• Korean Journal of Environmental Agriculture
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• v.38 no.2
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• pp.76-82
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• 2019

BACKGROUND: For sustainable agriculture, there are various agricultural practices including low input. Over the last few decades high input of chemical fertilizer and compounds results in environmental pollution and deterioration of soil fertility. Soybean (Glycine max L.) is well known eco-friendly crop due to their symbionts. Soybean has a relationship with nitrogen fixation bacteria called rhizobia. In this research work, we investigated effects of soybean cultivation on soil microorganism activities. METHODS AND RESULTS: Experiments were conducted in pots and potato cultivation was used as reference. Soil chemical properties were analyzed considering soil nutrient over cropping period. For the soil microbial community analysis, dehydrogenase activity analysis (DHA) analyzed along with denaturing gradient gel electrophoresis. The results showed that higher soil organic matter in the soybean cultivation soil than in the potato cultivation soil. Available $P_2O_5$ concentration increased gradually in both pots but showed higher value in the potato cultivation soil. DHA value implying microbial activities showed higher value in the soybean cultivation soil over all cropping period. CONCLUSION: The cause of high microbial activity in the soybean cultivation soil was considered to the effects of some specific microorganisms related to soybean cultivation. Therefore, the availability of soybean cultivation for sustainable agriculture should be encouraged in terms of microorganism community activity in soil.

• Journal of the Korea Organic Resources Recycling Association
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• v.30 no.4
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• pp.151-163
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• 2022

This study was conducted to promote organic fertilizer(s) that sustain soil productivity for corn production and protect the environment as required by the Act on the promotion of eco-friendly agriculture. It was conducted at the research station of the Organic Agriculture Division of the National Institute of Agricultural. The treatments consisted of Compost (Com), Bokashi as fermented organic fertilizer (FOF), and mixed expeller pressed cake (PC). They were applied at 174 kg N /ha to field corn, together with a 'no fertilizer' check in Randomized Complete Block Design. At eight weeks after transplanting (WAT) corn, compost increased soil carbon (C) and nitrogen (N) to 7.48 and 0.76 g/kg respectively, while other fertilizers maintained the initial levels (before treatment application). At corn harvest (13 WAT), soil chemical properties (total C, total N, pH, electrical conductivity, P₂O₅, Ca, K, and Mg) were similar among all organic fertilizer treatments. For soil respiration, FOF increased soil CO₂ respiration by 31-76% above other fertilizer treatments. However, there were no prominent changes in the trends of CH₄ fluxes following the two mechanical weeding operations. Fermented organic fertilizer affected N₂O emissions between 87-96% lower than other fertilizer treatments. Compared to the initial microbial densities, FOF increased fungi and actinomycete colony foming unit by 25 and 16% at harvest. Therefore, the additional potential of improving soil biological fertility and local availability of raw materials make FOF a better option to sustain soil productivity while protecting the environment.

• Korean Journal of Community Nutrition
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• v.26 no.6
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• pp.467-481
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• 2021

Objectives: The purpose of this study was to examine the biochemical characteristics, intake of energy, and nutrients by household income levels of Korean adolescents aged 12 to 18 years. Methods: Data from the 6th (2013 ~ 2015) Korea National Health and Nutrition Examination Survey (KNHNES) were used for the study. A total of 1,839 (966 boys, 873 girls) subjects were included, and they were divided into four income groups according to their household income level. We examined general characteristics (gender, region of residence, skipping or not-skipping breakfast, lunch, dinner, frequency of eating-out), anthropometric characteristics (height, weight, weight status), biochemical characteristics (fasting plasma glucose, blood urea nitrogen, creatinine, triglycerides, cholesterol, HDL-cholesterol, hemoglobin, and hematocrit), the quantitative intake of energy and nutrients using the Korean Dietary Reference Intakes (KDRI), and the qualitative intake evaluated by the nutrition adequacy ratio (NAR) and mean nutrition adequacy ratio (MAR) of the four groups. Results: There were significant differences by income group within the region of residence and the rate of skipping breakfast, lunch, and dinner. The low-income group had a higher rate of skipping breakfast, lunch, and dinner. According to the income group, there was a difference in the height of boys, and there was no difference in the weight and obesity of boys and girls. In the biochemical characteristics, only the hematocrit of girls showed differences by income group. The quantitative intake of energy and nutrients compared with KDRI differed by income group. There were differences in energy, carbohydrates, proteins, thiamin, riboflavin, niacin, and phosphorus levels in boys and protein, vitamin A, niacin, and sodium levels in girls. The qualitative intake of energy and nutrients examined using NAR and MAR also differed according to the income group. The NAR showed differences in calcium in boys and vitamin C and calcium in girls. The MAR revealed differences in both boys and girls by income group. Conclusions: Among adolescents in the low-income group, the rate of skipping meals was high, and the quantitative and qualitative intake of energy and some nutrients was low. It is suggested that the nutritional intake can be improved by lowering the rate of skipping breakfast, lunch, dinner. We suggest that even just providing breakfast in schools can be considered highly effective in improving the rate of avoidance of skipping meals and improving nutrient intake. Also, we suggest that it is necessary to improve the food environment, food availability, and food accessibility through national and social support for low-household income adolescents.

