• Magazine of the Korean Society of Agricultural Engineers
• /
• v.32 no.1
• /
• pp.72-86
• /
• 1990

This study was carried out to get the basic information of irrigation plans for upland crops such as the optimum irrigation level and the project water requirement. Red peppers and cucumbers were cultivated in PVC pot lysimeters filled with 60cm deep clay loam soil. Four tensiometers were installed in each pot to measure the soil water pressure head. Six levels of irrigation were used. The results obtained from this study are summarized as follows: 1.The optimum irrigation level. The irrigation level of FC-PF2.7 was found to be the optimum level for both red pepper and cucumber with respect to the yield and the weight per fruit. In case of FC-PF2.7, total ET during the irrigation period were 1005.2mm for red pepper, and 429.6mm for cucumber, respectively. 2.soil moisture extraction patterns. Average soil moisture extraction patterns (SMEP)during the irrigation period were from 1st soil layer 43% : 32% : 16% : 9% for red pepper and 39% : 34% : 15% : 12% for cucumber, respectively. The extraction ratio of the upper soils showed very large values during the early stage of growth and decreased largely during the middle stage, and became larger in the last stage. 3.The project water requirement. Among the reference crop evapotranspiration(ETo) computation methods presented by FAO, the Penman method was found to be the best. The effective rainfall was computed by a modified USDA-SCS curve number equation. Availability ratios of the total rainfall during irrigation season were 59.2% for red pepper and 48.9% for cucumber, respectively. Net project water requirement of design year are 837.3mm for red pepper. and 502.Smm for cucumber, respectively.

• KCID journal
• /
• v.11 no.1
• /
• pp.64-76
• /
• 2004

For effective development of upland areas, e development model of upland area integrated improvement project are suggested which on standard type and integrated infrastructure improvement type, rural Income raising type and eco-friendly consolidation type

• Magazine of the Korean Society of Agricultural Engineers
• /
• v.38 no.1
• /
• pp.98-106
• /
• 1996

An irrigation scheduling model, IRIS developed to evaluate irrigation demand and irrigation time for upland crops. For IRlS modeling the soil moisture simulation model, SWATRER was adopted and modified. The developed model, IRIS operated under 5 different soil moisture level that is 20%, 40%, 60%, 80% of available soil moisture and optimum soil moisture level, OSML, which is different about the growing stage and no rainfall condition during growing period. As a result for IRIS simulation, irrigation demand for 5 different soil moisture level was 332.3, 409.8, 569.3, 732.2, 539.3mm, irrigation number was 5, 8, 18, 54, 16 times and irrigation interval during peak time of consumptive use was 20, 13, 6, 2, 6 days respectively. It is appeared that the higher soil moisture level the more irrigation demand and irrigation number and the higher soil moisture level the less irrigation interval.

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

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.44 no.4
• /
• pp.330-338
• /
• 1999

Extensive research has been conducted on effects of drought stress on growth and development of soybean but information is rather restricted on the limited-irrigation system by way of precaution against a long-term drought condition in the future. The experiment for limited-irrigation was conducted in transparent vinyl shelter at Asian Vegetable Research and Development Center (AVRDC), Taiwan in 1997. Two soybean varieties, Hwangkeum and AGS292, improved in Korea and AVRDC, respectively were used for this experiment. The relationships between normalized transpiration rate (NTR) and fraction of transpirable soil water (FTSW) in both varieties were similar that the NTR was unchanged until FTSW dropped to about 0.5 or 0.6. At FTSW less than those values, NTR declined rapidly. Days required to harvest in both varieties were significantly prolonged at IR6 treatment compared to any other treatments. Daily mean transpiration rate was significantly higher at IR5 treatment, as averaged over varieties. Similarly, water use efficiency was also high at 1R5 treatment. In both varieties, seed yield was the greatest at the IR5 treatment, as compared to any other limited-irrigation treatments, due to the increased seed number and high transpirational water use efficiency. The indices of input water and seed yield for the different limited-irrigation treatments against control indicated that Hwangkeum produced 59.6% or 60.7% of seed yield using 36.1% or 44.9% of input water, as compared to control, by irrigation at only R5 or R6 stages, respectively. The AGS292 produced 56.1% of seed yield with 35.4% of input water of control, when irrigated at R5 stage. The results of this study have elucidated that the limited irrigation at R5 stage in soybean can be minimized yield loss with such small quantity of water under the environment of long-term drought stress and the expected shortage of agricultural water in the future.

• Journal of The Korean Society of Agricultural Engineers
• /
• v.58 no.5
• /
• pp.81-90
• /
• 2016

Due to droughts and water shortages causing severe damage to crops and other vegetations, much attention has been given to efficient irrigation for upland farming. However, little information has been known to measure soil moisture levels in a field scale and apply their spatial variability for proper irrigation scheduling. This study aimed to characterize the spatial variability and temporal stability of soil water contents at depths of 10 cm, 20 cm and 30 cm on flat (loamy soil) and hill-slope fields (silt-loamy soil). Field monitoring of soil moisture contents was used for variogram analysis using GS+ software. Kriging produced from the structural parameters of variogram was applied for the means of spatial prediction. The overall results showed that the surface soil moisture presented a strong spatial dependence at the sampling time and space in the field scale. The coefficient variation (CV) of soil moisture was within 7.0~31.3 % in a flat field and 8.3~39.4 % in a hill-slope field, which was noticeable in the dry season rather than the rainy season. The drought assessment analysis showed that only one day (Dec. 21st) was determined as dry (20.4 % and 24.5 % for flat and hill-slope fields, respectively). In contrary to a hill-slope field where the full irrigation was necessary, the centralized irrigation scheme was appeared to be more effective for a flat field based on the spatial variability of soil moisture contents. The findings of this study clearly showed that the geostatistical analysis of soil moisture contents greatly contributes to proper irrigation scheduling for water-efficient irrigation with maximal crop productivity and environmental benefits.

• KCID journal
• /
• v.9 no.1
• /
• pp.9-13
• /
• 2002

• Magazine of the Korean Society of Agricultural Engineers
• /
• v.19 no.2
• /
• pp.4347-4353
• /
• 1977

• KCID journal
• /
• v.12 no.1
• /
• pp.50-59
• /
• 2005

This study was carried out to obtain basic data for the agricultural water development project in Jeju-do. In this study, Jeju-do was divided into four regions considering the precipitation and soil characteristics. Water used for irrigation of the major

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