• Journal of The Korean Society of Grassland and Forage Science
• /
• v.13 no.2
• /
• pp.93-98
• /
• 1993

To determine the effects of potassium($K_2O$) fertilization level(0, 100, 200 and 300 kg/ha/year) on the growth, dry matter(DM) yield, nutritive value and nitrate nitrogen($NO_3$-N) concentration of grasses grown under shading condition, this experiment was carried out in Grassland Div., LES, 1989. The plants were sampled on different growing seasons (spring, summer and autumn) and growth stages (grazing and soiling), respectively. Shade was controlled artificially ca. 45-50%, and the level of nitrogen fertilization was 200 kg/ha/year in all treatments. Higher DM was produced in spring 1, 453 kg at grazing and 2, 364 kg/ha at soiling stage, and DM production was increased with increasing level of $K_2O$. In this experiment, the optimum amount of $K_2O$ fertilizer was 200 kg/ha. The neutral detergent fiber, acid detergent fiber, DM digestibility, and relative feed value of grasses were not affected by $K_2O$ fertilization, regardless of growing season and growth stage. The $NO_3$-N concentration of grasses grown in spring was very low (ca. 1.0%), regardless of growth stage and $K_2O$ level. However, $NO_3$-N concentration was very high in summer and autumn season, also $NO_3$-N was decreased significantly with increasing level of $K_2O$ fertilization (P<0.05). Application of $K_2O$ fertilizer, therefore, is thoughs to be desirable for reducing $NO_3$-N concentration of grasses, especially in summer and autumn season. So annual split fertilization of $K_2O$ could be recommended on woodland pasture.

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.22 no.1
• /
• pp.37-44
• /
• 2002

This study was conducted to investigate the effects of the application rate of cattle slury and urea N on productivity of corn and environmental pollution in com cultivation soil. The experiment was conformed in lysimeter which was constructed with 0.33m diameter and 1m height. This study was arranged in split plot design. Main plots were the application rate of mineral fertilizer, as urea, such as 0, 100 and 200kgN/ha and subplots were the application rate of cattle slurry, such as 0, 200 and 400kgN/ha. The results obtained were summarized as follows. 1. Dry matter yields of corn increased as the application rate of cattle slurry and urea increased. 2. Total nitrogen content of whole corn was increased as the application rate of cattle slurry and urea increased 3. The average nitrate content in leaching water by application rate of the slurry and urea N was 7.78$\mu\textrm{g}$/$m\ell$(ranged from 6.27 to 9.02$\mu\textrm{g}$/$m\ell$). Nitrate content was hardly influenced by application rates of the slurry and urea. However, nitrate content rises in proportion to a rise in precipitation.

• Korean Journal of Soil Science and Fertilizer
• /
• v.23 no.3
• /
• pp.220-226
• /
• 1990

This experiment was carried out to study the effects of Bradyrhizobium moculation and fertilizer N application on symbiotc $N_2$ fixation of peanut (Arachis hypogaea L. cv. Younghotangkong) at newly reclaimed soil. Treatments consisting of B. sp. (Vigna) HCR-3 and HCR-46 with control and five levels of nitrogen (0, 4, 8, 16, 32kg/10a) were arranged with split design of four repetitions. The results obtained were as follows. The number of viable Bradyrhizobium in rhizosphere was decreased to 20 days after sowing and thereafter it was remarkably increased, until full ripe stage of pods, decreased as fertilizern rates increased. Nodulation and nitrogenase activity were reduced with increasing levels of fertilizer, whereas top dry matter and nitrogen accumulation where increased. Seed yield of Bradyhizobium inoculation under the fertilizer N zero level was similar to that N : 8kg/10a under uninoculation. It suggested that Bradyrhizobium inoculation could replace the effect of nitrogen application.

• Asian Journal of Turfgrass Science
• /
• v.26 no.2
• /
• pp.135-139
• /
• 2012

Creeping bentgrass (Agrostis stolonifera) is one of the most popular turfgrasses for high-quality playing surface such as putting green on golf courses and athletic fields. Continues damage such as divot injury on creeping bentgrass is major issue to maintain golf course properly. Although plentiful researches to maximize divot resistance have been reported, minimal research has focused on relation between nitrogen (N) sources and divot resistance. The study was conducted to determine the effect of N source for turfgrass divot recovery and overall tee performance. Eleven fertilizer treatments as N sources were applied to creeping bentgrass 'Penncross'. Before the first application, divot injuries were simulated by removing a core of soil and turfgrass from established plots and backfilling with native soil. Data collection included turfgrass color and quality. N release speed did not influenced divot recovery. Frequency of urea application had no effects on divot recovery. Urea with split application had no difference with no treatment for divot recovery. Polyon product especially polyon mini (41-0-0) had the best performance for divot recovery and for maintaining better turfgrass quality. Overall, small particle size of slow-release N form would influence creeping bentgrasss to recover divot damage.

