• Magazine of the Korean Society of Agricultural Engineers
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• v.37 no.E
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• pp.72-78
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• 1995

To support some knowledge in planning irrigation system, short or long-term irrigation scheduling or determining irrigation reservoir capacity, it is necessary to estimate peak irrigation requirements and seasonal distribution of water demands for various return periods. In this paper Dry Day Index and Probable Evapotranspiration were evaluated to decide seasonal consumptive use of paddy rice for a design year using several decades' daily rainfall data and 5 years'('82~'86) actual evapotranspiration data, respectively. To obtain Dry Day Index that is defined as the number of probable dry days for a given period, Slade unsymmetrical distribution function was adopted. Dry Day Index was analysed for 5 and 10-day intervals. Each of them was evaluated with return periods of 1, 3, 5, 10 and 20 year. Their singnificance was tested by X$^2$ method. Based on these values, the Probable Evaportanspiration, that is the average daily ET both in dry days and rainy days during a given period, was estimated. Crop coefficient was also determined by the modified Penman equation proposed by Doorenbos & Pruitt.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2001.10a
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• pp.69-73
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• 2001

At this project we developed water management program for sungju district. This program include flood forecast program, drought reduction program, irrigation scheduling program and database program. With these program we expect that operator can improve the irrigation efficiencies of the irrigation systems due to the timely irrigation on a right place, in a proper quantity and reduce the cost of maintenance. In agricultural engineering respect, the databases including water level, rainfall, the amount of flowing can be useful to the researcher who make a study of hydrology and hydraulics in rural area, Water management program record all of the TM/TC data to MDB format file per 10 minutes.

• Journal of Bio-Environment Control
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• v.28 no.4
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• pp.366-375
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• 2019

This experiment aims to determine the proper irrigation scheduling based on a whole-substrate capacitance using a newly developed device (SCMD) by comparing with the integrated solar radiation automated irrigation system (ISR) and sap flow sensor automated irrigation system (SF) for the cultivation of tomato (Solanum lycopersicum L. 'Hoyong' 'Super Doterang') during spring to winter season. For the SCMD system, irrigation was conducted every 10 minutes after the first irrigation was started until the first run-off was occurred, of which the substrate capacitance was considered to be 100%. When the capacitance threshold (CT) was reached to the target point, irrigation was re-conducted. After that, when the target drain volume (TDV) was occurred, the irrigation stopped. The irrigation volume per event for the SCMD was set to 50, 75, or 100 mL at CT 0.9 and TDV 100 mL during the spring to summer cultivation, and the CT was set to 0.65, 0.75, 0.80, or 0.90 in the winter cultivation. When the irrigation volume per event was set to 50, 75, or 100 mL, the irrigation frequency in a day was 39, 29, and 19, respectively, and the drain rate was 3.04, 9.25, and 20.18%, respectively. When the CT was set to 0.65, 0.75, or 0.90 in winter, the irrigation frequency was about 6, 7, 15 times, respectively and the drain rate was 9.9, 10.8, 35.3% respectively. The signal of stem sap flow at the beginning of irrigation starting time did not correspond to that of solar irradiance when the irrigation volume per event was set to 50 or 75 mL, compared to that of 100 mL. In winter cultivation, the stem sap flow rate and substrate volumetric water content at the CT 0.65 treatment were very low, while they were very high at CT 0.90 was high. All the integrated data suggest that the proper range of irrigation volume per event is from 75 to 100 mL under at CT 0.9 and TDV 100 mL during the spring to summer cultivation, and the proper CT seems to be higher than 0.75 and lower than 0.90 under at 75 mL of the irrigation volume per event and TDV 70 mL during the winter cultivation. It is going to be necessary to investigate the relationship between capacitance value and substrate volumetric water content by determining the correction coefficient.

