• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.356-356
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• 2017

A field experiment was performed to evaluate the effects of tillage systems and fertilizer management on yield and nutrient uptake in Soybean. The plant height, fresh weight and dry weight of conventional tillage were much higher those observed for no-tillage. Significant differences in plant height were observed under tillage practices combined with fertilizer treatment. However, the greatest plant height (128.47 cm) was observed in conventional tillage with chemical fertilizer, and the lowest (45.4 cm) was observed in the no-tillage with green manure treatment. The highest fresh weight (172.4 g) and dry weight (44.1 g) were observed from the no-tillage chemical treatment in the late flowering stage of soybean. The plant concentration of nitrate was higher (2.29%) in no-tillage with green manure than it was with chemical fertilization. However, nitrogen increased steadily in all treatments, and the highest quantity of total nitrogen (476.7 Kg/ha) was observed in no-tillage with green manure. The N content in the soil decreased gradually just after the vegetative stage. Tillage practices and additional fertilizer application had an adverse effect on the uptake of N, P and K in soybean seeds. The nitrogen concentration in seeds was found to be increased in the no-tillage with green manure treatment. The uptake of more nitrogen induced a better yield. Thus, the no-tillage with green manure treatment had the greatest yield, although no significant difference was observed among foliar-applications and additional fertilization. Additionally, the phosphorus and potassium concentrations in seeds remained the same between the conventional tillage and no-tillage treatments. The results obtained in this study indicate that no-tillage strategies with fertilizers may influence the growth characteristics and mineral uptake in soybean.

• Horticultural Science & Technology
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• v.30 no.2
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• pp.144-151
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• 2012

Diagnosis of nutrient disorders in cultivating crops is based on the visual symptoms and results of soil and plant analysis. This study was carried out to investigate the influence of B concentrations in fertilizer solution on the growth of and nutrient uptake by domestically bred strawberries. Tissue analysis based on the dry weight were also conducted to determine the threshold levels in plants when toxicity developed in boron. The growth was seriously restricted in the three strawberry cultivars as the B concentrations in fertilizer solution were elevated. The fresh and dry weights were heavier and crown diameters were thicker in the 0.25 mM boron treatment than the other treatments tested. The toxicity symptoms of boron appeared on the older leaves of three strawberry cultivars while interveinal chlorosis symptoms appeared on the young leaves of 'Keumhyang' and 'Seolhyang' strawberries. The toxicity symptoms in lower leaves were developed when B concentrations in fertilizer solution were higher than 2 mM in 'Keumhyang' and 0.5 mM in 'Maehyang' and 'Seolhyang' strawberries. The elevated boron concentrations in fertilizer solution did not influence the tissue K, Ca, and Mg contents, but influenced the phosphorus contents with decreasing tendency. The tissue Fe and Zn contents decreased and increased, respectively, as the B concentrations in fertilizer solution were elevated. When the concentration of boron at which the growth of a plant is retarded by 10% is regarded as a upper threshold level, the boron contents based on dry weight of above ground plant tissue should be lower than 25.1, 44.2, and 62.5 $mg{\cdot}kg^{-1}$ in 'Keumhyang', 'Maehyang', and 'Seolhyang' strawberries, respectively.

• Journal of the Korea Organic Resources Recycling Association
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• v.27 no.4
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• pp.61-70
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• 2019

This study aimed to investigate the physicochemical characteristics of fish meal, bone meal, and sesame oil cake, which are readily available by-products from agriculture and fisheries, during the process of liquid fertilizer fermentation, and to examine the effects of liquid fertilizer application on seed germination and growth of tomatoes. During processing the fermentation for liquid fertilizers by using fish meal, bone meal, and sesame oil cake liquid fertilizers, the pH of the fertilizer increased in the order of bone meal > fish meal > sesame oil cake, and the concentration increased rapidly up to 30 days in all types of liquid fertilizer. The nitrogen content of the liquid fertilizers increased as fermentation progressed in the order of fish meal > bone meal > sesame oil cake. The phosphorus content increased as fermentation progressed and the highest was 1.0 % in the liquid fertilizer of sesame oil cake. The germination rate and its index of radish seeds were compared for different dilutions of each of the liquid fertilizers. Excluding the 10-fold dilution of the fish meal and oil cake liquid fertilizer, all the treatment groups showed a germination rate ≥ 95 % and the germination index tended to increase with dilution rate of liquid fertilizers. For responses of tomato growth, there were no significant differences among the liquid fertilizer treatment groups; however, the organic content, microbial density, and microbial biomass C in the soil were higher than chemical fertilizer treatment. These results demonstrated that there were differences in the characteristics of liquid fertilizers depending on the materials used, and that liquid fertilizer can be used for nutrition management for the organic crop cultivation.