• Korean Journal of Soil Science and Fertilizer
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• v.18 no.2
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• pp.140-147
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• 1985

This experiment was conducted in the field to investigate the effects of mulched condition on nutrient's mineralization and its mobility as affected by environmental changes (soil moisture and soil temperature) in the plow layer. 1. Nitrogen mineralization was faster owing to the prevention of evaporation and the increase of soil temperature in the poly ethylene mulched plot. As a result, nitrate form of nitrogen was much earlier available for plant in mulched plot than in non mulched plot. 2. Available $P_2O_5$ content in the plow layer was kept highest in the fertilized zone (10-20 cm depth) regardless of difference between mulched and non mulched condition, and was nearly constant without showing difference between planting and non planting of tobacco due to the lower availability of phosphorus by tobacco. 3. Potassium applied in the plow layer was remained a large quantity until the latter growth stage resulting in the lower recovery of potassium by tobacco. 4. Mineralized nutrients such as $NH_4-N$, $NO_3-N$, and K in the plow layer of mulched plot were transported from the fertilized layer (10-20 cm depth) and accumulated to the surface layer (0-10 cm depth) as the growing time goes by, but those in non mulched plot were distributed to the deeper layer. 5. Mobility of available nutrients in the plow layer was If order as $NO_3-N$ $$\geq_-$$ $NH_4-N$ > K > available $P_2O_5$. 6. Leaching degree of mineralized nutrients in the mulched plot was much lower than in the non mulched plot.

• Korean Journal of Soil Science and Fertilizer
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• v.10 no.1
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• pp.49-53
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• 1977

In order to know the effect of lime application on the phosphorus and silicate, lime and phosphorus were applied in the soil where phosphorus concentration was low and pH 5.4 The results are as follows 1. The filled grain ratio increases by applying the lime in moderate quantity, conversely the large amount of lime reduced the number of panicles per hill and number of spikelets per panicle. 2. The phosphorus application increased the panicle number, grain number and filled grain ratio. Similarly the yield was also significantly increased. 3. Among the inorganic matter of plant absorbed at the heading time the nitrogen contents was highly correlated with the number of heads, grain number per head and yield, while contents of $P_2O_5$ and $SiO_2$ were significantly correlated with the grain number maturerate and yield respectively. 4. Under the lime application the silica of soil was partly correlated with yield and yield components. But there was a significant difference between contents of $P_2O_5$ in soil and yield componentas. And in the plot of double application of neutralizing lime, significance of 1% level was shown between the $P_2O_5$ in soil and the panicles number and grain number respectively, where as significance of 5% with yield. 5. The phosphorus concentration in soil was gradually increased by the increment of lime application. Also the rate of available silicate in soil was considerably increased by the increment of lime application. That is, the silicated concentration in soil was 86ppm with lime and 59ppm without lime.

