• Environmental Engineering Research
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• v.24 no.3
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• pp.495-500
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• 2019

Bioremediation of bacterial algae is one of wastewater treatment by utilizing symbiosis of bacterial algae, which is relatively inexpensive and safe for the environment. The aims of this research were: (1) to investigate initial characteristic of boezem water of Kalidami Surabaya, (2) to investigate the effect of potassium (K) element and carbon source addition toward the reduction of $NH_3-N$ content and organic matter in $KMnO_4$ of boezem water. The research conducted in a laboratory in batches without adding aeration. The initial stage of this research was conducting alga culture until it was obtained chlorophyll-a algae concentration of $3.5{\pm}0.5mg/L$. The best result of range finding test was a comparison of boezem water volume with algal which were about 25%:75%. The research conducted in duplo over 18 d. The result of the research can be concluded that boezem water of Kalidami Surabaya for the parameter of pH, temperature, $NH_3-N$, dissolved oxygen, chemical oxygen demand, biological oxygen demand, and number of $KMnO_4$ show that it enables to do bioremediation of bacterial algae. Decrease efficiency occurred in a reactor with the addition of element K 3% and source C. $NH_3-N$ and $KMnO_4$ final content 0.164 mg/L and 30 mg/L, respectively.

• Journal of The Korean Society of Grassland and Forage Science
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• v.43 no.3
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• pp.177-182
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• 2023

Iron (Fe) is a vital element for plants and other organisms, involving in several physiological processes including respiration, chlorophyll biosynthesis, and photosynthesis. Unfortunately, how Fe accumulation regulates in response to light quality has not been well established in plants. Therefore, the aim of the study was to explore the mechanism of Fe homeostasis by light quality. In this study, we found morpho-physiological attributes were significantly improved in response to blue (λmax: 450) compared to white (λmax: 500) and red (λmax: 660) light. The root-shoot length, plant biomass, photosynthesis efficiency (Fv/Fm) and leafgreen (SPAD) significantly declined in response to white and red light. However, these parameters were improved and iron deficiency was substantially alleviated by blue light exposure in alfalfa seedlings. This study might be useful to the forage breeders and farmers for improving alfalfa yield and nutritional benefits.

• Journal of Environmental Science International
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• v.25 no.3
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• pp.425-438
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• 2016

This study carried out zeta potential measurements of the Microcystis sp. under various solutions condition and investigated the characteristics of Microcystis sp. through the size control of microbubbles to eliminate algae that causes problems in aquatic ecosystems and human activities. DAF process was adopted and several coagulants were used to remove the Microcystis sp. CCD Camera was used to measure and analyze the size of microbubble, and fluorescent microscope was used to observe the particle, algae species and community. Zeta potential behavior of the algae was analyzed by using ELS-Z. Lab-scale and pilot-scale experiments were conducted to test flotation process. Polyaluminium chloride(PAC) coagulant was used, and the removal efficiency of the algae was assessed through Chlorophyll-a analysis. In the Lab-scale experiment, 2.2 ppm, 11 ppm, 22 ppm, and 44 ppm of polyaluminium chloride was injected to coagulate the algae. The coagulated algae was floated by the microbubble. The microbubbles in the experiments were generated at a air pressure of 450 ~ 550 kPa. The microbubble size was controlled in $36{\mu}m$, $100{\mu}m$, and $200{\mu}m$, respectively by using different diffuser. The results of lab-scale experiments on flotation plant indicated that the average removal rate was about 90% or above for 11 ppm, 22 ppm, and 44 ppm of polyaluminium chloride. On the other hand, in the pilot-scale experiment, the removal efficiency was in the range of 85% to 95% in all dose ranges of polyalumium chloride and aluminium sulfate coagulants.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.43 no.1
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• pp.49-53
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• 1998

