• Korean Journal of Soil Science and Fertilizer
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• v.12 no.3
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• pp.133-139
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• 1979

In order to evaluate the effect of developed Nk compound fertilizers, 17-0-17 granular and powder, and 17-0-14 granules in comparison with single fertilizers, urea and potassium on rice (Oryzae sativa) ; cultivar, Milyang 23, (Orizae Sativa), a field experiment was carried out. Results obtained are as follows : 1. The top dressing of NK compound fertilizers tended to produce higher paddy yield than that of single fertilizers; urea and patasstum muriate. 2. The absorption of potassium and nitrogen by rice plant from the plot of NK granular compound fertilizer, 17-0-17, was greater than from the plots the absorption of those elements received other types of ferilizers and application method The absorded K/Ca+Mg ratio in milli equivalent basis in plant was also appeared to be in same order as the absorption of nitrogen and potassium. 3. From the results of present study it seemed necessary to evaluate the NK compound fertilizer for the top dressing at effective tillering stage of rice as well.

• Korean Journal of Soil Science and Fertilizer
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• v.48 no.5
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• pp.456-463
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• 2015

The objective of this study was to determine the effects of granular type of silicate fertilizer on watermelon growth, yield, and characteristics of soil in the greenhouse. Four different levels of silicate fertilizer, 0(control), 600, 1,200, $1,800kg\;ha^{-1}$ were applied for experiment. The silicate fertilizer was applied as a basal fertilization before transplanting watermelon. Compost and basal fertilizers were applied based on the standard fertilizer recommendation rate with soil testing. All of the recommended $P_2O_5$ and 50% of N and $K_2O$ were applied as a basal fertilization. The N and $K_2O$ as additional fertilization was split-applied twice by fertigation method. Watermelon (Citrullus lanatus Thunb.) cultivar was 'Sam-Bok-KKuol and main stem was from rootstock (bottle gourd: Lagenaria leucantha Standl.) 'Bul-Ro-Jang-Sang'. The watermelon was transplanted on April, 15. Soil chemical properties, such as soil pH, EC, available phosphate and exchangeable K, Mg, and available $SiO_2$ levels increased compared to the control, while EC was similar and the concentrations of soil organic matter decreased. Physical properties of soils, such as soil bulk density and porosity were not different among treatments. The growth characteristics of watermelon, such as stem diameter, fresh and dry weight of watermelon at harvest were thicker and heavier for silicate treatment than the control, while number of node was shorter than the control. Merchantable watermelon increased by 3-5% compared to the control and sugar content was 0.4 to $0.7^{\circ}Brix$ higher than the control. These results suggest that silicate fertilizer application in the greenhouse can improve some chemical properties of soils and watermelon stem diameter and dry weight, which are contributed to watermelon quality and marketable watermelon production.

• Journal of Biosystems Engineering
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• v.14 no.4
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• pp.242-250
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• 1989

The performance of a vertical type centrifugal distributor of granular materials was studied by means of mathematical models and experimental investigations. To develop the mathematical description of particle motion, some assumptions were made. The distribution process consisted of three stages: the entrance of a particle to the blade, the motion of the particle on the blade, and the motion of the particle in the air. The physical properties of fertilizer, which affected the particle motion, were investigated: bluk density, coefficient of friction, coefficient of restitution, and particle size distribution. The particle motion were simulated by using a computer. A prototype distributor was designed and constructed for experimental tests. The following conclusions were drawn from the computer simulation and experiment results. 1. The fertilizer may slide or roll at the point of contact when they impact on the blade and move along the blade. 2. The interaction among fertilizers may prevent them from bouncing. 3. When fertilizers roll on the blade, rolling resistance is one of the factors affecting the particle's motion. 4. The trajectory angle and position of fertilizers from a disc depend on the blade position and particle shape, but the rotating speed of the disc affected them only slightly.

• Asian Journal of Turfgrass Science
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• v.11 no.3
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• pp.167-172
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• 1997

This experiment was carried out to study an effect of organic fertilizer, IBDU complex and humate on the growth of creeping bentgrass(penncross) and the change of soil chemical characteristics. Results obtained are summarized as follows :1.Content of a total nitrogen in soil was increased in more IBDU complex and organic fertilizer than humate plot. 2.Content of a organic matter in soil was increased in organic fertiliter and humate plot. 3.CEC in soil was improved a little in humate-granular plot. 4.The yield of dry weight and leaf color 'was increased in more organic fertilizer than humate plot. 5.Root length was the most effective in humate plot.

