• Journal of Korea Water Resources Association
• /
• v.54 no.spc1
• /
• pp.1107-1118
• /
• 2021

Climate change brought on by global warming increased the frequency of flood and drought on the Korean Peninsula, along with the casualties and physical damage resulting therefrom. Preparation and response to these water disasters requires national-level planning for water resource management. In addition, watershed-level management of water resources requires flow duration curves (FDC) derived from continuous data based on long-term observations. Traditionally, in water resource studies, physical rainfall-runoff models are widely used to generate duration curves. However, a number of recent studies explored the use of data-based deep learning techniques for runoff prediction. Physical models produce hydraulically and hydrologically reliable results. However, these models require a high level of understanding and may also take longer to operate. On the other hand, data-based deep-learning techniques offer the benefit if less input data requirement and shorter operation time. However, the relationship between input and output data is processed in a black box, making it impossible to consider hydraulic and hydrological characteristics. This study chose one from each category. For the physical model, this study calculated long-term data without missing data using parameter calibration of the Soil Water Assessment Tool (SWAT), a physical model tested for its applicability in Korea and other countries. The data was used as training data for the Long Short-Term Memory (LSTM) data-based deep learning technique. An anlysis of the time-series data fond that, during the calibration period (2017-18), the Nash-Sutcliffe Efficiency (NSE) and the determinanation coefficient for fit comparison were high at 0.04 and 0.03, respectively, indicating that the SWAT results are superior to the LSTM results. In addition, the annual time-series data from the models were sorted in the descending order, and the resulting flow duration curves were compared with the duration curves based on the observed flow, and the NSE for the SWAT and the LSTM models were 0.95 and 0.91, respectively, and the determination coefficients were 0.96 and 0.92, respectively. The findings indicate that both models yield good performance. Even though the LSTM requires improved simulation accuracy in the low flow sections, the LSTM appears to be widely applicable to calculating flow duration curves for large basins that require longer time for model development and operation due to vast data input, and non-measured basins with insufficient input data.

• Korean Journal of Environmental Biology
• /
• v.41 no.4
• /
• pp.400-412
• /
• 2023

In this study, the biogeochemistry management (BGC-MAN) model was applied to North and South Korea pine and oak forest stands to evaluate the Net Primary Productivity (NPP), an indicator of forest ecosystem productivity. For meteorological information, historical records and East Asian climate scenario data of Shared Socioeconomic Pathways (SSPs) were used. For vegetation information, pine (Pinus densiflora) and oak(Quercus spp.) forest stands were selected at the Gwangneung and Seolmacheon in South Korea and Sariwon, Sohung, Haeju, Jongju, and Wonsan, which are known to have tree nurseries in North Korea. Among the biophysical information, we used the elevation model for topographic data such as longitude, altitude, and slope direction, and the global soil database for soil data. For management factors, we considered the destruction of forests in North and South Korea due to the Korean War in 1950 and the subsequent reforestation process. The overall mean value of simulated NPP from 1991 to 2100 was 5.17 Mg C ha^-1, with a range of 3.30-8.19 Mg C ha^-1. In addition, increased variability in climate scenarios resulted in variations in forest productivity, with a notable decline in the growth of pine forests. The applicability of the BGC-MAN model to the Korean Peninsula was examined at a time when the ecosystem process-based models were becoming increasingly important due to climate change. In this study, the data on the effects of climate change disturbances on forest ecosystems that was analyzed was limited; therefore, future modeling methods should be improved to simulate more precise ecosystem changes across the Korean Peninsula through process-based models.

• Korean Journal of Soil Science and Fertilizer
• /
• v.33 no.6
• /
• pp.482-492
• /
• 2000