• Journal of Wetlands Research
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• v.14 no.4
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• pp.607-628
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• 2012

The watershed of Gohyeon Stream was divided into the 10 sub-basins, and 19 sampling points were selected in their tributaries, which the characteristics of the water quality and pollution loads variance were investigated for during the rainy and dry seasons. The results of water quality analysis revealed that the upper watershed(T1~T8) of Gohyeon Stream had a feature of rural area, and its lower watershed(T9~T19) had a feature of the municipal area. The non-point pollution loads of the tributaries were estimated with 2,063, 601, 365, and 45 ton/yr of SS, COD, DIN, and DIP, respectively. The pollution loads of the parameters except DIP were generated about 60% during the rainy season, which suggested that a precipitation significantly influenced on the discharge of non-point source pollution. Meanwhile, the non-point pollution load of DIP was generated about 60% during the ordinary and dry seasons, which suggested that control of a phosphorus pollution source was significantly required during these seasons. Pearson's correlation analysis revealed that SS pollution source of the upper watershed was definitely different from that of the lower watershed, that is, the pollution load from the upper watershed was mainly caused by the discharge of SS due to soil erosion in the farmland and forest land during the rainy season, and that of the lower watershed by the discharge of sewage and municipal run-off.

• Journal of Korea Water Resources Association
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• v.48 no.1
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• pp.9-21
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• 2015

This study examined pollution level of sediment in Sookchun lake, and studied dredging validity by examining phosphorous release characteristics on surface polluted soil. Total phosphorous, the principal cause of algal blooms, exceeded dredging assessment standards regarding Daechung lake (1.5 mg/g) at all points. Also at all points, total nitrogen exceeded the dredging assessment standard regarding Paldang Lake (1.1 mg/g), but fell short of the standard regarding Daechung lake (3.0 mg/g). Dredging zone was suggested in this study is Chuso water body (WS-6~WS-12) in Sookchun lake. In relation to sediment pollution levels measured at different depths, LOI tended to decrease as it became deeper. The concentrations of T-N varied depending upon the depth as well as points, but no regular pattern was observed. The depth and site did not significantly influence T-P. From the results of phosphorous release tests, it was shown that total phosphorous release flux was calculated to be $7.2{\sim}15.4mg/m^2/d$ for anaerobic condition, $0.5{\sim}2.0mg/m^2/d$ for aerobic condition and $2.0{\sim}4.1mg/m^2/d$ for facultative condition. Release flux and T-P concentration of surface sediments had positive correlation ($R^2$ 0.7871). And The corelation between release flux and DO condition in reactor had strong negative correlation ($R^2$ 0.8824).

• Journal of The Korean Society of Agricultural Engineers
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• v.62 no.1
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• pp.1-16
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• 2020

The APEX model has been developed for assessing agricultural management efforts and their effects on soil and water at the field scale as well as more complex multi-subarea landscapes, whole farms, and watersheds. Recently, a key component of APEX application, named APEX-Paddy, has been modified for simulating water quality by considering paddy rice management practices. In this study, the performance of the APEX-Paddy model was evaluated using field data at Iksan experimental paddy sites in Korea. The discharge and pollutant load data during 2013 and 2014 were used to both manually and automatically calibrate the model. The APEX auto-calibration tool (APEX-CUTE 4.1) was used for model calibration and sensitivity analysis. Results indicate that APEX-Paddy reasonably performs in predicting runoff discharge rate and nitrogen yield. However, sediment and phosphorus yield is not correctly predicted due to the limitation of model schemes. With APEX-Paddy, the performance in reproducing the discharge and nitrogen yield is found to be a satisfactory level after manual calibration. The manually calibrated model performed better than the automatically calibrated model in nearly all comparisons. For runoff, manual calibration reduced PBIAS while R² and NSE values of the automatically calibrated model were the same as the manual calibration. For T-N, NSE and PBIAS were reduced when using manual calibration, whereas R² value was the same as manual calibration. The limitation of the APEX-Paddy model for predicting sediment, as well as the phosphorous yield, was discussed in this study.