• Korean Chemical Engineering Research
• /
• v.57 no.3
• /
• pp.331-337
• /
• 2019

Titania has become the most applicable material for photocatalytic application. Nevertheless, titania has the weak point in its wide band gap energy that is mainly activated by UV irradiation. There have been vast research challenges in order to make the wide band gap energy of titania narrow that could be activated in the presence of visible light. Various modifications of titania surface were popular because titania needs to change its surface to respond in visible light. Among the methodological approaches, N-doping to titania can be the alternative candidate because it is facile process and eco-friendly. The activated electron from valence band in N-doped $TiO_2$ migrates to conduction band in the presence of visible light irradiation, which shows photocatalytic activity as well. In this study, focused on the evaluation of nitrogen state after N-doping through brief review. Arguments are still existed in nitrogen states and their different effects on photocatalytic activity. In particular, two nitrogen states are generally reported; substitutional and interstitial states. The research articles regarding N-doped $TiO_2$ are continuously appearing because the potential application of water split in visible light is still fascinate. The future of N-doped $TiO_2$ is also presented by referrals based on various literature.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.16 no.6
• /
• pp.88-96
• /
• 2008

Currently, due to the serious world-wide air pollution by substances emitted from vehicles, emission control is enforced more firmly and it is expected that the regulation requirements for emission will become more severe. A new concept combustion technology that can reduce the NOx and PM in relation to combustion is urgently required. This study used a split injection method at a 4 cylinder common-rail direct injection diesel engine in order to apply the partially premixed charge compression ignition combustion method without significantly altering engine specifications And it is investigated that the effects of the injection ratio and SCV(swirl control valve) to emission characteristics. From these tests, soot(g) and NOx(g) emission could be reduced to 40% and 92% compared to base engine performance at specified engine driving conditions(6 points with weight factors) according to application of split injection and SCV(swirl control valve).

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.29 no.3
• /
• pp.197-210
• /
• 2009

To improve the forage quality and reduce nitrogen input, trial was conducted on the effect of seeding method, combination, and nitrogen fertilizer with WCB (whole crop barley) and leguminous plant. Present experiment was carried out by split-split design having seeding methods for main plot, combinations for sub-plot, and nitrogen fertilizers for sub-sub plot with three replications. When WCB and leguminous plant were mixed-sown, WCB showed earlier heading and maturing than those of inter-sown, and the more nitrogen delayed growth stage a little. Occurrence of BaYMV (Barley Yellow Mosaic Virus), a serious disease caused by soil fungi and decrease barley yield, was deterred by mixed-seeding as compared to inter-sown barley a little. Inter-sown WCB increased the number of spike per $m^2$ as compared to mixed-seeding showing more spikes with nitrogen increase. WCB produced much fresh and dry matter yield at mixed-seeding than inter-seeding, and had advantage with hairy vetch (HV). Increased nitrogen showed much forage yield, however, half application of it is considerable for environmental-friendly farming. Electric conductivity (EC) decreased in inter-cropping or mixed-sowing soil with WCB and leguminous crop after harvest. But, organic matter (OM) content of soil after harvesting was vice versa. Acid detergent fiber (ADF) and Neutral detergent fiber (NDF) of WCB plant were higher at mixed-seeding than those of inter-sown ones. It showed increased tendency with time progress.

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.5 no.2
• /
• pp.100-105
• /
• 1985

To find out the optimum level of nitrogen fertilization and better distribution of application time for seed production of Festuca arundianacea S. (var. Alta), this filed experiment was performed at Livestock Experiment Station in Suweon, during 1979 to 1981. The treatments used in this study were three nitrogen fertilizing levels (120, 180 and 240kg/ha) and four different methods of nitrogen distribution (i. single application of whole amount in early Spring, ii. 50 percent each in Autumn and early Spring, iii. 50 percent each in early Spring and at begin of heading stage and iv. 50 percent in Autumn and 25 percent in early Spring and at begin of heading stage respectively). The experiment was arranged as a split-plot design with 4 replications and performed at the experimental field of the Livestock Experiment Station in Suweon, during 1979 to 1981. The results obtained are summarized as follows: 1. Date of heading stage of Festuca arundinacea was about May 21 and that of flowering stage was June 1 to 3. The optimum stage for the seed harvesting of Festuca arundinacea (var. Alta) was June 25 about 22 to 23 days after full flowering stage. Average plant height was about 127cm and the panicle length, 24cm. 2. 1000 grain weight was 2.72g and the number of panicles were 85 to 107 per square meter. 3. The mean seed wield for two years was 678.8kg/ha with the average of whole treatments and 781.9kg/ha with the best treatment (50 percent in Autumn and 25 percent in early Spring and at begin of heading stage with 240kg/ha respectively). 4. The average germination rate of harvesting seeds was 87.0 percent and it was increasing trend according to frequent application of fertilizer. 5. The average DM yield of aftermath seed harvesting was 6155kg/ha with two cut, and it was the largest DM yield from the higher nitrogen level and also from the single application in early Spring.

