• The Korean Journal of Pesticide Science
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• v.7 no.3
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• pp.228-237
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• 2003

Temporary control schedules were tested at sweet persimmon orchards to development new control programs to meet the quarantine repuirements of America in 2001 and 2002. The 'MRL-type control orchards' were sprayed with chemicals which were possibly adaptable to the pome trees in America. A control schedule consisted of those chemicals registered for persimmon in Korea was incorporated in the 'domestic-type control orchards'. The efficacy of these two control type against insect pests was compared with that of a conventional control schedule. In 2001, MRL orchard and domestic orchard were sprayed 7 and 6 times, and two conventional orchards were 6 and 9 times, respectively. In 2002, acaricide was added once to the MRL orchards at late September to reduce the density of mites on harvested fruits. However no insecticide to plant bug control could be applied to the MRL orchards, because no insecticide against bugs was registered for pome trees in America. This resulted in 7 times of applications in MRL and domestic orchards. The conventional orchard was sprayed 9 times. Only the occurrence of the peach pyralid moth, Dichocrocis puntiferalis (PPM) out of 4 quarantine inset species was observed. The PPM was observed during growing season in MRL, domestic, and conventional orchards. However no fruits damaged by PPM larvae were observed after mid October and after harvest. In 2002 only 1 fruit out of 1,350 fruits inspected in June was damaged by the larvae of PPM at MRL orchards. A fungus-feeding mites and collembolan were under calyx of vested fruits. In 2001 they were found on 45.3% of harvested fruits at MRL orchard. However the percentage of fruits with mites in 2002 was greatly reduced to 3.5% at MRL orchard, presumably because of a added application of acaricide at late September. However percentage of fruits damage by hemipteran bugs at harvesting time was quite high 11.3 % at MRL orchards, because no application of insecticide against plant bugs.

• Korean Journal of Agricultural and Forest Meteorology
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• v.3 no.1
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• pp.44-54
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• 2001

This study was conducted to estimate microclimate of natural deciduous forest in national forest of Pyungchang, Kangwon province and to investigate the effects of the microclimatic conditions on the periodic annual increment of diameter by site types. In this study, site was first classified by nine types considering both elevation (higher than 1,000 m, 700∼1,000 m, and lower than 700 m) and topographical conditions (ridge, slope and valley). For each of site types, diameter growth was measured by using increment borer and periodic annual increment of diameter was then analyzed. A topoclimatological technique, for estimating microclimatic conditions, which make use of empirical relationships between the topographical factor and the climatic normals in the study area was applied to produce monthly mean, maximum and minimum temperatures, relative humidity, precipitation and hours of sunshine. From these monthly estimtes, 17 weather variables such as warmth index, coldness index, index of aridity etc. which affect the diameter growth were computed for each of site types. The periodic annual increment of diameter was then correlated with and regressed on the 17 weather variables to examine effects of microclimatic conditions on the diameter growth by site types. From the correlation analysis, it was found that the diameter growth by site types was positively correlated with all of 17 weather variables except the warmth index. Especially, the conditions such as high relative humidity and large amount of sunshine hours provide favorable environment for the growth of diameter. On the other hand, it was also found that diameter growth was negatively iufluenced by warmth index. According to the regression analysis, the periodic annual increment of diameter could be well predicted by index of aridity and mean relative humidity for the growing season.

• Korean Journal of Agricultural and Forest Meteorology
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• v.11 no.4
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• pp.162-173
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• 2009

Information on the expected geographical shift of suitable zones for growing crops under future climate is a starting point of adaptation planning in agriculture and is attracting much concern from policy makers as well as researchers. Few practical schemes have been developed, however, because of the difficulty in implementing the site-selection concept at an analytical level. In this study, we suggest site-selection criteria for quality Fuji apple production and integrate geospatial data and information available in public domains (e.g., digital elevation model, digital soil maps, digital climate maps, and predictive models for agroclimate and fruit quality) to implement this concept on a GIS platform. Primary criterion for selecting sites suitable for Fuji apple production includes land cover, topography, and soil texture. When the primary criterion is satisfied, climatic conditions such as the length of frost free season, freezing risk during the overwintering period, and the late frost risk in spring are tested as the secondary criterion. Finally, the third criterion checks for fruit quality such as color and shape. Land attributes related to these factors in each criterion were implemented in ArcGIS environment as relevant raster layers for spatial analysis, and retrieval procedures were automated by writing programs compatible with ArcGIS. This scheme was applied to the A1B projected climates for South Korea in the future normal years (2011-2040, 2041-2070, and 2071-2100) as well as the current climate condition observed in 1971-2000 for selecting the sites suitable for quality Fuji apple production in each period. Results showed that this scheme can figure out the geographical shift of suitable zones at landscape scales as well as the latitudinal shift of northern limit for cultivation at national or regional scales.

