• Journal of Bio-Environment Control
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• v.31 no.4
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• pp.401-408
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• 2022

As research on a controlled environment system based on crop growth environment sensing for sustainable production of horticultural crops and its industrial use has been important, research on how to properly utilize soil moisture sensors for outdoor cultivation is being actively conducted. This experiment was conducted to suggest the proper method of utilizing the TEROS 12, an FDR (frequency domain reflectometry) sensor, which is frequently used in industry and research fields, for each orchard soil in three regions in Korea. We collected soils from each orchard where fruit trees were grown, investigated the soil characteristics and soil water retention curve, and compared TEROS 12 sensor calibration equations to correlate the sensor output to the corresponding soil volumetric water content through linear and cubic regressions for each soil sample. The estimated value from the calibration equation provided by the manufacturer was also compared. The soil collected from all three orchards showed different soil characteristics and volumetric water content values by each soil water retention level across the soil samples. In addition, the cubic calibration equation for TEROS 12 sensor showed the highest coefficient of determination higher than 0.95, and the lowest RMSE for all soil samples. When estimating volumetric water contents from TEROS 12 sensor output using the calibration equation provided by the manufacturer, their calculated volumetric water contents were lower than the actual volumetric water contents, with the difference up to 0.09-0.17 m³·m^-3 depending on the soil samples, indicating an appropriate calibration for each soil should be preceded before FDR sensor utilization. Also, there was a difference in the range of soil volumetric water content corresponding to the soil water retention levels across the soil samples, suggesting that the soil water retention information should be required to properly interpret the volumetric water content value of the soil. Moreover, soil with a high content of sand had a relatively narrow range of volumetric water contents for irrigation, thus reducing the accuracy of an FDR sensor measurement. In conclusion, analyzing soil water retention characteristics of the target soil and the soil-specific calibration would be necessary to properly quantify the soil water status and determine their adequate irrigation point using an FDR sensor.

• Korean journal of applied entomology
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• v.14 no.3 s.24
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• pp.141-146
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• 1975

Experiments were carried out to know the effects of emulsifiable DBCP, (Dibromo Chloropropane) for control of the citrus-root nematode, Tylenchulus semipenetrans in Orchards of chinese citron and mandarine orange for four years of 1967-1970. Nematode population density decreased as the amount of DBCP increased. In mandarine orange orchard, the nematode population density decreased after second treatment mainly because of bad drainage of the soil, while in Chinese citron orchard, it fell off sharply after just one treatment since the soil was well drained. Yields of Chinese citron increased as much as $26\%$ in 4.4l/10a injection, 1$18\%$ in 4.4l/10a drench; yields of mandarine orange increased as much as $11\%$ in 4.41/10a injection and $13\%$ in 4.4l/10a drench.

• Korean Journal of Agricultural Science
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• v.49 no.3
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• pp.561-570
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• 2022

This study investigated the changes in planting environment and growing conditions of 'Arisoo' apple trees under shading net treatments. Apple tree canopies were fully covered with Blue (blue color net, mesh size: 4 mm × 5 mm), Black-A (black color net, mesh size: 4 mm × 5 mm), Black-B (black color net, mesh size: 5 mm × 6 mm), and uncovered trees were used as the control. Inside the tree canopies, the illuminance was observed as 100% (85.0 Klux) in the control, but it decreased to 75% (64.3 Klux) in the Blue, 73% (63.0 Klux) in the Black-A, and 77% (65.9 Klux) in the Black-B nets, respectively. The solar irradiance was observed as 755 w·m^-3 in the control, but it was decreased to 715 w·m^-3 in the Blue, 624 w·m^-3 in the Black-A, and 647 w·m^-3 in the Black-B nets, respectively. The average daily temperature was observed to be the highest in the Black-A net (31.8℃) while it was observed to be around 30.0℃ in the control, Blue, and Black-B nets. In addition, the average fruit surface temperature was observed to be the highest (39.4℃) in the control, but it was decreased to 38.1℃ in the Blue, 37.3℃ in the Black-A, and 39.0℃ in the Black-B nets. However, the average soil temperature, the shoot growth rate, and leaf SPAD values were not different in all the treatments. Fruit sunburn disorders were the highest in the control while it was observed to be lower in the fruits from trees covered with the shading nets. However, at harvest, the fruit quality parameters were not different in all the treatments. Overall, this study suggests that the apple trees covered with the shading nets reduced the illuminance, solar irradiance, fruit surface temperature, and fruit sunburn disorders. However, the shading nets did not affect tree growth and apple fruit quality.