• Journal of Animal Science and Technology
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• v.51 no.3
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• pp.217-224
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• 2009

This study was carried out to investigate the nutritional value of soybean meal (SBM) from various geographic origins and the effects of their dietary supplementation on performance of broiler chickens. Nutritional value of dehulled SBM originating from USA, and non-dehulled SBM from India (IND), Argentina (ARG) and Korea (KOR) were evaluated by analyzing chemical composition, urease activity (UA) and KOH solubility, and determining true metabolizable energy (TME), nitrogen corrected TME (TMEn) and true amino acid availability (TAAA). The contents of crude protein ranged from 45.43% (ARG) to 48.47% (USA) and those of crude fiber varied widely from 3.48% (USA) to 7.12% (IND). The measurements of lysine varied from 2.79% (IND) to 3.09% (USA) and those of methionine from 0.56% (IND) to 0.65% (USA). The values of TMEn varied from 2986.6 kcal/kg (IND) to 3228.9 kcal/kg (USA) and the averages of TAAA were from 91.61% (IND) to 92.27% (USA). UA was found to be from 0.02 (ARG) to 0.04 (KOR, USA) and those of KOH solubility from 73% (ARG) to 84% (USA). A total of four hundred 20-days-old male broiler chicks were divided into four groups and fed with isocaloric and isonitrogenous experimental diets containing 27.5% of SBM and same amounts of lysine and sulfur amino acids for 15 days. Final body weight and body weight gain were the highest in birds fed with SBM from USA and lowest in birds fed with SBM from IND although the differences were not statistically significant. The feed/gain in chicks fed diet containing SBM from USA was significantly improved (p<0.05) compared to those of the other groups. There were no significant differences in carcass characteristics and the concentration of total cholesterol in serum among the treatments. The results of in vitro assay and bioassay agreed with the performance of broiler chicks, and thus there were close correlation between the broiler performance and the measured nutritive values of SBM. In conclusion, dehulled SBM from USA was superior to non- dehulled SBM from ARG and IND with regard to nutritive values.

• Korean Journal of Soil Science and Fertilizer
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• v.8 no.3
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• pp.135-152
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• 1975

The following informations are known from physical and chemical characteristics of orchard soils and nutritional diagnosis of orange leaves in Jeju. 1. Most orange orchards are located on terrace and cindercone thus soil moisture and microclimate of an orchard will greatly be affected by its topography. 2. Excessive well drainage, shallow soil depth, high content of gravels, low solid phase ratio and strong wind will give severe problem of soil moisture and wind errosion, thus the exte- nsion of soil depth is necessary for maintain nutrients, water and sufficient root volume. 3. Available soil water was significantly and positively correlated with organic matter content and clay content also contributes to available soil water. Vinyl mulching was greatly helpful for soil water conservation, wind errosion prevention, soil temperature increases during winter. 4. Abundant amphoteric amorphous allophane take a key role to fix phosphorus and also rations and thus it is the major factor to determine fertilizer efficiency. Lime and phosphorus must be applied in deeper soil layer. Release of filed phosphorus must be reevluated for availability. 5. Organic matter such as see weeds will greatly increase fertilizer efficiency and low fertilizer efficiency during spring may be related to available soil water. 6. Nitrogen was in superoptimum and Mg was enough but P and Ca were somewhat deficient according to leaf analysies while K was deficient according to fruit analysis. Phosphorus application increased sugar/acid ratio and potassium decreases rind percentage. 7. Manganese deficiency and toxicity appeared in a few places. Iron and boron were enough. Most places showed tendency of copper excess but some places showed copper deficiency. 8. Soiling after elimination of rock base, application of slow release fertilizer and abundant organic matter, vinyl mulching and drip irrigation will increase fertilizer efficiency greatly and fruit yield drastically.

• Journal of Korean Society of Environmental Engineers
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• v.34 no.4
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• pp.260-269
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• 2012

The aim of this study is to evaluate the applicability of adsorption models for understanding the thermodynamic properties of adsorption process. For this study, the adsorption isotherm data of $NO_3$-N ion onto a commercial anion exchange resin obtained at various experimental conditions, i.e. different initial concentrations of adsorbate, different dosages of adsorbent, and different temperatures, were used in calculating the thermodynamic parameters and the adsorption energy of adsorption process. The Gibbs free energy change (${\Delta}G^0$) of adsorption process could be calculated using the Langmuir constant $b_M$ as well as the Sips constant, even though the results were significantly dependant on the experimental conditions. The thermodynamic parameters such as standard enthalpy change (${\Delta}H^0$), standard entropy change (${\Delta}S^0$) and ${\Delta}G^0$ could be calculated by using the experimental data obtained at different temperatures, if the adsorption data well fitted to the Langmuir isotherm model and the plot of ln b versus 1/T gives a straight line. As an alternative, the empirical equilibrium constant(K) defined as $q_e/C_e$ could be used for evaluating the thermodynamic parameters instead of the Langmuir constant. The results from the applications of D-R model and Temkin model to evaluate the adsorption energy suggest that the D-R model is better than Temkin model for describing the experimental data, and the availability of Temkin model is highly limited by the experimental conditions. Although adsorption energies determined using D-R model show significantly different values depending on the experimental conditions, they were sufficient to show that the adsorption of $NO_3$-N onto anion exchange resin is an endothermic process and an ion-exchange process.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.16 no.1
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• pp.27-38
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• 2011

