• Applied Biological Chemistry
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• v.44 no.2
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• pp.97-102
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• 2001

Cheju island depends on a hydrogeologically vulnerable aquifer system as its principle source of drinking water. Most of golf courses are located in the area which is important for the ground water recharge, and pesticides are applied to golf courses often at relatively high rates. Therefore, turf pesticides in golf course should be applied without adversely impacting ground water. In this experiment, downward movement of pesticides was monitored in model greens of golf course, where different adsorbents were layered in 3-cm thickness at 35-cm depth, and effect of the adsorption layer on the leaching loss of pesticides was investigated. Major leachings were observed in the periods of heavy rain and very limited leaching was observed under artificial irrigation. Fenitrothion and triadimefon, which have relatively short persistence and high adsorption coefficient, were found in the leachate in low concentrations only at the first rainfall event, around 20 days after the pesticide application. However, diniconazole, which has a relatively long half-life (97 days), was detected in the leachate during the whole period of experiment and concentration was much higher than those of the other pesticides. Maximum leachate concentrations were 1.9, 10.3, and 84.5 ${\mu}l^{-1}$ for fenitrothion, triadimefon, and diniconazole, respectively. Therefore, in golf course green which allows rapid water percolation and has extremely low adsorption capacity, persistence in soil could be more important factor in determination of leaching potential of pesticides. Total quantity of pesticides leached from the model green was <0.2% for fenitrothion and triadimefon and 1.8% for diniconazole. Adsorption layers significantly reduced pesticide leaching, and active carbon and Orpar were more effective than zeolite. In the model green having adsorption layer of active carbon or Orpar, leaching loss of pesticides was reduced below 0.01% of the initial application.

• Korean Journal of Weed Science
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• v.30 no.3
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• pp.233-242
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• 2010

This study was conducted to know that if ionic liquids can be applicable as control agents of harmful algae in water-ecosystem and to find out problems caused by ionic liquid application. Firstly, the differential selectivity of various fresh-water algal species to several 1-alkyl-3-methylimidazolium chloride ionic liquids was investigated. There was a distinct differential response between alkyl chain lengths from butyl to dodecyl and towards the algal organisms : Generally algicidal activity was increased with increase of chain length and among the algae used in this study, Stephanodiscus hantzschii f. tenuis, Oscillatoria tenuis and Spirulina pratensis were most sensitive to 1-dodecyl-3-methylimidazolium chloride (MAIC12), next was Microcystis aeruginosa, and the others were relatively less sensitive to the chemical. The selectivity degree was about ten to twenty times based on the $EC_{80}$ (Effective concentration required for 80% growth inhibition). Secondly, an activity persistence of ionic liquids was investigated in natural mimic condition (using water bottle containing soil-sediments under the greenhouse condition). At the application of $1.0{\mu}g\;mL^{-1}$ of 1-octyl-3-methylimidazolium chloride (MAIC8), the algal growth did not occur at all until 6 days after treatment(DAT) and observed a only little growth at 9 DAT. But the algae grew rapidly after 9 DAT. So at 20 DAT, total chlorophylls was $264.4{\mu}g\;L^{-1}$ and the growth was inhibited by 58.2% compared to untreatment. On the other hand, MAIC12 also had a similar persistence pattern to MAIC8, showing nearly 5 times more activity than MAIC8. At 20 days after $0.2{\mu}g\;mL^{-1}$ application of MAIC12, that is, total chlorophylls was $251.2{\mu}g\;L^{-1}$ and the growth was inhibited by 55.2% compared to untreatment. In summary, 1-alkyl-3-methylimidazolium chloride ionic liquids is likely to be applicable for selective control of harmful algae as potent compounds having long lasting activity. However, the difficulty of degradation seems to be a limiting factor in an eco-friendly application of the compounds.