• Applied Biological Chemistry
• /
• v.8
• /
• pp.51-59
• /
• 1967

A split plot was laid out in 1965 for perennial application of straw by 500kg per 10 are, as main plot, and of chemical fertilizer in conventional way, as sub-plots. The sub-plot included the following 5 fertilizer treatments as (1) non-fertilized, (2) nitrogen-free, (3) phosphate-free (4) potassium-free, (5) completely fertilizer applied plots. Trends in the growth and yield of rice was observed at present experimental site in the first year, 1965, and second year, 1966, as follows: 1. Each treatmental plot showed nearly identical trends between the first and second year, in term of growth, yield and yield components. 2. Straw application deterred the initial growth at non-fertilized and nitrogen-free plots. But straw application raised the effective stem ratio and enlarged the values in yield components, finally to be resulted in the second year with significant difference. 3. Both phosphate and potassium did not much affected to plants for longer stem and larger number of tillers. 4. Effect of nitrogen, phosphate and potassium was recorded as investigated by previous research works. Phospate deficiency decreased maturing rate to a great extent. 5. Numerical index was calculated for the comparison of plots in yield, where the non-straw, completely fertilizer applied plot stands for 100. The indexes of the first and second year were as follows : at non-straw plot(indexes in the blank are from the first year trial); non-fertilized : 80.2(80.9), nitrogen-free: 83.6(89.4), phosphate-free : 89.4(93.1) and potassium-free plot: 93.5(102.4) at non-straw plot. On the other hand, indexes at straw applied plots were non-fertilized : 84.0(86.6), nitrogen-free 82.6(93.9), phosphate-free : 91.7(96.3), potassium-free: 103.2(102.0) and complete plot: 98.7(109.8).

• Asian Journal of Turfgrass Science
• /
• v.9 no.4
• /
• pp.293-316
• /
• 1995

Nitrogen fertilization and cutting practice were studied on turfgrasses and cover plants to investigate the possibility of maintaining green color during the growing season. Research also involved the effect of the nitrogen on a few morphological characteristics of leaf performance elements which might give an information to coloration and life-span of turf leaves. Treatments in the first experiment undertaken on pot included one N level: 350kgN /ha applied as compound fertilizer in split applications of one-half in mid-May and the rest both in late June and August, and four spring-summer cuts: late May, late June, late July and late August. The soil filled in pot a moderately well-drained sandy loam. In the second experiment(field observation) leaf length and width, inflorescence and flowering, and color performance were also investigated. With nitrogen fertilizer applied on turfs, desirable turf color was maintained during a period of poor coloration in specific seasons such as mid-summer for cool season grasses and late fall for warm season grasses comparing to the non-treatment. However, this was not stimulated by cutting treatment to nitrogen status existed. Cutting effect on coloration was more remarkable in both Korean lawngrass and Manilagrass than in cool season turfgrasses such as Italian rye-grass, perennial ryegrass and tall fescue. Especially down-slide of leaf color in cool season turfgrasses could he detected in mid-summer /early fall season ranging up to mid-September. In early November as well as mid-September, Italian ryegrass, perennial ryegrass and tall fes-cue retained a high level of green color as followed by nitrogen application and cutting treatment, and little detectable variation of leaf color notation between cool season turfgrasses was obtained. However, Korean la'vngrass and Manilagrass failed to retain the green color until early November. Color notations in cool season turfgrasses investigated early November on the final date of the experiment ranged from 5 GY 3/1 to 4/8 in 'Ramultra' Italian ryegrass, 'Reveile' perennial ryegrass and 'Arid' tall fescue, but those in Zoysiagrasses were 7.5 YR 4/8 in Korean lawngrass and 2.5 y 5 /6 in Manilagrass. Life-span of leaves was shorter in Italian ryegrass, perennial ryegrass and tall fescue than in beth Korean lawngrass and Manilagrass with and without nitrogen application. In general, leaves appeared in early May had a long life-span than those appeared in late April or mid-June. Nitrogen application significantly prolonged the green color retaining period in perennial ryegrass, Italian ryegrass, Korean lawngrass and Manilagrass, and this was contrasted with the fact that there was no prolonged life-span of leaves emerging in early May and mid-June in tall fescue. SPAD reading values in 48 turfs and cover plants investigated in the field trial were increasing until late June and again decreasing till September. Increasing trends of reading value could be observed in the middle of October in most of grasses. On the other hand, clovers and reed canarygrasses did not restore their color values even in October. Color differences between inter-varieties, and inter-species occurred during the growing season under the field condition implicated that selection of species and /or cultivars for mixture should be taken into consideration. In Munsell color notation investigated in the final date in the middle of November, 32 cultivars belonged under the category of 5 GY and 10 cultivars under the category of 7.5 GY. This was implying that most of cool season turfs and cover plants grown in the center zone of Korean Peninsula which are able to utilize for landscape use can bear their reasonable green color by early or mid-November when properly managed. The applicable possibilities of SPAD readings and Munsell color notation to determine the color status of turfgrasses and cover plants used in this study were discussed.