• Korean Journal of Environmental Agriculture
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• v.27 no.3
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• pp.267-273
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• 2008

Energy efficiency and nutrient balance are good methods for environmental assessment of the environmentally-friendly agriculture. The objectives of this study were 1) to estimate the energy efficiency and nutrient balance of the organic rice farming, and 2) to suggest a solution to improvement the energy efficiency and nutrient balance. The set of estimation was performed at the organic rice farming area (8.9 ha) in Wanju-gun during the paddy cultivation period from 2006 to 2007. The organic farming complex consists of four weeding methods using 1) duck, 2) apple snail, 3) duck and apple snail and 4) hands and machinery. Results from this estimation should that the organic rice farming area was less efficient than conventional rice farming. The efficiency of organic farming area in 2006 was higher than in 2007. For the calculation of the nutrient balance, the N, P and K contents of input materials (cattle manure, milk vetch, mixed oilcake, rice bran, rice straw and barley straw) and output (farm products) were analysed. Annual environmental loads of N, $P_2O_5$ and $K_2O$ were estimated at 4.4 kg/10a, 13.8 kg/10a and 14.5 kg/10a, respectively. Cattle manure had the largest portion among the inputs items and nutrient concentration of cattle manure was high. Thus energy efficiency and nutrient balance depend on cattle manure input. Therefore it is necessary to control the manure input to improve the efficiency of organic rice farming.

• Korean Journal of Environmental Biology
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• v.27 no.3
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• pp.261-265
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• 2009

Litter production, nutrient concentration of each component of litterfall and amount of nutrients input to forest floor via litterfall were investigated for three years from May 2005 through April 2008 in Pinus densiflora forest at Mt. Worak National Park. Amount of litterfall in 2005, 2006, 2007 were 3.070, 3.066, 3.099 ton $ha^{-1}yr^{-1}$, respectively. Average amount of litterfall for three years was $3.078{\pm}0.018\;ton\;ha^{-1}yr^{-1}$. Average percentage of leaf litter, branch and bark, reproductive organ and the miscellaneous for three years were 61.9, 10.4, 5.2, 22.5%, respectively. Average amount of N, P, K, Ca and Mg returned to forest floor via litterfall for three years in this P. densiflora forest were 18.014, 0.878, 4.240, 7.349 and 2.172 kg $ha^{-1}yr^{-1}$, respectively.

• Korean Journal of Organic Agriculture
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• v.13 no.4
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• pp.339-355
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• 2005

Nutrient balance is important to develop environmentally friendly agriculture. Phosphorus surplus in nutrient balance was more serious than that of nitrogen. Nitrogen and phosphorus exceeded twice the requirement at 30 cities/counties and 32 among 165, respectively. Given livestock waste and optimal nutrient balance, the proper number of animal feeding was 1.68LU/ha. Considering livestock waste only, the optimal number of livestock feeding was 3,918,000LU (heads) and, including fertilizer that would be 2,288,000LU. It is recommended to introduce the regional control system to regulate nutrient input and output, and the trading system of livestock feeding rights to control that.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.9 no.4
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• pp.153-163
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• 2004

In order to estimate the nutrient flux of the Seomjin River into the coastal waters of South Sea, and to understand the estuarine reactions during mixing between river water and seawater, we collected surface water along the salinity gradient in the Seomjin River estuary from Mar. 1999 to Apr. 2001. We found that nitrate and silicate were delivered by fluvial input, while phosphate was, supplied from disposed wastes in the Gwangyang Bay. Mean annual flux of dissolved inorganic nitrogen (DIN), phosphate and silicate into the Gwangyang Bay was estimated 10.9 molesㆍsec$^{-1}$(4,820 tonnesㆍyr$^{-1}$), 0.07 molesㆍsec$^{-1}$(68 tonnesㆍyr$^{-1}$), 13.3 molesㆍsec$^{-1}$(11,747 tonnesㆍy$^{-1}$), respectively. An evident removal of phosphate, silicate and ammonium at the mid-salinity zone during the dry season was attributed to the active uptake of phytoplankton, and consequently nutrient flux into the Gwangyang Bay was low. Whereas, during the flood season in summer, conservative or additional distribution of the nutrients was observed in the estuary. As a rsult nutrient flux into the Gwangyang Bay was maintained high. High concentrations of chlorophyll a and the active removal of nutrient during the dry season at the mid-salinity zone suggest that nutrient distribution in the Seomjin River estuary was mainly controlled by biological processes and nutrient fluxes into the Gwangyang Bay might be significantly modified of by the primary production.

