• Korean Journal of Medicinal Crop Science
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• v.15 no.6
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• pp.367-370
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• 2007

To make the soil moisture proper is the important factor in the seedbed cultivation of Yangjik for producing a good quality of ginseng seedling. This study was carries out to investigate the effect of soil moisture on photosynthesis and yield of ginseng seedling under the different condition of the soil moisture, such as $100{\sim}400$ mbar. Photosynthesis rate was decreased gradually by the reduction of soil moisture, and in particular it was decreased distinctly under the lower condition of soil moisture, such as $300{\sim}400$ mbar. Photosynthesis rate in air temperature of $30^{\circ}C$ was decreased more distinct than that of $25^{\circ}C$, Light saturation point of leaves was at the quantum of $600{\mu}mol/m^3/s$ at $25^{\circ}C$ while it was decreased by $300{\mu}mol/m^3/s$ at $30^{\circ}C$ according to the increase of air temperature. Respiration rate was increased by the increase of quantum, and decreased by the reduction of soil moisture. Respiration rate under the condition of high quantum was increased regardless of air temperature, but it was decreased distinctly under the condition of low soil moisture and high air temperature, such as 400 mbar at $30^{\circ}C$. There were a gradual decrease by the reduction of soil moisture in leaf length, leaf width, chlorophyll content, and water content of leaves, but heat injury ratio was increased distinctly by the reduction of it. Total root weight, root weight per plant, the yield of usable seedling were decreased by the reduction of soil moisture, and optimal content of soil moisture to produce a good quality of seedling was 63% of field capacity or 18.9% in absolute soil moisture content.

• Korean Journal of Soil Science and Fertilizer
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• v.21 no.1
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• pp.61-71
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• 1988

This study was conducted to find out the effect of herbicides on soil micro-organism and soil enzyme in loam soil, and on pathogenic microorganism in continuous pepper cropping soil. The result was summarized as follows: When herbicides were treated, the number of soil microorganism generally decreased at the early stage of incubation, and gradually increased at 30 days incubation. The number of fungi was significantly decreased seven times comparison with control plot. The number of actinomycetes was increased at 20 days incubation and that of pytium was increased for all days incubation in Linuron treatment plot. Although the activity of soil enzyme tended to decrease when herbicides were treated, the activities of urease and phosphatase were higher than that of control plot at the early stage of incubation in MO, Linuron and Simetryne treatment plot. In Simetryne treatment plot, the activity of protease was increased at the early stage, and suddenly decreased after 30 days incubation. There was no significant effect of herbicides on the activities of ${\beta}$-glucosidase and polygalacturonase. The activity of cellulase was inhibited at the early stage of incubation, but that of cellulase was higher than that of control plot after 20 days incubation. High significance was showed the correlation coefficient between soil microorganisms except fungi and soil respiration as herbicides were treated, and the total microorganism and soil respiration in Linuron plot. when Dicamba and Simetryne were treated, the correlation coefficient between the total microorganism and the activities of protease and urease were considerably significant.

• Journal of Climate Change Research
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• v.4 no.2
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• pp.77-93
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• 2013

Global warming accelerates both carbon (C) input through increased forest productivity and heterotrophic C emission in forest soils, and a future trend in soil C dynamics is uncertain. In this study, the Korean forest soil carbon model (KFSC model) was applied to 1,467,458 ha of Pinus densiflora forests in Korea to predict future C dynamics under RCP 8.5 climate change scenario (RCP scenario). Korea was divided into 16 administrative regions, and P. densiflora forests in each region were classified into six classes by their stand ages : 1 to 10 (I), 11 to 20 (II), 21 to 30 (III), 31 to 40 (IV), 41 to 50 (V), and 51 to 80-year-old (VI+). The forest of each stand age class in a region was treated as a simulation unit, then future net primary production (NPP), soil respiration (SR) and forest soil C stock of each simulation unit were predicted from the 2012 to 2100 under RCP scenario and constant temperature scenario (CT scenario). As a result, NPP decreased in the initial stage of simulation then increased while SR increased in the initial stage of simulation then decreased in both scenarios. The mean NPP and SR under RCP scenario was 20.2% and 20.0% higher than that under CT scenario, respectively. When the initial age class was I, IV, V or VI+, predicted soil C stock under CT scenario was higher than that under RCP scenario, however, the countertrend was observed when the initial age class was II or III. Also, forests having a lower site index showed a lower soil C stock. It suggested that the impact of temperature on NPP was higher when the forests grow faster. Soil C stock under RCP scenario decreased at the end of simulation, and it might be derived from exponentially increased SR under the higher temperature condition. Thus, the difference in soil C stock under two scenarios will be much larger in the further future.

