• Korean Journal of Organic Agriculture
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• v.19 no.2
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• pp.273-282
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• 2011

This study was conducted to investigate the effects of germanium (Ge) application types on the nutrient concentrations in soil and leaves and leaf characteristics in a 'Niitaka' pear orchard in 2004. Ge application included foliar application, fertigation in soils, trunk injection, and the three-combined application. All Ge treatedplots had lower soil $NO_3$-N, K, and Ca concentrations than those of control plot. Ge concentrations in Ge treated-soils were approximately 50 times higher than those of the control. Ge applications significantly increased area, dry weight, and specific weight in leaves compared to the control. Control treated-trees had greater K concentrations in leaves than the Ge treated-trees, which was oppositively observed for the leaf Ca; leaf Ca was higher on the Ge treated-trees than control. Leaf Ge concentrations were significantly higher on the Ge treated-trees compared to the control, except for the Ge fertigation. Ge concentrations in fruits were greater on the Ge-treated trees than the control trees.

• Journal of Environmental Science International
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• v.20 no.3
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• pp.361-372
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• 2011

This study analyzed the characteristics of stormwater runoff by rainfall type in orchard areas for two years. Effluents were monitored to calculate the EMCs and runoff loads of each pollutant. The runoff characteristics for nonpoint sources from vineyards were also inspected based on independent variables that affect runoff such as rainfall and rainfall intensity. The average runoff loads of each pollutant from vineyard_A and vineyard_B were found as follows: BOD 39.13 mg/$m^2$, COD 112.13 mg/$m^2$, TOC 54.98 mg/$m^2$, SS 1,681.8 mg/$m^2$, TN 18.29 mg/$m^2$, and TP 4.06 mg/$m^2$, which indicates that the COD's runoff load was especially high. The average EMCs from vineyard_A and vineyard_B, which represents the quality of rainfall effluent, were also analyzed: BOD 3.5 mg/L, COD 11.5 mg/L, TOC 5.2 mg/L, SS 211.7 mg/L, TN 1.774 mg/L, and TP 0.324 mg/L. This suggested that the COD, as an indicator of organic pollutants, is high in terms of EMCs as well. As rainfall increased, the EMCs of BOD, COD, TOC and SS kept turning upward. At a point, however, the high rainfall brought about dilution effects and began to push down the EMCs. Higher rainfall intensities led to the increase in the EMCs that displays the convergence of rainfall. Low rainfall intensities also raised pollutant concentrations, although the concentrations themselves were slightly different among pollutants.

• Korean Journal of Environmental Agriculture
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• v.3 no.2
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• pp.23-29
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• 1984

Agricultural soil samples collected from 121 sites (plastic film house 59, up-land 30 and orchard 32 sites) were evaluated by steam distillation and GLC-ECD analysis for organochlorine pesticides (${\gamma}-BHC$, heptachlor, p,p'-DDE, dieldrin, p,p'-DDD, and p,p'-DDT) in Jeollanam-Do area. Total residues of organochlorine pesticide in orchard, plastic film house and up-land were 0.415, 0.234 and 0.156ppm, respectively. Ninety-four percent of total residue was p,p'-DDT and its homologues (p,p'-DDE and p,p'-DDD). ${\gamma}-BHC$ was detected in all soil samples at $trace{\sim}0.050ppm$ range. Residue levels of organochlorine pesticide increased in the order of p,p'-DDE, ${\gamma}-BHC$, heptachlor, dieldrin, p,p'-DDT and p,p'-DDD.

• Applied Biological Chemistry
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• v.39 no.6
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• pp.488-493
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• 1996

As a first step of pesticide runoff studies, runoff losses of captafol were measured under natural rainfall conditions in apple orchard area. The maximum concentration of captafol was 180 ppb at 5 th sampling period when the rainfall occurred within 24 hours after captafol was applied, and the concentration of samples from other periods was below than 20 ppb. Total runoff loss of captafol was below 0.1%. About 10 fold of dilution factor was observed at the merging point with stream near outlet from orchard and about 50 fold was observed at the next merging point which is located further down. Therefore, captafol will not harm the aquatic organisms due to dilution factor$(10{\sim}50\;fold)$ and rapid hydrolytic degradation rate even when it was run off into a stream nearby.

