• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.27 no.1
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• pp.683-692
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• 2009

On-site remote sensing technique by using single lens reflex(SLR) digital camera will be expected as the useful tool for the vegetation measurement field such as a crop growth management, the monitoring of revegetation slope and the evaluation of environment. We reviewed the availability of the vegetation measurement using a digital camera which is sailed for general-purpose. As a result, we could analysis relationship with the illuminance of image plane and incidence energy of multitemporal observation images by doing gamma correction and exposure compensation. And also, we proposed the model formulas for the correction of influences of capturing angle and illuminance. In addition, we obtained high correlation of normalized difference vegetation index(NDVI) between digital camera and spectral photometer.

• Korean Journal of Organic Agriculture
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• v.7 no.2
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• pp.125-151
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• 1999

After the release of facts that the high nitrate contents in vegetables by Korean organic farming, organic farmers were recommended by Korean Organic Farmer Association to apply 20t/ha compost while they applied before as much as they could, sometimes even more than 100t/ha. This study was aimed to check the safety of Korean organic product in terms of nitrate content. Current nitrate content in leaf and root vegetables by 3 different farming systems(organic farming, conventional farming, greenhouse farming) were monitored and furthermore it was compared with previously published another data in Korea to find out any changes among the monitored years(1993-1999). Current nitrate content in chinese cabbage, lettuce and kale became less compare to those of the beginning of monitoring, and especially those cultivated organic farming got the lowest value while previous organic vegetables at beginning of 90's showed the higher value than those cultivated in greenhouse. This decrease in organic vegetables was affected by less application rate of organic fertilizer than before at 20t/ha. But the nitrate level by organic farming was still higher compare to those cultivated by conventional farming in open field, since currently monitored organic vegetables were cultivated basically in greenhouse condition. It shows the organic farmer the necessity of transfer their farming site and condition from greenhouse to open field in order to decrease of its high level of nitrate caused long-term application and slow release characteristics of organic fertilizer. It was concluded the adoption of soil nitrate test to recommend a organic farmer the exact application rate for need of crop growth. Additionally the mechanism of lower nitrate accumulation in rice and fruit vegetables were also discussed in the paper.

• The Plant Pathology Journal
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• v.39 no.4
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• pp.351-360
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• 2023

Citrus melanose, caused by Diaporthe citri, has been one of the serious diseases, and chemical fungicides were used for protection in many citrus orchards of Jeju Island. Establishing a disinfectant resistance management system and reducing pesticide usage would be important for contributing to safe agricultural production. In this study, monitoring of chemical resistance was performed with 40 representative D. citri isolates from many citrus orchards in Jeju Island. Four different fungicides, kresoxim-methyl, benomyl, fluazinam, and prochloraz manganese, with seven different concentrations were tested in vitro by growing the mycelium of the fungal isolates on the artificial medium potato dextrose agar. Among the 40 fungal isolates, 12 isolates were investigated as resistant to kresoxim-methyl which could not inhibit the mycelium growth to more than 50%. Especially isolate NEL21-2 was also resistant against benomyl, whose hyphae grew well even on the highest chemical concentration. However, any chemical resistance of fungal isolates was found against neither fluazinam nor prochloraz manganese. On the other hand, in vivo bio-testing of some resistant isolates was performed against both kresoxim-methyl and benomyl on young citrus leaves. Typical melanose symptoms developed on the citrus leaves pre-treated with both agrochemicals after inoculation with the resistant isolates. However, no or less symptoms were observed when the susceptible isolates were inoculated. Based on these results, it was suggested that some resistant isolates of D. citri occurred against both systemic fungicides, which may be valuable to build a strategy for protecting citrus disease.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.49 no.3
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• pp.167-171
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• 2004

The growth of soybean sprout was greatly influenced by watering systems： Fixed watering system (water tub was loaded at ceiling upper of culture box and water was showered by bottom holes) was estimated the better than that of reciprocating watering and tub immersing watering because it could cool down the temperature in culture box and wash the organic substances on the body of sprout. The fixed watering system showed good body color and preventing effect of partial rotting of sprout because it could discharge $\textrm{CO}_2$ gas effectively in culture box and keep the concentration below 5%. The concentration of gases at the bottom (about 30 cm height from basal plate) of culture box in fourth or fifth days was L6% for $\textrm{CO}_2$ and 13-16% for $\textrm{O}_2$, respectively. The optimum gas concentration in culture box was considered to be over 10% for $\textrm{O}_2$ and below 5% for $\textrm{CO}_2$.