• Korean Journal of Agricultural Science
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• v.41 no.4
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• pp.291-298
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• 2014

Plastic film houses are directly associated with increases in plant growth and yield of vegetable crops through a year round cultivation, however, at the same time temperature stresses are one of fates which are difficult to avoid during crop growth. The objective of this study was to examine the translocation and distribution of minerals (N, P, K) and carbohydrates as well as seasonal fluctuation of mineral uptake and carbohydrate production in cucumber plant grown under moderately high temperature. The temperature treatments consisted of 2-layers film houses (optimal temp.) and 3-layers (high temp.). Shoot growth of cucumber plants were linearly increased until 14 weeks after transplanting (WAT) without any significant difference between both temperatures, and the slowdown was observed from 16 WAT. The level of soluble sugar and starch was slightly greater in optimal temperature compared to the high. Cumulative accumulation of soluble sugar was significantly different before and after 12 WAT in both treatments, whereas starch level represented a constant increase. Monthly production of soluble sugar reached the peak between 12 to 16 WAT, and starch peaked between 4 to 8 WAT and 12 to 16 WAT. Total uptake of N, P and K in optimal and high temperature conditions was $18.4g\;plant^{-1}$ and 17.6 for N, 4.7 and 5.1 for P, and 37.7 and 36.2 for K, respectively, and the pattern of monthly N uptake between optimal and high temperatures was greater in early growth stage, whereas was greater in mid growth stage in both P and K. Thus, this study suggests that moderately high temperature influences much greater to photosynthesis and carbohydrate production than plant biomass and mineral uptake. On the basis of the present result, it is required to indentify analysis of respiration rates from plant and soil by constantly increasing temperature conditions and field studies where elevated temperatures are monitored and manipulated.

• Journal of the Korean Institute of Landscape Architecture
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• v.37 no.4
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• pp.64-71
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• 2009

Excessive soil organic matter (SOM) is detrimental to turfgrass quality when used intensively in sand-based root zones, thereby affecting the sustainability of turfgrass systems. As part of a major project examining the sustainable management of SOM on golf greens, microbial decomposition on soil organic matter accumulation with depth was assessed and the effect of soil air-condition improvement and Ca fertilization was investigated by soil microbial respiration (SMR). Three soil samples from three depths(0~5, 5~10, and 10~15cm) of 5 year and 30 year old green were analyzed for SOM content. In 30 year old green, SMR and dehydrogenase activity(DHA) were analyzed to assess the soil microbial decomposition with depth. It was then divided into 4 plots: untreated as a control, dolomite-treated, 0~5cm deep section-removed, and 0~5 cm deep section-removed+dolomite-treated. After treatment, three soil samples were taken at 1, 2 and 4 weeks by the above-mentioned method, and analyzed for SMR to better understand SOM decomposition. SOM accumulation in the 0~5cm depth of golf greens can be controlled by intensive cultivation such as coring, but below 5cm is more difficult as the results showed that SOM content below 5cm increased over time. Soil microbial decomposition of organic matter will be necessary to reduce SOM accumulation, but SMR below 5cm was low and wasn't significantly altered by increasing exposure to air and fertilizing with Ca. As a result, aeration treatments such as coring and Ca fertilization might not be effective at improving soil microbial decomposition below 5cm depth in aged greens.

