• Journal of Bio-Environment Control
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• v.24 no.4
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• pp.333-340
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• 2015

Because soils in reclaimed lands nearby coastal areas have much higher salinity and moisture content than soils in inland area, parts of greenhouses embedded in such soils are exposed to highly corrosive environments. Owing to the accelerated corrosion of galvanized steel pipes for substrucrture and structure of greenhouses in saline environments, repair and reinforcement technologies and efficient maintenance and management for the construction materials in such facilities are required. In this study, we measured the corrosion rates of the parts used for greenhouse construction that are exposed to the saline environment to obtain a basic database for the establishment of maintenance and reinforcement standards for greenhouse construction in reclaimed lands with soils with high salinity. All the test pipes were exposed to soil and water environments with 0, 0.1, 0.3, and 0.5% salinity during the observation period of 480 days. At the end of the observation period, salinity-dependent differences of corrosion rate between black-surface corrosion and relatively regular corrosion were clearly manifested in a visual assessment. For the soils in rice paddies, the corrosion growth rate increased with salinity (0.008, 0.027, 0.036, and $0.043mm{\cdot}yr^{-1}$ at 0, 0.1, 0.3, and 0.5% salinity, respectively). The results for the soils in agricultural fields are 0.0002, 0.039, 0.040, and $0.039mm{\cdot}yr^{-1}$ at 0, 0.1, 0.3, and 0.5% salinity, respectively. The higher corrosion rate of rice-paddy soil was associated with the relatively high proportion of fine particles in it, reflecting the general tendency of soils with evenly distributed fine particles. Hence, it was concluded that thorough measures should be taken to counteract pipe corrosion, given that besides high salinity, the soils in reclaimed lands are expected to have a higher proportion of fine particles than those in inland rice paddies and agricultural fields.

• Journal of the Korea Organic Resources Recycling Association
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• v.9 no.1
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• pp.56-64
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• 2001

Composting of livestock feces is economic and safe process to decrease the possibility of direct leakage of organic pollutants to ecosystem from commercial and environmental point of view. This study was conducted with three different experiments related to composting of livestock feces. The purpose of experiment 1 was to investigate changes of characteristic of compost pile during composting period by low temperature in cold season. To compare composting effect of experimental compost pile and control pile exposed in cold air, experimental compost piles were warmed up by hot air until their temperatures were reached at $35^{\circ}C$. Sawdust, Ricehull and Ricestraw were mixed with livestock feces as bulking agent. The highest temperatures of compost pile during composting period were in sawdust, rice hull, rice straw, and control were $75^{\circ}C$, $76^{\circ}C$, $68^{\circ}C$, $45^{\circ}C$ respectively. Moisture content, pH, C/N and volume of compost were decreased during composting period. Experiment 2 was carried out to study utilization effect of compost by plant. A corn was cultivated for 3 years on fertilized land with compost and chemical fertilizer. The amount of harvest and nutrition value of corn were analyzed. In first year of trial, the amount of harvest of corn on land treated with compost was lower by 20% than that of land treated with chemical fertilizer. In second year, there was no difference in yield of com between compost and chemical fertilizer. In third year, the yield of com on land fertilized with compost was much more than that of land fertilized with chemical fertilizer. The purpose of experiment 3 was to estimate the decrease of malodorous gas originating from livestock feces by bio-filter. Four types of bio-filters filled with saw dust, night soil, fermented compost and leaf mold were manufactured and tested. Each bio-filter achieved 87-95% $NH_3$ removal efficiency. This performance was maintained for 10 days. The highest $NH_3$ removal efficiency was achieved by leaf mold on the first day of operation period. It reduced the concentration of $NH_3$ by about 95%. Night soil and fermented compost showed nearly equal performance of 93 to 94% for 10 days from the beginning of operation. The concentration of hydrogen sulfide and methyl mercaptan originating for compost were equal to or less than $3mg/{\ell}$ and $2mg/{\ell}$, respectively. After passing throughout the bio-filter, hydrogen sulfide and methyl mercaptan were not detected.

• Journal of The Korean Society of Grassland and Forage Science
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• v.6 no.1
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• pp.31-37
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• 1986

In order to study the possibility of grassland improvement by spring sowing in the forest, microenvironmental conditions, emergence, percentage of grasses and weeds, root weight and dry matter yield of grasses were investigated. Two field sites (forest grassland and full-sunlight grassland) and two sowing times (March 20 and April 10) were assigned. The condition of the forest grassland was area of pine trees with 50% shading, and the experiment was performed at the Livestock Experiment Station in Suweon, 1984. The results obtained are summarized as follows: 1. For germination and early growth of grasses, full-sunlight grassland was more advantageous than forest grassland. Growth after that stage, on the other hand, forest grassland was more suitable. Especially, during dry and high temperature season, temperature of soil surface and underground in the forest grassland were decreased by $6-7^{\circ}C$ and $3-4^{\circ}C$ each other, compared with those of the full-sunlight grassland. Also soil moisture content was continuously higher in the forest grassland. 2. At March 20 sowing the emergence time in the full-sunlight grassland was shortened by 8 days, compared with that of the forest grassland. In case of sowing on April 10, however, there was no difference between two grassland sites. 3. Grasses grown in the forest was more prostrate and leaves from them decayed more, compared with those of the full-sunlight grassland. 4. The percentage of grasses in the forest grassland was 80 to 85 %, on the other hand, that of the full-sunlight grassland was only 15 to 20 %. And the percentage of grasses tended to be high in the plot of early sowing time. 5. Dry root weight and root length of grasses grown in the forest were inferior to those of the full-sunlight grassland (P<0.05), but there was no significant difference between two sowing times. 6. Dry matter yield of grasses was significantly higher (P<0.05) in the forest grassland than in the full-sunlight grassland, and yield was influenced by sowing time. Higher yield (4,011 kg/ha) was produced in the plot of the forest grassland with early spring sowing. 7. From above results, it is suggested that grassland improvement by spring sowing in the forest is possible, and it is desirable to sow in early spring.

