• 한국농공학회지
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• 제31권2호
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• pp.82-91
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• 1989

This study was carried out to get the basic information of irrigation plans for the red pepper, such as optimum irrigation level and irrigation requirement in Taegu and Kyungpook province. In this study, red peppers were cultivated in 6 PVC pot lysimeters filled with 60cm deep clay loam soil. Four tensiometers were installed in each plot to measure the soil water pressure head. Field measurements were made during the period June 6 to October 31, 1988 at the experimental farm of Kvungpook National University. Six levels of irrigation were used. They were PF 1.8-2.0, PF 2.2-2.4, PF 2.8-3.0, FC-PF.1.7, FC-PF 2.2, and FC-PF 2.7. The results obtained from this study are summarized as follows : 1. In case of irrigation levels of narrow ranges of water contents, the higher the soil water content was, the larger the ET was. Hut in case of the irrigation levels returning to the field capacity, the lager the PF value of irrigation point was, the larger the ET was. Considering ET, yield and weight per fruit, the latter is much better than the former irrigation method. 2. The mean daily ET and mean ET ratio for each 10-day period showed that the maximum value occured in the last of August. The ranges of those were 3.74-14.64 mm/day and 0.87-3.40, respectively. These values showed that small during the early stage of growth, large during the middle stage and getting smaller in the last stage. 3. In case of irrigation levels of narrow ranges of water contents, the increase of irrigation water supplied increased the ET. The relationship between the two showed nearly straight line. Most of irrigated water was consumed as ET and the rest as percolation. But, in case of irrigation levels returning to the field capacity, the higher the PF value of irrigation point was, the larger the ET ratio was. However, their relationship didn't show straight line. 4. The irrigation level of PC - PP 2.7 was found to be the optimum irrigation level with respect to the yield, the weight per fruit, stem length, irrigation requirement and percolation quantity. In this case, mean daily ET and mean ET ratio were 6.79 mm/day (total 10052 mm) and 1.67, respectively. The maximum mean daily ET and mean ET ratio for 10-day period were 14.64 mm/day and 3.40, respectively, in the last of August, and the maximum daily ET was 2126 mm/day on August 24. 5. In case of PC - PP 2.7 which is found the optimum irrigation level, mean irrigation water required, mean ET and mean percolation water quantity were 7.44 mm/day, 6.79 mm/day(91.3% of irrigation water), and 0.38 mm/day (5.5% of it), respectively.

• Current Research on Agriculture and Life Sciences
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• 제18권
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• pp.33-42
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• 2000

A field case study was performed to investigate the effect of shallow ponding in paddy field on irrigation water requirement of direct seeded rice. In addition, an economic analysis was made to see the effect of no-till direct seeded rice on cost reduction. A field study was performed at a 2.1ha paddy field in Kimjae city, Chonbuk province from 1991 to 1999. Various direct seeding methods such as dryland seeding, wetland seeding, and no-till wetland seeding were introduced. Then, cost reductions due to the direct seeding and no-till were calculated. In addition, to investigate the effect of shallow ponding on irrigation water requirement, field measurements such as irrigation water volume, drainage water volume, rainfall depth, and ponding depth, were made at a 40a plot within the same area in 1988 and 1990. The results of the shallow ponding study showed that the irrigation water depth, rainfall, and the drainage depth were 379mm, 458mm, and 448mm in 1988 growing season, and 274mm, 819mm, and 736mm in 1990, respectively. The shallow ponding irrigation method saved irrigation water by about 20% with higher yield compared with the traditional method. The economic analysis showed that won \640,000 per ha can be saved by direct seeding due to no nursery cost, and \1,220,000 per ha due to no-till and no nursery cost. The yields ranged 540 to 640 kg per 10a during the study period with an average of 590kg per 10a. If these cropping techniques with no-till direct seeding and shallow ponding depth for rice cropping prove to be advantageous with further study, they can be adopted for the most of the paddy fields in Korea.

