• Korean Journal of Environmental Agriculture
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• v.25 no.1
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• pp.64-70
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• 2006

This study was conducted to investigate the concentration of fertigation for optimum yield and soil management of tomato cultivation in soils with different Electrical conductivity (EC) level under PE film house. The EC levels of soil were adjusted to 1.4, 3.0 and 5.4 dS/m and fertigation concentrations were supplied with 0.0 (groundwater), 1.0, 2.0 and 3.0 dS/m, respectively. When the concentration of fertigation was supplied over 3.0 dS/m to soil with EC 1.4 dS/m, the concentrations of $NO_3-N,\;avail.-P_2O_5$, and exchangeable K in soil were increased after the experiment. When fertigation concentration was supplied over 2.0 and 1.0 ds/m to soil with EC 3.0 and 5.4 dS/m respectively, the nutrient were also accumulated in the soil. Thus, the optimum concentrations of fertigation for optimum yield and soil management for tomato cultivation were recommended $1.0{\sim}2.0dS/m$, 1.0 dS/m and ground water (0.0 dS/m) to soils with EC 1.4, 3.0 and 5.4 dS/m, respectively. The fruit weight marketability and marketable yield of tomato were not significant among the treatments at 5% level by LSD. The concentrations of T-N, $P_2O_5\;and\;K_2O$ in tomato leaf were increased with increasing of fertigation concentration whereas the concentrations of CaO and MgO decreased with increasing of fertigation concentration.

• Journal of Bio-Environment Control
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• v.26 no.4
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• pp.424-431
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• 2017

This study was conducted to set the optimum nutrient solution concentration by growth stage for new strawberry cultivars 'Berrystar' and 'Jukhyang'(Fragaria ${\times}$ ananassa Duch. cvs. 'Berrystar', 'Jukhyang') grown through hydroponics to improve the quality and yield. Three different EC levels were applied to the nutrient solution. The treatment levels were 0.7, 1.0 and 1.3 times higher than the nutrient concentration standard for 'Seolhyang' based on the 'Manual for strawberry cultivation' of Rural Development Administration. Based on the results, there were no significant differences in growth of 'Berrystar' by EC level. 'Jukhyang' showed the most vigorous growth grown in 1.3 times higher nutrient concentration. While the growth of 'Berrystar' and 'Jukhyang' grown in higher EC level has leaves with more chlorophyll concentration. However the quantum yield of leaves was not affected by the treatments. On the treatment with 1.3 times higher EC level, the weight, length, width and firmness of 'Berrystar' and 'Jukhyang' were significantly high. The sugar contents of the harvest analyzed by HPLC did not differed particularly, but the percentage composition of reducing sugar and non-reducing sugar were presented differently depending on the treatments. Marketable fruit yield increased as nutrient concentration increases. However, there were no large differences by treatments. Meanwhile, 'Jukhyang' showed significant difference by nutrient concentration and had the largest yield for a treatment grown in 1.3 times higher EC level. Based on these results, it is recommended to provide the same nutrient solution concentration level to the nutrient concentration standard of 'Seolhyang' for 'Berrystar', and the 1.3 times higher level for 'Jukhyang'.

• Korean Journal of Agricultural and Forest Meteorology
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• v.24 no.3
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• pp.145-154
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• 2022

Due to abnormal weather conditions caused by climate change, natural disasters and damages are gradually increasing around the world. Global climate change as accompanied by warming is projected to exert adverse impact on production of potato, which is known as cool season crop. Even though, role of potato as a food security crop is expected to increase in the future, the climate change impacts on potato and adaption strategies are not sufficiently established. Therefore, this study was conducted to analyze the damage pattern of potatoes due to high temperature treatment and to evaluate the response of cultivars. T he high temperature treatment (35~38℃) induced heat stress by sealing the plastic house in midsummer (July), and the quantity and quality characteristics of potatoes were compared with the control group. T otal yield, marketable yield (>80 g) and the number of tubers per plants decreased when heat treatment was performed, and statistical significance was evident. In the heat treatment, 'Jayoung' cultivar suffered a high heat damage with an 84% reduction in yield of >80 g compared to the control group. However, in Jopung cultivar, the decrease was relatively small at 26%. Tuber physiological disturbances (Secondary growth, Tuber cracking, Malformation) tended to increase in the heat stress. Under heat conditions, the tubers were elongated overall, which means that the marketability of potatoes was lowered. T he tuber firmness and dry matter content tended to decrease significantly in the heat-treated group. T herefore, the yield and quality of tubers were damaged when growing potatoes in heat conditions. T he cultivar with high heat adaptability was 'Jopung'. T his result can be used as basic data for potato growers and breeding of heat-resistant cultivars.