• Journal of the Korean Wood Science and Technology
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• v.28 no.2
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• pp.57-65
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• 2000

Objective of research is obtain fundamental data of carbonized wood wastes for soil condition, de-ordorization, absorption of water, carrier for microbial activity, and purifying agent for water quality of river. The carbonization technique and the properties of carbonized wood wastes(wood-based materials) were analyzed. Proximate analysis showed the wood-based materials contains 0.37~2.27% ash, 70~74% volatile matter, and 17~20% fixed carbon. As carbonization temperature was increased, the charcoal yield was decreased. However, no difference in charcoal yield was found due to time increase. The specific gravity after the carbonization decreased about 30~40% comparing to green wood. The charcoal had 1.08~4.18% ash, 5.88~13.79% volatile matter, and 80.15~90.94% fixed carbon. The pH of plywood and particleboard(pH 9 at $400^{\circ}C$, pH 10 at $600^{\circ}C$ and $800^{\circ}C$) made charcoals was higher than that of fiberboard. The water-retention capacity was not affected by the carbonization temperature and time. The water-retention capacity within 24h was about 2~2.5 times of sample weight, and the Equilibrium moisture content(EMC) became 2~10% after 24h. EMC of charcoal from the thinned trees were 9.40~11.82%($20^{\circ}C$, RH 90%), 6.87~7.61%($20^{\circ}C$, RH 65%), and 1.69~2.81%($20^{\circ}C$, RH 25%). EMC of charcoal from the wood-based materials under $20^{\circ}C$, relative humidity(RH) 90% was similar to EMC of charcoal from the thinned trees(9~11 %). However, under $20^{\circ}C$, RH 25.65%, EMC of charcoal from the wood-based materials were higher(2~3%) than EMC of charcoal from the thinned trees. Every charcoal from the wood-based materials fulfilled the criteria in JWWA K 113-1947.

• Korean Journal of Plant Resources
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• v.24 no.4
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• pp.413-418
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• 2011

This study was carried out to establish a proper cultivation site and diagnose the drought-tolerance of Aster scaber and Synurus deltoides leaves by using Pressure-volume curves. In order to measure pressure-volume (P-V) curves, Aster scaber and Synurus deltoides were cut off above ground part and the tip of the cutting were placed in water, which was covered with a plastic bag. Samples were kept overnight (about 12 hours) in darkness at room temperature (20~25$^{\circ}C$) to achieve maximal turgor (full saturation). The pressure in the chamber was gradually increased from 0.3MPa to 1.8MPa by nitrogen gas. After measured, leaf samples were dried at 80$^{\circ}C$ for 48 hours and dry weight of each samples were determined. The result of the original bulk osmotic potential at maximum turgor ${\Psi}^{sat}_o$ sat was lower -0.8 MPa in Aster scaber leaves than -0.7 MPa Synurus deltoides leaves. Also the osmotic potential at incipient plasmolysis ${\Psi}^{tlp}_o$ in Aster scaber leave was -0.9 MPa. In contrast, the value of maximum bulk modulus of elasticity $E_{max}$ of Aster scaber leaves were approximately two folds higher than that of Synurus deltoides leaves. The values of the relative water content at incipient plasmolysis $RWC^{tlp}$ are all above 90% showing that the function of osmoregulation is somewhat better, and Vo/DW, Vt/DW, Ns/DW of Synurus deltoides leaves were approximately 1~2 times higher than that of Aster scaber leaves. Thus, responses to water relations of Aster scaber and Synurus deltoides such as ${\Psi}^{sat}_o$, ${\Psi}^{tlp}_o$, $E_{max}$, ${\Psi}_{P,max}$, $RWC^{tl}$ were shown that the Aster scaber leaves was slightly higher drought-tolerance than Synurus deltoides leaves. However, in both of Aster scaber and Synurus deltoides, occurring incipient plasmolysis at the high water content, have a relatively lower drought-tolerance property indicating that growth of these plants are cultivated appropriate in high moisture soil sites.

