoff for the experimental paddy plot during the irrigation period was 1,297.8, 223.2, and 825.4mm, respectively. Total-N concentrations ranged from 3.73 to 18.10mg/L, which was generally higher than the quality standard of agricultural water (1.0mg/L). Total-P concentrations ranged from 0.111 to 0.243mg/L and the average was 0.139mg/L. The observed runoff pollutants loadings from the paddy plot were measured as 34.4 kg/ha for T-N, 1.0 kg/ha for T-P and 213.8 kg/ha for SS. The non-point sources pollutant load in drainage water depends on rainfall and surface drainage water amount from the paddy plot. We are considering that these results were affected by rainfall as well as hydrological condition, soil management, whether or not fertilizer application, cropping, rice straw and plowing.

• Korean Journal of Soil Science and Fertilizer
• /
• v.43 no.1
• /
• pp.68-74
• /
• 2010

Since ${NO_3}^-$ is amore favorable electron acceptor than Fe, high ${NO_3}^-$ loads function as a redox buffer limiting the reduction of Fe and following release of ${PO_4}^{3-}$ in flooded paddy soil. The effect ${NO_3}^-$ loaded through irrigation water on Fe reduction and ${PO_4}^{3-}$ release in paddy soil was investigated. Pot experiment was conducted where irrigation water containing 5 or 10 mg N $L^{-1}$ of ${NO_3}^-$ was continuously applied at 1 cm $day^{-1}$, and changes of ${NO_3}^-$, $Fe^{2+}$ and ${PO_4}^{3-}$ concentrations in soil solution at 5 and 10 cm depths beneath the soil surface were monitored as a function of time. Irrigation of rice paddy with water containing 5 mg N $L^{-1}$ of ${NO_3}^-$ led to reduced release of $Fe^{2+}$ and prevented solubilization of P at 5 cm depth beneath the soil surface. And application of irrigation water containing 10 mg N $L^{-1}$ of ${NO_3}^-$ could further suppress Fe reduction and solubilization of P through 10 cm depth soil layer beneath the surface. These results suggest that the introduction of high level ${NO_3}^-$ with irrigation water in rice paddy can strongly limit Fe reduction and P solubilization in root zone soil layer in addition to the excessive supply of N to rice plants.

• The Journal of Korean Academy of Prosthodontics
• /
• v.30 no.2
• /
• pp.167-189
• /
• 1992

Frictional heat produced by cutting tools during dental implantation procedure may destroy the surrounding bone tissue and regenerative capacity and interfere ossointegration by formation of undifferentiated connective tissue. To study the effect of frictional heat according to various rotational speeds on the regenerative capacity of surrounding bone tissue, 13 ITI HS implants (8 mm) were inserted at 4 mongrel dogs. Temperatures were measured using thermocouple located 6 mm below from the marginal crest and 0.5 mm from the periphery of trephine mill during implant bed preparation. After 4 and 9 months, animals were sacrificed and specimens were examined using x-rays and light microscope. Results were as follows: 1. With drill speeds of 300, 800, 2,000, 3,500 rpm and saline irrigation, temperatures of surrounding bone were decreased from $-2.9^{\circ}\;to\;-1.7^{\circ}C$. Temperature rises of $2.0^{\circ}\;and\;2.1^{\circ}C$ were recorded with a drill speed of 5,000 rpm and irrigation. 2. With drill speeds of 800, 3,500, 5,000 rpm and no irrigation, temperatures of surrounding bone rose from $+1.5^{\circ}\;to\;+6.8^{\circ}C$, but maximum temperature was $40^{\circ}C$ at 5,000 rpm. 3. On radiographic examination, bone resorptions were observed at the upper half of implant of 5,000 rpm without irrigation and one case of 5,000 rpm with irrigation. 4. Osseointegration was unsuccessful in cases of 3,500, 5,000 rpm without irrigation due to fibrous connective tissue formation to the outer surface and hollow, but it was successful in a case of 800 rpm without irrigation. 5. Osseointegration was successful in cases of 300, 800, 2,000 and 3,500 rpm with irrigation. But fibrous connective tissue formation was observed at the hollow of implant inserted with 5,000 rpm with irrigation.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2019.05a
• /
• pp.164-175
• /
• 2019

