• Journal of The Korean Society of Agricultural Engineers
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• v.65 no.2
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• pp.73-80
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• 2023

This study was conducted to analyze changes of irrigation water and soil volumetric water content by irrigation method of field soil in Saemangeum reclaimed tideland. The main test irrigation methods was surface drip irrigation, sprinkler irrigation, and sub drip irrigation. In addition, the correlation between irrigation amounts and crop yield by irrigation method was investigated. For soil volumetric water contents increases by 25%, surface drip irrigation took 1.5 hour, sprinkler irrigation took 2.0 hours, and sub drip irrigation took 3.0 hours. As a result of analyzing the irrigation amounts according to the yield, the surface drip irrigation was 2.66 mm/day in the seedling stages, 3.31 mm/day in the vegetative growth stages, and 5.09 mm/day in the flowering stages. Sprinkler irrigation was 2.90 mm/day in the seedling stages, 3.87 mm/day in the vegetative growth stages, and 7.11 mm/day in the flowering stages. Sub drip irrigation was 2.42 mm/day in the seedling stages, 3.09 mm/day in the vegetative growth stages, and 4.87 mm/day in the flowering stages. It was analyzed that there was a statistically significant difference in irrigation amounts by fresh weight and irrigation method (F=4.002, p=0.022), and irrigation amounts by dry weight and irrigation method (F=3.499 p=0.034). Surface drip irrigation was judged to be more appropriate than sprinkler irrigation or sub drip irrigation for field crops in Saemangeum reclaimed land.

• Journal of Bio-Environment Control
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• v.18 no.3
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• pp.225-231
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• 2009

'Nokkwang' green pepper plants were grown in soil system (silty loam with pH 6.5) under the greenhouse, to determine the effects of subsurface drip irrigation (SDI) and subsurface drip irrigation plus aeration (SDIA) into root zone comparing with conventional surface drip irrigation (DI) in terms of water use efficiency, soil properties, and growth and fruit yield. Two drip lines per crop row were layed on the soil surface in DI system, buried at a depth of 20cm below the soil surface in SDI system, and also buried at a depth of20cm below the soil surface and aerated for 3minutes a hour during the daytime ($08:00{\sim}19:00$) by a air compressor in SDIA system. A automatic irrigation with starting point of -20kPa and ending point of -10kPa based on soil moisture contents was applied by controllers and electronic vacum soil moisture sensors. Reduction in soil moisture contents was delayed in SDI and SDIA, compared to DI. Irrigation amount applied in pepper cultivation was around 30% less in SDI than in DI. Electric conductivity and nitrate nitrogen content in the surface soil grown green pepper were significantly lowered in SSDI and SDIA, compared to DI. Better development of root system was observed in SDIA and SDI than in DI. Results showed that pepper fruit yield increased by 30% in SDIA and 22% in SDI in comparision with DI.

• Korean Journal of Soil Science and Fertilizer
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• v.46 no.2
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• pp.99-104
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• 2013

Vegetables production in greenhouse are typically intensely managed with high inputs of fertilizers and irrigation water, which increases the risk of ground-water nitrate contamination. In 2010 and 2011, a study was conducted to determine the appropriate depth of soil moisture sensor for automatic irrigation control to use water and nitrogen efficiently under subsurface drip irrigation (SDI) systems. The irrigation line for SDI placed 30 cm below soil surface and tensiometer was used as soil moisture sensor. Three tensiometer treatments placed at 10 (SDI-T10), 20 (SDI-T20) and 30 cm (SDI-T30) depths below soil surface under SDI. These are also compared to SUR-T20 treatment where tensiometer placed at 20 cm below soil surface under surface drip irrigation (SUR) systems. The growth of cucumber was not statistically different between SUR and SDI without SDI-T30 treatment. Fruit yields (Mg/ha) were 57.0 and 56.9 (SDI-T10), 56.0 and 60.5 (SDI-T20), 40.9 and 41.2 (SDI-T30) and 56.6 and 54.3 (SUR-T20) for 2010 and 2011, respectively. Slightly higher total yield was observed in tensiometer placed 20 cm below the soil surface, although no significant differences were found between SDI-T10 and SDI-T20 under SDI treatments. In addition, nitrogen application rates and daily irrigation rates were lowest in SDI-T20 compared with other SDIs and SUR treatments. Nitrogen and daily irrigation application under SDI-T20 was lower than that under SUR-T20 by 6.0%. These findings suggested tensiometer 20 cm depth under SDI systems was best for cucumber production in greenhouse.