• Food Science and Preservation
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• v.21 no.6
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• pp.808-814
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• 2014

The nutrient contents of pumpkins depend on many factors, including the species, climate, soil type, and plant part. The nutritional compositions of five pumpkin cultivars (red boujjang, mini hong, mini gold, boujjang, and yakhobak) were investigated. To analyze the nutrient contents of the edible parts, the other parts (seeds, skin, and stem) of each pumpkin were removed. The results showed that the proximate compositions of the edible parts of the pumpkins ranged from 74 to 87 g per 100 g for moisture, 1.6 to 3.2 g per 100 g for crude protein, 10.1 to 20.7 g per 100 g for carbohydrate content, and 2.0 to 3.4 g per 100 g for total dietary fiber. The proximate contents of the pumpkin samples were not significantly different. The thiamine contents of the pumpkins, except for red boujjang, varied from 0.03 to 0.15 mg per 100 g, but that of red boujjang had the highest level (0.60 mg per 100 g). The vitamin C contents of the pumpkins, except for boujjang, ranged from 13.0 to 14.0 mg per 100 g, but that of boujjang was the highest (49.0 mg per 100 g). In particular, yakhobak showed the highest total carotenoid and folate levels (279.5 and $74.0{\mu}g$ per 100 g, respectively). These results will be useful for coming up with better pumpkin varieties through breeding, and established the nutrient compositions of pumpkins.

• Magazine of the Korean Society of Agricultural Engineers
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• v.13 no.2
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• pp.2262-2275
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• 1971

Fourteenes rervoirs maintained by the local land improvement associations in the province of Chullabuk-Do and 20 reservoir maintained by thos in the province of Chullanam-Do, were surveyed in connection with a correction between storage capacity and sediment deposit. In addition to this survey, 3,347 of small reservoir, that lie scattered around in the above-mentioned two provinces were investigated by using existing two provinces were investigated by using existing records pertaining to storage capacity in the office of City and country, respectively. According to this investigation the following comclusions are derived. 1. A sediment deposition rate is high, being about $10.63m^3/ha$ of drainage area, and resulting in the average decreasc of storage capaity by 27.5%. This high rate of deposition coule be mainly attributed to the serve denudation of forests due to disorderly cuttings of trees. Easpecially, in small reservoir, an original average design storage depth of 197mm in irrigation water depth is decreased to about 140mm. 2. An average unit storage depth of 325.6mm as the time of initial construction is decreased to 226mm at present. This phenomena causes a greater shortage irrigation water, since it was assumed that original storage quantity was already in short. 3. Generally speaking, seepage rates through dam abutment intakepipe, etc, are high due to insufficient maintenance and management of reservoir. 4. It is recommended that sediment deposit should be dredged when a reservoir is dry in drought. 5. Farmers usually waste excessive irrigation water. 6. Water saving methods should be practiced by applying only necessary water for growing stage of rice. 7. In are as where water defficiency for irrigation is severe, a soil moisture content should be kept at about 70% by applying water once in several days. 8. Tube wells should be provided so as to exploit ground water and subsurface current below stream bed as much as possible. 9. If an intake weir was constructed, a water collection well should be built for the use in drought. 10. Water conservation should be forced by converting devastated forests contained in the drainage area of reservoir to protected forests so as to take priority of yrefor estation, gully control, the prohibition of disorderly cutting of trees, etc. 11. Collective rice nurseries should be adopted, and it should be recommended that irrigation water for rice nurseries is supplied by farmer themselves. 12. Sediment desposit in reservoir should be thoroughly dreged so as to secure a original design storage capacity. 13. The structure of overflow weir should be automatic so as to freely control flood level and not to increase dam height.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.63 no.2
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• pp.140-148
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• 2018

As the global warming causing desertification increase, there is growing concern about damage of crops. It was to investigate how the treatment with hydrogen peroxide before leaf development affects the growth and yield of sorghum for minimizing a damage of crops to drought. The germination experiment was conducted at alternating temperature of $25^{\circ}C/20^{\circ}C$(12 hr/12 hr) under water stress condition of 0 ~ -0.20 MPa adjusted with PEG solution containing 0 and 10 mM $H_2O_2$. In order to know the effect of foliar application of hydrogen peroxide on the growth of sorghum, 10 mM hydrogen peroxide was treated to leaves at 3-leaf stage of sorghum growing in greenhouse conditions. Seed germination rate was increased by 20% in hydrogen peroxide treatment as compared to the Control. under water stress conditions (-0.15 ~ -0.20 MPa). The length of seedlings was also on the rise by the hydrogen peroxide treatment. In the greenhouse pot experiment, the morphological characteristics (plant height, stem diameter, leaf length, and leaf number) and physiological characteristics (chlorophyll content, chlorophyll fluorescence (Fv/Fm), stomatal conductance) were higher in the plants treated with hydrogen peroxide under the drought stress condition than those of plants of $H_2O$ treatment. Experiment conducted with the soil moisture gradient system showed that the foliar application of hydrogen peroxide increased photosynthetic ability of sorghum plant with respect to SPAD value and stomatal conductance and rooting capacity (root weight and root length) under drought condition. Generally, hydrogen peroxide treatment in sorghum increased the tolerance to drought stress and maintained better growth due to ameliorating oxidative stress.