Direct-seeding has major advantages such as labor and cost saving by eliminating preparation of seed bed and transplanting. But, it required increased input of fertilizers and pesticides because of the extended paddy period. Direct seeding in wet paddy (DSWP) gives faster growth and more uniform seedling emergence than direct-seeding in dry paddy. This research had an objective to develop an efficient N management practices for DSWP with split application of N fertilizer. A paddy field experiment was conducted to evaluate effects of starter N and N-topdressing which was delayed N application until 5-leaf stage, with comparison to transplanting (TP). Total amount of N application were two levels; 110kg and 77kg/ha. The N applications were split four times during rice growth stages; starter, topdressing at 5-leaf stage, top dressing at tillering stage, and topdressing at panicle initiation stage. DSWP had more tillers/$m^2$ than TP, but with the delayed heading. The DSWP plots which received N-topdressing at 5-leaf stage without starter N had higher leaf area index (LAI) and leaf greenness than the TP plot. Also, these DSWP plots had high leaf-N concentration at the heading stage, as calculated from leaf chlorophyll meter readings. Rice yield in DSWP with N-topdressing at 5-leaf stage was significantly higher than that in TP and in DSWP with starter N. Energy and N use efficiency were improved in DSWP with N-topdressing at 5-leaf stage. But, there were no significant differences in grain yield between the two levels of total amounts of N applications, 77kg and 110kg/ha. We concluded that starter N could not be used effectively by rice seedlings, but topdressing N at 5-leaf stage was an efficient N management for rice growth and yield in DSWP system.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.56 no.2
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• pp.134-139
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• 2011

This study was conducted to evaluate the weed suppressing effects of two winter cover crops, hairy vetch and rye in foxtail millet and sorghum fields in 2010. Crop growth and development and weed occurrences in the fields were examined to know the efficiency of proposed cropping system. In hairy vetch treated plots, heading of minor cereals occurred early. The heading date was earlier by 1 day and 2 days in sorghum and foxtail millet, respectively. However, rye treatment delayed heading by 12 days and 8 days in sorghum and foxtail millet, respectively. Besides he effect of cover crop on ear emergence of crops, the Besides changed growth-related characteristics. Plant height, chlorophyll content and chlorophyll fluorescence of sorghum ere increased in hairy vetch treatment by 46.4% 88.7% and 7.9%, respectively. In foxtail millet, the characteristics ere also increased by 45.6%, 50.9% and 37.8%, respectively, s compared to control. Yields of sorghum and foxtail millet were increased by 105.1% and 135% as compared o control by hairy vetch treatment, respectively. However, he yields of cereal crops were decreased by rye cover crop treatment, the yields of sorghum and foxtail millet were decreased by 25.8% and 119.1%, respectively. Rye cover crop treatment inhibited crop growth suggesting nitrogen starvation in rye treated plots. In rye treatment, plant height, chlorophyll contents and chlorophyll fluorescence of sorghum ere slightly decreased by 7.1%, 10.8% and 10.8%, respectively, as compared to control whereas the inhibitory effects were greater in foxtail millet. Weed occurrences based n weed number in hairy vetch and rye plots were reduced n weed number in hairy vetch and rye plots were reduced y 27% and 20%, respectively. The smothering effect was weakened or disappeared after heading of crops. Weed number and dry weight in hairy vetch plot were increased by 159% and 55.2%, respectively, as compared to control. The results implied that weed suppressing of cover crops could be reduced drastically after heading of crops.

• Korean Journal of Ecology and Environment
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• v.41 no.spc
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• pp.86-92
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• 2008

This study was conducted to determine removal effect on phytoplankton (chlorophyll-${\alpha}$ as whole algae) and cyanobacteria by a fish Pseudorasbora parva and macroinvertebrate Palaemon paucidens in September 2006. Three treatments with 25 (T1), 50 (T2) and 100 (T3) individuals along with control (C1, no input fish), and two treatments with 25 (T4) and 50 (T5) individuals along with control (C1) were made for fish and macroinvertebrate, respectively. The initial concentrations of chlorophyll-${\alpha}$ $(Chl_i)$ in each 10L test tank were set up for the levels of $95{\sim}100{\mu}g\;L^{-1}$ and the daily values were monitored in the test tank during 7 days. In the lab tests, P. parva did not show Chl-${alpha}$ removal effect; the removal rate of Chl-${alpha}$ for P. parva was -58% in T1, -56% in T2, and 61% in T3 during the test period. In contrast, P. paucidens. in the treatments of T4 and T5 removed the phytoplankton effectively and the removal effect were appeared to be 33% and 22%, respectively. Also, P. paucidens showed high feeding efficiency in the removal of cyanobacteria. The levels of cyanobacteria were greatly lowed from 6,048 to 927 cells $mL^{-1}$ in T4 and from 6,539 to 1,053 cells $mL^{-1}$ in T5, resulting in 85% and 84% in the removal effect, respectively. Our results for biomanipulation tests suggest that P. paucidens may be used as a potential candidate organism for algae control in spite of the preliminary results by laboratory tests.