• Korean Journal of Environmental Agriculture
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• v.26 no.4
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• pp.313-318
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• 2007

In greenhouse farming, a variety of humic acids have been applied to improve soil conditions and plant growth. However, it is still unclear that how humic acids combined with chemical fertilizers affect growth and quality of fruit vegetable crops. This study was conducted to determine the combination effect of humic acids and chemical fertilizers on the growth and fruit quality of tomato (Lycopersicon esculentum MILL.) grown under greenhouse conditions. Three different formulation types of humic acid were used: liquid type A, liquid type B and solid type C. The tomato plants were grown in three treatment combination plots and in conventional fertilizer (CF) plot with recommended levels of nitrogen, phosphorus and potassium: HA combined with CF (HA+CF), HB combined with CF (HB+CF) and HC combined with CF (HC+CF). For most of growth characteristics (i.e. leaf number, internode length, maximum leaf length, leaf width and chlorophyll contents) determined in this experiment, no significant differences were observed between all combination treatments and CF. However, integrated fruit qualities (i.e. averaged weight, sugar contents and acidity) were slightly improved in the humic acid combined with CF treatments when compared with CF alone treatment. No phytotoxicity was observed with humic acid treatments. However, further studies will probably be needed to use widely and safely these humic acids, in order to ensure a maximizing growth, fruit yield and quality of tomato.

• Korean Journal of Environmental Agriculture
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• v.12 no.3
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• pp.219-229
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• 1993

Effects of paper mill sludge-fertilizers were investigated on the growth performances of tree seedlings under field conditions. Two types of sludge-fertilizers applied were an organic sludge compost and a processed sludge-pellet fertilizer strengthened with several components of organic and inorganic nutrients. Three species of tree seedlings studied were ibota privet(Ligustrum obtusifolium) and yellow poplar(Liriodendron tulipifera) of 1-0 year seedlings and also eastern white pine(Pinus strobus) of 2-2 year seedlings. Nitrogen and phosphorus contents of plot soil treated with sludge compost+sludge-pellet fertilizer+sludge-pellet fertilizer plot were increased to 8 times and 2.6 times as those of control plot, respectively. The growth performances of root collar diameter and seedling height were repeatedly measured up to five times through the growing season and the results were analyzed statistically by analysis of variance of randomized block design and Duncan's multiple range test. The growth performances of dry weight were measured after last fifth measurements.

• Journal of Radiation Protection and Research
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• v.41 no.4
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• pp.359-367
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• 2016

Background: As new legislation has come into force implementing radiation safety management for the use of naturally occurring radioactive materials (NORM), it is necessary to establish a rapid and accurate measurement technique. Measurement of $^{238}U$ and $^{232}Th$ using conventional methods encounter the most significant difficulties for pretreatment (e.g., purification, speciation, and dilution/enrichment) or require time-consuming processes. Therefore, in this study, the applicability of ED-XRF as a non-destructive and rapid screening method was validated for raw materials and by-product samples. Materials and Methods: A series of experiments was conducted to test the applicability for rapid screening of XRF measurement to determine activity of $^{238}U$ and $^{232}Th$ based on certified reference materials (e.g., soil, rock, phosphorus rock, bauxite, zircon, and coal ash) and NORM samples commercially used in Korea. Statistical methods were used to compare the analytical results of ED-XRF to those of certified values of certified reference materials (CRM) and inductively coupled plasma mass spectrometry (ICP-MS). Results and Discussion: Results of the XRF measurement for $^{238}U$ and $^{232}Th$ showed under 20% relative error and standard deviation. The results of the U-test were statistically significant except for the case of U in coal fly ash samples. In addition, analytical results of $^{238}U$ and $^{232}Th$ in the raw material and by-product samples using XRF and the analytical results of those using ICP-MS ($R^2{\geq}0.95$) were consistent with each other. Thus, the analytical results rapidly derived using ED-XRF were fairly reliable. Conclusion: Based on the validation results, it can be concluded that the ED-XRF analysis may be applied to rapid screening of radioactivities ($^{238}U$ and $^{232}Th$) in NORM samples.

• Korean Journal of Weed Science
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• v.13 no.1
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• pp.1-6
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• 1993

The experiments were conducted in order to find out the response of algae as affected by fertilizer and salinity, and to determine the chemical control method of algae in 1991. The higher the nitrogen fertilizer level, the more the occurrence of a blue-green alga Oscillatoria concerning with soil flakes. An increase in phosphorus fertilizer level stimulated the growth of green alga Hydrodictyon, whereas an increase in nitrogen level caused its abrupt reduction due to the harmful effect at high concentration of nitrogen, The high level of nitrogen fertilizer also reduced the growth of Euglena, although the detrimental effect was less compared with that of Hydrodictyon. A blue-green alga Oscillatoria, a green alga Cladophora and a diatom Navicula were tolerant to salinity. Piperophos/dimethametryn was highly effective in controlling various algae such as a green alga Hydrodictyon, suspended unicellular green algae and Euglena species. A fungicide propineb and copper sulfate also effectively controlled Hydrodictyon.