• Journal of Bio-Environment Control
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• v.22 no.4
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• pp.349-354
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• 2013

This study examined a technique for cooling root zone aimed at lowering substrate temperature for sweet pepper (Capsicum annum L. 'Orange glory') cultivation in coir substrate hydroponics during hot season, from the $16^{th}$ of July to $15^{th}$ of October in 2012. The root zone cooling technique was applied by using an air duct (${\varnothing}12$ cm, hole size 0.1 mm) to blow cool air between two slabs during night (5p.m. to 3a.m.). Between the $23^{rd}$ of July and $31^{st}$ of August (hot temperature period), average daily substrate temperature was $24.7^{\circ}C$ under the root zone cooling, whereas it was $28.2^{\circ}C$ under condition of no cooling (control). In sunny day (600~700 W $m^{-2}{\cdot}s^{-1}$), average substrate temperatures during the day (6a.m. to 8p.m.) and night (8p.m. to 6a.m.) were lower about $1.7^{\circ}C$ and $3.3^{\circ}C$, respectively, under the cooling treatment, compared to that of control. The degree of temperature reduction in the substrate was averagely $0.5^{\circ}C$ per hour under the cooling treatment during 6p.m. to 8p.m.; however, there was no decrease in the temperature under the control. The temperature difference between the cooling and control treatments was $1.3^{\circ}C$ and $0.6^{\circ}C$ in the upper and lower part of the slab, respectively. During the hot temperature period, about 32.5% reduction in the substrate temperature was observed under the cooling treatment, compared to the control. Photosynthesis, transpiration rate, and leaf water potential of plants grown under the cooling treatment were significantly higher than those under the control. The first flowering date in the cooling was faster about 4 days than in the control. Also, the number of fruits was significantly higher than that in the control. No differences in plant height, stem thickness, number of internode, and leaf width were found between the plants grown under the cooling and control, except for the leaf length with a shorter length under the cooling treatment. However, root zone cooling influenced negligibly on eliminating delay in fruiting caused by excessively higher air temperature (> $28^{\circ}C$), although the substrate temperature was reduced by $3^{\circ}C$ to $5.6^{\circ}C$. These results suggest that the technique of lowering substrate temperature by using air-duct blow needs to be incorporated into the lowering growing temperature system for growth and fruit set of health paprika.

• Journal of Bio-Environment Control
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• v.22 no.4
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• pp.385-391
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• 2013

In this study, the availability of slurry composting and biofiltration (SCB) solution as an alternative for synthetic nutrient solution was determined by monitoring the growth, fruit yield, and fruit quality of cherry tomato (Solanum lycopersicum L. 'Unicon'). Treatments for nutrient solution were consist of SCB 1/2N, 1N, 2N, and commercial nutrient solution 1N (CNS 1N) based on nitrogen concentration (218.32 $mg{\cdot}L^{-1}$) of cherry tomato nutrient solution (control 1N). All nutrient solution including SCB solution (440~520 mL per day) was supplied to rock wool medium using a timer. After 31 days of transplanting, fresh and dry weights of shoots, leaf area, plant height, stem diameter, SPAD value and number of node were measured. After measuring growth characteristics of tomato plants, total fruit yield, ratio of marketable fruit yield, fruit weight, total soluble solids content, total acidity, total phenolic concentration, and antioxidant capacity were determined once a week for 7 weeks. As a result, among the SCB treatments, SCB 1/2N was similar to control 1N and CNS 1N in terms of fresh and dry weights of shoots, leaf area, stem diameter, number of node, and SPAD value. Increased N concentration of SCB inhibited the growth of tomato plants. Total fruit yield of SCB 1/2N was 47% of that of control 1N which showed the best result. Percentage of marketable fruit yield in SCB 1/2N was about 58%. Soluble solids contents, total acidity, total phenolic concentration and antioxidant capacity was the highest in SCB 2N and the other treatments were not shown any difference. Blossom-end rot rarely occurred in control 1N and CNS 1N while SCB treatments without Ca induced the physiological disorder of 7~19%. In conclusion, SCB 1/2N was good for the vegetative growth of cherry tomato plants but reduced yield and quality of fruit compared with control 1N and CNS 1N. Thus, it is possible to apply SCB solution to grow cherry tomato plants hydroponically but in the consideration of fruits yield and quality additional supply of several minerals would be required.

