• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.15 no.5
• /
• pp.3345-3350
• /
• 2014

We investigated to assess the relationships between the major nutrients and phytoplankton dynamics during the spring season in 2010 and 2011 at 23 stations in Jinhae Bay, Korea. The bay is divided into four different zones based on pollutant sources and geographical characteristics. Nutrient limitation (>80%) was significant in Zone II, which is located in central bay and is influenced by the water well mixed from outer bay. The limited nutrient was followed in Zone III and IV that was occupying between 17% and 83%. However, the low levels are being kept below 35% in Zone I, which is characterized by the semi-enclosed eutrophic area of Masan and Haegam bays. Based on the PCA (principle component analysis) analysis, the nitrogen (N) sources in 2010 were particularly dominant and it may be due to the water mixing and wastewater formed from bottom layers and sewage. In 2011, major nutrients including nitrogen, silicon and phosphorus were dominant in the bay and are supplied by the river discharge after rainfalls with low salinity conditions. In particular, the N nutrients being supplied in 2010 are correlated with pennate diatoms Pseudo-nitzchia spp. and is not related to the phytoplankton population densities in 2011. The present study suggests that N sources play an important role in the proliferation of diatom, and the rapid nutrient uptakes by them are potential nutrient limitation factors in the bay.

• Journal of Plant Biotechnology
• /
• v.48 no.3
• /
• pp.193-200
• /
• 2021

Barley (Hordeum vulgare cv. Hangmaeg) sprouts are important microgreens that contain high levels of polyphenols and flavonoids, as well as minerals, vitamin and chlorophyll. Barley sprouts were grown for 9 days and growth was checked every 3 days. In this study, the cultivation efficiency according to the nutrient solution treatment was evaluated by analyzing the length of barley sprouts, fresh weight, chlorophyll, and the yield by growth period. In addition, we tried to increase the industrial applicability of germinated barley through analysis of inorganic component, total polyphenol and total flavonoid content of the extract, and functional substance analysis using HPLC. As a result, the growth rate of the nutrient solution treatment group was faster than that of the control group. When harvested on the 9th day of sowing, the nutrient solution treatment group showed a significant increase in yield compared to the control group. And the barley sprout extract of the nutrient solution treatment group had higher total flavonoid content and luteolin content. Also, the efficiency of water was higher than that of ethanol when extracting phenolics from barley sprouts. Therefore, this study suggests that nutrient input is effective for increasing polyphenol content and increasing production in barley sprout hydroponics.

• Environmental Engineering Research
• /
• v.19 no.3
• /
• pp.197-203
• /
• 2014

This study estimated spatial and seasonal variation of water quality to understand characteristics of Nakdong river basin, Korea. All together 11 parameters (discharge, water temperature, dissolved oxygen, 5-day biochemical oxygen demand, chemical oxygen demand, pH, suspended solids, electrical conductivity, total nitrogen, total phosphorus, and total organic carbon) at 22 different sites for the period of 2003-2011 were analyzed using multivariate statistical techniques (cluster analysis, principal component analysis and factor analysis). Hierarchical cluster analysis grouped whole river basin into three zones, i.e., relatively less polluted (LP), medium polluted (MP) and highly polluted (HP) based on similarity of water quality characteristics. The results of factor analysis/principal component analysis explained up to 83.0%, 81.7% and 82.7% of total variance in water quality data of LP, MP, and HP zones, respectively. The rotated components of PCA obtained from factor analysis indicate that the parameters responsible for water quality variations were mainly related to discharge and total pollution loads (non-point pollution source) in LP, MP and HP areas; organic and nutrient pollution in LP and HP zones; and temperature, DO and TN in LP zone. This study demonstrates the usefulness of multivariate statistical techniques for analysis and interpretation of multi-parameter, multi-location and multi-year data sets.