• Journal of Bio-Environment Control
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• v.22 no.4
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• pp.421-426
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• 2013

This study was conducted to investigate the effects of timing of nutrient starvation during transplant production on growth of runner plants and yield of strawberry 'Seolhyang' (Fragaria ${\times}$ ananassa). Nutrient solution supply at the level of EC (electrical conductivity) 0.8 $dS{\cdot}m^{-1}$ was terminated at interval about 10 days between July 25 and September 5. As a result, the growth of above-ground part was inhibited while root growth increased when the nutrient starvation treatment had been brought forward to July 25. It also reduced the T/R ratio significantly and chlorophyll content was tended to be lower than the other treatment. In addition, it significantly promoted the budding, flowering and harvest of first flower cluster. On the other hand, the period of harvest was delayed more than two weeks when the nutrients were continuously supplied after the middle of August. An accumulated marketable fruit yield per plant until the end of January and February was 169 and 266g, respectively in the treatment of nutrient starvation on July 25, which was 71 and 12% increase, respectively, as compared with those in the treatment of September 5. Therefore, the appropriate nutrient starvation in the late season of strawberry nursery period could be expected the increase in yield and income during the winter season by promoting the flower bud differentiation as reducing the endogenous nitrate level of the plantlet.

• Korean Journal of Organic Agriculture
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• v.10 no.1
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• pp.75-86
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• 2002

This study was conducted to investigate the effects of pig manure composting using starch pulp m growth and yield characteristics of potato cropping. Four treatments ; No compost, 1 : 1 : 0, 1 : 0.75 : 0.25 and 1 : 0.5 : 0.5 the mixing ratio of pig manure, saw dust, and dehydrated starch pulp and composting by Piling and blowing methods. Plant heights in first growth stage were higher for the treatment of saw dust compost and starch pulp compost than the treatment of chemical fertilizer, but after the stage, there were no significant difference among treatments. The number of stolons were met for 10.9 in 1 : 0.5 : 0.5 treatment, following 1 : 0.75 : 0.25 and 1 : 1 : 0. On the other hand, tuber diameter and top dry matter weight tended to be larger for manure treatment than no treatment but there was no significant difference. Total number of tubers were largest for 1 : 0.5 : 0.5, and those for 1 : 1 : 0 and 1 : 0.75 : 0.25 were similar. Tuber yields of not more than 80g tended to be different, but those of between 81g and 120g and more than 120g were apparently larger for the compost treatment than no treatment. The ratio of marketable tubers appeared large to be about 86% for 1 : 0.75 : 0.25 and 1 : 0.5 : 0.5 treatments. Ratio of infected common scab on potato tubers tended to be highest for 1 : 0.5 0.5 but there were no statistical significance. However, when compost was made by mixing starch pulp in future, the solutions to the occurrence of infected common scab must be considered, The contents of N. P, K and Ca in leaves were larger for the compost treatment than no treatment, but no significant difference was observed, Accordingly, the effects of treating starch pulp compost on growth and yield characteristics of potato cropping were more affirmative than those of saw dust compost.

• Journal of Bio-Environment Control
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• v.24 no.3
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• pp.173-177
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• 2015

This experiment was conducted to determined the optimum planting density for the production of high quality bitter gourd (Momordica charantia L.) adapted in spring cultivation with the unheated greenhouse condition. 'Erave' variety was planted at three different planting densities (235, 305, $380plants{\cdot}10a^{-1}$) on March 26. The training method was six lateral vines with pinching the main one. The light intensity was lower in the higher planting density than the lower one. Net photosynthetic rates of the bitter gourd leaves in the higher density were significantly lower (41 to 71%) than the lower one. There was no difference in the fruit characteristics among treatments. But the root weight was heavier in the lower planting density ($235plants{\cdot}10a^{-1}$) as 113.1g than 96.0g of the higher planting density ($380plants{\cdot}10a^{-1}$). The number of the harvested fruit also higher in the lower planting density ($235plants{\cdot}10a^{-1}$) with 60.7 than 39.9 of the higher planting density ($380plants{\cdot}10a^{-1}$). The average fruit weight was the highest in the plot of $305plants{\cdot}10a^{-1}$ as 338.7g and lowest in the lower planting density ($235plants{\cdot}10a^{-1}$) as 285.2g. The total yield of $305plants{\cdot}10a^{-1}$ density was $5,359kg{\cdot}10a^{-1}$, which was higher than $4,068kg{\cdot}10a^{-1}$ of the lower planting density ($235plants{\cdot}10a^{-1}$). Marketable yield was increased by 24% in the planting density of $305plants{\cdot}10a^{-1}$($4,767kg{\cdot}10a^{-1}$) as compared to the lower density in $235plants{\cdot}10a^{-1}$($3,629kg{\cdot}10a^{-1}$) and increased by 13% in the planting density as $380plants{\cdot}10a^{-1}$($4,137kg{\cdot}10a^{-1}$). Therefore, the planting density of bitter gourd was desirable in $305plants{\cdot}10a^{-1}$ density for the higher yield and quality in the protected cultivation.

• 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.

