• Journal of Ginseng Culture
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• v.4
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• pp.128-141
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• 2022

Baengnyeongdo Island, which belongs to Ongjin-gun, Incheon, is an island in the northernmost part of the West Sea in South Korea. Baengnyeong Island is the 15th largest island in Korea and covers an area of 51 km². The Korea Ginseng Corporation (KGC) investigated the possibility of growing ginseng on Baengnyeong Island in 1996. In 1997, thanks to the support of cultivation costs from Ongjin-gun, the first ginseng seedbed was built on Baengnyeong Island. In 1999, the seedlings were transplanted to a permanent field under a contract with KGC. In 2003, the first six-year-old ginseng harvest was performed, and KGC purchased all production according to the contract. Since then, KGC has signed on to grow ginseng until 2012 and purchased six-year-old ginseng until the fall of 2016. Since 2014, the GimpoPaju Ginseng Agricultural Cooperative Association has signed a ginseng production contract. According to a survey of nine 6-year-old ginseng fields (total 5,961 units) on Baengnyeong Island, the top five with good growth had a survival rate of 42.6 to 68%, and the bottom four with poor growth had an extremely low survival rate of 11.1 to 21.3%. The four fields with low survival rates were where hot peppers were planted before ginseng cultivation. It is believed that the excess nitrogen remaining in the soil due to the treatment of compost or manure during pepper cultivation causes ginseng roots to rot. The average incidence of Alternaria blight was 8.6%. Six six-year-old ginseng gardens were low at 1.1 to 4.7%, while the other three were high at 16.7 to 20.9%. It is assumed that the reason for the low survival rate and high incidence of Alternaria blight is a rain-leaking shield. Farmers used rain-leaking shields because the precipitation on Baengnyeong Island was smaller than on land. One field showed 3% of leaves with yellowish brown spots, a symptom of physiological disturbance of the leaf, which is presumed to be due to the excessive presence of iron in the soil. To increase the production of ginseng on Baengnyeong Island, it is necessary to develop a suitable ginseng cultivation method for the island, such as strengthening the field management based on the results of a scientific study of soil, using rain-resistant shading, and installing drip irrigation facilities. I hope that ginseng will become a new driving force for the development of Baengnyeong Island, allowing ginseng products and food to thrive in the beautiful natural environment of the island.

• Research in Plant Disease
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• v.28 no.3
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• pp.113-121
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• 2022

Rice blast is a major plant disease that occurs worldwide and significantly reduces rice yields. Rice blast disease occurs periodically in Korea, causing significant socio-economic damage due to the unique status of rice as a major staple crop. A disease outbreak prediction system is required for preventing rice blast disease. Epidemiological investigations of disease outbreaks can aid in decision-making for plant disease management. Currently, plant disease prediction and epidemiological investigations are mainly based on quantitatively measurable, structured data such as crop growth and damage, weather, and other environmental factors. On the other hand, text data related to the occurrence of plant diseases are accumulated along with the structured data. However, epidemiological investigations using these unstructured data have not been conducted. The useful information extracted using unstructured data can be used for more effective plant disease management. This study analyzed news articles related to the rice blast disease through text mining to investigate the years and provinces where rice blast disease occurred most in Korea. Moreover, the average temperature, total precipitation, sunshine hours, and supplied rice varieties in the regions were also analyzed. Through these data, it was estimated that the primary causes of the nationwide outbreak in 2020 and the major outbreak in Jeonbuk region in 2021 were meteorological factors. These results obtained through text mining can be combined with deep learning technology to be used as a tool to investigate the epidemiology of rice blast disease in the future.