• Korean Journal of Agricultural and Forest Meteorology
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• v.19 no.4
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• pp.223-231
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• 2017

This study was conducted to determine the impact of elevated temperature based on climate change scenario on growth and bulb quality of extremely early-maturing onion (Allium cepa L. cv. Singsingball) in the temperature gradient tunnels. There were treated with 3 groups, one is a control group (ambient temperature, mean temperature at $9.8^{\circ}C$), another ambient temperature $+2^{\circ}C$ (mean temperature at $12.0^{\circ}C$), and the other ambient temperature $+5^{\circ}C$ (mean temperature at $14.3^{\circ}C$). Compared with the control, plant height, neck diameter, leaf area, top fresh weight and dry weight were significantly increased at ambient $+2^{\circ}C$ temperature. Bulb diameter and bulb weight was highest at ambient $+2^{\circ}C$ temperature (mean temperature at $12.0^{\circ}C$) during the growth period. Bulb/neck diameter ratio, over 2.0 a good indicator of development of bulb, increased rapidly at ambient $+2^{\circ}C$ temperature. This result suggests that extremely early-maturing onion (Allium cepa L. cv. Singsingball) could maintain the higher productivity and bulb quality at ambient $+2^{\circ}C$ temperature. On the contrary, $5^{\circ}C$ higher than atmospheric temperature shows negative effects on yields under a future climate change scenario.

• Journal of Sericultural and Entomological Science
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• v.24 no.2
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• pp.43-54
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• 1983

In a field trial, the influence was studied by measurement of growth and leaf yields and chemical composition (in organic cations and anions and total nitrogen) with two nitrogen dressings (lower nitrogen treatment 25kg and higher nitrogen treatment 75kg urea/10a as the summer fertilizer) after the summer cutting. The results were as follows; 1. With increasingn nitrogen dressing, branch length and weight were enchanced. The fresh weight of leaves was higher to be 273.6kg/10a in the higher nitrogen treatment than in the lower nitrogen treatment on 20 September. 2. The moisture content of leaves lasted above 73% until on 30 August. Afterward it decreased sharply upto 63% on 20 September. In higher nitrogen treatment it was higher about 0.1∼1.8% than in lower nitrogen treatment. The increasing nitrogen dressings combined with leaf condition led to be soft until on 10 October. 3. Dry matter weight of leaves started decreasing around on 10 September, whereas that of branches increased until around 30 September indicating that the dry matter moved to branch and root from leaves. 4. The increase in Ca$\^$2+/ content was particularly evident, whereas the K$\^$+/ and Mg$\^$2+/ decreased with growth. The Ca$\^$2+/ content was much higher in the high nitrogen treatment than in the low nitrogen treatment. 5. With rapid decrease in total nitrogen and water in the leaves around the end of August, the Ca$\^$2+/ and Cl$\^$-/ which were higher in the lower part moved up to the upper part. Whereas the K$\^$+/, H$_2$PO$_4$$\^$-/ and SO$_4$$\^$2-/ which were higher in the upper part moved down to the lower part. 6. Total nitrogen content decreased sharply 3,200me/kg DM to 2,000me/kg DM at the end of August changing the maxmium content of total nitrogen from upper to lower part in the low nitrogen treatment on 12 September and in the high nitrogen treatment on 22 September, and an apex of branches was died and fallen 10 days after respectively. 7. The sum of cation in leaves (∑C) increased from 1400me/kg DM to 1600me/kg DM with growth, wherease that of anions (∑A) was approximatly the same during the whole growing season. As the result, the ionic balance (C-A) increased from 1000me/kg DM to 1200me/kg DM. 8. ∑C, ∑A and (C-A) were higher in the high nitrogen treatment than in the low nitrogen treatment due to be much higher of Ca$\^$2+/ content and higher of NO$\^$-/$_3$, SO$\^$2-/$_4$ and H$_2$PO$_4$$\^$-/ content.