• Journal of Bio-Environment Control
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• v.22 no.3
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• pp.248-255
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• 2013

This study examined an automated irrigation technique by a frequency domain reflectometry (FDR) sensor for scheduling irrigation for tomato (Solanum lycopersicum L. 'Starbuck F1') cultivation aimed at avoiding effluent from an open hydroponic system with coir substrate containing different ratios of chip-to-dust (v/v) content. Specifically, the objectives were to undertake preliminary measurements of irrigation volumes, leachate volume, volumetric water content and electrical conductivity (EC) in the substrate, plant growth, fruit yield, and water use efficiency resulting from variation in chip content as an initial experiment. Commercial coir substrates containing different percentages of chips and dust (0 and 100%, 30 and 70%, 50 and 50%, or 70 and 30%), two-story coir substrates with different percentages of chips in the lower layer and dust in the upper layer (15 and 85%, 25 and 75%, or 35 and 65%), or rockwool slabs were used. The results showed that a negligible or no leachate was found for all treatments when plants were grown under a technique for scheduling non-drainage irrigation using a frequency domain reflectometry (FDR) sensor. Daily irrigation volume was affected by chip content in both commercial and two-story slabs. The highest plant growth, marketable fruit weight, and water-use efficiency were observed in the plants grown in the commercial coir slab containing 0% chips and 100% dust, indicating that the FDR sensor-auto-mated irrigation may be more useful for tomato cultivation in coir substrate containing 0% chips and 100% dust using water efficiently and minimizing or avoiding leachate and thus increasing yield and reducing pollution. Detailed experiment is necessary to closely focus on determining appropriate irrigation volume at each of irrigation as well as duration of each individual irrigation cycle depending on different physical properties of substrates using an automated irrigation system operated by the FDR sensor.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 1998.10a
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• pp.65-70
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• 1998

Soil moisture measuring is important for irrigation scheduling of upland crops, estimation of evapotranspiration, and hydrologic modeling. Hence, the comparative study was implemented for the soil moisture measuring instruments, Neutron probe and TDR with soil sampling methods, and the result was represented.

• Korean Journal of Soil Science and Fertilizer
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• v.48 no.5
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• pp.499-504
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• 2015

Decision making by farmers regarding irrigation is critical for crop production. Therefore, the precision irrigation technique is very important to improve crop quality and yield. Recently, much attention has been given to remote sensing of crop canopy temperature as a crop water-stress indicator, because it is a scientifically based and easily applicable method even at field scales. This study monitored a series of time-variant canopy temperature of cucumber under three different irrigation treatments: under-irrigation (control), optimal-irrigation, and over-irrigation. The difference between canopy temperature ($T_c$) and air temperature ($T_a$), $T_c-T_a$, was calculated as an indicator of cucumber water stress. Vapor pressure deficit (VPD) was evaluated to define water stress on the basis of the temperature difference between leaf and air. The values of $T_c-T_a$ was negatively related to VPD; further, cucumber growth in the under- and over-irrigated fields showed water stress, in contrast to that grown in the optimally irrigated field. Thus, thermal infrared measurements could be useful for evaluating crop water status and play an important role in irrigation scheduling of agricultural crops.

• Journal of The Korean Society of Agricultural Engineers
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• v.62 no.3
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• pp.1-13
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• 2020

The management of agricultural water can be divided into management of agricultural infrastructure and operation to determine the timing and quantity of water supply. The target of water management is classified as water-supply facilities, such as reservoirs, irrigation water supply, sluice gate control, and farmland. In the case of agricultural drought, there is a need for water supply capacity in reservoirs and for drought assessment in paddy fields that receive water from reservoirs. Therefore, it is necessary to analyze the water supply amount from intake capacity to irrigation canal network. The analysis of the irrigation canal network should be considered for efficient operation and planning concerning optimized irrigation and water allocation. In this study, we applied a hydraulic analysis model for agricultural irrigation networks by adding the functions of irrigation canal network analysis using the SWMM (Storm Water Management Model) module and actual irrigation water supply log data from May to August during 2015-2019 years in Sinsong reservoir. The irrigation satisfaction of ponding depth in paddy fields was analyzed through the ratio of the number of days the target ponding depth was reached for each fields. This hydraulic model can assist with accurate irrigation scheduling based on its simulation results. The results of evaluating the irrigation efficiency of water supply can be used for efficient water distribution and management during the drought events.