• Korean Journal of Soil Science and Fertilizer
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• v.40 no.2
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• pp.136-144
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• 2007

The objectives of this study were to compare nutrient input by throughfall, stemflow and litterfall and concentration of nutrient in soil water between deciduous forest stand and Larix kaempferi plantation at Mt. Joongwang, Pyongchang-gun, Gangwon-do. The amount of rainfall interception during study period in deciduous forest stand and L. kaempferi plantation was 12% and 36%, respectively. Concentrations of cation ($Na^+$, $Mg^{2+}$, $K^+$ and $Ca^{2+}$) in throughfall were not different, while concentration of $Cl^-$ in stemflow was higher in L. kaempferi plantation. The results indicated that annual nutrient inputs by rainfall with the exception of $Cl^-$ were significantly greater in deciduous forest stand. In soil water, concentrations of anion ($Cl^-$, $NO_3{^-}$ and $SO{_4}^{2-}$) in A-layer, and $Ca^{2+}$ and $Cl^-$ in B-layer were higher in L. kaempferi plantation. Litterfall input during study period was $2,589kg\;ha^{-1}$ in deciduous forest stand and $1,046kg\;ha^{-1}$ in L. kaempferi plantation. Concentration of N was higher in L. kaempferi plantation, while N input from litterfall was greater in the deciduous forest stand ($36.81kg\;ha^{-1}yr^{-1}$) than L. kaempferi plantation ($16.16kg\;ha^{-1}yr^{-1}$). $Na^+$, $Mg^{2+}$, $K^+$ and $Ca^{2+}$ in litterfall collected from deciduous forest stand were found to be higher than those from the L. kaempferi plantation. Also, input of those were greater in deciduous forest stand. Thus, total nutrient input by throughfall, stemflow and litterfall was greater in deciduous forest stand than L. kaempferi plantation, significantly.

• Nutrition Research and Practice
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• v.17 no.6
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• pp.1255-1266
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• 2023

BACKGROUND/OBJECTIVES: This study aimed to predict the association between nutritional intake and diabetes mellitus (DM) by developing an artificial neural network (ANN) model for older adults. SUBJECTS/METHODS: Participants aged over 65 years from the 7th (2016-2018) Korea National Health and Nutrition Examination Survey were included. The diagnostic criteria of DM were set as output variables, while various nutritional intakes were set as input variables. An ANN model comprising one input layer with 16 nodes, one hidden layer with 12 nodes, and one output layer with one node was implemented in the MATLAB^® programming language. A sensitivity analysis was conducted to determine the relative importance of the input variables in predicting the output. RESULTS: Our DM-predicting neural network model exhibited relatively high accuracy (81.3%) with 11 nutrient inputs, namely, thiamin, carbohydrates, potassium, energy, cholesterol, sugar, vitamin A, riboflavin, protein, vitamin C, and fat. CONCLUSIONS: In this study, the neural network sensitivity analysis method based on nutrient intake demonstrated a relatively accurate classification and prediction of DM in the older population.

• Korean Journal of Community Nutrition
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• v.7 no.4
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• pp.548-558
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• 2002