• Journal of Bio-Environment Control
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• v.31 no.4
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• pp.356-365
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• 2022

Agrivoltaic systems, also called solar sharing, stated from an idea that utilizes sunlight above the light saturation point of crops for power generation using solar panels. The agrivoltaic systems are expected to reduce the incident solar radiation, the consequent surface cooling effect, and evapotranspiration, and bring additional income to farms through solar power generation by combining crops with solar photovoltaics. In this study, to evaluate if agrivoltaic systems are suitable for viticulture, we investigated the microclimatic change, the growth of vines and the characteristics of grape grown under solar panels set by planting lines compared with ones in open vineyards. There was high reduction of wind speed during over-wintering season, and low soil temperature under solar panel compared to those in the open field. There was not significant difference in total carbohydrates and bud burst in bearing mother branches between plots. Despite high content of chlorophyll in vines grown under panels, there is no significant difference in shoot growth of vines, berry weight, cluster weight, total soluble solid content and acidity of berries, and anthocyanin content of berry skins in harvested grapes in vineyards under panels and open vineyards. It was observed that harvesting season was delayed by 7-10 days due to late skin coloration in grapes grown in vineyards under panels compared to ones grown in open vineyards. The results from this study would be used as data required in development of viticulture system under panel in the future and further study for evaluating the influence of agrivoltaic system on production of crops including grapes.

• Journal of Korean Society of Forest Science
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• v.111 no.4
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• pp.613-621
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• 2022

The study aim was to investigate changes in the diameter, number of standing trees, stand volume per ha and site index by the forest survey order, climate zone (northern temperate, central temperate, southern temperate, and warm temperate regions), and altitude in 100 m intervals) by collecting samples of Robinia pseudoacacia from the fifth, sixth, and seventh national forest survey datasets. The rotation cutting age, which is a standard used for wood, was calculated. The changes were statistically analyzed by performing ANOVA and the Duncan multiple test. Diameter growth naturally increased according to the forest survey order and was lowest in the southern temperate region by climate zone and lowest at the 301-400 m altitude. The number of standing trees per ha did not change according to the forest survey order and altitude, and the density was highest in the central temperate region and lowest in the southern temperate region. The stand volume per ha increased according to the forest survey order, and the climate zone was divided into two groups: ① northern temperate region and central temperate region, ② southern temperate region and warm temperate region. The stand volume growth was highest at the 201-300 m point. Thesite index showed results similar to the change pattern of the stand volume per ha. The growth curve, which can be seen by the change in stand volume per ha, was estimated by applying theWeibull formula, and the stand volume per ha was estimated to reach approximately 200 m³/ha at 50-60 years. The rotation of the highest production in volume, which is the standard for using trees as wood rather than honey sources, was calculated to be 34 years.

• Journal of Korean Society of Forest Science
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• v.111 no.4
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• pp.567-582
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• 2022

Chainsaw use for motor-manual timber harvesting in South Korea is associated with worker safety issues. However, forestry operations such as timber harvesting have already been mechanized to reduce hazards to workers and increase productivity. This study analyzed the productivities and costs of felling and processing, felling and processing using an excavator-based stroke harvester for Pinus rigida and Quercus mongolica stands. To efficiently operate the stroke harvester, we developed a regression equation to estimate the productivities of felling and processing, felling, and processing operations,and we conducted sensitivity analysis of the operation costs using DBH and machine utilization. The felling and processing productivity was 6.53 and 4.02 m³/SMH for P. rigida a nd Q. mongolica, respectively, and the cost was 17,983 and 29,210 won/m³, respectively. The felling productivity for P. rigida a nd Q. mongolica wa s 40.9 and 23.0 m³/SMH, respectively, and the cost was 2,667 and 4,743 won/m³, respectively. The processing productivity for P. rigida and Q. mongolica was 8.25 and 7.75 m³/SMH, respectively, and the cost was 15,296 and 16,283 won/m³, respectively. In the developed regression equation, the DBH, traveling distance, and number of cuttings were found to be important factors (p<0.05). Therefore, it is necessary to construct a DB considering the various conditions and species associated with harvester operations, and further research is needed to increase the accuracy of predicting operation productivity and costs.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.67 no.3
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• pp.172-179
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• 2022