Vesicular arbuscular mycorrhizal (VAM) fungi are known to increase plant growth as well as to enhance salt tolerance of plants where plant roots are colonized by VAM. In pot experiment, pepper was grown in soil containing 0, 200, 400, and $600P\;kg\;ha^{-1}$ with and without mycorrhizal inoculum. Pots were irrigated with saline water containing 0.5, 2.0, and $6.0dS\;m^{-1}$. At 0, 200, and $400P\;kg\;ha^{-1}$ of three EC treatments, plant hight in mycorrhizal treatments was significantly different compared to nonmycorrhizal treatments. However, plant hight at $600P\;kg\;ha^{-1}$ was not different between mycorrhizal and nomycorrhizal treatments. Leaf area at $0P\;kg\;ha^{-1}$ of three EC treatments, and $200P\;kg\;ha^{-1}$ of $6.0dS\;m^{-1}$ in mycorrhizal treatments significantly increased compared to nonmycorrhizal treatments. However, these increase were not discovered in high salinity and P level. Level of EC affected dry weight, and especially, interection of P and EC, or P and VA inoculation highly affected root dry weight. R/S ratio generally decreased in mycorrhizal treatments. Significantly decreased R/S ratio was shown at 0, 400, and $600P\;kg\;ha^{-1}$ of $6.0dS\;m^{-1}$. Chlorophyll content generally increased with decreased salinity and P level where mycorrhizal treatments showed higher chlorophyll content compared to nonmycorrhizal treatments. The benefits of VAM inoculation on fruit production was discovered at only low P level and salinity. Mycorrhizal dependency on dry weight basis was generally shown in $0P\;kg\;ha^{-1}$ of three EC treatments and 0.5, $2.0dS\;m^{-1}$ of $200P\;kg\;ha^{-1}$ level. Colonization rate ranged 3.3 to 43.3% and number of spores was 47.7 to 198.3 $100g^{-1}$ soil. Colonization rate and number of spores increased with decreased P level and salinity where there was high correlation ($r=0.858^{**}$) between both. Also improved uptake of mineral nutrients was discovered at mycorrhizal treatments in decreased P level and salinity.

• Korean Journal of Weed Science
• /
• v.12 no.1
• /
• pp.70-79
• /
• 1992

From the beginning of the chosun dynasty, an agriculture-first policy was imposed by being written farming books, for instance, Nongsajiksul, matched with real conditions of local agriculture, which provided the grounds of new, intensive farming technologies. This farming book was the collection of good fanning technologies that were experienced in rural farm areas at that time. According to Nongsajiksul, rice culture systems were divided into "Musarmi"(Water-Seeded rice), /"Kunsarmi"(dry-seeded rice), /transplanted rice and mountainous rice (upland rice) culture. The characteristics of these rice cultures with high technologies were based of scientific weeding methods, improved fertilization, and cultivation works using cattle power and manpower tools systematically. Reclamation of coastal swampy and barren land was possible in virtue of fire cultivation farming(火耕) and a weeding tool called "Yoonmok"(輪木). Also, there was an improved hoe to do weeding works as well as thinning and heaping-up of soil at seeding stages of rice. Direct-seeded rice culture in flat paddy fields were expanded by constructing the irrigation reservoirs and ponds, and the valley paddy fields was reclaimed by constructing "Boh(洑)". These were possible due to weed control by irrigation waters, keeping soil fertility by inorganic fertilization during irrigation, and increased productivity of rice fields by supplying good physiological conditions for rice. Also, labor-saving culture of rice was feasible by transplanting but in national-wide, rice should not basically be transplanted because of the restriction of water use. Thus, direct-seeded rice in dry soils was established, in which rice was direct-seeded and grown in dry soils by seedling stages and was grown in flooded fields when rained, as in the book "Nongsajiksul". During the middle of the dynasty(AD 1495-1725), the excellent labor-saving farmings include check-rowing transplanting because of weeding efficiency and availability in rice("Hanjongrok"), and, nurserybed techniques (early transplanting of rice) were emphasized on the basis of rice transplanting ["Nongajibsung"]. The techniques for deep plowing with cattle powers and for putting more fertilizers were to improve the productivity of labor and land, The matters advanced in "Sanlimkyungje" more than in "Nongajibsung" were, development of "drybed of rice nursery stock", like "upland rice nursery" today, transplanting, establishment of "winter barly on drained paddy field, and improvement of labor and land-productivity in rice". This resulted in the community of large-scale farming by changing the pattern of small-farming into the production system of rice management. Woo-hayoung(1741-1812) in his book "Chonilrok" tried to reform from large-scale farmings into intensive farmings, of which as eminent view was to divide the land use into transplanting (paddy) and groove-seeding methods(dry field). Especially as insisted by Seo-yugo ("Sanlimkyungjeji"), the advantages of transplanting were curtailment of weeding labors, good growth of rice because of soil fertility of both nurserybed and paddy field, and newly active growth because rice plants were pulled out and replanted. Of course, there were reestimation of transplanting, limitation of two croppings a year, restriction of "paddy-upland alternation", and a ban for large-scale farming. At that period, Lee-jiyum had written on rice farming technologies in dry upland with consider of the land, water physiology of rice, and convenience for weeding, and it was a creative cropping system to secure the farm income most safely. As a integrated considerations, the followings must be introduced to practice the improved farming methods ; namely, improvement of farming tools, putting more fertilizers, introduction of cultural technologies more rational and efficient, management of labor power, improvement of cropping system to enhance use of irrigation water and land, introduction of new crops and new varieties.

