• Korean Journal of Environmental Agriculture
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• v.10 no.1
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• pp.1-10
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• 1991

The object of this stduy was to investigate the pollution of Pb in paddy field soil with different distance from roadside and to find out the relationship between the ratio of chemical fractions of total Pb and soil characteristics. Lead from automobiles is exhausted as particulates composed primarily of halide compounds (PbBrCl, $PbBr_2$, $PbCl_2$). The samples of soil were collected directly from the paddy fields with different distance from the roadside of highway and expressway which are located in Kyungpook province. A sequential extraction procedure was used to fractionate Pb in paddy field soil into the disignated forms of water soluable, exchangeable, organically bounded, carbonate, sulfide, and residual Pb. Results obtained are summerized as follows. 1. The content of Pb in paddy field soil was the highest in Chungdo, 30.0 ppm, the lowest in Koryung, 14.8 ppm, and the total average content was 21.9 ppm. The effect of traffic volume was not clear, but a slight difference according to the order of opened year of roads was showed. 2. The effect of distance from roadside was not clear. The content of Pb in paddy field soil with different distance from roadside was 22.2 ppm within l0m, 22.1 ppm in 10∼30m, 22.2 ppm in 30∼50m. and 21.3 ppm beyond 50m. 3. The distribution of Pb fractions in soil showed a wide difference depending on soil properties. The average content of exchangeable. organically bounded, carbonate, sulfide, and residual Pb was 8.6%, 33.6%, 29.8%, 21.5%, and 6.7%, of total Pb in the soil, respectively. 4. The content of organically bounded Pb in soil showed highly positive correlation with organic matter and CEC, while the content of exchangeable Pb was highly negative correlation. 5. With higher soil organic matter and CEC, organically bounded Pb fraction tend to be higher but exchangeable Pb fraction tend to be lower. Other forms of Pb showed no difference with soil organic matter contend and CEC. The distribution of Pb fraction related to CEC showed similiar tendency with that of organic matter content.

• Journal of Bio-Environment Control
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• v.27 no.4
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• pp.341-348
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• 2018

To investigate the effect of light sources on the growth and photosynthesis of the dwarf apple rootstock M.9 for the production of standard seedlings, the plants were cultivated in a controlled environment for 6 weeks. The sources of light are six treatments [Red (R), Blue (B), White (W), RBUV (R7B3 containing UV-A), RBW (R3B1W1), SMF (high pressure sodium + metal halide + fluorescent lamp) under $154{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$. Growth characteristics of apple seedlings varied depending on artificial light source at 3 weeks and 6 weeks. The plant height of apple seedling was high in the R, RBUV, RBW, and SMF light sources at 3 weeks, and in the R light at 6 weeks. There was no significant difference on stem diameter among the treatments at 3 weeks, but showed high in RBUV and RBW light at 6 weeks. Leaf number was the highest in RBUV light at 3 and 6 weeks. The chlorophyll content (SPAD value) was high in the B and RBUV light at 3 weeks, but it was not significant at 6 weeks. The growth rate to height of the R light (1.12mm/day) was the highest among the treatments, followed by RBUV, RBW, SMF, W and then B. Leaf area was the highest in RBUV and RBW lowest in B. Specific leaf area was high in W and fresh and dry weight were high in RBUV. The photosynthetic rate at 6 weeks was highest in the B and lowest in the R. Stomatal conductivity and transpiration rate were higher in the B and W compared to the other light sources. Therefore, we are considered that light sources for growth of dwarf apple rootstock M.9 seedlings are suitable the R, RBUV, and RBW light sources with a high mixing ratio of Red and Red +Blue.

• Korean Journal of Environmental Agriculture
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• v.34 no.1
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• pp.38-45
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• 2015

BACKGROUND: For commercial production of greenhouse crops under shorter day length condition, supplementary radiation has been usually achieved by the artificial light source with higher electric consumption such as high-pressure sodium, metal halide, or incandescent lamps. Light-Emitting Diodes (LEDs) with several characteristics, however, have been considered as a novel light source for plant production. Effects of supplementary lighting provided by the artificial light sources on growth of Kale seedlings during shorter day length were discussed in this experiment. METHODS AND RESULTS: Kale seedlings were grown under greenhouse under the three wave lamps (3 W), sodium lamps (Na), and red LEDs (peak at 630 nm) during six months, and leaf growth was observed at intervals of about 30 days after light exposure for 6 hours per day at sunrise and sunset. Photosynthetic photon flux (PPF) of supplementary red LEDs on the plant canopy was maintained at 0.1 (RL), 0.6 (RM), and $1.2(RH){\mu}mol/m^2/s$ PPF. PPF in 3 W and Na treatments was measured at $12{\mu}mol/m^2/s$. Natural light (NL) was considered as a control. Leaf fresh weight of the seedlings was more than 100% increased under the 3 W, Na and RH treatment compared to natural light considering as a conventional condition. Sugar synthesis in Kale leaves was significantly promoted by the RM or RH treatment. Leaf yield per $3.3m^2$ exposed by red LEDs of $1.2{\mu}mol/m^2/s$ PPF was 9% and 16% greater than in 3W or Na with a higher PPF, respectively. CONCLUSION: Growth of the leafy Kale seedlings were significantly affected by the supplementary radiation provided by three wave lamp, sodium lamp, and red LEDs with different light intensities during the shorter day length under greenhouse conditions. From this study, it was suggested that the leaf growth and secondary metabolism of Kale seedlings can be controlled by supplementary radiation using red LEDs of $1.2{\mu}mol/m^2/s$ PPF as well as three wave or sodium lamps in the experiment.