• 한국농공학회지
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• 제31권4호
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• pp.90-95
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• 1989

The purpose of this study is to seek out the harrow water requirement applicable for the irrigation plan of paddy field and to find out the factors influenced on a variation in the requirement. The plots of experiment were arranged with randomized block design which was compo- sed of three kinds of soil texture (sandy loam, loam and silty loam) and ploughing depth (12cm, 17cm, and 22cm). The results obtained from this experimental study are summarized as follows. 1. Harrow water reguirement is not only changed by soil texture, but influenced by soil water content just before irrigating 2. Magnitude of total harrow water reguirement appli(able for the irrigation plan, when surface water depth and the water content just before irrigating is fixed on the basis of 30 mm and a shrinkage limit respectively, generally becomes to be 177.5mm, 116.3mm and 113. 8mm in the sandy loam, loam amd silty loam block, respectively. 3. The more a percolation of soil layer occurs, the more the harrow water requirement increases, but it is not much influenced by the increase in ploughing depth. 4. The larger a porosity of soil layer is, the more a net harrow requirement increases 5. The factors that influence on a variation in the harrow water requirement are appea- red to be percolation of soil layer, soil water content just before irrigating, porosity of soil layer, ploughing depth and designed surface water depth etc.

• 한국농공학회:학술대회논문집
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• 한국농공학회 2003년도 학술발표논문집
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• pp.291-294
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• 2003

The Water resources utilization pattern of Jangsung reservoir was studied. The observed precipitation and existing reservoir operation data such as irrigation amount, reservoir storage, river maintenance requirement, flood control discharge were collected for ten years period and analyzed. Major findings of this study are as follows: The observed average, minimum, maximum annual precipitation were 905.1mm, 1,977.3mm, 1,554.3mm during study period, respectively. The average annual irrigation amount was 554.5mm, irrigation amount of drought years of '92 and '94 was 604.6mm, 679.2mm, respectively. However, irrigation amount of extended drought year '95 was 384.9mm. It showed that supplying capacity of Jangsung reservoir was limited when consecutive 2 year drought occurred. The main water resources usage of Jangsung reservoir was irrigation, but flood control discharge exceed irrigation amount exceptionally when high precipitation occurred. The reservoir operation record revealed that discharge for river maintenance was delivered even drought years.

• Asian-Australasian Journal of Animal Sciences
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• 제28권5호
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• pp.703-715
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• 2015

One of the challenges to increase milk production in a large pasture-based herd with an automatic milking system (AMS) is to grow forages within a 1- km radius, as increases in walking distance increases milking interval and reduces yield. The main objective of this study was to explore sustainable forage option technologies that can supply high amount of grazeable forages for AMS herds using the Agricultural Production Systems Simulator (APSIM) model. Three different basic simulation scenarios (with irrigation) were carried out using forage crops (namely maize, soybean and sorghum) for the spring-summer period. Subsequent crops in the three scenarios were forage rape over-sown with ryegrass. Each individual simulation was run using actual climatic records for the period from 1900 to 2010. Simulated highest forage yields in maize, soybean and sorghum- (each followed by forage rape-ryegrass) based rotations were 28.2, 22.9, and 19.3 t dry matter/ha, respectively. The simulations suggested that the irrigation requirement could increase by up to 18%, 16%, and 17% respectively in those rotations in El-Nino years compared to neutral years. On the other hand, irrigation requirement could increase by up to 25%, 23%, and 32% in maize, soybean and sorghum based rotations in El-Nino years compared to La-Nina years. However, irrigation requirement could decrease by up to 8%, 7%, and 13% in maize, soybean and sorghum based rotations in La-Nina years compared to neutral years. The major implication of this study is that APSIM models have potentials in devising preferred forage options to maximise grazeable forage yield which may create the opportunity to grow more forage in small areas around the AMS which in turn will minimise walking distance and milking interval and thus increase milk production. Our analyses also suggest that simulation analysis may provide decision support during climatic uncertainty.

• 한국농공학회논문집
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• 제51권1호
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• pp.27-32
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• 2009

The objective of this study is to assess the feasibility of wastewater reuse for the vegetable farming. The study region, about 250 ha in size, is located on the west coast of Jejudo, Korea. Major agricultural products of the study area are the cabbage, broccoli, garlic and onion. To confirm the feasibility of wastewater reuse, the drought duration and the water requirement analysis were conducted respectively. The average annual precipitation of the study region (1,121 mm) was smaller than that of Jeju island (1,975 mm). The drought duration for a ten-year return period in October through November was more than 20 days. The water requirement for irrigation was calculated by the FAQ Penman-Monteith method which took into account the cultivated crops, planting system, and meteorological conditions of the study region. The water requirement for a ten-year return period was estimated 4.7 mm/day and the water demand for irrigation was $4,584\;m^3/day$. As a result, the irrigation water for the crops was insufficient during their breeding season, especially in October through November. Thus, the result indicated that the study region required the alternative water supply such as wastewater reuse during the non-rainy season. As drought continues to place considerable stress on the availability of fresh water supplies in the study region, irrigation with reclaimed wastewater will play an important role in helping to meet future water demands.