• Journal of The Korean Society of Agricultural Engineers
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• v.56 no.5
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• pp.77-87
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• 2014

The impacts of climate change on upland crops is great significance for water resource planning, estimating crop water demand and irrigation scheduling. The objective of this study is to predict upland crop evapotranspiration, effective rainfall and net irrigation requirement for upland under climate change, and changes in the temporal trends in South Korea. The changes in consumptive use and net irrigation requirement in the six upland crops, such as Soybeans, Maize, Potatoes, Red Peppers, Chinese Cabbage (spring and fall) were determined based on the soil moisture model using historical meteorological data and climate change data from the representative concentration pathway (RCP) scenarios. The results of this study showed that the average annual upland crop evapotranspiration and net irrigation requirement during the growing period for upland crops would increase persistently in the future, and were projected to increase more in RCP 8.5 than those in RCP 4.5 scenario, while effective rainfall decreased. This study is significant, as it provides baseline information on future plan of water resources management for upland crops related to climate variability and change.

• Korean Journal of Agricultural Science
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• v.50 no.4
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• pp.883-902
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• 2023

Water is critical to the health and productivity of fruit trees. Efficient monitoring of water stress is essential for optimizing irrigation practices and ensuring sustainable fruit production. Short-range sensing can be reliable, rapid, inexpensive, and used for applications based on well-developed and validated algorithms. This paper reviews the recent advancement in fruit tree water stress detection via short-range sensing, which can be used for irrigation scheduling in orchards. Thermal imagery, near-infrared, and shortwave infrared methods are widely used for crop water stress detection. This review also presents research demonstrating the efficacy of short-range sensing in detecting water stress indicators in different fruit tree species. These indicators include changes in leaf temperature, stomatal conductance, chlorophyll content, and canopy reflectance. Short-range sensing enables precision irrigation strategies by utilizing real-time data to customize water applications for individual fruit trees or specific orchard areas. This approach leads to benefits, such as water conservation, optimized resource utilization, and improved fruit quality and yield. Short-range sensing shows great promise for potentially changing water stress monitoring in fruit trees. It could become a useful tool for effective fruit tree water stress management through continued research and development.

• Journal of The Korean Society of Agricultural Engineers
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• v.54 no.2
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• pp.147-156
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• 2012

가뭄강도와 지속기간을 고려하여 관개구역을 몇 개의 관개블록으로 나누어 순차적으로 제한하여 급수함으로써 관개용수를 절약하고 관개기간을 연장하여 가뭄을 극복하는 윤환관개모형 (RISS)을 제안한 바 있다. 이 RISS는 작물생육기별 관개저수지 저수율별 급수구역과 제한 급수율을 제시함으로써 가뭄기간에 저수지 운영자가 언제, 얼마나 제한하여 급수할 것인지 제시해주는 모형으로 전북 남원군 동화댐의 물 관리시스템 자동화 프로그램에 2004년 설치하여 운용되도록 하였다. 이 연구에서는 2004년부터 2009년까지 동화 댐 저수위 관측기록과 급수실적을 분석하여 RISS의 절수효과를 평가하고자 하였다. 그러나 실제로는 동화댐의 물 관리시스템 자동화 프로그램이 계획대로 운용되지 않고 있었다. 따라서 이 RISS의 절수효과와 효용성을 입증하여 계획대로 자동화시스템을 유용하게 활용하도록 하기 위해서 급수실적 및 저수위 관측기록과 RISS로 모의 발생한 저수위 결과를 비교 평가하였다. 모의발생 평가결과 가뭄이 극심했던 2007년에는 3.8백만 $m^3$을 절수하여 관개기간을 23일 연장하고 2009년에는 3.3백만 $m^3$을 절수하여 관개기간을 13일 연장하여 가뭄이 극심한 해에는 RISS 모형의 효용성이 크다는 것을 알 수 있었다.