The Tor Tong Daeng Irrigation Project with the irrigation area of 61,400 hectares is located in the Ping Basin of the Upper Central Plain of Thailand where farmers depended on both surface water and groundwater. In the drought year, water storage in the Bhumipol Dam is inadequate to allocate water for agriculture, and caused water deficit in many irrigation projects. Farmers need to find extra sources of water such as water from farm pond or groundwater as a supplement. The operation of Bhumipol Dam and irrigation demand estimation are vital for irrigation water allocation to help solve water shortage issue in the irrigation project. The study aims to determine the smart dam operation system to mitigate water shortage in this irrigation project via introduction of machine learning to improve dam operation and irrigation demand estimation via soil moisture estimation from satellite images. Via ANN technique application, the inflows to the dam are generated from the upstream rain gauge stations using past 10 years daily rainfall data. The input vectors for ANN model are identified base on regression and principal component analysis. The structure of ANN (length of training data, the type of activation functions, the number of hidden nodes and training methods) is determined from the statistics performance between measurements and ANN outputs. On the other hands, the irrigation demand will be estimated by using satellite images, LANDSAT. The Enhanced Vegetation Index (EVI) and Temperature Vegetation Dryness Index (TVDI) values are estimated from the plant growth stage and soil moisture. The values are calibrated and verified with the field plant growth stages and soil moisture data in the year 2017-2018. The irrigation demand in the irrigation project is then estimated from the plant growth stage and soil moisture in the area. With the estimated dam inflow and irrigation demand, the dam operation will manage the water release in the better manner compared with the past operational data. The results show how smart system concept was applied and improve dam operation by using inflow estimation from ANN technique combining with irrigation demand estimation from satellite images when compared with the past operation data which is an initial step to develop the smart dam operation system in Thailand.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.67 no.3
• /
• pp.147-154
• /
• 2022

This study was conducted by directly sowing Asemi in late April at 30 × 10 cm intervals to determine the optimal irrigation method and irrigation amount to maximize the use of limited agricultural water and to increase the yield when growing rice in a desert climate. Conventional irrigation (Conv.), surface drip irrigation (Sur), subsurface drip irrigation (Sub.), and sprinkler irrigation (Spr.) methods were used. The following amounts of irrigation were tested based on field capacity (0.33 bar): 80% (V/V, FC80), 100% (FC100), and 120% (FC120), and data for 2 years were averaged. The total amount of irrigation by irrigation method was the lowest, at 627 ton/10 a, for Sub. irrigation with the FC80 treatment, which was 60.4% less than the amount of irrigation with the FC120 treatment (1,584 ton/10a). Sub. irrigation with the FC120 treatment gave the greatest amount of rice, at 665 kg/10 a, and this condition obtained a yield of 88.1% (754 kg/10 a) of the yield obtained with the conventional treatment. Therefore, when planting rice in a desert climate, subsurface drip irrigation at 120% of field capacity is considered advantageous to increase water use efficiency and crop yield.

• Proceedings of the Korean Society of Agricultural Engineers Conference
• /
• 1998.10a
• /
• pp.527-532
• /
• 1998

The inflow and outflow loads of T-N and T-P from a paddy field area during the irrigation period were investigated. For the concentration of T-N and T-P, surface water in paddies showed highest among irrigation water, drainage water and percolation water. For T-N, the average concentration of drainage water is higher than that of irrigation water before middle of June but is lower since. It is shown that the L(load)-Q (discharge) equation of T-N has high correlation for irrigation water, but the L-Q equation of T-P has high correlation for drainage water.

• Journal of Korean Society of Rural Planning
• /
• v.29 no.1
• /
• pp.69-79
• /
• 2023

Uiseong-gun, Gyeongsangbuk-do, one of the representative small rain regions, has developed a traditional irrigation farming system while overcoming and adapting to unfavorable agricultural environments from the days of the ancient nation of Jomunguk to the present. In 2018, its value was recognized and designated as Nationally Important Agricultural Heritage System No. 10. This study was conducted with the purpose of examining the characteristics of the traditional irrigation farming system in Uiseong from the viewpoints of irrigation facilities, irrigation communities, and agricultural activities. The research results are as follows. Uiseong-gun has been expanding irrigation facilities for agriculture since long ago, and it has been investigated that a total of 6,227 irrigation facilities are currently distributed along the Wicheon water system that crosses Uiseong-gun from east to west. Irrigation facilities appear differently depending on the topography. The irrigation facility has a 'su-tong' as an irrigation passage and a corkscrew structure 'mot-tchong' as a water quantity control device, so the amount of water was adjusted as needed. Through this facility, surface water with warmer temperature is supplied to the farmland to prevent cold damage to crops. Uiseong has developed activities to organize irrigation communities in one village or several villages to secure agricultural water from an early age. Currently, this tradition continues, and a total of 213 irrigation communities manage 375 irrigation facilities (6.0% of all irrigation facilities). Through this organization, called Mong-ri-gye, water for agriculture is obtained, managed, and distributed equitably. In order to increase agricultural production, Uiseong implemented double cropping by converting rice fields and fields. In the case of Mt. Geumseong, double cropping of rice and barley was mainly carried out until the 1970s, but since the 1980s, double cropping of rice and garlic has been implemented with higher income. One of the unique features of the agricultural system of this region is the spectacular landscape that changes simultaneously from field to rice field in spring and from rice field to field in autumn.

