• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.34 no.s02
• /
• pp.66-80
• /
• 1989

Salt injury in rice is caused mainly by the salinity in soil and in the irrigated water, and occasionaly by salinity delivered through typhoon from the sea. The salt concentration of rice plants increased with higher salinity in the soil of the rice growing. The climatic conditions, high temperature and solar radiation and dry conditions promote the salt absorption of rice plant in saline soil. The higher salt accumulation in the rice plant generally reduces the root activity and inhibits the absorption of minerals of rice plant, resulting the reduction of photosynthesis. The salt damages of rice plant, however, are different from different growth stage of rice plants as follows: 1. Germination of rice seed was slightly delayed up to 1.0％ of salt concentration and remarkably at 1. 5％, but none of rice seeds were germinated at 2.5％. This may be due to the delayed water uptake of rice seeds and the inhibition of enzyme activity, 2. It was enable to establish rice seedlings at seed bed by 0.2％ of salt concentration with some reduction of leaf elongation. The increasing of 0.3％ salt concentration caused to the seedling death with varietal differences, but most of seedlings were death at 0.4％ with no varietal differences. 3. Seedlings grown at the nursery over 0.1％ salt, gradually reduced in rooting activity after transplanting according to increasing the salt concentration from 0.1％ up to 0.3％ of paddy field. However, the seedlings grown in normal seed bed showed no difference in rooting between varieties up to 0.1％ but significantly different at 0.3％ between varieties, but greatly reduced at 0.5％ and died at last in paddy after transplanting. 4. At panicle initiation stage, rice plant delayed in heading by salt damage, at meiotic stage reduced in grains and its filling rate due to inhibition of glume and pollen developing, and salt damage at heading stage and till 3 weeks after heading caused to reduction of fertilization and ripening rate. In viewpoint of agricultural policy the overcoming strategy for salt injury is to secure sufficient water source. Irrigation and drainage systems as well as underground drainage is necessary to desalinize more effectively. This must be the most effective and positive way except cost. By cultural practice, growing the salt tolerant variety with high population could increase yield. The intermittent irrigation and fresh water flooding especially at transplanting and from panicle initiation to heading stage, the most sensitive to salt injury, is important to reduce the salt content in saline soil. During the off-cropping season, plough and rotavation with flooding followed by drainage, or submersion and drainage with groove could improve the desalinization. Increase of nitrogen fertilizer with more split application, and soil improvement by lime, organic matter and forign soil addition, could increase the rice yield. Shift of trans-planting is one of the way to escape from the salt injury.

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.27 no.4
• /
• pp.229-234
• /
• 2007

To select the most proper soil for root initiation from stem cuts of Birdsfoot trefoil (Lotus corniculatus L.), eight-week-old stem cuts were cultured on three types of soil [commercial bed soil, decomposed granite (DCG), and river sand] for one month. The results showed that the root initiation ratios on DCG (77.8%) and river sand (70.0%) were relatively high, but the ratio on commercial bed soil (41.1%) was very low. To examine the effect of rare earth (RE) and Indole-3-Butyric Acid (IBA) on root initiation from stem cuts of Birdsfoot Trefoil, stem cuts were cultured on two types of soil (DCG and river sand) with treatment of RE and IBA for one month. The root initiation ratios turned out to be 90.0% (DCG with 60 ppm of RE), 80.0% (river sand with 20 ppm of RE), 96.7% (DCG with 40 ppm of IBA), and 96.7% (river sand with 40 ppm of IBA). These results suggested that the most efficient way for root initiation of Birdsfoot trefoil was to culture the stem cuts on river sand or DCG over 30 days with IBA treatment (40 ppm).

• Journal of the Korean GEO-environmental Society
• /
• v.15 no.4
• /
• pp.13-27
• /
• 2014