• Journal of Korea Water Resources Association
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• v.38 no.11
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• pp.927-935
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• 2005

Soil erosion by rainfall is important factor for basin management because it reduces reservoir capacity and breaks out the contamination of water caused by turbid water. Recently, soil erosion study with GIS is in progress but does not consider soil erosion source area. This study calculated soil erosion amount using GIS-based soil erosion model in Imha basin and examined soil erosion source area using SPOT 5 High-resolution satellite image and land cover map. As a result of analysis, dry field showed high-density soil erosion area and we could easily investigate source area using satellite image. Also we could examine the suitability of soil erosion area by applying field survey method in common areas such as dry field and orchard area those are difficult to confirm soil erosion source area using satellite image.

• Korean Journal of Environmental Agriculture
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• v.38 no.3
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• pp.213-218
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• 2019

BACKGROUND: Monitoring of the dynamic changes of chemical properties in agricultural land is very important for agricultural sustainability. Chemical properties of agricultural soils in Korea have been investigated at four-year interval in the order of paddy, plastic film house, upland, and orchard soils since 1999. METHODS AND RESULTS: Total 8,160 topsoil samples were taken from the upland in 2001, 2005, 2009, 2013, and 2017, respectively. Soil chemical properties such as pH, electrical conductivity (EC), organic matter (OM), available phosphate (Avail. $P_2O_5$), and exchangeable (Exch.) cations (K, Ca, and Mg) were analyzed. Soil pH and Exch. Ca contents have increased since 2001. Average concentration of Avail. $P_2O_5$ increased from $547mg\;kg^{-1}$ in 2001 to $657mg\;kg^{-1}$ in 2017. Average concentration of Exch. Ca in 2017 was higher than the upper limit of its optimal range for upland cultivation. Excess and deficiency of chemical properties of upland soils comply with soil analysis and fertilizer prescription. CONCLUSION: We concluded that excessive nutrient in upland needed to be properly managed with soil test.

• Korean Journal of Soil Science and Fertilizer
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• v.6 no.4
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• pp.205-211
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• 1973

General physical and chemical characteristics of eleven apple orchard soils derived from granite, granodiorite, diorite, arkose sandstone and shale were investigated in relation to soil profile. The results are summerized as follows: 1. Soils were mostly sandy and showed pH 4.35 to 6.75, 1.14 to 5.58 of organic matter, 0.065 to 0.209% of nitrogen. All properties decreased with depth. 2. Total exchangeable bases of surface soils were comparablly low (4.89 to 17.81me/100g, Ca>Mg>K>Na). Cation exchange capacity ranged from 7.74 to 21.72 mg/100g and base saturation percentage from 22.52 to 94.62%. 3. Phosphorus content of surface soil was very low (less than 35.5 mg/100g). The contents of potassium (7.2-79.2 mg/100g), available copper (1.0-16.9 ppm) and water soluble boron (0.18-0.72 ppm) were high in surface soil but low with depth. The content of manganese showed clear difference with pH, that is, at pH 4 to 6 water soluble manganese ranged from 0.42 to 17.8 ppm and exchangeable manganese from 9.82 to 66.38 ppm but above pH 6 the water soluble was less than 0.70 ppm and the exchangeable less than 22.25 ppm.

