• Magazine of the Korean Society of Agricultural Engineers
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• v.39 no.1
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• pp.93-101
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• 1997

This paper presents yield surfaces and hardening laws for describing the state of an unsaturated soil under isotropic compression and suction changes. The yield surface is formulated within the framework of hardening plasticity using two independent sets of stress variables : the excess of total stress over air pressure and the suction. And the application of the yield surfaces and hardening laws are confirmed from the result of the experiment. To this end a series of suction-controlled isotropic tests are conducted on clayey soils. Matric suction is controlled by the axis translation technique using high air entry ceramic disk. The specimens are compacted using a half of Proctor compaction energy with 5 % lower of water content than the optimum moisture contents. From test results, existence of the yield surfaces and an application of hardening laws to samples are confirmed by comparison between test and predicted results. And it is confirmed that LC yield locus is extened with the total plastic deformations induced by suction or stress changes, however, SI yield locus is only extended with the plastic deformations by induced suction changes.

• Journal of The Korean Society of Grassland and Forage Science
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• v.17 no.2
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• pp.110-116
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• 1997

The objective of this experiment was to suggest the optimum nitrogen fertilization level for orchardgrass(0G)- red clover(RC) mixtures. The field trials were conducted from 1993 to 1994 in order to evaluate the dry matter yield, botanical composition, chemical composition, dry matter digestibility(DMD), crude protein dry matter (CPDM) and digestible dry matter(DDM) yields on the nitrogen levels( 0, 50, 100, 150 and 300kgha). The results obtained were summarized as follows : 1. With increasing nitrogen levels, the DM yield of OG-RC mixttures significantly increased(P<0.05). The maximum total DM yield (7,964kgha) was obtained at N 300kgha level, However, there was no significant difference between N 150 and 300kgha. 2. With increasing the nitrogen levels, the botanical composition of OG in OG-RC mixttures was significantly increased(P< 0.05), whereas that of RC was remarkably decreased(P< 0.05). 3. The CP content was decreased by increasing nitrogen level(P

• Korean Journal of Soil Science and Fertilizer
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• v.48 no.3
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• pp.218-224
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• 2015

Zeolite may help crop growth, yield increase, and salt removal. Field experiment under greenhouse cultivation was conducted to study the effect of zeolite application on growth and yield of Chinese cabbage (Brassica campestris L.) and soil. Soil was classified as Gyuam series (coarse silty, mixed, nonacid, mesic family of Aquic Fluvaquentic Eutrudepts). Six zeolite rates were 0, 3, 5, 10, 20 and $40Mg\;ha^{-1}$. Experimental design was a completely randomized design. Chinese cabbage was grown three times consecutively. Established plant number of plant and yield as fresh weight (F.W.) were measured and soil samples were taken before and after harvesting. Chinese cabbage yield was $76.9Mg\;ha^{-1}$ at a rate of $20Mg\;zeolite\;ha^{-1}$, $54.3Mg\;ha^{-1}$ at a rate of $5Mg\;zeolite\;ha^{-1}$, and $51.3Mg\;ha^{-1}$ at control (no zeolite), respectively. Second order regression analysis using zeolite rate and yield showed that optimum zeolite application rate was between 24 and $26Mg\;ha^{-1}$. The regression equation explained about 88% of the yield variability. The electrical conductivity (EC) decreased from 3.2 to $1.0dS\;m^{-1}$ for all treatments so that salt accumulation was not a concern. Based on the results, we recommend that optimum zeolite application rate is between 20 and $24Mg\;ha^{-1}$ for Chinese cabbage under greenhouse cultivation.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.29 no.3
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• pp.218-226
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• 1984

This study was conducted to establish fundamental of cultivation system in the southern warm region of Korea by investigation of variation of yield component and yield under the different nitrogen fertilizing levels. And that levels in this experiment were 10, 15, 20 and 25 Kg/10a. Optimum fertilizing level of nitrogen was 20 kg/10a in Seokwang variety and 25 kg/ 10a in Dongjin variety. On the optimum fertilizing level (Seokwang; 20 kg/10a, Dongjin; 15 kg/10a), the correlation coefficient between No. of panicles per unit area and the rate of ripened grains were showed negative correlation (Seokwang; r =-0.6023$\^$*/, Dongjin; r=-0.858l$\^$**/). In the primary, secondary branches and spikelets, the degeneration ratio was increased significantly under the level of N=25 kg/10a in Seokwang, N$\geq$20 kg/10a in Dongjin. In Dongjin, the rate of ripened grains was decreased with increase in nitrogen fertilizing levels and that caused to decrease the yield.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.1
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• pp.1-13
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• 2006

Response of grain yield and milled-rice protein content to nitrogen topdress (N) timing at panicle initiation stage (PIS) is critical for quantifying real-time N requirement for target grain yield and milled-rice protein content. Two split-split-plot experiments with three replications, one in 2004 and the other in 2005, were conducted in Experimental Farm, Seoul National University, Suwon, Korea. The experiments included three N rates at tillering stage (TS), three N timing treatments at panicle initiation stage (PIS) and two rice cultivars. The N rates at TS, N timing at PIS, and rice cultivars were randomly assigned to main plot, sub plot, and sub-sub plot, respectively. Results showed that the delayed N application at PIS reduced grain yield in 2004 and increased milled-rice protein content in both years significantly at 0.05 probability level. The calculated optimum N timing at PIS from pooled data by N rates and rice cultivars in two years was at 28 days before heading (DBH). However, real-time of N timing at PIS was dependent on plant growth and N status around PIS that in turn was dependent on applied N rates at TS. The optimum N timing at PIS was at 30 DBH for no N treatments at TS while at 27 DBH for 3.6 and 7.2 kg N/10a treatments and at 27 and 29 DBH for Hwaseongbyeo and Daeanbyeo, respectively. In general, earlier applied N at PIS resulted in lower milled-rice protein content but the highest grain yield was expected to be obtained when N topdress at PIS was applied at the time when shoot N concentration started to drop below about 23 mg/g due to dilution effect after transplanting. In conclusion, the results of our experiments imply that the currently recommended N topdress time (24DBH) at PIS in Korea should be reconsidered for the higher grain yield and the better quality of rice.