Catchments soil erosion, one of the most serious problems in the mountainous environment of the world, consists of a complex phenomenon involving the detachment of individual soil particles from the soil mass and their transport, storage and overland flow of rainfall, and infiltration. Sediment size distribution during erosion processes appear to depend on many factors such as rainfall characteristics, vegetation cover, hydraulic flow, soil properties and slope. This study involved laboratory flume experiments carried out under simulated rainfall in a 3.0 m long ${\times}$ 0.8 m wide ${\times}$ 0.7 m deep flume, set at $17^{\circ}$ slope. Five experimental cases, consisting of twelve experiments using three different sediments with two different rainfall conditions, are reported. The experiments consisted of detailed observations of particle size distribution of the out-flow sediment. Sediment water mixture out-flow hydrograph and sediment mass out-flow rate over time, moisture profiles at different points within the soil domain, and seepage outflow were also reported. Moisture profiles, seepage outflow, and movement of overland flow were clearly found to be controlled by water retention function and hydraulic function of the soil. The difference of grain size distribution of original soil bed and the out-flow sediment was found to be insignificant in the cases of uniform sediment used experiments. However, in the cases of non-uniform sediment used experiments the outflow sediment was found to be coarser than the original soil domain. The results indicated that the sediment transport mechanism is the combination of particle segregation, suspension/saltation and rolling along the travel distance.

• Journal of the Korean Society of Environmental Restoration Technology
• /
• v.14 no.5
• /
• pp.127-136
• /
• 2011

This study was conducted on the field application for a method which is currently used. Although the method was performed with experimental knowledge, this study attempted to approach scientific ways through thirty sets of test-bed and three times monitoring limited by control variations for three months. The factors on previous studies are slope location, slope degree, type (roadfill vs. roadcut), aspect, vegetation cover, species, thickness, vertical length, horizontal length, soil type, elevation, erosion, soil-moisture, soil-hardness, pH, and so on. However, the factors of a suitable and significant level are slope degree, type, aspect, thickness, soil-moisture, vertical length and horizontal length in slope revegetation. the results were as follows : As a result of survey on soil types based on the status before construction, the rate of vegetation cover with non-mesh construction in soil areas was better than the rate of vegetation cover with fiber meshes and wire meshes. The rate of vegetation cover with fiber meshes in weathered rocks was better than using wire meshes. The rate of vegetation cover with the wire meshes in blasted rocks was better than using fiber meshes. Also, the factors affecting the rate of vegetation cover presented the number of appearance species, soil-moisture, thickness. this result presented the more appearance species as a positive role, and the lower soil-moisture and the thicker soil as a negative role.

• Journal of The Korean Society of Agricultural Engineers
• /
• v.54 no.6
• /
• pp.77-87
• /
• 2012

Recently, Load and Resistance Factor Design (LRFD) based on reliability analysis has become a global trend for economical and rational design. In order to implement the LRFD, quantification of uncertainty for load and resistance should be done. The reliability of result relies on input variable, and therefore, it is important to obtain exact uncertainty properties of load and resistance. Since soil stress is the main reason causing the settlement or deformation of ground and load on the underground structure, it is essential to clarify the uncertainty of soil stress distribution for accurately predict the uncertainty of load in LRFD. In this study, laboratory model test on silty sand bed under probabilistic load is performed to observe propagation of upper load uncertainty. The results show that the coefficient of variation (COV) of soil stress are varied depending on location due to non-linear relationship between upper load increment and soil pressure increment. In addition, when the load uncertainty is transmitted through ground, COV is decreased by damping effect.

• Journal of Forest and Environmental Science
• /
• v.36 no.1
• /
• pp.55-61
• /
• 2020

In this study, basic data with respect to the introduction of Hipphophae rhamnoides L. and its cultivation in Korea could be obtained. According to the size of the plug cell tray, Chinese origin's rate of seed germination was relatively high in 128 plug cell tray, and growth was vibrant in 50 plug cell tray. The germination and growth of Russian origin seeds showed that they were relatively effective in 50 plug cell tray and with respect to soil environment, TKS-2 soil with untreated shading relatively promoted both germination and growth for Chinese origin, the rate of germination was high in bed soil for horticulture and growth result was good in TKS-2 in the case of Russian origin. It was confirmed that the germination rate of Chinese origin H. rahmnoides L. was highest in untreated shading and the shoot growth was vibrant in 70% shading while the growth in roots was vibrant in the untreated shading. In the Russian origin, H. rhamnoides L. the germination rate in 30% and 70% shading was about 50% which was higher than that in the untreated shading and general growth was vibrant in 30% shading.