The distributions of phytoplankton assemblages and environmental factors in Jinhae Bay and their relationships were investigated to estimate the potential limiting nutrient for phytoplankton growth and community structure. In situ algal bioassay experiments were also conducted to assess the species-specific characteristics in phytoplankton responses under different nutrient conditions (control, N(+) and P(+) treatment). During the study periods, bacillariophyceae and cryptophyceae occupied more than 90% of total phytoplankton assemblages. Phytoplankton standing crops in the inner part of Masan Bay were higher than that of Jinhae Bay. The DIN:DIP ratio, pH and transparency showed the significant positive correlation with phytoplankton biomass. According to cluster and multidimensiolnal scaling (MDS) analysis based on phytoplankton community data from each station, the bay was divided into three groups. The first group included stations from the south-western part of Jinhae bay where cryptophyta species were dominated. The second group was distinguished from inner stations in Masan Bay. These stations showed low transpancy and high DIN:DIP ratio. The other cluster included the stations from the eastern part and central part of Jinhae Bay, which was characterized by the high DSi:DIP ratio and dominant of diatom species. Phosphorous (P) was limited in Masan Bay due to significantly increases in the phytoplankton abundances. Based on stoichiometric limitation and algal bio-assay in Jinhae Bay, nitrogen (N) was a major limiting factor for phytoplankton production. However, silicate (Si) was not considered as limiting factor, since Si/DIN and Si/P ratio and absolute concentration of nutrient did not create any potential stoichiometric limitation in the bay. This implies that high Si availability in winter season contributes favorably to the maintenances of diatom species.

• Journal of Animal Environmental Science
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• v.15 no.1
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• pp.51-58
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• 2009

The compost leachate was dark-colored solution that leaches out of the bottom of the compost pile. The compost leachate was rich in nutrients and can potentially used in plant culture. In the organic production, commercial liquid fertilizer was used to insure the availability of nutrients during the formation of the yield. The cost of supplemental liquid fertilizer could be reduced by developing a fertilizer based on animal fertilizer. This experiment was conducted to investigate the effect of different combination of compost leachate and conventional inorganic solution in hydroponic culture for lettuce growth. Six different treatments were applied. The compost leachate(CL) and nutrient solution(NS) were mixed by six different mixing ratios of 0:100, 20:80, 40:60, 60:40%, 80:20 and 100%:0% based on nitrogen content. The chemical nutrient solution was the solution of National Horticulture Research Station for the growth of leaf lettuce. The concentration of nutrient solution was adjusted 1.5 mS/cm in EC. The compost leachate was low in phosphorus(P), calcium(Ca), magnesium(Mg), but rich in potassium(K). The plant height of lettuce treated with CL 20+NS 80% was similar with 100% NS of control plot. Plant height was highest in the plot of CL 20+NS 80%. The treatment of 100% compost leachate was lowest in the growth characteristics of leaf lettuce. Number of leaf was very low in 100% compost leachate compared with plot of chemical nutrient solution. In the beginning of growth stage, SPAD value was reduced in plot treated with CL100%, but CL20+NS80% plot was higher compared to 100% compost leachate. SPAD value of leaf lettuce leaves was decreased as the amount of CL was increased. The dry weight of lettuce were 107.4, 104.2g in plot of NS 100% and CL 20%+NS80%, respectively. The leaf number and plant weight were decreased at high application plots of compost leachate. The leaf lettuce showed lowest in the plot treated with 100% compost leachate, and the growth of lettuce severely decreased after application of 100% CL treatment. The results showed that compost leachate can be use as liquid fertilizer for the organic hydroponic production. The mixture solution of 20% of compost leachate and 80% of nutrient solution could be used as a nutrition solution in hydroponic culture of leaf lettuce. Our studies have shown that is possible to produce using compost leachate, although growth is slower than when using a conventional inorganic hydroponic solution.