• Journal of Applied Biological Chemistry
• /
• v.59 no.1
• /
• pp.83-90
• /
• 2016

The aim of the present study was to evaluate the degree of metal contamination of the Turag River water and its suitability for irrigation. Twenty water samples were analyzed for physicochemical parameters and metals viz., calcium, magnesium, potassium (K), sodium, copper (Cu), zinc (Zn), iron (Fe), manganese (Mn), lead (Pb), cadmium (Cd), chromium (Cr), and nickel (Ni). All water samples were slightly alkaline to alkaline. Regarding electrical conductivity (EC), all samples were suitable for crop in soils with moderate permeability and leaching. Water samples were medium salinity and low alkalinity hazard classes. In terms of total dissolved solids (TDS), all samples were classified as freshwater. As per sodium adsorption ratio (SAR) and soluble sodium percentage (SSP), all samples were classified as excellent. No residual sodium carbonate (RSC) was detected in any of the samples, indicating suitability for irrigation; and all samples were considered very hard. Cr and Mn contents in all samples were above FAO guideline values and, therefore, these metals were considered toxic. Zn, Cu, Pb, Cd, and Ni concentrations were below acceptable limit for irrigation and do not pose a threat to soil environment. Significant relationships were found between EC and TDS, SAR and SSP, SAR and RSC, and SSP and RSC. The combinations of ions such as K-Zn, K-Fe, K-Cu, K-Mn, K-Pb, Zn-Fe, Zn-Cu, Zn-Mn, Fe-Mn, Cu-Mn, Cu-Pb and Mn-Pb exhibited significant correlation. This study revealed that Turag River water samples are contaminated with Cr and Mn. This fact should not be ignored because water contamination by metals may pose a threat to human health through food chain.

• Journal of Wetlands Research
• /
• v.13 no.2
• /
• pp.275-289
• /
• 2011

We investigated the hydrological and geomorphological characteristics of small irrigation ponds in civilian control zone of Paju city in Korea. Among 85 small irrigation ponds, water level of 52 ponds changed seasonally and that of 33 was constant. Water sources of 12 ponds were surface water, 29 surface water and ground water, and 44 ground water. 4 ponds locate in the edges of forests, 33 in flat-lands, and 48 in valleys. Water in 45 ponds was exchanged with paddy fields and 40 ponds were isolated from paddy fields. Endangered or endemic species were inhabited in 26 ponds, which have ground water as water source and constant water level. Based on these characteristics, we suggested 4 types of small irrigation ponds: spring, water exchanging, stagnant/spring, stagnant water. This classification system will help ecosystem managers to investigate ponds systematically and manage them based on pond type.

• Korean Journal of Agricultural Science
• /
• v.50 no.4
• /
• pp.785-798
• /
• 2023

Considering irrigation facilities are currently insufficient and drought vulnerability due to climate change is high, efficient measures are required to secure water supply for field crops. This study, therefore, calculated the water shortage to secure water for representative field crops. An economic analysis was further conducted by comparing the production income to the input cost for each method. Here, five distinct regions were selected to represent each crop-Cheongyang-gun for chili peppers, Yesan-gun for apples, Dangjin-si for cabbages, Seosan-si for garlic, and Goesan for beans. The regions with insufficient water supply were estimated by calculating the water requirements and the supplied water from public groundwater wells for each area. A comprehensive set of four scenarios was presented as a strategy to ensure water security and manage irrigation facilities. These scenarios comprised the maintenance of existing groundwater wells, the construction of new water storage tanks, the installation of additional groundwater wells, and the utilization of surface water. B/C (benefit/cost) analysis was conducted for each scenario. As a result, the construction of water storage tanks was selected as a facility and water management plan in Cheongyang-gun, Dangjin-si, and Seosan-si. The analysis additionally indicated the economic viability of installing surface water utilization facilities in Yesan-gun and developing water storage tanks and groundwater (aquifer) wells in Goesan-gun. The results of this study are considered to serve as foundation data that may be utilized in the selection of water management plans for drought-prone areas in the future.