• Journal of The Korean Society of Grassland and Forage Science
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• v.33 no.2
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• pp.105-110
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• 2013

This study was carried out to investigate the effect of nitrogen (N) fertilization on the forage growth, production and quality of native reed (Phragmites communis) grasses. Field experiments were conducted in Cheonan and in Ansan, 2012. Treatments were control (no N fertilization), 50 kg/ha and 100 kg/ha in Cheonan plots (fertilization on April $30^{th}$, and harvest on June $21^{st}$). Treatments in Ansan plots were control (no N fertilization) and 60 kg/ha (fertilization on May first, and harvest on August first). Forage growth and leaf colors were improved in N fertilized plots. However, the drymatter (DM) percentage was slightly decreased with N fertilization. Forage yields, in terms of DM, crude protein (CP) and digestible DM (DDM), were significantly increased with N fertilization in both sites. In Cheonan, DM, CP and DDM yields per ha were 4,026 kg, 235 kg and 1,850 kg, respectively, in the control plot, and were 4,658 kg, 306 kg and 2,388 kg, respectively, in the N 50 kg plot, and 5,622 kg, 446 kg and 3,143 kg, respectively, in the N 100 kg plot. In Ansan, DM, CP and DDM yields per ha were 2,802 kg, 177 kg and 1,288 kg, respectively, in the control plot, and were 3,876 kg, 294 kg and 1,853 kg, respectively, in the N 60 kg plot. Forage quality in terms of CP content, in vitro DM digestibility (IVDMD) and relative feed value (RFV) were also increased with N fertilization in both sites. In Cheonan, the CP content, IVDMD and RFV were 5.85%, 45.96% and 64.5 (grade 5), respectively, in the control plot, 6.58%, 51.27% and 72.3 (grade 5), respectively, in the N 50 kg plot, and 7.94%, 55.91% and 72.7 (grade 5), respectively, in the N 100 kg plot. In Ansan, the CP content, IVDMD and RFV were 6.30%, 45.98% and 70.2 (grade 5), respectively, in the control plot, and 7.59%, 47.80% and 78.3 (grade 4), respectively, in the N 60 kg plot. In conclusion, N fertilization of 60~100 kg/ha was desirable for greater forage production, with a higher quality of native Phragmites communis achievable. This should only be applied if the fertilization area is not located at a riverside/streamside or in riparian land where there is a high risk of water pollution by fertilization.

• 한국전산유체공학회:학술대회논문집
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• 2004.10a
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• pp.121-125
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• 2004

The preprocessor - solver - postprocessor software for 2D/Axisymmetric CSCM Upwind Flux Difference Splitting Navier-Stokes code has been developed for undergraduate educational purpose. This computational fluid dynamics (CFD) software allows students to setup, solve, visualize and control dynamically server for their own fluid problems via Internet. The preprocessor Is capable of generating geometry and grid, initial solution data and required solver control parameters. The postprocessor shows vector plot and contour plot with different options while residual plot shows root-mean-square (RMS) error history graphically and retrieves the data from solver interactively. Special feature of the preprocessor is grid generation part which is based on MFC/Visual C++ application and FORTRAN single block grid generator process. Many users can access solver via Internet from client computers and solve desired problems using locally installed pre- and postprocessor and remote powerful solver part.

• Journal of Plant Biology
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• v.20 no.2
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• pp.103-107
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• 1977

Two sample varieties of Yushin and Jinheung were used for the experiment in low-level wetty paddy field which was arranged with PVC pipe underdrainage of 6m in distance and 60cm, 90cm, and 120cm in depth and control, using sprit plot design with three replications. On the yield of brown rice, Yushin was increased by 24.8% in the 90cm plot and Jinheung by 16.7% in the 120cm plot, respectively, over the control. The ratio of matured grains of these two varieties was increased significantly by the underdrainage and the number of grains per head of Yushin was also increased in drained plots. Otherwise, the underdrainage enhanced the plant height in the early growth of rice plant and further increased the culm height and panicle length. It seemed that these results might enhance the light-receiving effciency in the latter growth of rice plant and bring about the effect fo increased yields by the underdrainage.

• Korean Journal of Organic Agriculture
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• v.12 no.4
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• pp.427-436
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• 2004

This study was conducted to investigate the effect of microbial product on microorganisms in soil and the growth of leaf lettuce. The test material were treated with chitosan, wood vinegar and EM activity liquid, and treatment concentration was 50 times solution and 100 times solution level with foliar application. The results were summarized as follows : Among foliar application of microorganisms treatments diluted by chitosan 100 times solution level was effective considering growth of leaf lettuce as compared other dilutions and control plot. Change of microorganism number in the soil for cultivation of chinese cabbages and leaf lettuce was increased with microorganism treatment plot as compared with control plot. Specially chitosan 100 times solution level showes the most significant effect.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.45 no.3
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• pp.167-170
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• 2000

This study was conducted to investigate the changes of potato growth and soil properties in highland mounding-soil. Experimental plot was designed with control, chemical improvement and zeolite+chemical improvement plots. Mounding-soil was low in organic matter and phosphate contents, and that soil texture was loamy sand soil. The growth and yield of potato were highest in the zeolite treatment plot. Yield of that increased by 3.7% than control plot. Increasing ratios of potato tubers decreased at 60-70 days after planting. Increasing ratio of zeolite plot was higher or than other treatment plots. After harvesting, the contents of soil organic matter increased by 12-125%, and those of phosphate were by 29-73% respectively. The manurial value of fused and superphosphate was higher than that of potassium chloride.