• Magazine of the Korean Society of Agricultural Engineers
• /
• v.39 no.2
• /
• pp.53-61
• /
• 1997

The interface system, GIS-AGNPS was to be validated with field data from six tested small watersheds ranging from 0.7 to 4.7$km^2$ in size which have steep topography and complex landuses. The model validation involved the calibration of input parameters and component modifications, in efforts to develop a model applicable to general uses for identifying and controlling nonpoint source pollution loads from agricultural watersheds. The simulated direct runoff from AGNPS was in good agreement with the field data for the averaged antecedent moisture conditions or AMC- II. The results differed, however, from the observed for AMC- I or III. A simple empirical relationship was proposed to estimate the curve number for AMC- I or m from AMC- II, which was found to result in simulated runoff close to the observed. The peak runoff relationship at AGNPS was also modified to reflect the watershed conditions and tested satisfactorily with the field data. The simulated sediment yields from the watersheds were fair as compared to the observed. Nutrient loads simulated from the model were different from the observed data. It appeared that the model was incapable of adequate depicting nutrient transport processes at paddy field and other landuses of the tested watersheds. Some modifications may be needed for the accurate representing the processes at paddy field.

• Journal of Ecology and Environment
• /
• v.44 no.2
• /
• pp.81-89
• /
• 2020

In the forest ecosystems, litterfall is an important component of the nutrient cycle that regulates the accumulation of soil organic matter (SOM), the input and output of the nutrients, nutrient replenishment, biodiversity conservation, and other ecosystem functions. Therefore, a profound understanding of the major processes (litterfall production and its decomposition rate) in the cycle is vital for sustainable forest management (SFM). Despite these facts, there is still a limited knowledge in tropical forest ecosystems, and further researches are highly needed. This shortfall of research-based knowledge, especially in tropical forest ecosystems, may be a contributing factor to the lack of understanding of the role of plant litter in the forest ecosystem function for sustainable forest management, particularly in the tropical forest landscapes. Therefore, in this paper, I review the role of plant litter in tropical forest ecosystems with the aims of assessing the importance of plant litter in forest ecosystems for the biogeochemical cycle. Then, the major factors that affect the plant litter production and decomposition were identified, which could direct and contribute to future research. The small set of studies reviewed in this paper demonstrated the potential of plant litter to improve the biogeochemical cycle and nutrients in the forest ecosystems. However, further researches are needed particularly on the effect of species, forest structures, seasons, and climate factors on the plant litter production and decomposition in various types of forest ecosystems.

• Korean Journal of Pharmacognosy
• /
• v.4 no.4
• /
• pp.173-179
• /
• 1973

Tobacco, which has nicotine for its main component, has been in medical use for a long time and in great demand for smoking throughout the world. The purpose of this study is to control nicotine amount and to increase yield more efficiently by the method of systematic variations. Nutrient solutions for tobacco culture were designed and prepared in 10 kinds with mineral ions: $NO_{3^-},\;SO_{4^{--},\;PO_4{^{-3},\;K,{^+}\;Ca,{^{++}\;Mg,{^{++}$, Mn, B, Cu, Zn, Mo, and Fe. Nicotiana tabacum L. Yellow Special A, grown for 50days from sowing, was replanted in plastic pot and cultured for 65 days supplying with prepared nutrient solutions. After harvest, their nicotine amount was determined by means of acid-base titrimetry and gas chromatography. The tobacco plants in KCa 4 and KMg 9 groups demonstrated the highest yield in total leaves weight and KMg 7 group in average nicotine amount. They have shown the increase of nicotine amount from lower leaf to 16th leaf, and thereafter decreased gradually. The author also pursued the optimum ionic proportions for the absolute nicotine amount in tobacco by means of systematic variations method.

• Journal of The Korean Society of Agricultural Engineers
• /
• v.53 no.4
• /
• pp.11-19
• /
• 2011

PADDIMOD2 was deloped to estimate nonpoint source pollution from paddy rice fields. The PADDIMOD2 was enhanced to estimate runoff and pollutant load during non-growing as well as growing season and to be easily used for public by development of Excel based system. Nutrient concentration and hydrology were based on Dirac delta function and continuous source function, and tank model for growing season and Event Mean Concentrations (EMCs) and SCS-Curve Number method for non-growing season. The PADDIMOD2 consists of three main component (input data, parameters data, and output data) by including eight Excel spread sheets. As a result of model application, total precipitation and irrigation were 1,051.7 mm and 439.2 mm, respectivley and surface runoff and water loss including infiltration and evapotranspiration were 463.0 mm and 947.9 mm, respectively. Annual nutrient loadings of T-N and T-P from study area were 6.7 kg/$km^2$/day and 0.5 kg/$km^2$/day, respectively. Development of PADDIMOD2 was focused on minimizing input data and maximizing user friendly system and is expected to be useful tool to evaluate various non-structure BMPs and estimate unit load from paddy rice fields for application at Korean TMDL.

