• Korean Journal of Soil Science and Fertilizer
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• v.40 no.1
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• pp.18-24
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• 2007

Paddy fields are apparently nonpoint source pollution and influence water environment. In order to improve water quality in rivers or lakes, to low nutrient load from paddy fields are required. To establish comprehensive plan to control agricultural non-point source pollution, it is imperative to get a quantitative evaluation on pollutants and pollution load from paddy fields. A field monitoring study was carried out to investigate the water balance and losses of nutrients from fields in Sumjin river basin. The size of paddy fields was 115 ha and the fields were irrigated from a pumping station. The observed total nitrogen loads from paddy fields were larger than those of the unit loads determined by Ministry of Environment data (MOE). It is because the nitrogen fertilization level at the studied field was higher than the recommended rate and the high irrigation and subsequent drainage amount. On the contrary, total phosphorus loads were less than those addressed by MOE since phosphorus fertilization level was lower than that of standard level. Therefore, it was found that fertilization, irrigation, and drainage management are key factors to determine nutrient losses from paddy fields. When the runoff losses of nutrients were compared to applied chemical fertilizer, it was found that 42 to 60% of nitrogen lost via runoff while runoff losses of phosphorus account for 1.3 to 7.6% of the total applied amount during the entire year.

• Korean Journal of Environment and Ecology
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• v.33 no.4
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• pp.422-439
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• 2019

The rear edge population is considered to have low genetic diversity and high risk of extinction according to a highly isolated distribution. However, the rear edge population is observed to have persisted for an extended period despite the low genetic diversity. As such, it is necessary to understand the ecological process involved in the persistence of the population. Viola mirabilis L. in Korea is considered the rear edge population from the perspective of the worldwide distribution. We surveyed the distribution range of V. mirabilis, which shows the isolated distribution in the central area of Korea, to find out the factors of its persistence. Next, we investigated and accessed the vegetational pattern of habitats, soil environment, phenology, self-compatibility, population structure, and extinction risk factors observed in the distribution area. V. mirabilis was distributed in the understory of the deciduous forest, planted forest of the deciduous conifer and deciduous broad-leaved trees, shrubland, and grassland in the limestone area. We also observed the re-establishment of seedlings in the population, and most of them showed a stable population structure. For chasmogamous flowers, the visit by pollinators has a significantly positive relationship with the production of fruits. However, we found that the production of the cleistogamous flowers was more numerous in all studied populations and that only the cleistogamous flowers were produced despite a more substantial plant size in some populations. The plant size was more related to the production of the cleistogamous flowers than that of the chasmogamous flowers. Accordingly, the cleistogamous flowers significantly contributed to seedling recruitment in the population. We found that the production of the chasmogamous flowers and the cleistogamous flowers did not have a correlation with the factors of the soil analysis except for phosphoric acid. V. mirabilis showed the self-incompatibility characteristics most likely due to the production capability of the cleistogamous flowers. Potential extinction risk factors observed in the distribution area was included the development of limestone mine, the expansion of agricultural fields, and the construction of houses. Although V. mirabilis showed an isolated distribution in the limestone area in the Korean peninsula, it showed a diverse distribution in a wide habitat environment ranging from the grassland to the understory of the trees with relatively low canopy closure rate. Moreover, we concluded that the persistence of the population was possible if we can maintain the current state of multiple populations and stable population structure.

• Korean Journal of Environment and Ecology
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• v.35 no.1
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• pp.68-80
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• 2021

This study aimed to provide basic data such as the structure of the Carpinus turczaninowii community and characteristics of the habitat environment for ex situ conservation by analyzing the plant community structure of Carpinus turczaninowii, an island plant resource. For the community structure analysis, this study established 29 plots, sized 100㎡ each, in Seokmo, Yeongjong, Yeongheung, and Daebu islands. TWINSPAN was used for the classification of communities. The classification identified six communities. Group I was the C. turczaninowii-Quercus serrata community, group II was the C. turczaninowii-Pinus densiflora community, group III was the C. turczaninowii-Quercus mongolica community, group IV was the C. turczaninowii-Sorbus alnifolia community, group V was the C. turczaninowii typical community, and group VI was the C. turczaninowii-Quercus variabilis community. The species diversity was 0.90008~1.12868, the dominance was 0.17536~0.25665, and the similarity index was 17.1429~38.2979%. The result of correlation analysis of 7 environmental factors for 6 communities by RDA ordination showed a positive correlation between the crown density and litter layer and a negative correlation between the bare rock, soil hardness, and altitude on the 1st axis. On the 2nd axis, the bare rock and crown density showed a positive correlation, and the slope showed a negative correlation. In the C. turczaninowii-Quercus serrata community (I), the crown density and the litter layer were the environmental factors affecting the vegetation distribution. In the C. turczaninowii-Pinus densiflora (II) and C. turczaninowii-Quercus mongolica (III) communities, the slope was the factor affecting vegetation distribution. In the C. turczaninowii-Sorbus alnifolia (IV), C. turczaninowii typical (V), and C. turczaninowii-Quercus variabilis (VI) communities, the bare rock, altitude, and soil hardness were the factors affecting vegetation distribution.