• Journal of Bio-Environment Control
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• v.27 no.2
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• pp.185-190
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• 2018

This study was conducted to investigate the optimum electrical conductivity (EC) levels of nutrient solution for growth of mother plants and increasing occurrence of daughter plants of strawberry ($Fragaria{\times}ananassa$ Duch. cv. Maehyang) using hydroponics. The mother plants of strawberry were transplanted in cultivation pot ($61{\times}27{\times}18cm$) filled with coir medium on March 22, 2017. Nutrient solution was supplied by the drip tape at $0.6dS{\cdot}m^{-1}$ of EC levels for rooting during 11 days. After rooting, the mother plants of strawberry was treated at the EC levels of 0.6, 1.2 or $1.8dS{\cdot}m^{-1}$, respectively. Growth characteristics, such as mother plants and daughter plants of strawberry were measured at 100 days after transplanting. The plant height of mother plant was significantly higher at $0.6dS{\cdot}m^{-1}$ treatment, and the crown diameter of mother plant was significantly greater at $1.8dS{\cdot}m^{-1}$ treatment. The fresh and dry weights of shoot were higher at both 0.6 and, $1.2dS{\cdot}m^{-1}$ treatments. The number of runners was not significantly different in all treatments. The fresh and dry weights of runner were heavier at $0.6dS{\cdot}m^{-1}$ than other treatments. The number of daughter plants was the highest, 16.7 at the $1.2dS{\cdot}m^{-1}$ treatment. However, the fresh and dry weights of third daughter plant were the heaviest at $0.6dS{\cdot}m^{-1}$ treatment. Although the daughter plants were a large of production at $1.2dS{\cdot}m^{-1}$ treatment, the low EC levels of strawberry were positive in terms of seedling quality during nursery. These results indicated that growth of mother plant and occurrence of daughter plants were greater at the EC $0.6dS{\cdot}m^{-1}$ nutrient solution for hydroponic cultivation of 'Maehyang' strawberry during nursery period.

• Journal of Bio-Environment Control
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• v.27 no.2
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• pp.180-184
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• 2018

This study was conducted to examine the effect OTR film type on the quality of garden cress (Lepidium sativum L.) baby leaf during MA storage. Garden cress harvested at baby leaf size of 10cm plant height packed with 1,300 cc, 10,000 cc, 20,000 cc, 40,000 cc, and $80,000cc{\cdot}m^{-2}{\cdot}day^{-1}{\cdot}atm^{-1}$ OTR (oxygen transmission rate) films and MP (micro-perforated) film, and then stored at $8^{\circ}C$ for 10 days. All of the OTR film treatments showed a decrease of 0.5% fresh weight until the storage end date and a 1.3% decrease in the MP film treatment. The oxygen concentration in the packaging during storage was maintained at 18% or more in 20,000 cc, 40,000 cc, and 80,000 cc OTR film treatments, while the 1,300 cc OTR film treatment decreased to 11% at the storage end date. And the concentration of carbon dioxide was steadily increased in the 1,300 cc and 10,000 cc OTR film treatments to show the levels of 4.5% and 3.4%, respectively, and the other OTR film treatments showed a concentration of less than 1%. Ethylene concentration in the package was maintained at the highest level of $3-5{\mu}L{\cdot}L^{-1}$ in the 1,300 cc treatment during the storage period. The lowest odor and the highest quality of appearance were observed in the 1,300 cc treatment, but the MP film treatment and the other OTR treatments lost marketable quality due to yellowing. The color of garden cress baby leaf was changed the lowest in 1,300 cc treatment that showed the highest chlorophyll content and Hue angle value, lowest $b^*$ value, present of yellowing at end of storage date. Therefore, 1,300 cc treatment which was most effective for yellowing and odor suppression during storage is considered to be suitable for packaging of garden cress baby leaf.

• Journal of Bio-Environment Control
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• v.17 no.3
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• pp.221-225
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• 2008

Lilium formolongi 'Fl August' plantlets with scale-leaves and scale-bulb were treated at 10, 15, 20, $25^{\circ}C$ for 15, 30, or 45 days and planted in February, March, April and May. In the April planting, flowering percentage was below 10% and in the May planting no flowering occurred. Sprouting and flowering percentages were lower at the late planting times. Days to flowering of the April planting was 110.8 days compared to 128 days for the February planting. Plant height and numbers of leaves were reduced to 7.2 in May planting, compared to 40.5 leaves in February planting, and almost no flowers emerged in either the April or May plantings. Plantlets exposed to 10 or $15^{\circ}C$ flowered at 80 percent or higher at all treatment durations, but at 20 or $25^{\circ}C$ flowering percentages were lower, with 30% or less in the $25^{\circ}C$ treatment. In the $15^{\circ}C$ treatment days to flowering were less than 100 days, while the number of flowers and flower bud differentiation were greatest in the $15^{\circ}C$ treatment. Cytokinin and auxin were analyzed in bulblets grown at 15, 20 and $25^{\circ}C$. T-zeatin content was three times greater in the $15^{\circ}C$ treatment than at $25^{\circ}C$, but the content of indoleacetic acid (IAA) was less at $15^{\circ}C$ than at 20 and $25^{\circ}C$. In the $15^{\circ}C$ treatment, T-zeatin content was about twice the IAA content in the scale- bulblet. The auxin and cytokinin balance may affect flower bud differentiation. $15^{\circ}C$ with 30 days was most effective for flowering in scale-bulblet and planting of February and March were effective for flowering too.