• Magazine of the Korean Society of Agricultural Engineers
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• v.20 no.2
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• pp.4688-4694
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• 1978

The result which I tried to get double crops of potatoes on the wet paddy fields through the underdrainage of P V.C pipe from March 1977 to June 1977 in Jung cheon-Ri, Jinseong-men, Jinyang gun, Kungsangnamdo are followings.1. During this experimental period, the temperature on the average was 15.67$^{\circ}C$ (yearly mean 14.78$^{\circ}C$ that was suitable in growing potatoes, while the amount of rainfall was not much heavier from middle of April to early in May. Therefore the yield of potatoes in the wet fields was so high. 2. The soil temperature of the treated plot in the underground of 10cm, 30cm, 60cm, 80cm, has risen to 1.38$^{\circ}C$, 1.32$^{\circ}C$, 1.45$^{\circ}C$, 1.28$^{\circ}C$, comparing to the soil temperature in the control plot respectively. 3. The discharge from subdrainage pipes was 0.6751/sec/ha on the average. 4. The treated plot showed better growth than the control plot, and the yield has been increased 424.8%, while they have been preserved to be voluntary from the level of "t" test.

• Korean journal of applied entomology
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• v.21 no.1 s.50
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• pp.15-18
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• 1982

The integrated soil improvement practice reduced neck blast incidence by ranging from 6.3 to 59.5 percent compared to control plot. However, effect of integrated soil improvement practice in reducing neck blast incidence was greater in Tongil type cultivars. On the contrary, mean value of plant height of eleven rice cultivars was taller by 6.4cm in the integrated soil improvement plot with 2.3 more tillers than that of control plot. As a result, yield increase of milled rice by metric tons per hectare was 24.1 percent in the integrated soil improvement plot.

• Journal of Korean Society of Forest Science
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• v.103 no.1
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• pp.30-36
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• 2014

This study examined the change in carbon (C) storage of soil, forest floor and coarse woody debris (CWD) for different thinning intensities in Pinus densiflora stands 4 years after the treatment. Two study stands were located in Jeongseon (Stand 1) and Gwangneung Experiment Forest (Stand 2). Three plots for different thinning intensities based on stand density were established at each stand in 2008; control plot (0%), T20 plot (20%) and T30 plot (30%) in Stand 1 and control plot (0%), T39 plot (39%) and T74 plot (74%) in Stand 2, respectively. The C storage of soil (0-50 cm), forest floor and CWD was measured in 2012. Total C storage of T30 plot ($109.80t{\cdot}C{\cdot}ha^{-1}$) was significantly higher than that of control plot ($86.69t{\cdot}C{\cdot}ha^{-1}$) in Stand 1. In stand 2, total C storage of T74 plot ($97.02t{\cdot}C{\cdot}ha^{-1}$) was significantly higher than that of control plot ($72.04t{\cdot}C{\cdot}ha^{-1}$) and T39 plot ($63.25t{\cdot}C{\cdot}ha^{-1}$). Total C storage of the heaviest thinned plot was the highest in each study stand. Since this study examined initial effects of thinning on C storage of soil, forest floor and CWD, further studies would be necessary to evaluate the long-term effects.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.513-518
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• 2001

As the machining depth increases, the drilling torque increases and fluctuates and the risk of drill failure also increases. Hence, drilling torque control is very important to prevent the drill from failure. In this study, a PID controller was designed to control the drilling torque in a machining center. The plant including the feed drive system, cutting process, and spindle system was modeled for controller design. The Ziegler-Nichols rule was used to determine the controller gain and control action times. The root locus plot was used to tune the controller gain for a certain cutting condition. Also, suggested was a simple method to obtain the tuned controller gain for an arbitrary cutting condition not using the Ziegler-Nichols rule and root locus plot. The cutting torque control, performance of the designed controller and the effect of gain tuning on the control performance were examined.

• Korean Journal of Weed Science
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• v.18 no.3
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• pp.186-190
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• 1998

To establish weed control method in no-tilled and rice straw-covered wheat sown coincidentally with rice harvest using combine-attached drill seeder, several herbicides and their combination were tested for 2 years. Similar number of panicle to hand-weeding plot was secured at sprayed plot with Buta EC + Glyphosate SL mixture just after seeding. Water-foxtail(Alopeculus aequalis) and broadleaf weeds were controlled effectively by Buta EC + Glyphosate SL mixture, showing the control efficacy of 92 percent. In the 1st cropping year, weed species occurred was simple and water-foxtail predominated nearly half. However, weed species was diversified and water-foxtail predominated 83.5 percent in the 2nd cropping year. Wheat yield of Buta EC + Glyphosate SL plot showed no difference with hand-weeding plot. Dry weight of water-foxtail showed closer linear relationship with wheat yield reduction than that of broadleaf weed.