• Korean Journal of Environmental Agriculture
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• v.37 no.3
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• pp.197-206
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• 2018

BACKGROUND: The present study aimed to examine the crops capable of growing and adapting to the external environment and various stresses of reclaimed agriculture land for the development of high value-added agricultural utilization technology based on reclaimed land through standardization and empirical study of cultivation environment for cultivating crops. METHODS AND RESULTS: Two crops namely turnips and beets were selected for the salt tolerance test of soil environmental conditions on reclaimed land. Turnip and beet seedlings were planted on the soil collected at the 'Seokmun' reclaimed land. There are five treatments such as non-treatment, 1.0, 2.0 (control), 4.0 and $8.0dS{\cdot}m^{-1}$ of EC. The contents of betacyanin in beet roots was highest in control and decreased with increasing salt concentration. The GSL contents in the turnip roots waswere highest at EC 2.0 and decreased with increasing salt concentration, whereas those in turnip leaves waswere high both in the non-treated control and atthe EC 1.0-treatment. But, tThere was, however, no statistical differences among the treatments. CONCLUSION: The degree of salt tolerance of crops was examined, and the limit EC iswas expected to be $3.0{\sim}4.0dS{\cdot}m^{-1}$ as reported to date. If the soil improvement is performed and irrigation systems are used in the actual reclaimed land, the EC of supplied irrigation will be low, and desalination effecttreatment by the lower EC of the supplied irrigation on the soil will lead to more favorable soil condition of the rhizosphere and cultivation environment offor the crops than those in the port experiment. Therefore, monitoring the salinity, water content and ground water level will enable prediction of the rhizosphere environment, and setting up irrigation management and supplying irrigation will lead to crop cultivation results that are close to normal.

• Korean Journal of Remote Sensing
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• v.36 no.6_2
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• pp.1523-1535
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• 2020

In order to produce crop information using remote sensing, we use classification and growth monitoring based on crop phenology. Therefore, time-series satellite images with a short period are required. However, there are limitations to acquiring time-series satellite data, so it is necessary to use fusion with other earth observation satellites. Before fusion of various satellite image data, it is necessary to overcome the inherent difference in radiometric characteristics of satellites. This study performed Korea Multi-Purpose Satellite-3 (KOMPSAT-3) cross calibration with Landsat-8 as the first step for fusion. Top of Atmosphere (TOA) Reflectance was compared by applying Spectral Band Adjustment Factor (SBAF) to each satellite using hyperspectral sensor band aggregation. As a result of cross calibration, KOMPSAT-3 and Landsat-8 satellites showed a difference in reflectance of less than 4% in Blue, Green, and Red bands, and 6% in NIR bands. KOMPSAT-3, without on-board calibrator, idicate lower radiometric stability compared to ladnsat-8. In the future, efforts are needed to produce normalized reflectance data through BRDF (Bidirectional reflectance distribution function) correction and SBAF application for spectral characteristics of agricultural land.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.12 no.3
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• pp.290-298
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• 2019

The proportion of farm households in the total population is decreasing every year. The aging of rural areas is expected to deepen. The aging of agriculture is continuing due to the aging of the aged population and the decline of the young population, and agricultural manpower shortage is emerging as a threat to agriculture and rural areas. The existing facility cultivation was concentrated on the production / yield per unit area. However, nowadays, not only production but also crop quality should be good so that the quality of crops must be improved because they can secure competitiveness in the market. Therefore, the government plans to increase the productivity by hi-techization of ICT infrastructure horticulture and to plan the dissemination of energy saving smart greenhouse. Therefore, it is necessary to develop a Smart Farm convergence service system based on a hybrid algorithm to enhance diversity and connectivity. Therefore, this study aims to develop smart farm convergence service system which collects data of growth environment of the rhizosphere environment of crops by wireless and monitor smartphone.