• Korean Journal of Environmental Agriculture
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• v.34 no.2
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• pp.77-90
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• 2015

BACKGROUND: The field margins, which are uncultivated area of permanent vegetation located adjacent to field, play an important role in enhancing biodiversity in the agricultural ecosystem. This study focused on floristic characteristics on dry field margins in Korea Peninsula. METHODS AND RESULTS: This study was conducted at margins of 196 dry fields in 32 areas in 8 provinces in May and September 2013. The vascular plants of the dry field margins were listed 347 taxa which contain 73 families, 219 genera, 311 species, 1 subspecies, 30 varieties and 5 forms. Of these 347 taxa, 48 taxa were woody plants and 299 taxa were herbaceous plants. Among total 73 families, Compositae (17.6%) was the most dominant family, and followed Gramineae (15.9%), Polygonaceae (5.8%), Leguminosae (4.9%) and Cyperaceae (3.8%). Based on relative frequency values of survey fields, the appearance frequency of Digitaria ciliaris (89.8%) was the highest, and followed Acalypha australis (86.2%), Artemisia princeps (82.1%), Commelina communis (80.6%) and Portulaca oleracea (80.6%). Disturbance index of dry field margins was 55.0% at national level, and Gangwon region was the highest among the 8 regions at regional level. Life form spectrum was determined to be $Th-R_5-D_4-etype$. CONCLUSION: These results will be used fundamental data for studies to improve or even stabilize the current state of plant biodiversity in agricultural environments.

• Korean Journal of Plant Resources
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• v.21 no.1
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• pp.73-82
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• 2008

The resource plants of the Mt. Geonji was listed 354 taxa; 92 families, 242 genera, 303 species, 48 varieties and 3 forms. 354 taxa listed consists of 205 taxa of edible plants(57.1%),234 taxa of medicinal plants(65.2%), 167 taxa of ornamental plants(46.5%) and 218 taxa of the others(60.7%). Specific plant species by floral region were total 22 taxa; Trapella sinensis var. antennifera in class IV, Iris ensata var. spontanea in Class II, 16 taxa(Salix glandulosa, Alnus hirsuta, Chrysosplenium flagelliferum, Mallotus japonicus, Ilex macropoda, Grewia biloba var. parviflora, Vaccinium oldhami, Lysimachia barystachys, Fraxinus mandshurica, etc.) in class I. The naturalized plants in this site were 12 families, 23 genera, 28 species, 2 varieties, 30 taxa(Bromus unioloides, Phytolacca americana, Oenothera erythrosepala, Ipomoea hederacea var. hederacea, Aster pilosus, Erechtites hieracifolia) and naturalization rate was 8.5% of all 354 taxa vascular plants. Wild plants disturbing ecosystem like Solanum carolinense and Ambrosia artemisiifolia var. elatior have been increasing. So, it needs continuing control and conservation measures on the plant ecosystem.

• Korean Journal of Environmental Agriculture
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• v.19 no.3
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• pp.201-205
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• 2000

Eleven runoff $plots(3{\times}15\;m)$ were built on a sloping field of a high plateau in Kangwon Province, Korea. The plots were treated with different tillage, residue covers and fertilizers, corn and potato were cultivated, and sediment discharge was measured from the plots for 3 years. Agricultural management practices were monitored around the plots to develop adequate best management practices. The least sediment occurred from the plots with no-till and 100% residue cover $(corn,\;0.1{\sim}2.2\;t/ha/year)$ and with contour tillage and vinyl sheet cover plots $(potato,\;0.1{\sim}0.2\;t/ha/year)$. The largest sediment was measured from the plots with up-and-down till and no cover ($11{\sim}33$ and $16{\sim}31\;t/ha/year$ from corn and potato plots, respectively). The type of organic and commercial fertilizers seemed not to affect sediment discharge. Sediment discharge from contour plots were largely dependent on the collapse of ridges due to the flush of water stored in furrows. The sediment discharge from contour corn and potato plots with no residue cover was $10{\sim}27$ and $16{\sim}24\;t/ha/year$, respectively. No-till with residue cover, vinyl cover for tuber crops, construction of furrow dam, frost heave research, furrow and ridge tillage with furrow dam after tuber crop harvest, limited stalk harvest of row crops, use of winter cover crops, and other common best management practices were recommended to minimize the sediment discharge from a high plateau sloping land culture.