• Korean Journal of Environmental Biology
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• v.36 no.2
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• pp.117-123
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• 2018

In this study, the efficiency of photosynthetic electron transfer according to LED color temperature was verified in order to find a way to efficiently grow trees under night illumination. The experiment was carried out with White treatment, Warmwhite treatment, and non-treatment with donarium cherry. The study uses to a method for analyzing and evaluating the color temperature of an LED light source by photochemical analysis. We found that all treatments 115 DAT of maximum fluorescence amount(P) had the lowest. In the treatment using white light and the Warm-white light, the T amount of florescence of the late stage during the transition of the J-I level was increased, and the photosystem I electron transfer efficiency was decreased. Therefore, the electron transport efficiency of $RE1_O/CS$ and RE1o/RC were reduced. Especially, compared to Warmwhite, the light intensity increased greatly in the white-light treatment, The $PI_{TOTALABS}$ of 7 DAT was the highest value, but it was decreased to the lowest value on 115 DAT. This study has shown that the white treatment was low in electron transfer efficiency and soundness. Warmwhite-light treatments showed lower stress.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.1
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• pp.109-113
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• 1998

The clay and yellow loess have capability to adsorb and precipitate particles. The removal efficiencyes of those flocculents on the dinoflagellate, Cochlodinium polykrikoides, have been studied in laboratory and in field near Tongyong fish farm in September, 1996. The removal efficiencyes in the laboratory experiment was $43\%$ for $2\;g/{\ell}$, $64\%$ for $6g/{\ell}$ and $88\%$ for $10\;g/{\ell}$ in one hour after dispersion. No big difference of removal efficiency was found between the raw and the acid-activated loess. In the field survey, the removal rates ranged from 72 to $80\%$ in 30 min after the dispersion. The effect of loess scattering on water quality was estimated. The concentrations of dissolved inorganic nitrogen (DIN), chemical of gen demand (COD) and chlorophyll a decreased more or less after dispersion, while the concentration of suspended solid (SS) increased. The concentrations of dissolved oxygen (DO) and dissolved inorganic phosphorous (DIP) were kept constant. These results indicated that the dispersion concentration of more than $10g/{\ell}$ has a good removal efficiency of above $80\%$ without big variation of water quality after dispersion of yellow loess.

• Korean Journal of Organic Agriculture
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• v.24 no.4
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• pp.773-786
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• 2016

Grape cultivar "Campbell Early" account for 70% of table grape in Korea and Leaf Spot Disease caused by Pseudocercospora vitis is one of a major disease in greenhouse and field grown area during late summer season in both of organic and conventional grape farm. Leaf spot disease can cause lowing of sugar content in fruit and vine growth and very difficult to control especially in organic field. Photosynthesis ability and chemical components are compared between leaf spot disease infected leaves with degree of necrotic area. With increase of disease necrotic area, $CO_2$ differential value, water use efficiency and $CO_2$ assimilation and respiration ratio are decreased proportionally and on the other hand, stomatal conductance value is not affected by disease necrotic area. Chlorophyll contents are also decreased by 50% in heavily infected leaves and imply decrease of chlorophyll contents is a major source of photosynthesis ability decline. With increase of disease necrotic area in leaves, total nitrogen and phosphate contents are decreased and on the other side, total carbon, potassium, calcium and magnesium contents are increased. From this research, we can infer that not only chemical control program is important in control of leaf spot disease but also fertilizing program is significant especially in organic agronomical control of fungal disease in grape cultivar "Campbell Early".

• Korean Journal of Environmental Biology
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• v.34 no.4
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• pp.264-271
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• 2016

The objective of this study was to determine the growth and light utilization efficiency of garden plants in shade area through chlorophyll fluorescence reaction analysis. Ten garden plants was grown for 75 days under 50% and 80% shading conditions. Under shading, $ET2_O/RC$, the fluorescence parameter related to electron-transport in photosystem II, was effectively enhanced. However, the electron transport flux until PSI acceptors per reaction center ($RE1_O/RC$) was reduced. These changes in photochemical parameters evoked a decrease in performance index (PI) and driving force (DF) of electron transport flux. In addition, some photochemical parameters such as $F_V$, $FV/F_O$, $RE1_O/RC$, $ET2_O/RC$, $PI_{TOTAL\;ABS}$, and $DF_{TOTAL\;ABS}$ were found to be important for shade tolerance. Three species (Pachysandra terminalis Siebold & Zucc, Physostegia virginiana L., and Carex maculata Bott) were found to be shade tolerant. Based on these results, shading factor index (SFI) deduced from photochemical parameters is useful for evaluating of shading stress of garden plants.