• Journal of Bio-Environment Control
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• v.27 no.4
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• pp.400-406
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• 2018

In this experiment the effect of supplemental lighting on the growth and yield of cucumber (Cucumis sativus L. 'Fresh') plants during low radiation period of winter season were investigated in glasshouses using common high-pressure sodium (HPS) lamps and newly developed plasma lighting system (PLS) lamps. Plants grown without supplemental lighting were considered as a control. Supplemental lighting was provided from November 20th, 2015 to March 15th, 2016 to ensure 14-hour photoperiod (natural+supplemental light), also lamps were operated automatically when the outside sun radiation levels were less than $100W{\cdot}m^{-2}$. Spectral analysis showed that HPS lamp had a discrete spectrum, lacked of the radiation in the 400-550 nm wave band (blue-green light), but had a high output in the orange-red region (550-650 nm). A higher red light output resulted in an increased red to far-red (R/FR) ratio in HPS lamp. PLS had a continuous spectrum and had a peak radiation in green region (490-550 nm). HPS has 12.6% lower output in photosynthetically active radiation (PAR) but 12.6% higher output in near infra-red (NIR) spectral regions compared to PLS. Both HPS and PLS lamps emitted very low levels of ultra-violet radiation (300-400 nm). Supplemental lighting both from HPS and PLS lamps increased plant height, leaf number, internode number and dry weight of cucumber plants compared to control. Photosynthetic activity of cucumber plants grown under two supplemental lighting systems was comparable. Number of fruits per cucumber plant (fruit weight per plant) in control, PLS, and HPS plots were 21.2 (2.9 kg), 38.7 (5.5 kg), and 40.4 (5.6 kg), respectively, thereby increasing yield by 1.8-1.9 times in comparison with control. An analysis of the economic feasibility of supplemental lighting in cucumber cultivation showed that considering lamp installation and electricity costs the income from supplemental lighting increased by 37% and 62% for PLS and HPS lamps, respectively.

• Korean Journal of Soil Science and Fertilizer
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• v.33 no.6
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• pp.482-492
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• 2000

Vesicular arbuscular mycorrhizal (VAM) fungi are known to increase plant growth as well as to enhance salt tolerance of plants where plant roots are colonized by VAM. In pot experiment, pepper was grown in soil containing 0, 200, 400, and $600P\;kg\;ha^{-1}$ with and without mycorrhizal inoculum. Pots were irrigated with saline water containing 0.5, 2.0, and $6.0dS\;m^{-1}$. At 0, 200, and $400P\;kg\;ha^{-1}$ of three EC treatments, plant hight in mycorrhizal treatments was significantly different compared to nonmycorrhizal treatments. However, plant hight at $600P\;kg\;ha^{-1}$ was not different between mycorrhizal and nomycorrhizal treatments. Leaf area at $0P\;kg\;ha^{-1}$ of three EC treatments, and $200P\;kg\;ha^{-1}$ of $6.0dS\;m^{-1}$ in mycorrhizal treatments significantly increased compared to nonmycorrhizal treatments. However, these increase were not discovered in high salinity and P level. Level of EC affected dry weight, and especially, interection of P and EC, or P and VA inoculation highly affected root dry weight. R/S ratio generally decreased in mycorrhizal treatments. Significantly decreased R/S ratio was shown at 0, 400, and $600P\;kg\;ha^{-1}$ of $6.0dS\;m^{-1}$. Chlorophyll content generally increased with decreased salinity and P level where mycorrhizal treatments showed higher chlorophyll content compared to nonmycorrhizal treatments. The benefits of VAM inoculation on fruit production was discovered at only low P level and salinity. Mycorrhizal dependency on dry weight basis was generally shown in $0P\;kg\;ha^{-1}$ of three EC treatments and 0.5, $2.0dS\;m^{-1}$ of $200P\;kg\;ha^{-1}$ level. Colonization rate ranged 3.3 to 43.3% and number of spores was 47.7 to 198.3 $100g^{-1}$ soil. Colonization rate and number of spores increased with decreased P level and salinity where there was high correlation ($r=0.858^{**}$) between both. Also improved uptake of mineral nutrients was discovered at mycorrhizal treatments in decreased P level and salinity.