Sweet potato varieties with high fiber content in the storage root have poor texture when steamed or roasted. This study investigates the difference in fiber content among sweet potato varieties by soil and climate. The average fiber content of 'Hogammi', 'Sodammi', 'Pungwonmi', 'Danjami', and 'Jinyulmi' cultivars from the samples collected at farms in Haenam, Muan, and Unbong, Korea were 95.71, 66.73, 44.55, 40.55, and 38.53 mg/100g FW, respectively. There was no significant difference between site-specific conditions and varieties. Based on the degree of visual fibrousness, 'Hogammi' has an average of 3.6-4.0 with many thick stringy fibers. The fiber content of the 'Hogammi' cultivar was measured across 19 sites representing the main sweet potato growing regions of Korea. The fiber content was between 115.82 and 114.6 mg/100g in Haenam 2 and Boryeong 1, and 87.46 mg/100g in Hamyang. However, the fiber content at the remaining 16 sites was within the range of 94.63-108.52 mg/100g, although there were some site-level differences. The fiber content of the sweet potato storage roots were positively correlated with soil phosphorus (R² = 0.58^**), organic matter (R² = 0.52^*), and pH (R² = 0.51^*), which had a significance of 1% and 5%. The fiber content of sweet potato storage roots was found to have increased with increasing phosphorus content, organic matter and pH in the soil. However, there was no correlation with the amount of precipitation, days of precipitation and hours of sunshine with the fiber content of sweet potato at the selected sites.

• Journal of the Korea Organic Resources Recycling Association
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• v.30 no.2
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• pp.17-28
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• 2022

The application of supplemental activated biochar pellet fertilizers (ABPFs) was evaluated by investigating key factors such as changes of surface paddy water and soil chemical properties and rice growth responses during the growing season. The treatments consisted of control, activated rice hull biochar pellet (ARHBP-40%), and activated palm biochar pellet (APBP-40%) applications. It was shown that the lowest NH₄⁺-N and PO₄^--P concentrations were observed in surface paddy water to the ARHBP-40%, while the NH₄⁺-N concentration in the control was abruptly decreased until 30 days after transplant in the soil. However, the lowest NH₄⁺-N concentration in the blended biochar application was 9.18 mg L^-1 at 1 day of transplant, but its ABPFs application was observed to be less than 1 mg L^-1 at 56 days after transplant. The lowest PO₄^--P concentration in paddy water treated ARHBP-40% ranged from 0.06 mg L^-1 to 0.08 mg L^-1 until 30 days after transplant among the treatments. For the paddy soil, the NH₄⁺-N concentration in the control was abruptly decreased from 177.7 mg kg^-1 to 49.4 mg kg^-1, while NO₃^--N concentration was highest, 13.2 mg kg^-1 in 14 days after transplant. The P₂O₅ concentrations in the soils increased from rice transplants until the harvesting period regardless of the treatments. The highest K₂O concentration was 252.8 mg kg^-1 in the APBP-40% at 84 days after transplant. For the rice growth responses, plant height in the control was relatively high compared to others, but grain yield was not significantly different between the control and ARHBP-40%. The application of ARHBP-40% can minimize nitrogen and phosphorous application rates into the agro-ecosystem.

• Journal of Bio-Environment Control
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• v.31 no.4
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• pp.423-431
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• 2022

Due to increase of interest in 'carbon neutrality', attempts at agricultural use of CO₂ are increasing. In this study, we used the dry-ice made by CO₂ as by-product in thermoelectric power plant on CO₂ fertilization for production of leafy vegetable in greenhouses. The dry-ice was supplied on three leafy vegetable farms (Allium tuberosum Rottl. ex Spreng, Aster scaber, and Oenanthe stolonifera DC.) located in Hadong, Gyeongsangnamdo. Two greenhouses were used in each leaf vegetable crops, one greenhouse used as the control (non-treatment), other greenhouse used as supplied CO₂. For CO₂ fertilization, a gas sublimated from dry ice was supplied to the greenhouse using a specially designed prototype supply machine. A. tuberosum greenhouse has no difference of CO₂ concentration between the control, and CO₂ fertilization and shown high CO₂ concentration both greenhouses. However, the CO₂ concentrations in A. scaber and O. stolonifera greenhouses were increased in CO₂ fertilization treatment. The growth of A. scaber and O. stolonifera were increased in CO₂ fertilization, and the yield also increased to 36% and 25% than the control, respectively. As a result of economic analysis, the A. scaber has increase of income rate, however A. tuberosum and O. stolonifera has decreased income rate. Thus, the use of the dry-ice made by CO₂ as by-product in thermoelectric power plant has possibility to increase productivity of the leafy vegetable in greenhouse and have agricultural use value.