• KIPS Transactions on Computer and Communication Systems
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• v.5 no.10
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• pp.347-352
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• 2016

Recently, IoT technology has been applied in various field. In particular, the technology focuses on analysing large amount of data that has been gathered from the environmental sensors, to provide valuable information. This technique has been actively researched in the agro-industrial sector. Many researches are underway in the monitoring and control for growth crop environment in agro-industrial. Normally, the average weather data is provided by the manual agro-control method but the value may differ due to the different region's weather and environment that may cause problem in the disease and insect-pest prevention. In order to develop a suitable integrated system for fruit tree, all the necessary information is obtained from the Jeollanam-do province, which has the high production rate in the Korea. In this paper, we propose an integrated support platform for the growing crops, to minimize the damage caused due to the weather disaster through image analysis, forecasting models, by using the micro-climate weather information collection and CCTV. The fruit tree damage caused by the weather disaster are controlled by utilizing various IoT technology by maintaining the growth environment, which helps in the disease and insect-pest prevention and also helps farmers to improve the expected production.

• Horticultural Science & Technology
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• v.34 no.1
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• pp.77-83
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• 2016

The measurement of total fresh weight of plants provides an essential indicator of crop growth for monitoring production. To measure fresh weight without damaging the vegetation, image-based methods have been developed, but they have limitations. In addition, the total plant fresh weight is difficult to measure directly in hydroponic cultivation systems because of the amount of nutrient solution. This study aimed to develop a real-time, precise method to measure the total fresh weight of Romaine lettuce (Lactuca sativa L. cv. Asia Heuk Romaine) with growth stage in a plant factory using a nutrient film technique. The total weight of the channel, amount of residual nutrient solution in the channel, and fresh shoot and root weights of the plants were measured every 7 days after transplanting. The initial weight of the channel during nutrient solution supply (Wi) and its weight change per second just after the nutrient solution supply stopped were also measured. When no more draining occurred, the final weight of the channel (Ws) and the amount of residual nutrient solution in the channel were measured. The time constant (${\tau}$) was calculated by considering the transient values of Wi and Ws. The relationship of Wi, Ws, ${\tau}$, and fresh weight was quantitatively analyzed. After the nutrient solution supply stopped, the change in the channel weight exponentially decreased. The nutrient solution in the channel slowly drained as the root weight in the channel increased. Large differences were observed between the actual fresh weight of the plant and the predicted value because the channel included residual nutrient solution. These differences were difficult to predict with growth stage but a model with the time constant showed the highest accuracy. The real-time fresh weight could be calculated from Wi, Ws, and ${\tau}$ with growth stage.

• Weed & Turfgrass Science
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• v.4 no.1
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• pp.1-9
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• 2015

Many irrigated and drainage canals, reservoirs, lakes, and rivers are choked by the explosive growth of aquatic weeds, resulting in enormous direct loss in Korea. Distribution of aquatic weeds and exotic invasive plant species in irrigation and drainage waterways, and riparian wetlands was reviewed to provide basic information for management of aquatic weeds and invasive plant species in wetlands. Dominant emergent weeds in canals, reservoirs and lakes were Phragmites communis, Leersia japonica, Zizania latifolia, Conyza canadensis, C. annuus, Rumex crispus, Panicum dichotomiflorum, Bidens frondosa, and Oenothera odorata. Dominant emergent weeds in wetlands of rivers include Digitaria sanguinalis, P. communis, R. crispus, Artemisia princeps, Humulus japonicus, Echinochloa crusgalli, B. frondosa, and Persicaria thunbergii. In irrigation and drainage canals and lakes, dominant submersed weeds were Hydrilla verticillata, Najas minor, Potamogeton malaianus, P. crispus, Ceratophyllum demersum, Myriophyllum verticillatum, Salvinia natans, and Trapa natans. Dominant exotic weeds in wetlands include Trifolium repens, O. odorata, C. annuus, B. frondosa, Avena fatua, Ambrosia artemisiifolia, X. strumarium, and P. dichotomiflorum. Approaches to aquatic weed control were mechanical, chemical and biological control techniques. Periodic monitoring of aquatic weeds and exotic weeds, and their integrated management studies are needed in waterways and riparian wetlands in Korea.