• Korean Journal of Agricultural Science
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• v.47 no.2
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• pp.349-360
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• 2020

Fire-blight disease is a kind of contagious disease affecting apples, pears, and some other members of the family Rosaceae. Due to its extremely strong infectivity, once an orchard is confirmed to be infected, all of the orchards located within 100 m must be buried under the ground, and the sites are prohibited to cultivate any fruit trees for 5 years. In South Korea, fire-blight was confirmed for the first time in the Ansung area in 2015, and the infection is still being identified every year. Traditional approaches to detect fire-blight are expensive and require much time, additionally, also the inspectors have the potential to transmit the pathogen, Thus, it is necessary to develop a remote, unmanned monitoring system for fire-blight to prevent the spread of the disease. This study was conducted to detect fire-blight on pear trees using discriminant analysis with color information collected from a rotary-wing drone. The images of the infected trees were obtained at a pear orchard in Cheonan using an RGB camera attached to a rotary-wing drone at an altitude of 4 m, and also using a smart phone RGB camera on the ground. RGB and Lab color spaces and discriminant analysis were used to develop the image processing algorithm. As a result, the proposed method had an accuracy of approximately 75% although the system still requires many flaws to be improved.

• Korean Journal of Ecology and Environment
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• v.50 no.2
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• pp.254-265
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• 2017

To elucidate occurrence patterns of naturalized plants in agroecosystems, we surveyed flora in uplands, orchards and rice paddy fields in middle regions (Gyeonggi-do and Chungcheong-do) of Korea in summer and fall from 2013 to 2015. Our results showed that there are 77 species of naturalize plants in 54 genera and 20 families of vascular plants among total 420 species occurred in the agricultural areas composing 18.3% of naturalized index. Community compositions of both native and naturalized plants were different among agricultural types. We suggested that Cerastium glomeratum Thuill., Bidens frondosa L. and Erigeron philadelphicus L. are capable of dispersal to other regions based on our results with getting to broaden distribution of naturalized plants. The mean naturalized index was the highest in the upland (25.1%) followed by in the orchard (23.0%) and the paddy field (16.1%), while the mean number of naturalized species was the highest in the orchard (21.8 species) followed by in the upland (16.6 species) and paddy field (10.3 species). The numbers of naturalized plants in the orchard were increased along with increasing size of the agricultural land and decreasing ecological area rate. In addition, the number of native species was significantly correlated with the number of naturalized species in the upland. Our results would provide useful information to manage dispersion of naturalized plants in agricultural ecosystems.

• Research in Plant Disease
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• v.10 no.4
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• pp.272-278
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• 2004

The disease development of Anthracnose of sweet persimmon in relation to release of conida of Colletotrichum gloeosporioides were observed in a farmer's field located in Jinju from 1998 to 2002. The conidia started to release from early April and reached maximum in June to late July. The amount of conidia production reduced drastically from early August. The number of conidia trapped was closely related to amount of precipitation at the same period and number of new infections on the emerging branches and young fruits in orchard. The conidia released during the April was not effected to disease occurrence of persimmon tree but the spores produced from inoculum source after early May significantly important to the infection of the pathogen on emerging branch and this infection was directly related to infections on young fruits. Consequently the early infections on the branches brought severe occurrence of Anthracnose in the orchard. Most of the infected fruits were dropped in unripe state. The earlier infection caused the earlier fruit drop. The rate of fruit drop was reached up to 84.1% in August when the disease was occurred severely. Anthracnose of sweet persimmon also occurred in market shelf and storage warehouse. The anthracnose fruits are presumed to be infected while in orchard. Because the symptom formed on the fruit was too tiny to eliminate, the infected fruits were involved in storage boxes and anthracnose gradually developed in storage condition. The rate of diseased fruit observed in Jinju area were 1.2 to 1.6%.