• Korean Journal of Soil Science and Fertilizer
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• v.35 no.5
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• pp.290-295
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• 2002

Fertilizer granulation test was carried out by a small pan granulator. A premixture composed of SOP 60%, urea 22% and RP powder 18% was rolled in the pan granulator while 10% phosphoric acid solution(binder) was sprayed on the rolling powder bed. Granules were developed very fast along with a little amount of binder. Hardness, brittle ratio in water and hygroscopicity of granules were improved enough to evaluate physical properties of the fertilizer. Growth responses of tobacco plant to the fertilizer were investigated at seedling and flowering stage by pot experiment under plastic film roof. Seedlings showed poor growth at nursery pot cell. In virgin soil with deficient available phosphate tobacco plant showed poor growth until budding and flowering stage but good growth in tillage soil with high cumulative phosphate.

• Asian Journal of Turfgrass Science
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• v.20 no.1
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• pp.47-55
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• 2006

Golf course community has always been concerned about water quality regarding to pesticide and fertilizer managements. This study conducted to investigate sorption and leaching behavior of common pesticides used for golf course in granular activated carbon I (GAC 1), granular activated carbon II(GAC II), and charcoal. We used batch study to investigate the influence of concentrations of Smithion and Folicur and particle sizes of GAC I, GAC II, and charcoal on sorption. Also, column study was used to investigate the leaching effect of Smithion in GAC I and charcoal. We found that sorption of Smithion and Folicur were higher in less $45{\mu}m$ of particle size for GAC I, GAC II, and charcoal compared to $1.7{\sim}2.0mm$ size, and the sorption of Smithion and Folicur in less $45{\mu}m$ of particle size ranged from 90 to 99%. In the column study, there was no difference in leaching effect between GAC I and charcoal. Overall, we found that charcoal might offer a cost effective adsorbent as a pesticides in leachate.

• Journal of Biosystems Engineering
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• v.31 no.3 s.116
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• pp.203-208
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• 2006

This study was conducted to improve the control performance of a current variable-rate controller for granular fertilizers. Simulation model was developed. Optimized proportional, integral and derivative gains were determined by simulation model using 2nd order PID gain learning algorithm, and these control gains were evaluated through the field tests. Important results of this study are as follows; 1. Principles of pre-existing variable-rate application of granular fertilizers were investigated. 2. Simulation model of a PID controller that could simulate the control system was developed by using Matlab/Simulink program. The program was to determine PID control coefficients through the simulation model and 2nd order PID gain learning algorithm. 3. PID control coefficients obtained from the simulation were applied to the developed model. When the step input was given, Maximum overshoot were 1.96%, rise time were 0.05 sec, settling time were 0.06 sec and steady state error were 0.21 % respectively. 4. The simulation model was verified through field tests. The errors of maximum overshoot were 10%, rise time were 0.11 sec, settling time were 0.40 sec and steady state error were 8% because of loads and noises. Rise time was decreased to one third of that of the pre-existing system. 5. If the speed of a fertilizing machine is $0.3{\sim}0.6\;m/s$ and the maximum rotation speed of a discharging roller is 64 rpm, rise time would be 0.26 sec and fertilizing machine would cover the distance of $0.07{\sim}0.15\;m$ with settling time of 0.4 sec, fertilizing machine would cover the distance of $0.12{\sim}0.24\;m$.

• Proceedings of the Korean Society of Crop Science Conference
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• 2005.08a
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• pp.194-195
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• 2005

• Korean Journal of Soil Science and Fertilizer
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• v.49 no.6
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• pp.807-812
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• 2016

Soil amendment, especially addition of clay minerals, has been widely conducted to improve the physical and chemical properties of cultivated soils. However, there are no systematic studies on the effects of the structural type of clay minerals added. This study was conducted to investigate the effects of structural type of clay minerals on physical properties of soils. Two experimental soils, layer-dominant and granule-dominant ones, were mixed with either a layer-type smectite or a granule-type zeolite at a level of 2.0 wt%. It was observed that water permeability of soils was decreased by smectite whereas not significantly changed by zeolite. This effect was much greater in layered clay-dominant soil than in granular clay-dominant soil. Our results clearly indicated that the relationship of structural type between a soil and an amendment plays a decisive role in the soil properties. Therefore, it is highly recommended that the structural types of both soil and amendment be taken into consideration for soil amendment by clay minerals.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.05a
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• pp.598-601
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• 2006

The Purpose of this study is to develope the method for early recovery of the biodiversity in the oligotrophical costal area, it is important in the recovery of the biodiversity to make kelp forest grow in the concerned area. In order for it, sufficient nutrient is required as well as the proper seedbed, Hence in this study, granulated fertilizer, which contains nutrient, such as nitrogen, phosphorus and etc, is coated by cement paste, and then is mixed in to the porous concrete in order to provide seedbed and nutrient simultaneously. As a result of examination of growth property of marine plants of multiple performance concrete for kelp forest regeneration, seaweeds is adhered plentifully when the number of days is longer. when the granular fertilizer mixed. adherence and growth of marine plants is excellent and is stabilized over the long run. In case 6 month of the number of days immersed, marine plants and growth will appear.