• Journal of The Korean Society of Grassland and Forage Science
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• v.30 no.4
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• pp.317-324
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• 2010

Recently, fallow paddy land located in the mid-mountain area (FPL) due to a decrease in rice consumption has increased in some regions of our country. So, grasses and forage crops available for years in once sowing should be introduced in FPL. This study was conducted to develop the technique for cultivation of grasses and forage crops using animal manure in FPL The field experiments were carried out from 2007 to 2009 on FPL at Kumsan, Chungbuk province in Korea. Cattle feedlot manure (CFM) was prepared by mixing feces and urine of cattle with rice straw in cattle feedlot for 6 months. The experimental plots were consisted of four treatments; tall fescue-based mixed pasture applied with chemical fertilizer (Control), mono-tall fescue pasture (MTFP), tall fescue-based mixed pasture (TFBMP), mono-Perennial ryegrass (MPR-FCM), mono-Italian ryegrass (MIR-FCM), mono-Red clover (MRC-FCM) and mono-Reed canarygrass (MRCG-FCM) applied with FCM. The field of tall fescue-based pasture had been sown with a grasses mixture containing 'Fawn' tall fescue, 'potomac' orchardgrass, 'Reveille' Perennial ryegrass, and 'kenblue' Kentuky bluegrass, 'Kenland' Red clover. Seeding rates were 16, 6, 4, 2 and $2\;ha^{-1}$, respectively. DM yields of forages and rates of grass coverage was higher in MTFP, TFBMP and MRCG-FCM as compated with control treatment. This result means that FPL has contained with favorable conditions for growing grass, because forage productivity is more than 15 tons per ha per year in fallow paddy land. In addition, the farmer can save the trouble of repeated plowing and sowing every year, due to the introduction of perennial grasses. The farmer must conduct the re-seeding and induce the improvement of management methods for the elevation of the persistence of red clover and perennial ryegrass, because both red clover and perennial ryegrass having high nutritive value and palatability was less persistent. Therefore, we suggest that FPL may be the good land for forage production utilizing FCM and FCM can be applied on FPL without any negative effects on DM production and the property of soil. FPL of Korea can be better utilized by applying FCM to the mono and/or mixed swards.

• Journal of The Korean Society of Grassland and Forage Science
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• v.32 no.4
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• pp.411-418
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• 2012

This study was conducted to develop the technique for cultivation of forage crops using swine slurry in fallow paddy land located in the mid-mountain area (FPL). The field experiments were carried out from 2007 to 2009 on FPL at Kumsan, Chungbuk province in Korea. Swine slurry was prepared which decayed for 6 months. The experimental plots were consisted of seven treatments; tall fescue-based mixed pasture applied with chemical fertilizer (Control), mono-tall fescue pasture (MTF), tall fescue-based mixed pasture (TFBM), mono-Perennial ryegrass (MPR), mono-Italian ryegrass (MIR), mono-Red clover (MRC and mono), Reed canarygrass (MRCG) applied with swine slurry. The field of tall fescue-based pasture had been sown with a grasses mixture containing 'Fawn' tall fescue, 'potomac' orchardgrass, 'Reveille' Perennial ryegrass, and 'kenblue' Kentuky bluegrass, 'Kenland' Red clover. Seeding rates were 16, 6, 4, 2 and 2 (kg) per ha, respectively. DM yields of forages and rates of grass coverage were higher in MTF, TFBM and MRCG as compared with control treatment. This result means that FPL has contained with favorable conditions for growing grass, because forage productivity is more than 14.5 tons per ha per year in fallow paddy land. In addition, the farmer can save the trouble of repeated plowing and sowing every year, with the introduction of perennial grasses. The farmer must conduct the re-seeding and induce the improvement of management methods for the elevation of the persistence of red clover and perennial ryegrass, because both red clover and perennial ryegrass having high nutritive value and palatability was less persistent. Therefore, we suggest that FPL may be the good land for forage production utilizing swine slurry and swine slurry can be applied on FPL without any negative effects on DM production and the property of soil. FPL of Korea can be better utilized by applying swine slurry to the mono and/or mixed swards.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.40 no.1
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• pp.26-32
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• 1995