• 기술사
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• 제1권1호
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• pp.18-25
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• 1968

Higher yield in rice paddies is greatly dependent on adequately balanced and timely supply of water. A majority of rice paddy in Korea is generally irrigated by rainfall, but in many cases it has to be supplemented by artificial irrigation for optimum rice culture. Although the water requirement of rice plant is for higher Than that of athec crops, submerged condition of rice paddy is not Necessarily required. The moisture requirement of rice plant varies with its growing stages, and it is possible to increase the irrigation efficiency through reduction of water loss due to percolation in rice paddies. An experimental plots were set up by means of sandomized block design with three duplication; (a) All time submerged, (b) Economically controlled, and (c) Extremely controlled. Three different irrigation periods Were (a) Initial sage, (b) Inter-stage, and (c) Yast stage. The topsoil of the three plots were excavated to the depth of 30 cm and then compacted with clay of 6 cm thickness. There after, they were piled up with the excavated top soils, leveled and cored with clay of 6 cm thickness around footpath in order to prevent leakage. The results obtained from the experiments are as follows, 1. There is no difference among the three experiments plots in terms of physical and chemical conditions, soil properties, and other characteristics. 2. Culm length and ear length are not affected by different irrigation methods. 3. There is no difference in the mature rate and 1, 000 grain weight of rice for the three plots. 4. The control plot which was irrigated every three days shows an increased yield over the all the time submerged plot by 17.8 percent. 5. The clay lined plot whose water holding capacity was held 5 days long, needs only to be irrigated every 7 days. 6. The clay lined plot shows an increased yield over the untreated plot ; over all-the-time submerged plot by 18 percent ; extremely controlled plot by 18 percent, and economically controlled plot by 33 percent. 7. It may be saved in water requirement about one Thirds.

• 한국농공학회논문집
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• 제59권5호
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• pp.31-40
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• 2017

The aim of this study is to estimate net irrigation requirements for red pepper during growing period using soil moisture model. The soil moisture model based on water balance approach simulates soil moisture contents of 4 soil layers in crop root zone considering soil moisture extraction pattern. The LAMP (Land-Atmosphere Modeling Package) high resolution meteorological data provided from National Center for AgroMeteorology (NCAM) was used to simulate soil moisture as the input weather data. Study area for the LAMP data and soil moisture simulation covers $36.92^{\circ}{\sim}37.40^{\circ}$ in latitude and $127.36^{\circ}{\sim}127.94^{\circ}$ in longitude. Soil moisture was monitored using FDR (Frequency Domain Reflectometry) sensors and the data were used to validate the simulation model from May 24 to October 20 in 2016. The results showed spatially detailed soil moisture pattern under different weather conditions and soil texture. Net irrigation requirements were also different by location reflecting the spatially distributed weather condition. The average of the requirements was 470.7 mm and averages about soil texture were 466.8 mm, 482.4 mm, 456.0 mm, 481.7 mm, and 465.6 mm for clay loam, sandy loam, silty clay loam, clay, and sand respectively. This study showed spatial differences of soil moisture and the irrigation requirements of red pepper about spatially uneven weather condition and soil texture. From the results, it was demonstrated that high resolution meteorological data could provide an opportunity of spatially different crop water requirement estimation during the irrigation management.

• 한국농공학회논문집
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• 제57권2호
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• pp.93-101
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• 2015

The purpose of this study is to evaluate the paddy irrigation efficiency using real-time water level monitoring data and intermittent irrigation model in Gimjae, Dong-Jin irrigation district. For this study, the real-time water level data in Gimjae main canal and other secondary canals were collected from 2012 to 2014 and converted to daily discharge using rating curve in each canal. From intermittent irrigation model in paddy, irrigation water requirement was estimated and irrigation efficiency was calculated. The average amount of irrigation water supply per unit irrigation area was 1,011 mm in Gimjae main canal for 12,749 ha irrigation area, 1,011 mm in the secondary canal of upper region and 1,470 mm in the secondary canal of lower region. The median irrigation loss was 43 % in Gimjae main canal, 25 % in secondary canal of upper region and 35 % in the secondary canal of lower region. The larger irrigation area is, the irrigation loss rates tend to decrease in secondary canals. Monthly median irrigation losses in upper region were 10 (June) - 40 % (September) and those in lower region were 25 (May) to 40 % (April, June, August, and September). The results of canal management loss can be available as the basic data for irrigation water management and estimating guideline of optimal irrigation water supply to improve agricultural water use efficiencies.

• 한국관개배수논문집
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• 제4권1호
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• pp.68-72
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• 1997