• Journal of Bio-Environment Control
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• v.11 no.3
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• pp.127-132
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• 2002

Enhanced supply of $Ca^{2＋}$ as well as NO$_3$$^{[-10]}$ is known to restrict the uptake of the Na$^{＋}$ and Cl$^{[-10]}$ ion and ameliorate growth under saline conditions. This test was conducted to investigate the ameliorating effects of Ca(NO$_3$)$_2$ or CaCl$_2$ on the growth and yield of NaCl-stressed tomato plants grown in plastic pot filled with soil. All treatments except for the control were supplied with 80 mM NaCl fur two weeks after transporting. The saline solutions with nutrient were supplemented with either 0, 10 or 20 mM Ca(NO$_3$)$_2$ and either 0, 10 or 20 mM CaCl$_2$ during harvesting time from two weeks after transporting. Ca(NO$_3$)$_2$ or CaCl$_2$ application enhanced the growth such as plant height, fresh weight, dry weight, fruit number, and fruit weight, and yield of NaCl-stressed tomato, and also their effects increased greater as concentration of supplemented Ca(NO$_3$)$_2$ or CaCl$_2$increased. Yield increased in 20 mM Ca(NO$_3$)$_2$ compared with the others except fur the control. Photosynthetic rate in Ca treatments was lower than that of the control, but higher than that of NaCl treatment. Leaf chlorophyll content was higher in Ca treatments compared with the others, especially in younger leaf, while that was not affected by concentration of supplemented Ca. Ca(NO$_3$)$_2$ or CaCl$_2$ supply increased the $K^{＋}$ and $C^{2＋}$ concentration of tomato plants, whereas the Na$^{＋}$ transport to the leaves was inhibited. There was a strong increase in the $K^{＋}$/Na$^{＋}$ ratio in plants treated Ca(NO$_3$)$_2$, or CaCl$_2$. Cl$^{[-10]}$ content of plants was decreased by supplemental Ca(NO$_3$)$_2$ but Cl$^{[-10]}$ was increased in plants with CaCl$_2$compared with Ca(NO$_3$)$_2$. N concentration in plants of tomato increased with enhanced Ca(NO$_3$)$_2$ or CaCl$_2$supply, In conclusion, our study confirms the potential of Ca(NO$_3$)$_2$ or CaCl$_2$to alleviate NaCl-induced growth reductions in tomato.

• Journal of Bio-Environment Control
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• v.13 no.4
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• pp.233-239
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• 2004

This research was conducted to determine the effect of soil pH change followed by leaching with ground water on crop growth, yield and nutrient uptake of strawberry. Treatments were leaching with ground water (A), hydrated lime application of dissolved portion in $500g{\cdot}L^{-1}$ solution followed by leaching (B), application of $Al_2SO_4$ solution with the concentration of $0.75g{\cdot}L^{-1}$ followed by leaching (C), pH elevation by (B) followed by pH lowering by (C), then leaching (D). Soil samples taken before experiment had 6.0 in soil pH. But the pH of all treatments taken after pH changes and leaching were in the range from 5.8 to 6.2 without statistical differences among treatments. Electrical conductivity of soils taken before experiment was $1.82dS{\cdot}m^{-1}$ and those of (A), (B), (C), and (D) were 1.65, 1.72, 1.71 and $1.83dS{\cdot}m^{-1}$, respectively. The plant height in treatment (C) was 20.4 cm at 80 days after transplanting which was the highest among treatments tested. The other growth characteristics did not show statistical differences among treatments. Tissue contents of Fe, Mn, Zn, Cu and B in treatment (C) were higher than those of other treatments at 80 days after transplanting. The treatment (C) had the highest number of special sizes and fruit weight per 50 plants such as 137 and 3.784 g, respectively. The treatment also had 3.123 kg in total fruit weight and 2,489 kg in marketable fruit weight per 10 are. The treatment (B) also had good results such as 2,820 kg in marketable fruit weight per 10 are.