• Korean Journal of Soil Science and Fertilizer
• /
• v.23 no.1
• /
• pp.53-59
• /
• 1990

The antagonistic fluorescent pseudomonas, which was isolated from continuous cropping rhizosphere of pepper and cucumber, was identified as Pseudomonas fluorescens (P.f.). For further study, transformant was derived from the isolated P.f. after spontaneous mutation to give antibiotic resistance to nalidixic acid and rifampicin as marked strain. Both P.f. and transformant strains were used for this study and the results obtained were summarized as follows. 1. One of the most effective antagonistic strain, KR164, was selected against F. solani, F. oxysporum, R. solani and this strain was identified and classified as Pseudomonas fluorescens biotype IV. 2. Transformant, KR1641, was derived from strain KR164 and both strains had the same biological and biochemical characteristics. 3, Mycelial lysis and abnormal mycelia of plant pathogenic fungi were microscopically observed after simultaneous culture of fungus and given bacterial strain. 4. The length of chinese cabbage to the autolyzed became longer with given bacterial strain in dark culture. 5. Percentage of germination, number of leaves, length of height, and length of root in chinese cabbage in pot experiment were improved by inoculation of given bacterial strain. 6. The number of given bacterial strain kept generally stable until 34 days after inoculation of itself in pot experiment. Inoculation of given bacterial strain did affect the number of plant disease fungi to be decreased but did not affect the number of other bacteria, Bacillus, in pot experiment.

• Korean Journal of Medicinal Crop Science
• /
• v.6 no.2
• /
• pp.131-136
• /
• 1998

This experiment was carried out to investigate the effect of several organic fertilizers on the growth and root yield of Achyranthes japonica N. from 1995 to 1996. Four organic fertilizers were applied: rice straw manure (RSM), fermented rice straw manure (FRSM), mixed oil cake manure (MOCM) and mighty soil manure (MSM). Organic matter, available phosphate, $K_2O$, CaO, and MgO of soil increased in all plots with the addition of organic fertilizers, specifically with MOCM application. The highest contents of total nitrogen were 6.16% for MOCM and the available phosphate contents were very high in all of organic fertilizers except MSM. RSM and MSM with C/N ratios of 22.5, 17.7, respectively, were easily decomposed but C/N ratios of FRSM and MOCM, which were considered as irresolvable organic fertilizers, were 40.9 and 8.4, respectively. FRSM and MOCM applications increased emergence rate and improved the growth characters of shoot and root parts of plants compared to those of N - P - K fertilization. The highest dry root yield resulted from FRSM 20% and MOCM 26% treatment. There were significantly positive correlations between the growth characters of shoot, root parts of plants and dry root yield in A. japonica grown under organic fertilizer applications.

• Journal of the Korean Institute of Landscape Architecture
• /
• v.37 no.6
• /
• pp.12-18
• /
• 2010

This study was carried out in order to propose a planning index for improved school forests in Gyeonggido. For the purpose of this study we selected 42 out of 75 school forests established during 2005 in Gyeonggido. All 42 school forests were surveyed and analyzed by frequency, cross tabulation, and group average analysis with SPSS 12.0 version. The present condition of the school forests was analyzed with in conjunction with items such as the surrounding environment, centralization, and locational characteristics as nominal points. Other items: trees, shrubs, pavement, fruit trees, transplantation, evergreen trees, and recreation facility content percentage were analyzed as a proportion point. After reviewing the literature and analyzing the present condition of school forests, we constructed a conceptual framework and formulated a hypothesis for this research. Data were obtained through a questionnaire, given to 98 students majoring in landscape architecture at Hankyong University in 2007. Results showed that the primary variables for tree health were soil compaction and the depth of soil filling. They were the most serious factors that deteriorate the health of trees. Based on the relationship between tree health and growing conditions, trees inside the school forest should be managed to provide more growing space and less abuse. The minimum area for trees inside the school forest for good growth conditions should be within the drip lines. We have found that the minimum percentage of tree content is 0.13, which means that more than 130 trees need to be planted over $1,000m^2$ green space. More than 3,580 shrubs need to be planted over $1,000m^2$ green space. The pavement area should be controlled to less than 19% of the total size of the school forest area. Finally, more than 39 trees out of 100 trees planted should be evergreen. The research results suggest that the construction planning index of Gyeonggido school forest be recommended in the planning and development process of the construction project carried out every year.