• Korean Journal of Environmental Agriculture
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• v.26 no.4
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• pp.306-312
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• 2007

To investigate the effect of N fertigation on the growth, yield, and water and nitrogen use efficiencies during tomato cultivation, seedlings were transplanted in a sandy loam soil under plastic film house condition. 0, 88, 132, 176, $220\;kg\;ha^{-1}$ N rates, which correspond to 0 (NF0), 40 (NF40), 60 (NF60), 80 (NF80), 100% (NF100) N level of soil test-based N fertilization, were injected weekly through drip irrigation system for 15 weeks in N fertigation system, and the control (conventional N treatment) was installed for comparison. Herein, nitrogen was applied by top-dressing with 60% as a basal and 40% as additional fertilizer. There was little different in stem diameter growth among N fertigation treatments, but plant height and dry matter increased with increasing N fertigation rates as well as in N conventional treatment. Tomato yield was increased with increasing the number of marketable fruits in N fertigation treatments, and the fruit yield was maximized in NF 80 treatment ($176\;kg\;ha^{-1}$ N supply or $96.6\;mg\;L^{-1}$ N injection). Dry matter productivity and nitrogen uptake amount were significantly increased with increasing N fertigation rates. The ratio of fruits to the dry weight of whole plant was decreased with increasing N fertigation rates, but this ratio was $2.6{\sim}5.3%$ higher in N fertigation treatments than in the control. In addition, the ratios of nitrogen distributed toward fruits in N fertigation treatments were $3.7{\sim}21.7%$ higher than that of control. The apparent N recovery percentages showed significantly higher values as $71.8{\sim}102.3%$ in N fertigation treatments, compared to 45% in N conventional treatment. Water use efficiency was significantly increased by fertigation system with the maximum $361\;kg/ha\;cm^{-1}$ in NF 80, which is comparable to $324\;kg/ha\;cm^{-1}$ of the conventional treatment. Conclusively, N fertigation system was effective on increasing tomato productivity and nutrient efficiency as well as 20% reduction of N fertilization level.

• Journal of Bio-Environment Control
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• v.14 no.2
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• pp.89-94
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• 2005

This study was conducted to investigate the effect of nonwoven fabrics weight(Ounce) on growth, quality and yield of oriental melon (Cucumis melo L. var. makwa Mak.). Seedling of 'Gumssaragi-Eunchun' was grafted on 'Shinthozoa' root stock. In this study, The minimum air temperature in 6 ounce at night was $4.8^{\circ}C,\;6.9^{\circ}C$ in 9 ounce, $7.9^{\circ}C$ in 12 ounce and $8.0^{\circ}C$ in 15 ounce, respectively. Leaf length, stem diameter, leaf numbers, leaf area, fresh weight and dry weight for 30 days after planting were better in high minimum air temperature at night than in low minimum air temperature, particularly leaf areas of the plant in 9 ounce was $370cm^2$ at 30 days after planting, $116\%$ in 12 ounce, $129\%$ in 15 ounce. The xylem exudates amount in 9 ounce for 24 hours just after basal stem abscission was 10.1mg. It was 1.2 times much in 12 ounce and 1.9times much in 15 ounce than in 9 ounce at 30 days after planting. The blooming of female was faster by 6 days in 15 and 12 ounce but was delayed by 3 days in 6 ounce than 9 ounce, and the days of blooming to harvesting were shorter by 3 days in 15 ounce and 4 days in 12 ounce but was delayed by 3 days in 6 ounce than in 9 ounce. Fruit weight, fruit length, fruit diameter, flesh thickness, soluble solids, and total yield was the highest in 15 ounce followed by 12 ounce,9 ounce and 6 ounce. Fermented fruit rate was the highest in 6 ounce followed by 9 ounce, 12 ounce and 15 ounce, and marketable fruit rates were 15, 12, 9 and 6 ounce in order. Compared to 1,781kg yield per 10a of 9 ounce, $19\%\;and\;49\%$ was increased under 12 ounce and 15 ounce but $47\%$ were decreased 6 ounce.

• Journal of Bio-Environment Control
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• v.30 no.3
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• pp.237-243
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• 2021

The objective of this study was to evaluate the effect of stem number on plant growth, fruit quality, and yield of sweet peppers grown in greenhouses under supplemental lighting in winter. The seedlings were transplanted at 3.2 plants·m^-2 on October 26, 2020, and started supplemental lighting with 32 high pressure sodium lamps for 16-hour photoperiod from December 1, 2020 to May 25, 2021. Stems were differently trained with 2 and 3 numbers after branching nodes were developed. In the final harvest, the plant height was significantly shorter in the 3 stem-plants than in the 2 stem-plants. The number of nodes per stem and the leaves per plant were increased in the 3 stem-plants than in the 2 stem-plants, while the leaf area was less affected. There were no significant differences in the dry mass of leaves, stems, and immature fruits between the 2 and 3 stem-plants. The fruit fresh weight and fruit dry weight in the 3 stem-plants were decreased by 17% and 12% at 156 days after transplanting (DAT), and by 17% and 15% at 198 DAT compared to those in the 2 stem-plants, respectively. The marketable fruit rates were 93.6% and 95.4% in the 2 and 3 stem-plants, respectively. The total fruit yield in the 3 stem-plants was increased by 30.2% as compared to that in the 2 stem-plants. We concluded that the 3-stem-training cultivation positively affected the total fruit yield by sustaining adaptive vegetative growth of the plants. This result will help producers make useful decisions for increasing productivity of sweet peppers in greenhouses.