• Korean Journal of Agricultural and Forest Meteorology
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• v.14 no.1
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• pp.39-44
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• 2012

This study was carried out to determine the relationships between cellulose decomposition and soil environmental factors in larch (Larix leptolepis) and pine (red pine: Pinus densiflora; rigitaeda pine: P. rigida ${\times}$ P. taeda) species planted in the same year (1963). The variation of cellulose mass loss with soil temperature, soil pH, soil $CO_2$ efflux rates, and soil water content was measured monthly for 4 months (July, August, September and October 2006) from three coniferous plantations. Mean mass loss rates during the study period were generally more rapid in rigitaeda pine (6.5 $mg\;g^{-1}\;day^{-1}$) than in red pine (6.2 $mg\;g^{-1}\;day^{-1}$) or larch (6.1 $mg\;g^{-1}\;day^{-1}$) plantations, although the mass loss rates were not significantly different among three tree species (P > 0.05). Cellulose mass loss rates among three tree species were positively correlated with soil temperature (red pine: r = 0.77, P < 0.05; rigitaeda pine: r = 0.59, P < 0.05; larch: r = 0.48, P < 0.05) at the 20 cm soil depth, while the mass loss rates were negatively correlated with soil pH (red pine: r = -0.63, P < 0.05; rigitaeda pine: r = -0.47, P < 0.05; larch: r = -0.43, P < 0.05). There was a significant correlation between cellulose mass loss and soil $CO_2$ efflux rates except for regitaeda pine plantation, while no significant correlation (P > 0.05) between cellulose mass loss and soil water content in larch or rigitaeda pine. The results suggest that cellulose mass loss rates in soil layers depend on the different soil environmental factors caused by tree species.

• Journal of Wetlands Research
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• v.17 no.3
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• pp.283-292
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• 2015

The total global emission of $CO_2$ from soils is recognized as one of the largest fluxes in the global carbon cycle. Especially it is necessary to quantify the amount of $CO_2$ emitted by the organic material decomposition processes of microorganisms in the soil, because it becomes one of a factor for determining the carbon stocks in the soil. This study was conducted to estimate the impact of the Korean water deer(Hydropotes inermis)' feces to the soil organic matter. Also, effects of Korean water deer' feces on $CO_2$ emissions of soil and land use pattern dependent $CO_2$ flux quantification are studied. The organic materials in the Korean water deer' feces significantly changed organic matter content of soil and influenced the activity of soil microorganisms, both changing of respiration of the soil and physical chemical components in soil. In particular, C/N ratio and the $CO_2$ flux of soil of four regions (Rice paddy, Fallow ground, Salix koreensis community, Phragmites australis community) showed a statistically highly significant correlation (P<0.01) with the presence or absence of feces. $CO_2$ flux of soil affected by the feces was 2-20 times higher than the soil unaffected by the feces. This study has great significance to quantify the extent of the material circulation and its impact to the terrestrial ecosystem and soil zone throughout Korean water deer' feces. Feces of wildlife can affect soil and soil material circulation.

• Journal of Ecology and Environment
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• v.31 no.3
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• pp.167-176
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• 2008

Atmospheric N deposition has far-reaching impacts on forest ecosystems, including on-site impacts such as soil acidification, fertilization, and nutrient imbalances, and off-site environmental impacts such as nitrate leaching and nitrous oxide emission. Although chronic N deposition has been believed to lead to forest N saturation, recent evidence suggests that N retention capacity, particularly in the forest floor, can be surprisingly high even under high N deposition. This review aims to provide an overview of N retention processes in the forest floor and the implications of changing C-N interactions for C sequestration. The fate of available N in forest soils has been explained by the competitive balance between tree roots, soil heterotrophs, and nitrifiers. However, high rates of N retention have been observed in numerous N addition experiments without noticeable increases in tree growth and soil respiration. Alternative hypotheses have been proposed to explain the gap between the input and loss of N in N-enriched, C-limited systems, including abiotic immobilization and mycorrhizal assimilation, both of which do not require additional C sources to incorporate N in soil N pools. Different fates of N in the forest floor have different implications for C sequestration. N-induced tree growth can enhance C accumulation in tree biomass as observed across temperate regions. C loss from forests can amount to or outweigh C gain in N-saturated, declining forests, while another type of 'C-N decoupling' can have positive or neutral effects on soil C sequestration through hampered organic matter decomposition or abiotic N immobilization, respectively.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 1999.04a
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• pp.149-156
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• 1999