• Journal of Species Research
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• v.5 no.3
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• pp.477-482
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• 2016

Mite of the genus Hypoaspis of family Laelapidae are free-living soil predators mostly observed on the open grass field. Five species in the genus Hypoaspis were listed in Korean Catalog (NIBR, 2013) without detail information. Recent series of soil acarine biodiversity survey in Gyeongbuk and Gangwon provinces during 2009-2015 recovered a new record of Hypoaspis sardous (Canestrini, 1884) to Korean inventory from apple orchard and riparian grass land. Detailed description and morphological comparison with the related species, H. aculeifer which is well known biological control agent of horticultural crop pests were provided with identification keys.

• The Korean Journal of Soil Zoology
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• v.1 no.1
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• pp.48-55
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• 1996

This study was carried out to investigate the arthropod fauna at tangerine orchards in Cheju-do island. To fulfil this purpose, samples were taken at 21 areas from the Cheju-do island 1985 to 1989. During this period, 33 species were identified, thus making 217 species, 99 genera, 31 families of spiders recorded from this island, In tangerine orchards alone, 26 species of spiders were found.

• Korean Journal of Environmental Agriculture
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• v.4 no.2
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• pp.88-94
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• 1985

In order to investigate the pollution potential of soils after the construction of Onsan Industrial Complex(non-ferrous metal refineries), concentrations of hazardous heavy metals were analyzed for soil samples collected from paddy, upland, orchard and forest soils around the Complex during the period of March 1978 to May 1979. The results are summarized as follows. 1) The concentrations of heavy metals (air-dry basis) for cultivated soil samples from 46 sites were obtained in the range of trace-9.3 ppm As, trace-0.6 ppm Cd, 4${\sim}$22 ppm Cu, trace-0.37 ppm Hg, 6${\sim}$43 ppm Pb and 27${\sim}$93 ppm Zn, which were regarded as non-polluted when compared with the whole Korea data for non-polluted paddy soils. 2) When the heavy metal concentrations were compared with respect to paddy, upland and orchard soils, no significant difference was observed in As, Cd, Cu and Zn whereas significant difference was observed in Hg and Pb. When they were compared with respect to region surrounding the Complex, no significant difference was observed in As, Cd, Hg whereas significant difference was observed in Cu and Pb. 3) Soil samples from several sites near Korea Zinc Refinery were contaminated with Cd, Pb and Zn, due to the accidental emission during its testing operation. Any further contamination was not observed after regular operation of the Refinery.

• Korean journal of applied entomology
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• v.13 no.4 s.21
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• pp.209-216
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• 1974

Life history and control methods of Aphanostigma iakusuiense Kishida were studied during April to November, 1974, in the Naju pear orchard area, Cholla Namdo. The results are summarized as follows: 1. More than $60\%$ of wintering eggs were found at the height of 1.5 to 2.0m from the soil surface, with approximately $10\%$ at 0.5 to 1.5m and 1.5 to 2.5m respectively. 2. There was little difference in the size of egg masses and hatching ratio $(12.7-13.7\%)$ between the varieties of host trees, Mansamkil and Kooksoo. 3. Hatching was not observed until April 6, but hatches of $12.8\%$ on April 13 and $90.6\%$ on May 4 were found. 4. During the hatching season in early spring, 8 chemicals were applied to test effectiveness of control. C8514, Metasystox, Acar 338, and Parathion were more effective than either Sevin or Malix for control of this insect. 5. Highest populations of pear phylloxera ocurred from August 20 to September 20 at which time levels of eggs and larvae were simillar in abundance. 6. In tests for control of this insect after in paper bags, DDVP, Loxon, C8514, Sevin, and Binapacryl were more effective than either EPN or Otran. 7. Predacious mite, Protolaelape pygmaeus Miller, and several species of lady beetles (Coccinellidae) preying on this insect as natural enemies were collected. The predation ratio of mites varied according to region: that is 0.77 to $18.6\%$ in Bia Orchard; $7.88-48.7\%$ in Noan Orchard and almost none in Youngsanoo Orchard. 8. The varietal difference in fruit damage by this insect was in the order of Choseng Chuck, Kooksoo, followed by Sin Ko, Mansamkil, Keumchon Choo, and Changsimrang.