• Journal of Bio-Environment Control
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• v.15 no.2
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• pp.162-166
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• 2006

The objectives of this study were to determine the effect of cultivation time on the incidence of brown fruit stem (BFS) in glasshouse sweet pepper (cv. Special) and to investigate environmental causes of this disorder. The plants transplanted on 31 August (T1) showed more incidence of BFS than those on 24 November (T2) (6.1% vs.2.9%; P<0.01). The BFS symptom began to appear after completion of fruit enlargement, more often around fruit coloring period. Comparing the environmental factors between T1 and T2, with their data collected for 3 weeks around fruit coloring period, the factor that was most likely responsible for BFS incidence was found to be the night-time humidity deficit (HD) ($1.9g{\cdot}m^{-3}\;vs\;2.9g{\cdot}m^{-3}HD$). These results were reconfirmed as T1 was compared to the plants (T3) that were transplanted at a similar time of the following year to T1, but designed to reduce BSF by increasing air HD via heating at night. That is,T3 had much higher night-time HD than T1 ($5.9g{\cdot}m^{-3}\;vs\;1.9g{\cdot}m^{-3}HD$), and showed no incidence of BFS. These results indicated that, to prevent BFS incidence in the winter-harvesting sweet pepper plants, air humidity at night should be controlled low, especially for the fruit coloring period after fruit enlargement period is completed.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.54 no.4
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• pp.397-406
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• 2009

This study was carried out to investigate the microclimate (photosynthetically active radiation and temperature) response to different shading materials(shade plate, and polyethylene net) on Korean ginseng(Panax ginseng C.A. Meyer) bed. Photosynthetically active radiation(PAR) under polyethylene net was approximately 24 ~ 30% higher than that under shade plate on sunny day. Also, PAR was remarkably decreased from the front to the rear rows of ginseng beds. Temperature under polyethylene net was higher than that of shade plate. Internal temperature under polyethylene net was 1.9 ~ 3.1% higher than that under shade plate at the different rows of ginseng bed. Mean of total daily temperature under polyethylene net was higher at the rear rows than at the front rows, while that under shade plate was higher at the front rows than at the rear row of ginseng bed. Mean of total daily temperature on sunny days(April 15 and May 17) was 7.3% lower under shade plate than above outside but, polyethylene net was 0.7% high, while that on cloudy days(April 11 and May 15) was 1.6% higher under polyethylene net than above outside, but shade plate was 0.7% low. Also, overall mean of total daily temperature under polyethylene net was 7.0, 7.8, and 8.8 % on sunny day(April 15 and May 17), and 1.7, 1.6, and 3.5% on cloudy day(April 11 and May 15) higher than that under shade plate, respectively. The SPAD values of 6 years old ginseng at two point(front, center) in bed under shade plate showed the highest value, and the lowest under polyethylene net. The SPAD of 6 years old ginseng at rear in bed was not statistically significant under two shading materials.

• Journal of Bio-Environment Control
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• v.21 no.3
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• pp.228-235
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• 2012

This study was carried out to investigate the effect of irrigation methods for reducing a drainage on the growth and yield in rockwool (Grodan co.) and cocopeat (chip : dust = 50 : 50 included fiber) culture. The nutrient solution was irrigated by $100J{\cdot}cm^{-2}$-100 mL, $50J{\cdot}cm^{-2}$-45 mL, $50J{\cdot}cm^{-2}$-40 mL, $50J{\cdot}cm^{-2}$-35 mL ($100{\sim}50J{\cdot}cm^{-2}$-100~35 mL, Nutrient solution 100~35 mL was irrigated per plant when the accumulated radiation was $100{\sim}50J{\cdot}cm^{-2}$). The drain rates per plant of 100-100, 50-45, 50-40, 50-35 were 26.3%, 8.8%, 6% 4.4% and 23.1%, 7.5%, 5% 3.4% in rockwool and cocopeat slabs. The water contents and EC of 100-100 and 50-45 were managed by the 55~70%, $3.0{\sim}5.0dS{\cdot}m^{-1}$ which were good condition for paprika culture in rockwool and cocopeat slabs, while those of 50-40 and 50-35 were managed by beyond 50%, $4.5{\sim}9.5dS{\cdot}m^{-1}$. The plant height, number of branches and leaf size of 100-100 and 50-45 were similarly increased while those of 50-40 and 50-35 were decreased. The fruit size and weight of 50-40 and 50-35 were small and light, while those of 100-100 and 50-45 were similarly big and heavy. The marketable fruits of 100-100 and 50-45 treatments were similarly more by 9.7~9.8 in rockwool and 8.8~8.9 in cocopeat, while the unmarketable fruits, the small and blossom end rot fruits were increased in 50-40 and 50-35 treatments. The yield of 100-100 and 50-45 treatments were similarly high.