• Journal of Bio-Environment Control
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• v.3 no.2
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• pp.119-127
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• 1994

This study was conducted to investigate the effects of temperature and light conditions on the vigor and growth responses of red pepper(Capsicum annuum L.) seedlings in the nonheated plastic houses with triple and quadruple coverings during winter. The results obtained were as follows ; 1. The growth in terms of plant height, number of leaves, leaf area and dry weight of each organ was reduced up to 50% in the triple coverings compared to quadruple ones. The greatest difference between the triple coverings and quadruple ones was the leaf area, showing two to five times larger in the quadruple ones. Therefore, the differences of the early environmental conditions during raising seedling stage was well reflected. 2. The leaf expansion in the early stage of seedling was delayed in the triple coverings and subsequently crop growth rate(CGR) significantly reduced. The specific leaf area (SLA) in the triple coverings was less than quadruple ones. The net assimilation rate (NAR) was increased in the early stage of seedlings and then reduced in the quadruple coverings. In triple ones, however, the great reduction showed at six weeks after sowing and then increased sharply. 3. The linear relationship among leaf area, total dry weight and leaf dry weight was observed in the all experimental areas, while between leaf area and crop growth rate only in the quadruple coverings, and between leaf area and net assimilation rate in both triple and quadruple ones. 4. The dry matter partitioned to the leaf increased up to six weeks after sowing in the triple coverings but reduced in the stem and root. However, the adverse results were obtained in the quadruple ones. 5. In the triple coverings, the number of branches showed the exponential increment while fruit weight showed linear increment in both triple and quadruple ones. Higher yield was obtained in the quadruple ones. 6. The shoot dry weight among the characteristics of seedlings was greatly contributed to the yield of red pepper after transplanting. Accordingly, one of the decisive criterion for good quality of red pepper seedlings was determined by the highest correlation between shoot dry weight of growing plant and fruit yield of pepper plant.

• Journal of Bio-Environment Control
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• v.24 no.3
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• pp.217-225
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• 2015

Local heating system providing hot air locally to growing parts including shoot apex and flower cluster which were temperature-sensitive organs of cherry tomato was developed to reduce energy consumption for greenhouse heating without decline of crop growth. Growing part following local heating system was composed of double duct distributer which connected inner and outer ducts with hot air heater and winder which moved ducts up and down following growing parts with plant growth. Growing part local heating system was compared with conventional bottom duct heating system with respect to distributions of air and leaf surface temperatures according to height, growth characteristics and energy consumption. By growing part local heating, air temperature around growing part was maintained $0.9{\sim}2.0^{\circ}C$ higher than that of lower part of crop and leaf surface temperature was also stratified according to height. Investigations on crop growth characteristics and crop yield showed no statistically significant difference except for plant height between bottom duct heating and growing part local heating. As a result, the growing part local heating system consumed 23.7% less heating energy than the bottom duct heating system without decrease of crop yield.

• Journal of Bio-Environment Control
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• v.14 no.1
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• pp.22-28
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• 2005

The use of blankets to preserve heat in oriental melon cultivation is a common practise without artificial heating and warming systems. Efficiency of blanket decreased with annually usage. This experiment was conducted to investigate the effect of double layer nonwoven fabrics on heat conservation, plant growth, fruit quality and yield of oriental melon in greenhouse. The results were compared among the non-woven fabrics of 9+3, 6+6, 6+3 and 12 ounce from transplanting to April 20, 2001, 2002. Night temperature within tunnel was high at 9+3, 6+6, 6+3 and 12 ounce in order. In plant growth, stem length, leaf numbers and exudate, under double layer nonwoven fabrics were better than single layer blanket of 12 ounce especially, 9+3 double layer blanket was the best. Fruit weight, flesh thickness, soluble solid and marketable yield rate remained same in all treatments. Fermented fruit rate was the highest in 12 ounce as $32.9\%,\;19.6\%\;under\;9+3,\;17.1\%\;under\;6+6,\;16.6\%$ under 6+3 double layer nonwoven fabric, respectively. Compared to 2,260kg yield per 10a of 12 ounce single layer nonwoven fabrics, $7\%$ was increased under 9+3 but $3\%\;and\;13\%$ were decreased under 6+6 and 6+3 double layer nonwoven fabrics, respectively. Compared to income, 4,499-thousand-won per 10a, of 12 ounce single layer blanket, $13\%\;and\;3$ were increased under 9+3 and 6+6 double layer nonwoven fabrics, respectively. Whereas, $10\%$ decreased under 6+3 double layer nonwoven fabrics. From this results it is evident that 9+3 double layer nonwoven fabrics was the best for thermokeeping, fruit quality, and was most economic under non heating system.