• Journal of the Korean Society of Industry Convergence
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• v.21 no.5
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• pp.227-234
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• 2018

The smart irrigation system using ICT technology is crucial for stable production of upland crops. The objective of this study was to develop a smart irrigation system that can control soil water, depending on irrigation methods, in order to improve crop production. In surface irrigation, three irrigation methods (sprinkler irrigation (SI), surface drip irrigation (SDI), and fountain irrigation (FI)) were installed on a crop field. The soil water contents were measured at 10, 20, 30, and 40 cm depth, and an automatic irrigation system controls a valve to maintain the soil water content at 10 cm to be 30%. In subsurface drip irrigation (SSDI), the drip lines were installed at a depth of 20 cm. Controlled drainage system (CDS) was managed with two ground water level (30 cm and 60 cm). The seasonal irrigation amounts were 96.4 ton/10a (SDI), 119.5 ton/10a (FI), and 113 ton/10a (SI), respectively. Since SDI system supplied water near the root zone of plants, the water was saved by 23.9% and 17.3%, compared with FI and SI, respectively. In SSDI, the mean soil water content was 38.8%, which was 10.8% higher than the value at the control treatment. In CDS, the water contents were greatly affected by the ground water level; the water contents at the surface zone with 30 cm ground water level was 9.4% higher than the values with 60 cm ground water level. In conclusion, this smart irrigation system can reduce production costs of upland crops.

• Korean Journal of Soil Science and Fertilizer
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• v.32 no.4
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• pp.357-364
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• 1999

This study measures the influence of grass cover on water use and shoot growth of apple trees growing under different soil water regimes in temperate climate conditions and evaluates monthly crop coefficients of such conditions during four months of the growing season in 1995. To do so, double pot lysimeter experiments of 3-year-old Fuji' apple (Males domestica Borkh.) trees under a transparent rain shield were designed and installed. Trees were triplicate under three soil water regimes: (A) drip-irrigation at -50 kPa of soil matric potential (IR50). (B) drip-irrigation at -80 kPa of soil matric potential (IR80), and (C) constant shallow water table at 0.45 m below the soil surface (WT45). In each treatment, two soil surface conditions were tested: the soil surface bare, and covered with turf grasses. Mean monthly water use increased with increasing soil matric potential for drip irrigation and was greatest in the WT45 treatment. Monthly crop coefficients increased linearly in time for drip-irrigated apple trees ($r^2$ values of $0.953^{***}$ for turf grass-covered system and of $0.862^{***}$ for bare surface system), while those obtained in the WT45 treatment fluctuated, Duncan's multiple range tests for shoot growth showed that grass-covered IR50 was most favorable to apple trees. while bare surface waterlogged situation was most adverse at least in part due to a lack of oxygen in the root zone. Mid-season leaf Kjeldahl-N was higher in drip-irrigated apple trees than in WT45 trees, while soil Kjeldahl-N was not different irrespective of treatments.

• Applied Biological Chemistry
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• v.43 no.2
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• pp.116-123
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• 2000

A numerical model of three-dimensional soil water distribution for drip irrigation management under cropped conditions was developed using Richards equation in Cartesian coordinates. The model accounts for both seasonal and diurnal changes in evaporation and transpiration, and the growth of plant root and the shape of root zone. Solutions were numerically approximated using the Crank-Nicolson implicit finite difference technique on the block-centered grid system and the Gauss-Seidel elimination in tandem. The model was tested under several conditions to allow the flow rates and configurations of drip emitters vary. In general, simulation results agreed well with experimental results and were as follows. The velocity of soil-water flow decreased drastically with distance from the drip source, and the rate of expansion of the wetted zone decreased rapidly during irrigation. The wetting front of wetted zone from a surface drip emitter traveled farther in vertical direction than in horizontal direction. Under this experimental weather condition, water use efficiency of a drip-irrigated apple field was greatest for 4-drip-emitter system buried at 25 cm, resulting from 10% increase in transpiration but 20% reduction in soil evaporation compared to those for surface 1-drip emitter system. Soil moisture retention curve obtained using disk tension infiltrometer showed significant difference from the curve obtained with pressure plate extractor.