• Journal of the Korean Geographical Society
• /
• v.37 no.5
• /
• pp.536-550
• /
• 2002

This paper investigated the spatial variations of nitrogen (N) and phosphorus (P) concentrations for 38 watersheds in Pennsylvania using 7 years of hydroclimatic and water quality data. Watersheds with higher percentage of urban and agricultural land uses exhibited larger variations of nutrient concentrations than forested watersheds. N and P concentrations were strongly associated with agricultural and urban land uses, respectively. The principle component analysis identified three components - land use and topography related, hydroclimate related factors, and size. Results of partial redundancy analysis showed the joint effect of climate, land cover, and topographic variables for explaining 28.1% of the variance of nitrogen concentrations and a pure effect of land cover for explaining 41.8% of total variance of P concentrations. The geographical pattern of statewide nutrient concentrations demonstrated a strong spatial gradient; low concentration in northwestern PA and high concentrations in southeastern PA. This pattern is associated with combined effects of hydroclimate, land use, topography, and water quality at the regional scale.

• Journal of Ecology and Environment
• /
• v.30 no.1
• /
• pp.63-68
• /
• 2007

Litter production, nutrient contents of each component of litterfall and amount of nutrients returned to forest floor via litterfall were investigated from May 2005 through April 2006 in Quercus mongolica, Quercus variabilis and Pinus densiflora forests at Mt. Worak National Park. Total amount of litterfall during one year in Q. mongolica, Q. variabilis and P. densiflora forests was 542.7, 459.2 and $306.9\;g\;m^{-2}\;yr^{-1}$, respectively. Of the total litterfall, leaf litter, branch and bark, reproductive organ and the others occupied 50.3%, 22.7%, 10.1 % and 16.9% in Q. mongolica forest, 81.9%, 7.2%, 3.1% and 7.9% in Q. variabilis forest, 57.4%, 12.8%, 5.6% and 24.1 % in P. densiflora forest, respectively. Nutrients concentrations in oak litterfall were higher than those in needle litter. N, P, K, Ca and Mg concentration in leaf litterfall were 13.8, 1.1, 7.2, 4.2 and 1.3 mg/g for Q. mongolica forest, 10.5, 0.7, 3.2, 3.7 and 1.6 mg/g for Q. variabilis forest, 5.3, 0.4, 1.2, 2.8 and 0.6mg/g for P. densiflora forest, respectively. The amount of annual input of N, P, K, Ca and Mg to the forest floor via litterfall was 43.36, 2.89, 21.38, 23.31 and $5.62\;kg\;ha^{-1}\;yr^{-1}$ for Q. mongolica forest, 32.28, 2.01, 10.23, 20.29 and $7.78\;kg\;ha^{-1}\;yr^{-1}$ for Q. variabilis forest, 15.80, 1.04, 3.99, 9.70 and $2.10\;kg\;ha^{-1}\;yr^{-1}$ for P. densiflora forest, respectively.

• Journal of Bio-Environment Control
• /
• v.4 no.1
• /
• pp.43-49
• /
• 1995

The main purpose of these studies were to clarify differences in Cheju - scoria and other solid media on quantity and quality of cherry tomatoes and on shift of component of the nutrient solution, and to use Practically Cheju-scoria as an excellent solid culture medium. The results obtained were summarized as follows ; 1. Among scoria plots, the rates of dry weights, fruits and their sugar-acid ratio were higher in the plot that was drained well with deep flow for one hour once a day. 2. Fresh fruit weights were lighter in rockwool and deep flow technique, but larger in scoria, Hyugashi (artificial gravel, $\Phi$10-12mm) and perlite in moving to higher flower cluster. 3. The results of analysis on microelement among solution components showed decrease of concentrations of P and K in the period of growth and development. 4. Yields and brix of cherry tomato showed a tendency to increase in rockwool and Hyugashi than anothers. 5. The concentration of fertilizer base was increased in general solution culture. Transpiration and absorption were similar in scoria plot and other media. 6. More studies of the Cheju-scoria development is required in order to use it as a solid medium for solution culture.