The purpose of this study was to develop a computer software program for nutritional assessment using a Semi-Quantitative Food Frequency Questionnaire (SQFFQs) and the 24-hour Recall Method. The software for the SQFFQ was divided into input, output, and database. For dietary analyses, recipe and food databases were used. The recipe database included 25 items and the food database was divided into 18 food groups. The food database was composed of 19 general nutrient items, 33 fatty acids, and 18 amino acids. The software developed in this study can be summarized as follows: 1) input items related to the individual s ages information, lifestyle, biological values, and dietary habits; 2) individualized data in percent of the Korean RDA, the energy ratios of carbohydrates, proteins and fats, the ratio of animal to plant source intakes, and the distribution of food group intakes; 3) Statistical data on the individual's information, lifestyle, biological values, and dietary intakes including the frequency of intake of cooked foods, the amounts of food, and the number of food groups, and nutrients. In the 24-hour Recall Method, the input and output consisted of the individual s information and cooked dish intakes. The individual s report included the amounts of nutrient intake according to number of meal and days, in comparison to the Korean RDA, the energy ratio for carbohydrates, proteins and fats, the ratio of animal to plant source intakes, and the distribution of food group intakes. The statistical report presented the number of food groups and foods, and the nutrient intakes. To evaluate the validity of the SQFFQ, the Spearman Rank Order Correlation and kappa values were used. As a result, correlation coefficients comparing the 24-hour Recall Method appeared to be more than 0.5, except for vitamin $B_1, B_2$, niacin, and vitamin E. The kappa values for energy and carbohydrate intakes were both 0.7, and protein, fat, vitamin C, folate, Ca, and iron intakes ranged from 0.3 to 0.7.

• Journal of Bio-Environment Control
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• v.1 no.1
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• pp.52-60
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• 1992

The optimum management of nutrient solution needs the effective combination of fertilizers as well as the accurate control of nutrient solution. This study was attempt to make a supporting system for effective fertilizer combination by using computer and also to develop a EC predicting equation for keeping the EC of solution within the allowable range after application of combined fertilizers. The supporting system consists of three parts : (1) data bases, (2) rules for deciding the kinds and amounts of fertilizers and (3) main control. With input data, the main control automatically constructs the network connecting the related data bases and subsequently executes the operation of searching proper fertilizers through it. For more effective searching, fertilizers are classified into two levels(level 1 and level 2) in consideration of solubility, price, and frequency in use, and searched in that order. The EC prediction equation, a extended form of the Robinson and Stroke's theoretical equation only available for a binary electrolyte, is suggested for predicting the EC of the nutrient solution containing many kinds of inorganic compounds. The comparison of predicted and measured ECs showed good agreements with the high correlation between the predicted EC decrement by ion interaction and the actual one(limiting EC minus measured EC).

• Journal of Environmental Science International
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• v.11 no.7
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• pp.705-711
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• 2002

In order to determine the factors causing Microcystis spp. bloom in the lower Nakdong River (Mulgum), we prepared wide ranges of pH, nutrient(N, P) concentration and the light through an enclosure experiment far 10days (pH gradient. 6.5, 7.5, 8.5, 9.5; gradient of N, P: ${\frac{1}{2}}DW+{\frac{1}{2}}River$ Water (RW), RW only; four different levels of nutrient addition/day; light: 100, 85, 60, 30, 15% of full sun light). From three days, the difference of Microcystis density in each enclosures was observed. The high density of Microcystis was maintained in the treatments over pH 9.5 and 85% of full sun light. However, in all nutrient treatments, relatively lower cell density than that of pH and light treatments was observed. These results suggested that pH and light input may play more important roles than nutrients in the early development of Microcystis bloom in the eutrophic lower Nakdong River.

• Journal of Crop Science and Biotechnology
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• v.10 no.2
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• pp.57-63
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• 2007

Due to the strong influence of nitrogen(N) on plant productivity, a vast amount of N fertilizers is used to maximize crop yield. Over-use of N fertilizers leads to severe pollution of the environment, especially the aquatic ecosystem, as well as reducing farmer's income. Growing of N-efficient cultivars is an important prerequisite for integrated nutrient management strategies in both low- and high-input agriculture. Taking maize as a sample crop, this paper reviews the response of plants to low N stress, the physiological processes which may control N-use efficiency in low-N input conditions, and the genetic and molecular biological aspects of N-use efficiency. Since the harvest index(HI) of modern cultivars is quite high, further improvement of these cultivars to adapt to low N soils should aim to increase their capacity to accumulate N at low N levels. To achieve this goal, establishment and maintenance of a large root system during the growth period may be essential. To reduce the cost of N and carbon for root growth, a strong response of lateral root growth to nitrate-rich patches may be desired. Furthermore, a large proportion of N accumulated in roots at early growth stages should be remobilized for grain growth in the late filling stage to increase N-utilization efficiency. Some QTLs and genes related to maize yield as well as root traits have been identified. However, their significance in improving maize NUE at low N inputs in the field need to be elucidated.