Weak persistence of white clover （Trifolium repens L.） under continuous grazing has been limited its availability in the mixture with grasses. The experiment was done to determine the effect of defoliation interval on $N_2$ fixation. nitrogen and carbohydrate partitioning of contrasting white clover cultivars. Individual plants of Osceola（large leaf）, Grasslands Huia （me-dium leaf）, and Aberystwyth S184 （small leaf） were grown in 15cm plastic pot containing a 1：2：1 soil：sand：Promix mixture for 55 days, and then clipped to remove all fully expanded leaves every 7, 14 or 28 days. To measure the cultivar response, plants were sampled immediately before final harvest （0） and on 1, 3, 7, 14, and 28 days after the final harvest, and then seperated leaves and petioles, stolons and roots for chemical analysis. Total nonstructural carbohydrate （TNC） concentrations of stolons and roots, and nitrogen con-centration of all the fractions inclined with increased defoliation interval. Those of Osceola, large leaved, were greater than the other cultivars showing different partitioning patterns between stolons and roots. Concentration of TNC was less in roots than in the other fractions while that of nitrogen declined in the order of leaves and petioles, roots and stolons. $N_2$ fixation rate of larger leaved cultivar, Osceola, was higher than that of smaller leaved cultivar. TNC and nitrogen concentrations of all the fractions and $N_2$ fixation rate were reduced as defoliation was imposed, defoliation interval declined or regrowing period become shorter. The partitioning patterns of TNC and nitrogen among the fractions were modified by defoliation interval and cultivars.

• Applied Biological Chemistry
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• v.50 no.4
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• pp.321-326
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• 2007

An organophosphorus insecticide, chlorpyrifos, has been of a great concern due to persistence, toxicity and accumulation in soils and groundwaters. This study deals with degradation efficiency and dechlorination kinetics of chlorpyrifos by various types of zerovalent irons (ZVIs) for effective remediation of the soils contaminated with chlorinated pesticides. Chlorpyrifos degradation rate was increased with increasing ZVI treatment amount and reaction time. The degradation rate and dechlorination kinetics of chlorpyrifos increased in the order of mZVI > nZVI > cZVI in solutions and soils. Dechlorination number value of chlorpyrifos by cZVI, nZVI and mZVI treatment exhibited 1.08, 3.09 and 3.18, respectively. In soils, degradation efficiency and kinetics of chlorpyrifos significantly were affected by moisture content because of the limited contact between ZVIs and chlorpyrifos. These results suggest that nanosized and functionalized mZVI could be effectively applied to degradation of chlorinated pesticides in the soil and aqueous environments.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.39 no.3
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• pp.245-255
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• 1994

Weak persistence of white clover (Trifolium repens L.) under continuous grazing management has been limited its availability in the mixture with grasses. The experiment was carried out to determine the effect of defoliation interval on the regrowth and morphological characters of the clover cultivars. Individual plants of Regal (large leaf), Grasslands Huia (medium-small leaf) and Aberystwyth S184 (small leaf) were grown in 15cm plastic pot containing a 1: 2: 1 soil:sand:Promix mixture for 55 days, and then clipped to remove all fully expanded leaves every 7, 14 or 28 days. For the analysis of the cultivar response, plants were sampled on the final harvest date(0), and 1, 3, 7, 14 and 28 days after the final harvest date. Harvested dry weight of all cultivars declined as defoliation interval was increased, and that of Regal was the highest compared to the other cultivars. During the regrowing period, increase of total plant dry weight was due to that of leaf and petiole dry weight, and that of Osceola was greater than the others. Although total leaf area and mean single leaf area were increased during the regrowing period, they were reduced with increased defoliation interval and those of Osceola were the greatest until 14-days regrowth. S184 possessed the most number of leaves and Osceola did the longest petiole since 14-days regrowth although the more defoliation, the less nunber of leaves per plant and the shorter petiole. Stolon length and growing tips of all cultivars increased steeply during regrowth, while they were decreased with increased defoliation interval and those of S184 were the highest. More frequent defoliation had detrimental effects on regrowth of white clover, although larger leaf type was productive but less persistent in a mixture with grasses than smaller leaf type.