• Journal of Biosystems Engineering
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• v.30 no.2 s.109
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• pp.102-109
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• 2005

Water consumption at the farm is up to 48 percent of water resource of South Korea while manufacturing industry's is only $9.6\%$. The area of arable land is 2,077,067 ha and 27 percent of it is used for growing fruits and vegetables using furrow or surface irrigation at the greenhouse. Surface irrigation at the greenhouse for fruits and vegetables has problems such as over watering and insufficient supply of water to the fine roots of the plant. However, the research on the new method of irrigation to save water usage is few. The characteristics of soil wetting was measured for using surface irrigation and underground trickle irrigation method where water was supplied at 10, 15, 20, and 25 cm beneath the surface ground. Followings are summary of this study. 1. The efficiency of underground trickle irrigation was expected to be as high as twice of surface irrigation such as drip watering or sprinkling. 2. This improvement could be possible by using less than $50\%$ of irrigation water than surface irrigation to supply similar amount of water near fine roots. 3. Surface irrigation causes soil compaction as deep as 20 cm below the surface ground which reduces soil porosity and root respiration ending up developing less fine roots. 4. Underground trickle irrigation can prevent overdamping in the greenhouse since it does not over wet the surface soil. At winter, the amount of agricultural chemical usage could be reduced since this irrigation method does not develop blight or crop disease from condensation of water vapor.

• Korean Journal of Soil Science and Fertilizer
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• v.42 no.6
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• pp.492-499
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• 2009

Effect of drip irrigation on soil salinity control and growth of vegetable crops was studied in the three reclaimed lands of Korea in 2007. Drip irrigation was done one or two times per month for reduction of salt stress by using vinyl hose with tiny holes laid on ridge surface under black plastic film mulch during growing season of cabbage and chinese cabbage. It was observed that drip irrigation was generally effective to soil salinity control, but soil salinity variation of some place was not fully solved to lower down under level of free salt stress. It is also considered that high salinity of runoff water spilled out from cultivation ridge plays another key role for soil salinity management. Consequentially, this soil salinity variation might be one of factors brought low average yield and low commercial ratio of agricultural products. Relation between soil salinity and head growth of cabbage and chinese cabbage was well expressed as logarithmic function. Surface soil EC to reach at 50% of growth reduction to the heaviest head can be estimated was $6.1dS^{\circ}{\S}m^{-1}$ for cabbage and $5.7dS\;m^{-1}$ for chinese cabbage transplanted at optimum season.

• Journal of Bio-Environment Control
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• v.24 no.4
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• pp.275-280
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• 2015

