• 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 The Korean Society of Agricultural Engineers
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• v.58 no.6
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• pp.1-8
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• 2016

Crop damages due to agricultural drought has been increased in recent years. In Korea, water resources are limited indicating that proper management plans against agricultural drought are required for better water-use efficiency in agriculture. In this study, irrigation intervals and amounts for various crops and soil physical properties (sandy and silt loams) were estimated using the IWMM model. Five different crops (soybean, radish, potato, barley and maize) at the Bangdong-ri site in Chuncheon were selected to test the IWMM model. IWMM assessed agricultural drought conditions using the soil moisture deficit index (SMDI), and irrigation intervals and amounts were determined based on the degree of agricultural drought (SMDI). Additionally, we tested the effects of surface irrigation and sprinkler irrigation methods and various irrigation intervals of 2, 3, 5 and 7 days. In our findings, the irrigation intervals of 5 and 7 days showed the minimum rrigation amounts than others. When we considered that the intervals of 3 or 5 days are usually preferred to fields, the interval of 5 days was determined in our study. The estimated irrigation amounts for different crops were shown as maize > radish > barley > soybean > potato, respectively. The irrigation amounts for maize and barley were highly affected by soil properties, but other crops have less differences. Also, small differences in irrigation amounts were shown between the surface and sprinkler irrigation methods. These might be due to the lack of consideration of water loss (e.g., evapotranspiration, infiltration, etc.) in IWMM indicating model structural uncertainties. Thus, possible water loss (e.g., evapotranspiration, infiltration) need to be considered in application to fields. Overall, IWMM performed well in determining the irrigation intervals and amounts based on the degree of agricultural drought conditions (SMDI). Thus, the IWMM model can be useful for efficient agricultural water resources management in regions at where available water resources are limited.

• Journal of Soil and Groundwater Environment
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• v.26 no.1
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• pp.76-87
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• 2021

Groundwater is considered to be the best water resource to solve water shortage problems during drought periods. Even though excessive pumping (overdraft) during short-period may give an unprofitable effect on groundwater hydrology, it has a primary role to solve a lack of water resources and to maintain incomes of farmers. This study evaluated maximum irrigation amounts of groundwater to each local-government and province during drought periods. Maximum irrigation amounts of groundwater were evaluated using cumulative groundwater usage data of each local-government during normal and drought years. Maximum irrigation amounts of groundwater during drought periods would be roughly identified as approximately 1.3 times more than the exploitable amounts of groundwater resources for each local-government. Drawdown-limitation depth on groundwater levels at each monitoring well was determined by transforming the maximum irrigating amounts into degree of change on levels. Universal limitation depth of drawdown on groundwater levels was evaluated to be approximately three times of annual fluctuating range on groundwater levels for each monitoring well. Systematic response on groundwater demands with abiding by drawdown-limitation depth can attain an optimal irrigation of groundwater resources during short-term drought.

• Journal of The Korean Society of Agricultural Engineers
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• v.56 no.5
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• pp.1-9
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• 2014

The DIROM (Daily Irrigation Reservoir Operation Model) was modified to estimate amounts of water release from reservoirs, considering customary irrigation water management practices, such as water supply for puddling and transplanting paddy rice from seeding beds and mid-season drainage. The applicability of the modified model was investigated by simulating amounts of water release from three study reservoirs: Hwamae, Ogi, and Doya Reservoirs. In terms of annual amounts of water release, the relative errors between the observed and simulated values in 2012 and 2013 ranged -26.20 % to 10.28 % and 4.90 % to 30.06 %, respectively; in case of reservoir water levels, the RMSE values ranged 0.45 m to 1.34 m and 0.40 m to 1.27 m, respectively. Also, it was revealed that the model provided better simulation results for monthly water releases than the original model. In addition, the model presented better performance in simulating 10-day amounts of water release from April to June. However, the model had still significant errors in the simulation results from July to September because the reservoirs were practically operated to adapt to water management circumstances. Finally, it is concluded that the modified DIROM can estimate the amounts of water release from reservoirs, reflecting irrigation water management customs in paddy-field districts. To achieve higher prediction accuracy of the model, it is necessary to incorporate practical reservoir operation rules into the model.

• Journal of The Korean Society of Agricultural Engineers
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• v.59 no.2
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• pp.37-47
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• 2017

In this study, we analyzed the variability of irrigation water amounts based on the combination of various crops and soil textures using the Irrigation Water Management Model (IWMM). IWMM evaluates the degree of agricultural drought using the Soil Moisture Deficit Index (SMDI). When crops are damaged by the water scarcity under the drought condition indicating that the SMDI values are in negative (SMDI<0), IWMM irrigates appropriate water amounts that can shift the negative SMDI values to "0" to crop fields. To test the IWMM model, we selected the Bandong-ri (BDR) and Jucheon (JC) sites in Gangwon-do and Jeollabuk-do provinces. We derived the soil hydraulic properties using the near-surface data assimilation scheme form the Time Domain Reflectrometry (TDR)-based soil moisture measurements. The daily root zone soil moisture dynamics (R: 0.792/0.588 and RMSE: 0.013/0.018 for BDR/JC) estimated by the derived soil parameters were matched well with the TDR-based measurements for validation. During the long-term (2001~2015) period, IWMM irrigated the minimum water amounts to crop fields, while there were no irrigation events during the rainy days. Also, Sandy Loam (SL) and Silt (Si) soils require more irrigation water amounts than others, while the irrigation water were higher in the order of radish, wheat, soybean, and potato, respectively. Thus, the IWMM model can provide efficient irrigation water amounts to crop fields and be useful for regions at where limited water resources are available.