In the United States (U.S.), the monitored natural attenuation (MNA) approach has been used as an alternative remedial option for organic and inorganic compounds retained in soil and dissolved in groundwater. The U.S. Environmental Protection Agency (EPA) defines the MNA as“in-situ naturally-occurring processes include biodegradation, diffusion, dilution, sorption, volatilization, and/or chemical and biochemical stabilization of contaminants and reduce contaminant toxicity, mobility or volume to the levels that are protective of human health and the environment”. The Department of Soil Environment. National Institute Environmental Research (NIER) is in the process for demonstrating the MNA approach as a potential remedial option for the BTEX contaminated site in Uiwang City. The project is charactering the research site in terms of the nature and extend of contamination, biological degradation rate, and geochemical and hydrological properties. The microbial-degradation rate and effectiveness of nutrient and redox supplements will be determined through laboratory batch and column tests. The geochemical process will be monitored for determining the concentration changes of chemical species involved in the electron transfer processes that include methanogenesis, sulfate and iron reduction, denitrification, and aerobic respiration. Through field works, critical soil and hydrogeologic parameters will be acquired to simulate the effects of dispersion, advection, sorption, and biodegradation on the fate and transport of the dissolved-phase BTEX plume using Bioplume III model. The objectives of this multi-years research project are (1) to evaluate the MNA approach using the BTEX contaminated site in Uiwang City, (2) to establish a standard protocol for future application of the approach, (3) to investigate applicability of the passive approach as a secondary treatment remedy after active treatments. In this presentation, the overall picture and philosophy behind the MNA approach will be reviewed. Detailed discussions of the site characterization/monitoring plans and risk-based decision-making processes for the demonstration site will be included.

• Journal of Ecology and Environment
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• v.37 no.3
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• pp.113-122
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• 2014

The purpose of this study is to compare soil $CO_2$ efflux between burned and unburned sites dominated by Pinus densiflora forest in the Samcheok area where a big forest fire broke out along the east coast in 2000 and to measure soil $CO_2$ efflux and environmental factors between March 2011 and February 2012. Soil $CO_2$ efflux was measured with LI-6400 once a month; the soil temperature at 10 cm depth, air temperature, and soil moisture contents were measured in continuum. Soil $CO_2$ efflux showed the maximum value in August 2011 as 417.8 mg $CO_2m^{-2}h^{-1}$ (at burned site) and 1175.1 mg $CO_2m^{-2}h^{-1}$ (at unburned site), while it showed the minimum value as 41.4 mg $CO_2m^{-2}h^{-1}$ (at burned site) in December 2011 and 42.7 mg $CO_2m^{-2}h^{-1}$ (at unburned site) in February 2012. The result showed the high correlation between soil $CO_2$ efflux and the seasonal changes in temperature. More specifically, soil temperature showed higher correlation with soil $CO_2$ efflux in the burned site ($R^2$ = 0.932, P < 0.001) and the unburned site ($R^2$ = 0.942, P < 0.001) than the air temperature in the burned site ($R^2$ = 0.668, P < 0.01) and the unburned site ($R^2$ = 0.729, P < 0.001). $Q_{10}$ values showed higher sensitivity in the unburned site (4.572) than in the burned site (2.408). The total soil $CO_2$ efflux was obtained with the exponential function between soil $CO_2$ efflux and soil temperature during the research period, and it showed 2.5 times higher in the unburned site (35.59 t $CO_2ha^{-2}yr^{-1}$, 1 t = $10^3$ kg) than in the burned site (14.69 t $CO_2ha^{-2}yr^{-1}$).