• Journal of Environmental Policy
• /
• v.9 no.2
• /
• pp.157-184
• /
• 2010

Global climate change is destroying the water circulation balance by changing rates of precipitation, recharge and discharge, and evapotranspiration. The Intergovernmental Panel on Climate Change (IPCC 2007) makes "changes in rainfall pattern due to climate system changes and consequent shortage of available water resource" a high priority as the weakest part among the effects of human environment caused by future climate changes. Groundwater, which occupies a considerable portion of the world's water resources, is related to climate change via surface water such as rivers, lakes, and marshes, and "direct" interactions, being indirectly affected through recharge. Therefore, in order to quantify the effects of climate change on groundwater resources, it is necessary to not only predict the main variables of climate change but to also accurately predict the underground rainfall recharge quantity. In this paper, the authors selected a relevant climate change scenario, In this context, the authors selected A1B from the Special Report on Emission Scenario (SRES) which is distributed at Korea Meteorological Administration. By using data on temperature, rainfall, soil, and land use, the groundwater recharge rate for the research area was estimated by period and embodied as geographic information system (GIS). In order to calculate the groundwater recharge quantity, Visual HELP3 was used as main model for groundwater recharge, and the physical properties of weather, temperature, and soil layers were used as main input data. General changes to water circulation due to climate change have already been predicted. In order to systematically solve problems associated with how the groundwater resource circulation system should be reflected in future policies pertaining to groundwater resources, it may be urgent to recalculate the groundwater recharge quantity and consequent quantity for using via prediction of climate change in Korea in the future and then reflection of the results. The space-time calculation of changes to the groundwater recharge quantity in the study area may serve as a foundation to present additional measures for the improved management of domestic groundwater resources.

• Journal of the Korean Institute of Landscape Architecture
• /
• v.46 no.3
• /
• pp.14-26
• /
• 2018

The Biotope Area Ratio (BAR) is a quantitative pre-planning index for sustainable development and an integrated indicator for the balanced development of buildings and outdoor spaces. However, it has been pointed out that there are problems in operations management: errors in area calculation, insufficiency in the underground soil condition and depth, reduction in biotope area after construction, and functional failure as a pre-planning index. To address these problems, this study proposes implementing LIM. Since the weights of the BAR are mainly decided by the underground soil condition and depth with land cover types, the study focused on the terrain and pavements. The model should conform to BIM guidelines and standards provided by government agencies and professional organizations. Thus, the scope and Level Of Detail (LOD) of the model were defined, and the method to build a model with BIM software was developed. An apartment complex on sloping ground was selected as a case study, a 3D terrain modeled, paving libraries created with property information on the BAR, and a LIM model completed for the site. Then the BAR was calculated and construction documents were created with the BAR table and pavement details. As results of the study, it was found that the application of the criteria on the BAR and calculation became accurate, and the efficiency of design tasks was improved by LIM. It also enabled the performance of evidence-based design on the terrain and underground structures. To adopt LIM, it is necessary to create and distribute LIM library manuals or templates, and build library content that comply with KBIMS standards. The government policy must also have practitioners submit BIM models in the certification system. Since it is expected that the criteria on planting types in the BAR will be expanded, further research is needed to build and utilize the information model for planting materials.

• Korean Journal of Soil Science and Fertilizer
• /
• v.45 no.6
• /
• pp.1086-1093
• /
• 2012

This research was carried out to develop the correction method of VDI4630 method improving accuracy, and investigated the effects of carbonate ion ($CO_3{^{2-}}$) and reactant water ($H_2O$) on anaerobic organic biodegradability in VDI4630 method. Pig blood, pig intestine residue, pig digestive tract content, and cattle rumen content were experimented as waste biomasses. Chemical formulas of pig blood, pig intestine residue, pig digestive tract content, and cattle rumen content were $C_{3.78}H_{8.39}O_{1.46}N_1S_{0.01}$, $C_{9.69}H_{15.42}O_{2.85}N_1S_{0.03}$, $C_{25.17}H_{43.32}O_{15.04}N_1$, $C_{27.23}H_{42.38}O_{15.93}N_1S_{0.11}$, respectively. And amount of reactant moisture for the anaerobic degradation of organic materials were 0.336, 0.485, 0.227, 0.266 mol, respectively. In pig blood, pig intestine residue, pig digestive tract content, and cattle rumen content, anaerobic organic biodegradability presented as $B_u/B_{th}$ were 82.3, 81.5, 70.8, and 66.1%, and anaerobic organic biodegradability (AB) by VDI4630 method were 72.2, 87.8, 74.2, 62.0%, and that were significantly different with anaerobic organic biodegradability presented as $B_u/B_{th}$. The effects of carbonate ion and reactant water on anaerobic organic biodegradability were not significant, But Accuracy of anaerobic organic degradability was expected to able to be improved by the correction method of VDI4630 considering the carbonate ion at digestate and the reactant water quantified.