• Journal of Korean Society of Environmental Engineers
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• v.29 no.12
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• pp.1381-1389
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• 2007

Wastewater discharged by industrial activities of metal finishing and electroplating units is often contaminated by a variety of toxic or otherwise harmful substances which have a negative effects on the water environment. The treatment method of heavy metal-cyanide complexes wastewater by alkaline chlorination have already well-known($1^{st}$ Oxidation: pH 10, reaction time 30 min, ORP 350 mV, $2^{nd}$ Oxidation: ORP 650 mV). In this case, the efficiency for the removal of ferro/ferri cyanide by this general alkaline chlorination is very high as 99%. But the permissible limit of Korean waste-water discharge couldn't be satisfied. The initial concentration of cyanide was 374 mg/L(the Korean permissible limit of cyanide is 1.0 mg/L max.). So a particular focus was given to the treatment of heavy metal-cyanide complexes wastewater by $Zn^{+2}/Fe^{+2}$ ion and coprecipitation after alkaline chlorination. And we could meet the Korean permissible limit of cyanide(the final concentration of cyanide: 0.30 mg/L) by $Zn^{+2}/Fe^{+2}$ ion and coprecipitation(reaction time: 30 min, pH: 8.0, rpm: 240). The removal of Chromium ion by reduction(pH: 2.0 max, ORP: 250 mV) and the precipitation of metal hydroxide(pH: 9.5) is treated as 99% of removal efficiency. The removal of Copper and Nickel ion has been treated by $Na_2S$ coagulation-flocculation as 99% min of the efficiency(pH: $9.09\sim10.0$, dosage of $Na_2S:0.5\sim3.0$ mol). It is important to note that the removal of ferro/ferri cyanide of heavy metal-cyanide complexes wastewater should be employed by $Zn^{+2}/Fe^{+2}$ ion and coprecipitation as well as the alkaline chlorination for the Korean permissible limit of waste-water discharge.

• Journal of Life Science
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• v.20 no.8
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• pp.1254-1260
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• 2010

Microorganisms near the plant rhizosphere usually inhabit the surface or the inside of the plant roots and have a direct effect on plant growth by secreting plant growth promoters or antagonistic materials which protect the root zone system from various pathogens. This study was carried out to identify and isolate the antagonistic materials after isolation of microorganisms showing high antagonistic activities, in hopes of contributing to the development of sustainable agriculture and the preservation of agricultural environments. A number of antagonistic bacteria were isolated from paddy soil. Among isolates, RRj 228 showed plant growth promotion and antagonistic activity. RRj 228 was identified as Pseudomonas sp. according to the results of physiological properties and genetic methods. On the basis of the results of anti-fungal spectrum against several pathogens by RRj 228, the antagonistic effect of the isolate against Botrytis cinerea, Pythium ultimum, Phytopthola capsici, and Rhizoctonia solani, especially against red-pepper anthracnose caused by Colletotrichum acutatum, was remarkable. The experiment evaluating the biological control effect by RRj 228 revealed that the $ED_{50}$ value by the RRj 228 culture against C. acutatum, R. solani and P. ultimum were 0.14 mg/ml, 0.16 mg/ml and 0.29 mg/ml, respectively. An antagonistic substance was isolated and purified by several chromatographies from the RRj 228 culture. The $^1H$ and $^{13}C$ assignment of the antagonistic substance was achieved from two-dimensional $^1H-^1H$ COSY, HMQC, and HMBC. Finally, the antagonistic substance was identified as Phenazine-1-carboxylic acid ($C_{13}H_8N_2O_2$, M.W.=224).