• Magazine of the Korean Society of Agricultural Engineers
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• v.12 no.1
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• pp.1861-1871
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• 1970

This experiment was carried out to compare soil moisture contents and the amounts of irrigation water by varying irrigating methods for chinese cabbages. The irrigating methods were non-irrigation (Plot A), furrow irrigation(Plot B). fixed nozzle pipe irrigation(Plot C), subsoil pipeline irrigation at the depths of 15cm. and 30cm., laying out in the middle of the rows of chinese cabbages(Plot D) and subsoil pipeline irrigation at the depths of 15cm, and 30cm., laying out beneath the rows of the roots of chinese cabbages(Plot E). In this experiment soil moisture contents were measured by using a simple electric device. As a result, the fallowing items are derived; 1) A significionce of 5% was observed between the yields produced at the furrow irrigation plot and fixed nozzle pipe irrigation plot, and those at the non-irrigation plot and subsoil pipe-line irrigation plot. 2) In the subsoil pipe-line irrgatiion, the Plot D type was observed to be slightly better than the Plot E type in the effect of the growth of cabbages. 3) The ratio of the amounts of irrigation water applied in the furrow irrigation plot, fixed nozzle pipe irrigation plot and subsoil pipe-line irrigation plot is approximately 3.2:2.1.

• Weed & Turfgrass Science
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• v.3 no.2
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• pp.130-136
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• 2014

Tall fescue is commonly well-adapted for low maintain area because of its wear resistance, deep root system, and drought tolerances. Deep and infrequent irrigation refers to applying large amounts of irrigation, 1.3 to 2.5 cm or more, in a single irrigation event. Light and frequent irrigation is commonly used with small amounts of water, 0.3 to 0.6 cm, every day or every other day. N use for turfgrass management is often unnoticed for water management. The objective of this field study was to evaluate the effects of irrigation frequency and N rates for tall fescue growth. The three irrigation treatments were no irrigation (precipitation only), 0.5 cm applied every other day, and 1.8 cm applied once a week at one irrigation event. The nitrogen (N) treatments were the low, medium, and high N rate treatments. The low, medium, and high N treatments were applied over 2, 4, and 6 applications, respectively. If high main maintenance of tall fescue is not important and water source is limited, irrigation is not necessary and, the $9.8gNm^{-2}yr^{-1}$ of two applications can be recommended for tall fescue under the weather condition of the study.

• Journal of The Korean Society of Agricultural Engineers
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• v.56 no.4
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• pp.1-8
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• 2014

Appropriate amount of water supply to paddy fields in proper time is important to achieve efficient agricultural water management. The purpose of this study is to evaluate the irrigation water supply adequacy for paddy fields using water level data in irrigation canals. For the evaluation, the real-time water level data were collected from main canals in the Dongjin irrigation district for 2 years. Using the water level data, delivered irrigation water amounts at the distribution points of each canal were calculated. The water balance model for paddy field was designed considering intermittent irrigation and the irrigation water requirement was estimated. Irrigation water supply adequacy was analyzed from main canals to the irrigation blocks based on the comparison between estimated requirement and delivered irrigation water amounts. From the adequacy analysis, irrigation water supply showed poor management condition in 2012 with low efficiency except the Daepyong canal section, and the adequacy in 2013 was good or fair except the Yongsung canal section. When irrigation water for paddy fields was insufficient, water supply adequacy was affected by irrigation area, but when irrigation water was enough to supply, adequacy was affected by distance from main canal to distribution points. These results of the spatial and temporal dimensions of the irrigation adequacy could be utilized for efficient irrigation water management to improve the temporal uniformity and equity in the water distribution for paddy fields.

• Magazine of the Korean Society of Agricultural Engineers
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• v.11 no.1
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• pp.1527-1533
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• 1969

In this experiment furrow and fixed nozzle methods in irrigating chiness cabbages were compared on the grounds of yields and amounts of irrigation water. A simple electric device was used to measure soil moisture contents. As a result, the following items were derived: 1) A slight significance was observed between the yield produced at the furrow irrigation test plot and that at the sprinkler irrigation plot. 2) The ratio of the amount of irrigation water applied at the furrow irrigation plot to that at the sprinkler irrigation plot was approximately 2.7 : 1.

• Magazine of the Korean Society of Agricultural Engineers
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• v.35 no.4
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• pp.31-38
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• 1993

For efficient irrigation of structured horiculture and upland crops, a new technique of drip irrigation using the turbo-tape for Autumn Chinese cabbage was developed. The turbo-tape worked well, and based on this study The following results were obtained ; 1. The emission uniformity of the turbo-tape was very good with a uniformity coefficient of 92.5%. 2. Starting point of irrigation at 80% of the wilting point was better than at the wilting point itself. 3. The irrigation amounts for the Autumn Chinese cabbage cultured ranged 315 to 470mm depending upon the irrigation methods, turbo-tape irrigation method could conserve irrigation water about 37% compared to the furrow irrigation method. 4. Average yields were 2, 430g when the starting point of irrigation was at the wilting point, while 2, 680g when it was at 80% of the wilting point.