• Korean journal of applied entomology
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• v.61 no.2
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• pp.319-330
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• 2022

Andong is a place to culture the great amount of hot pepper (Capsicum annuum L.) in Korea. This study reports a yearly occurrence (March 31~October 25, 2021) of thrips infesting the hot pepper in Andong. Thrips caught to yellow sticky traps were diagnosed by morphological characters and showed two dominant species: Frankliniella occidentalis and F. intonsa. During this period, a total of 107,874 thrips were caught and included F. occidentalis at about 82%, F. intonsa at about 17%, and the other thrips at about 0.3%. There were two main peaks at May~June and at September~October, respectively, in which the total number of thrips was higher in the second peak and most were F. occidentalis. Interestinly, a low level of thrips occurred during July~August was observed and explained by their susceptibility to high temperatures. A laboratory experiment by exposing thrips to high temperatures showed that thrips were susceptible to temperatures higher than 35℃ and not tolerant to 45℃ for 1 h. Indeed, high temperatures higher than 45℃ were recorded in the greenhouses in Andong during July~August. F. occidentalis was more tolerant to the high temperatures than F. intonsa. On the other hand, the thrips showed the highest occurrence peak at July~August in hot pepper-culturing greenhouse in Kangwon, where the average temperatures were mostly lower than those of Andong and no high temperatures higher than 45℃ were recorded during July~August. A viral disease caused by tomato spotted wilt virus (TSWV) was observed in the hot peppers cultured in Andong greenhouses. Multiplex PCR was used to detect the virus along with identification of thrips. With a high record of about 30%, the virus-infected thrips were detected during all the monitoring period. The virulent thrips were identified to be only F. intonsa. These results suggest that F. occidentalis gives a direct damage especially during harvesting period with their high populations while F. intonsa gives indirect damage by transmitting TSWV.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.30 no.3
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• pp.252-258
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• 1985

An experiment was conducted at the Yeongnam Crop Experiment Station to obtain basic informations about cultural techniques for high yielding by manipulating plant spacing using two rice cultivars, Samgangbyeo (Indica/Japonica type) and Nakdongbyeo (Japonica type), and four plant spacings, 10${\times}$10cm, 20${\times}$20cm 30${\times}$30cm and 40${\times}$40cm, with 4 kinds of seedling number per hill, 1,3,5 and 7, respectively. High photosynthetic efficiency (Eu) exhibited at the Samgangbyeo compared to Nakdongbyeo regardless of plant spacings and seedling numbers. For Samgangbyeo, Eu value was the highest at the 20${\times}$20cm plant spacing and five seedlings and seven seedlings per hill showed high Eu values at 10${\times}$10cm plant spacing and 20${\times}$20cm plant spacing, respectively, while other plant spacings were not significantly differed among seedling numbers. For Nakdongbyeo, however, one seedling plot obtained high Eu value at the 10${\times}$10cm plant spacing while this Eu value increased as the seedling number per hill increased in other plant spacings. There was a high positive correlation between rice grain yield and total competition index for both cultivars while kind of relationships differed in these two cultivars; linear relationship for Samgangbyeo and exponential relationship for Nakdongbyeo, respectively. Competition index between rice hill was more significant than within rice hill for Samgangbyeo while both competition indexs were important for Nakdongbyeo to increase rice yield.