• Asian-Australasian Journal of Animal Sciences
• /
• v.6 no.2
• /
• pp.205-209
• /
• 1993

A new treatment system for animal waste water has been developed as an alternative to the activated sludge process. It consists of two treatments; one is operated with 7 tanks, and the other is soil and plant cultivation bed. Aerobic microorganisms are added to the influent water in the tanks where the water is aerated so that the microbes utilize the pollutants, while sedimentation removes the indigestible solids. In the secondary treatment the water, which has already received a primary treatment, is filtered through soil where it also receives treatment by soil organisms. In addition there is transpiration of water and absorption of minerals by plants. In the primary treatment BOD, SS, coliforms (E. coli), TP and total bacteria were removed 79-99%, but COD and TN were removed only 58% and 36%, respectively. In the secondary treatment removal of nutrients proceeded further, and 93-99% of pollutants were removed. The treated waters met the quality standard of discharge water in Japan except for TN, which was in too great a concentration to meet discharge standards. This problem requires further study.

• Korean journal of food and cookery science
• /
• v.17 no.5
• /
• pp.510-516
• /
• 2001

Hydroponic cultivation is a technology of raising crops without use of soil. Generally farmers use the method of DFT(deep flow technology)to grow leafy or fruity vegetables; however, systematic and scientific researches are insufficient on this matter. This study investigated the possibility of cultivating Chinese cabbage steadily year long by using the method of DFT. Chinese cabbage was cultivated hydroponically with and without Ge addition, used to prepare kimchi, and the chemical and microbiological characteristics of kimchi were compared. The basic hydroponic cultivation condition was as follows: 30 days after seeding, the raised seeds were moved to a hydroponic bed and given underground water for 3 days so the roots grow normally Standard nutrient solution was provided and the early electric conductivity concentration was maintained between 1.5∼2.5 thickness. The temperature of the solution was maintained between 10 ∼25$^{\circ}C$ to allow the growth of Chinese cabbage. When soil-cultivated, organically cultivated and hydroponically cultivated Chinese cabbages were compared, hydroponically cultivated cabbages were smaller in size and showed less ability to build up and fold leaves into a head, but showed better quality than organically cultivated cabbages. The contents of protein and fat showed no significant differences. The contents of water. Ca, P, Fe, Vitamin A and Niacin were higher in control and Ge-added cabbages compared with soil-grown cabbage. There was no difference between soil-cultivated Chinese cabbage kimchi and hydroponically cultivated Chinese cabbage kimchi.

• Journal of the Korean Institute of Landscape Architecture
• /
• v.16 no.1
• /
• pp.37-42
• /
• 1988

For the purpose of cultivating landscape plants, the culture soil of briquet ashes and sludge cakes from urban drainages was used as a bed soil. And Taxus cuspidata, syringa vulgaris, Ligstrum obtusifolia and Buxus microphylla were selected as experimental materials on this soil. The comparison of their growth showed the following results. Each plant showed a slight difference in primary growth and two months after planting, there were notable differences between treated and control plots respectively. Syringa vulgaris shoved the highest growth and the next were Ligstrum obtusifolia and Taxus cuspidata in series. Especially Taxus cuspidata showed the lowest quantity of dry weight compared with other plants, and influenced a little by mean temperature and solar radiation. It is expected to get a high effect in landscape planting by using briquet ashes and sludge cakes.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.46 no.3
• /
• pp.165-169
• /
• 2001

Seed coat of sword bean (Canavalia gladiata) is very thick and hard, it is difficult to absorb water during germination and it requires much time that cotyledon come out from seed coat since seminal root appearanced. Therefore this experiment was carried out to increase the germination rate by easing water absorption through mechanical scarification on seed coat. Non-scarification seed did not germinated at 7 days after treatment but scarification seed showed germination rate of 98%. Therefore mechanical scarification of seed coat was increased germination rate. Non-scarification seed absorbed less than 10% water of dry weight at 8 hours after treatment but scarification seed absorbed about 90% water at 7 hours after treatment and more than 150% water at 8 hours and swelled about 1.4-1.5 times in length and width of seed. Germination rate of scarification seed was high under high temperature and it was 96% and 93% at $25^{\circ}C$ and 3$0^{\circ}C$, respectively. The rate of cotyledon emergence on clay loam soil was the highest among bed soils. Soaked seed after mechanical scarification in distilled water was germinated faster than non-soaked seed on early in bed soil. The rate of cotyledon emergence was more than 92% at 9 days after sowing but non-scarification and soaked seed was germinated late and showed very low germination rate as 67%.