The objective of this study was to investigate the effect of drip irrigation level on soil salinity and growth of broccoli (Brassica oleracea L. var. italica) at the 'Saemangeum Reclaimed Tidal Land' from April to June, 2015. Drip irrigation was conducted at 1.5, 3.0 and $6.0mm{\cdot}day^{-1}$ level for reduction of resalinization in the plastic vinyl house using 10cm spacing drip irrigation tape. At harvesting stage, the average EC of surface soil was $10.9dS{\cdot}m^{-1}$ for $1.5mm{\cdot}day^{-1}$, $11.5dS{\cdot}m^{-1}$ for $3.0mm{\cdot}day^{-1}$ and $5.1dS{\cdot}m^{-1}$ for $6.0mm{\cdot}day^{-1}$ and was significantly reduced by 52~56% in $6.0mm{\cdot}day^{-1}$ treated plot compared to those in 1.5 and $3.0mm{\cdot}day^{-1}$ plots. The fresh bud weights of 1.5, 3.0 and $6.0mm{\cdot}day^{-1}$ treatment plots were 60.9, 129.1 and $371.3g{\cdot}plant^{-1}$, respectively. The estimated soil EC for 50% yield reduction was $7.6dS{\cdot}m^{-1}$ and the desalinization depth by drip irrigation was 30~40cm in soil profile. The total amount of drip irrigation water was estimated to be 422mm and the daily drip irrigation level was $6.0mm{\cdot}day^{-1}$ for the prevention of resalinization during the broccoli growing period at the 'Saemangeum Reclaimed Tidal Land'. Our results suggested that drip irrigation shows effectiveness on the lowering the soil salinity according to the drip irrigation quantity but it needs more research on this study because dynamics of salts in soil can vary with many factors such as soil physico-chemical properties and seasonal climate.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.252-252
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• 2017

Nowadays water shortage is becoming one of the biggest problems in the Korea. Many different methods are developed for conservation of water. Soil water management has become the most indispensable factor for augmenting the crop productivity especially on soybean (Glycine max L.) because of their high susceptibility to both water stress and water logging at various growth stages. The farmers have been using irrigation techniques through manual control which farmers irrigate lands at regular intervals. Automatic irrigation systems are convenient, especially for those who need to travel. If automatic irrigation systems are installed and programmed properly, they can even save you money and help in water conservation. Automatic irrigation systems can be programmed to provide automatic irrigation to the plants which helps in saving money and water and to discharge more precise amounts of water in a targeted area, which promotes water conservation. The objective of this study was to determine the possible effect of automatic irrigation systems based on soil moisture on soybean growth. This experiment was conducted on an upland field with sandy loam soils in Department of Southern Area Crop, NICS, RDA. The study had three different irrigation methods; sprinkle irrigation (SI), surface drip irrigation (SDI) and fountain irrigation (FI). SI was installed at spacing of $7{\times}7m$ and $1.8m^3/hr$ as square for per irrigation plot, a lateral pipe of SDI was laid down to 1.2 m row spacing with $2.3L\;h^{-1}$ discharge rate, the distance between laterals was 20 cm spacing between drippers and FI was laid down in 3m interval as square for per irrigation plot. Soybean (Daewon) cultivar was sown in the June $20^{th}$, 2016, planted in 2 rows of apart in 1.2 m wide rows and distance between hills was 20 cm. All agronomic practices were done as the recommended cultivation. This automatic irrigation system had valves to turn irrigation on/off easily by automated controller, solenoids and moisture sensor which were set the reference level as available soil moisture levels of 30% at 10cm depth. The efficiency of applied irrigation was obtained by dividing the total water stored in the effective root zone to the applied irrigation water. Results showed that seasonal applied irrigation water amounts were $60.4ton\;10a^{-1}$ (SI), $47.3ton\;10a^{-1}$ (SDI) and $92.6 ton\;10a^{-1}$ (FI), respectively. The most significant advantage of SDI system was that water was supplied near the root zone of plants drip by drip. This system saved a large quantity of water by 27.5% and 95.6% compared to SI, FI system. The average soybean yield was significantly affected by different irrigation methods. The soybean yield by different irrigation methods were $309.7kg\;10a^{-1}$ from SDI $282.2kg\;10a^{-1}$ from SI, $289.4kg\;10a^{-1}$ from FI, and $206.3kg\;10a^{-1}$ from control, respectively. SDI resulted in increase of soybean yield by 50.1%, 7.0% 9.8% compared to non-irrigation (control), FI and SI, respectively. Therefore, the automatic irrigation system supplied water only when the soil moisture in the soil went below the reference. Due to the direct transfer of water to the roots water conservation took place and also helped to maintain the moisture to soil ratio at the root zone constant. Thus the system is efficient and compatible to changing environment. The automatic irrigation system provides with several benefits and can operate with less manpower. In conclusion, improving automatic irrigation system can contribute greatly to reducing production costs of crops and making the industry more competitive and sustainable.