• CELLMED
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• v.11 no.3
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• pp.15.1-15.9
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• 2021

The chemical constitution of a drug has been accepted as an important basis for pharmacological action in Unani medicine. Various dosage forms have been developed on this concept, such as decoctions (Joshanda), infusions (Khesanda), extract (Rub / Usara), and syrup. Zarawand Mudaharaj (ZM.) / Aristolochia rotunda L. root was subjected to extraction process using Soxhlet's apparatus by using Response Surface Methodology (RSM) to design the number of random runs of the extracts with variation in the factors of temperature, the concentration of ethanol in water, time for extraction, for optimizing and maximizing the yield concentration. The data obtained, was analyzed with regression equation and ANOVA two-way summary to interpret the interaction of the factors for yield maximization. Minitab version 18 was used to design and analyze data. Validation of the optimum conditions for maximum yield of the whole extract of ZM. Root was carried out by re-run of the extract using the optimized conditions. The maximum yield percentage thus obtained using RSM was 20.87% whereas using these optimum conditions 21.35 % yield was obtained thereby validating the method. The association between the response functions and the process variables was identified by a three-factor recorded Box-Behnken design. In the present study RSM is used because itis a cheap and affordable method to optimize maximum yield percentage which may be reliably used by researchers. The study set in the surface conditions for ZM. root extraction by the Soxhlet apparatus for maximizing the yield percentage.

• Korean Journal of Environmental Agriculture
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• v.42 no.4
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• pp.297-310
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• 2023

M.7 rootstock is moderately resistant to fire blight. However, M.7 is generally too vigorous for high-density apple systems, but it can be grafted onto cultivars that exhibit weak tree growth, such as 'Sansa'. This study investigated the vegetative growth, yield, and fruit quality of 'Sansa' apple trees grafted on M.7 or M.9 rootstocks to assess the feasibility of establishing domestic high-density apple systems using M.7 and to determine the optimum exposure length for rootstocks. Trees were planted with exposed rootstock lengths of 5, 10, and 15 cm. The vegetative growth of apple trees grafted onto M.7 was greater than that of M.9 and vegetative growth tended to decrease as the exposed length of rootstock increased. However, the differences in yield per tree, average weights, soluble solids contents, and titratable acidity due to the rootstock and its exposure length varied. The accumulated yield over a 10 year period and the yield efficiency of M.7 were lower than that of M.9 and the yield efficiency tended to decrease as the exposed length of rootstock increased. When apple trees were grafted onto M.9, biennial bearing and tree vigor weakening occurred if the exposed length of the rootstock was over 10 cm. Conversely, when apple trees were grafted onto M.7, vegetative growth was excessive if the exposed length of rootstock was below 10 cm. Based on the results from this study, the optimum M.7 and M.9 exposure lengths for 'Sansa' were 15 cm and 5 cm, respectively.

• 한국생물공학회:학술대회논문집
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• 2005.04a
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• pp.502-505
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• 2005

This study was concentrated to investigate the dependency of recovery yield on the extraction conditions. From fruiting body, the extracted amount of polysaccharide was studied with various solvent. In order to maximize the yield, the optimum extraction conditions were elucidated with respect to solvent, temperature and time. In addition, the dialysis was applied to obtain the higher purity of polysaccharide with varying the exposure time.

• Journal of the Korean Society of Safety
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• v.3 no.1
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• pp.37-45
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• 1988

This research investigated the condition for plant design on reclamation of waste plastic by heat decomposition. The results were summarized as follows 1. The highest of oil product by heat decomposition is about 54.7％. 2. The optimum reaction temperature is about 300­40$0^{\circ}C$. 3. The optimum reaction time is 2­3 hours. 4. When the flow rate of 8­16 cm/sec in column reactor the yield is maximum. 5. Waste plastics yielded of carbon black product by heat decomposition at the optimum condition is about 23.5%. 6. Calorific values 0：1 were 9820 Kcal/kg.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.43 no.2
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• pp.66-70
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• 1998

Four introduced forage rape (Brassica napus) cultivars, 'Akela', 'Ramon', 'Sparta', and 'Velox' and a leading rapeseed cultivar, 'Hallayuchae' were grown at nitrogen (N) rates of 0, 100, 250, 300, 350, and 400 kg/ha to (i) select forage rape cultivars adapted best to Cheju area, and (ii) determine the optimum N rate for the best cultivars. Days from seeding to flowering across the cultivars increased 190 to 195 days as N rate increased from 0 to 400 kg/ha. Average days to flowering of six cultivars ranged from 182 to 198 days. Plant height increased as N rate increased up to 300 kg/ha and then decreased with a further increase in N rate and ranged from 159 to 174 cm among the cultivars. The optimum N rate for the greatest dry matter yield of five cultivars ranged from 222 to 258 kg/ha. Sparta showed the greatest dry matter yield (35.79 Mg/ha), followed by Akela, Hallayuchae, Velox, and Ramon. As N rate increased, crude protein content linearly increased but crude fiber content declined curvilinearly. Akela and Sparta had higher protein content than the other cultivars did. The forage cultivars had lower crude fiber content than the oilseed cultivar Hallayuchae did. Our results demonstrated that Sparta was best adapted to Cheju area and the optimum N rate for Sparta was about 220kg/ha.