• Journal of the Korean association of regional geographers
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• v.5 no.1
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• pp.101-120
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• 1999

The purpose of this study is to analyze the impact of agricultural polices on the change of regional structure based on the specialization during the productivism period. Analysis are carried on through the comparison of distribution in 1950s and 1997. Since the 1950s, governmental policy has played a leading role in shaping the pattern of farming in Great Britain. The range of British measures have also been employed in an attempt to improve the efficiency of agriculture and raise farm income. Three fairly distinct phase can be identified in the developing relationship between government policies and British agriculture in the postwar period. In the 1st phase, The Agricultural Act of 1947 laid the foundations for agricultural productivism in Great Britain until membership of the EC. This was to be achieved through the system of price support and guaranteed prices and the means of a series of grants and subsidies. Guaranteed prices encouraged farmenrs to intensify production and specialize in either cereal farming or milk-beef enterprise. The former favoured eastern areas, whereas the latter favoured western areas. Various grants and subsidies were made available to farmers during this period, again as a way of increasing efficiency and farm incomes. Many policies, such as Calf Subsidy and the Ploughing Grant, Hill cow and Hill Sheep Schemes and the Hill Farming and Livestock Rearing Grant was provided. Some of these policies favoured western uplands, whilst the others was biased towards the Lake District. Concentration of farms occured especially in near the London Metropolitan Area and south part of Scotland. In the 2nd stage after the membership of EC, very high guaranteed price created a relatively risk-free environment, so farmers intensified production and levels of self-sufficiency for most agriculture risen considerably. As farmers were being paid high prices for as much as they could produce, the policy favoured areas of larger-scale farming in eastern Britain. As a result of increasing regional disparities in agriculture, the CAP became more geographically sensitive in 1975 with the setting up of the Less Favoured Areas(LFAs). But they are biased towards the larger farms, because such farms have more crops and/or livestock, but small farms with low incomes are in most need of support. Specialization of cereals such wheat and barely was occured, but these two cereal crops have experienced rather different trend since 1950s. Under the CAP, farmers have been paid higher guaranteed prices for wheat than for barely because of the relative shortage of wheat in the EC. And more barely were cultivated as feedstuffs for livestock by home-grown cereals. In the 1950s dairying was already declining in what was to become the arable areas of southern and eastern England. By the mid-1980s, the pastral core had maintained its dominance, but the pastoral periphery had easily surpassed arable England as the second most important dairying district. Pig farming had become increasingly concentrated in intensive units in the main cereal areas of eastern England. These results show that the measure of agricultural policy induced the concentration and specialization implicitly. Measures for increasing demand, reducing supply or raising farm incomes are favoured by large scale farming. And price support induced specialization of farming. And technology for specialization are diffused and induced geographical specialization. This is the process of change of regional structure through the specialization.

• Korean Journal of Ecology and Environment
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• v.48 no.4
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• pp.253-262
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• 2015

The sustainability of Cypripedium japonicum, a rare plant designated by the Korea Forest Service, is threatened due to artificial factors such as habitat loss and climate change etc. and internal factors such as changes in biological properties of the habitat etc. but conservation research has not been performed in South Korea. The objective of this study is to establish the species conservation strategies by analyzing the characteristics of their habitats, including: 1) Population characteristics, and 2) habitat analysis of the vegetation and abiotic environments. From April to September, 2014, population characteristics [density (stems $m^{-2}$), flowering rate (%), and leaf area ($cm^2$)] in Cypripedium japonicum habitats such as Chuncheon (CC), Hwacheon (HC), Muju (MJ), and Gwangyang (GY) and vegetation characteristics (plant sociological research and ordination analysis), and abiotic environments [temperature ($^{\circ}C$), relative humidity (%), transmitted light ($mol{\cdot}m^{-2}{\cdot}d^{-1}$) and canopy openness (%)] were measured. Cypripedium japonicum was mainly distributed at elevation 450 to 990 m and 5 to $30^{\circ}$ slope. Slope direction was shown as 0 to $110^{\circ}$. Habitats temperature (mean $18.94^{\circ}C$) was well matched to seasonal changes. Differences among sites showed greater level according to latitude difference. It showed the highest in habitat, GY located in the South. On the other hand, relative humidity (77.38%) didn't show much difference among sites. The average degree of canopy openness was 18.17%. It showed the highest at HC (22.1%) and the lowest at MJ (16.1%). The average degree of transmitted light was $9.1mol{\cdot}m^{-2}{\cdot}d^{-1}$. It showed the highest at CC ($10.6mol{\cdot}m^{-2}{\cdot}d^{-1}$) and the lowest at GY ($6.87mol{\cdot}m^{-2}{\cdot}d^{-1}$). Chlorophyll content showed average 26.12 SPAD. It showed the highest at MJ (30.64 SPAD value) and the lowest at HC (23.69 SPAD value). Leaf area was average $253.35cm^2$. It showed the highest at CC ($281.51cm^2$) and the lowest at HC ($238.23cm^2$).