• Korean journal of applied entomology
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• v.25 no.2 s.67
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• pp.63-70
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• 1986

Severity of incidence of white rot on apple fruit ranged from 5 to 16% and averaged 9% over major apple growing area in 1981. An isolate of Botryosphaeria ribis obtained from rotted apples developed lesions on leaves, branches and fruits of apple, pear, peach and grape in a series of wound inoculation test. B. ribis grew well on both potato sucrose agar and oatmeal agar. The best condition for vegetative growth on these two media was at $25{\sim}30^{\circ}C$ pH 4 and $10{\sim}15%$ sucrose content under light illumination. Rot development on fruit was first observed in the orchard at early August when sugar content in fruit reached 9.0%. Thereafter, number of rotted apples increased as sugar content increased. There was no correlation between the pH of juice of fruit and rot incidence. Infection on fruit began to occur as early as mid-June when young fruits were formed and infections were continued until harvest. When apple fruits were collected at 10-day intervals from the orchard beginning from early June and were wound-inoculated with B. ribis, rot lesion developed regardless of the stage of fruit growth. Incidence of white rot in the orchard was severe on Golden-delicious and Yukou, intermediate on Aoli, Fugi and Indo, and least on Jonathan and Red-delicious.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.1
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• pp.25-35
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• 2010

The periodic application effects of two different herbicides on soil physical properties were observed in a slightly hilly orchard of pear tree located on the southestern flank of the Palbong Mountain in Gongju Chungnam : (1) bare surface vegetation; (2) glyphosate-treated plot; (3) paraquat-treated plot. The slope of experimental plots ranged from 5.5%to 10.2%at an altitude of 125 mand 896 $m^2$ ($28m{\times}32m$) in area. The total respective rainfall events were 47, 52, 52 times during experimental period from 2006 to 2008, while approximately 65 percent of daily rainfall intensity from2006 to 2008 was less than 20 mm a day. The organic matter contents on the surface 15 cm soil ranging from1.23%to 1.84%in 2006 were changed into from1.35 %to 2.28%in 2008 in the order of control > glyphosate > paraquat > bare plot in 2008, indicating that the herbicide treatment influenced the accumulation organic matter in soil. The changes in soil particle contents showed that the loss of soil particles in top 5 cm soil depth was greater in a bare soil than in other treatments such as control, glyphosate, and paraquat-treated plot. The net changes in the bulk densities showed that there were little variations between May of 2006 and Nov. of 2008 even though there were some losses of the soil particles. The soil strength of the glyphosate-treated bare plots was much greater than those of other plots such as control, glyphosate, and paraquat plots. However the soil strengths in control plots were lower than those in the plots of glyphosate and paraquat treated ones.

• Korean Journal of Soil Science and Fertilizer
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• v.17 no.2
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• pp.161-166
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• 1984

The Cheju citrus orchards have been chemically fertilized with both phosphates high in Ca and Mg contents and potassium. The amount of chemical fertilizers consumed per unit area of cultivated land and the ratios of $P_2O_5$ and $K_2O$ to N in chemical fertilizers applied were much higher in the Cheju Island than those of the Korean mainland. These trends were particularly prominant in Southern Cheju where 70% of the Cheju citrus orchards are located. As the result of heavy applications of phosphate fertilizers, the available phosphorus of citrus orchard soils increased with increasing number of years under cultivation. The available phosphorus of sub-soil increased slightly with the number of years under cultivation compared to that of surface soil. Base saturation and pH increased with the number of years under cultivation, inasmuch as exchangeable bases such as Ca, Mg and K increased predominantly, but the cation exchange capacity did not vary in the citrus orchard soils.