• Korean Journal of Environment and Ecology
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• v.35 no.3
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• pp.237-255
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• 2021

Lychnis wilfordii (Regel) Maxim. is one of the wetland specialists mainly distributed in peatlands at high latitudes. In Korea, it is isolated in two regions. This study investigated habitats, growth traits, and self-compatibility of L. wilfordii and assessed the internal dynamics of its population persistence. Its population has remained stable in the Yongneup Wetland Protected Area (YWPA). There was a clear difference in vegetation environment between YWPA and the distribution area in Daegwallyeong (DWL), Pyeongchang-gun. It has self-compatibility while pollinators facilitate its seed production. It produces a large number of hibernacles and bears the maximum number of branches and fruits in soil with rich organic contents. However, it grows and bears fruits even under the condition of low organic contents. In YWPA, L. wilfordii is not distributed in high moor but widely distributed in low moor where tussocks by Carex thunbergii var. appendiculata are developed. It is mainly distributed on the top of tussocks also. Therefore, it is judged that the formation, growth, and extinction of tussocks by C. thunbergii var. appendiculata is closely related to the establishment, growth, and extinction of plants distributed in this space. It is assessed that the current YWPA has well-developed tussocks in which L. wilfordii is widely distributed, and extinction and re-establishment progress well. Accordingly, the L. wilfordii population is expected to be sustainable in the long term given if its current ecological process is maintained well.

• Korean Journal of Environment and Ecology
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• v.35 no.6
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• pp.644-658
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• 2021

Understanding the functional traits of dominant species in urban ecosystems provides insight into species' trait adaptation and ecosystem function in response to fragmented and isolated urban vegetation and reduced biological interactions. This study compared means and variances of environmental factors (geographic, meteorological, and soil attributes) and 4 leaf traits (leaf area, specific leaf area, leaf dry mass content, and leaf shape index) and 7 reproductive traits (fruit width, fruit length, fruit shape, fruit dry weight, fruit dry matter content, seed weight, and seed ratio) measured of 40 Sorbus alnifolia individuals in four mountainous areas south of Seoul downtown, South Korea. We then performed the multivariate analysis of trait combinations. While the measured environmental factors indicated the individuality of the survey sites, the urban vegetation was drier and had a longer growth period. The leaves of S. alnifolia in the urban areas were smaller and heavier, and the fruits produced longer and lighter seeds, showing the traits affected by long urbanization. The study confirmed changes in the growth and reproduction mechanism of the S. alnifolia population under the urban environment, indicating reduced biological interaction due to vegetation fragmentation and isolation. This study provides limited but distinct ecological information about the function and persistence of key species in cities with a reduced scale of biological interactions and many negative environmental factors such as air pollution.

• Korean Journal of Agricultural and Forest Meteorology
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• v.24 no.4
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• pp.346-352
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• 2022

Mountain meteorology in South Korea that is covered mountains with complex terrain is important for understanding and managing the forest disaster and forest ecosystems. In particular, recent changes in dryness and/or rainfall intensity due to climate change may cause an increase in the possibility of forest disasters. Therefore, accurate monitoring of mountain meteorology is needed for efficient forest management. Korea Forest Service (KFS) is establishing the Automatic Mountain Meteorology Observation Stations (AMOS) in the mountain regions since 2012. 464 AMOSs are observing various meteorological variables such as air temperature, relative humidity, wind speed and direction, precipitation, soil temperature, and air pressure for every minute, which is conducted the quality control (QC) to retain data reliability. QC process includes the physical limit test, step test, internal consistency test, persistence test, climate range test, and median filter test. All of AMOS observations are open to use, which can be found from the Korean Mountain Meteorology Information System (KoMIS, http://mtweather.nifos.go.kr/) of the National Institute of Forest Science and the Public Data Portal (https://public.go.kr/). AMOS observations with guaranteed quality can be used in various forest fields including the public safety, forest recreation, forest leisure activities, etc., and can contribute to the advancement of forest science and technology. In this paper, a series of processes are introduced to collect and use the AMOS dataset in the mountain region in South Korea.