• Journal of Sericultural and Entomological Science
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• v.14 no.2
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• pp.125-154
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• 1972

The major purpose of this survey is to collect the related information on technical aspects for solving the problems which are facing producing farmers and regions, provide scientific facts to farmers related personals and institutions and aimed at contributing the development of sericultural sector in Korea. The results are as follows; (1) The area of mulberry field per a farmer which was selected as sample ranges from 3.0 to 370a with its average 45. 1a. And yet, the average of new cultivated areas is above than that of ordinary ones by 56.3 to 33.8a. The largest area is Honam hill area with 101. 1a and e smallest is Muzinzang with 20.8a. Shortly, a large number of farmer belongs to 11 to 50a with 66.5 per cent. (2) The ratio of clay and loam soils which are inadequte for growing of mulberry trees is 28.3 per cent and particulary high in new cultivated area with 36.2 per cent. And yet, base soil is occupied with 45 per cent of heavy clay and particularly even 54.2 per cent in new cultivated area. On the other hand, the number of areas which the contents of organic matters is relatively low, with 48.2 per cent is near the half, but the ratio of mulberry fields which seems to contain organic matters abundantly is only 7.2 per cent. (3) The varieties of mulberry trees are Ilgirae, Gaeryangseoban, Suwonsang No.4 and Nosang. The ,ratio of the varieties are 33.3%, 25.7%, 18.0% and 10.5%, respectively. Consequently the four varieties enumerated above occupies 93.5 per cent. (4) The mulberry fields are almost composed of exclusive mulberry fields and its ratio was 92.3 per cent. The number of planted trees per 10a arrange from 480 to 1,390 and its average is 846. But most of them nearly belong to 701 to 1,000 with 91.3per cent. (5) The second year's autumn after planting is generally adopted as the first harvesting season, and its ratio is 73.0 per cent, but autumn of the years and next spring are not few, and its ratio are 12.7 and 8.7 per cent. The first harvesting method is relatively normal with 88.8 per cent of ratio. From the viewpoint of harvesting method, picking leaves was applied with 97.7 per cent of ratio in young larvae rearing and picking shoot and picking shoot after harvest with branches were applied with 80.0 per cent of ratio in grown larvae rearing. The ratio of applying the harvesting method of picking leaves were 97.7 and 91.7 per cent in young larva and grown larva in autumn rearings. But there was also picking leaves absolutely with 7.1 per cent of ratio(Chunwon was 47 per cent) and yet, the farmers applying cutting before shooting in spring was no more than 17.8 percent.

• Korean Journal of Weed Science
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• v.18 no.2
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• pp.128-135
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• 1998

The experiment was carried out to obtain basic informations on sod culture using water foxtail in apple orchard at Kyeongbuk Provincial RDA in 1996 to 1997. Period of seedling emergence varied with sowing time and accumulative temperature. Sowing at Nov. 25 required longer than 100 days, while it needed only 8 days when water foxtail was sowed at Sep. 20. In a view of accumulative temperature, sowing at March 15 needed $139^{\circ}C$ but it required about $1,000^{\circ}C$ at August 10. This result showed that the seed of water foxtail has strong summer-dormancy in natural condition. Water foxtail had s-shape growth curve during growing season, and growth rate was the highest from March to May in this period. Plant height increased 2 times and 4 times for dry weight from March 20 to April 20. However, growth was decreased by summer depression after May. Major weeds in apple orchard were horseweed, akino-nogeshi and shepherd's-purse. These species were suppressed by the dominance of water foxtail. Water foxtail as a cover plant could be used for a method of weed control instead of herbicide in apple orchard.

• Korean Journal of Weed Science
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• v.31 no.1
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• pp.34-40
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• 2011

Cover crop can be used to suppress weeds by competition for light and nutrient. Objective of this study was to evaluate the effectiveness of legume cover crops on change of weed community in no-till corn cultivation. Two legume cover crops, hairy vetch and crimson clover were grown in the field, and succeeding corn was sown on 4 May, 2010. The distribution of weed was surveyed at 15 April, 1 June, and 20 August. At 15 April, the weed biomass in hairy vetch field was higher than in crimson clover field. The dominant weeds were Capsella bursa-pastoris L. and Stellaria aquatica L. in hairy vetch and crimson clover fields, respectively. At vegetative stage of corn, occurred weeds in hairy vetch and crimson clover fields were four and six species, respectively, while the weed was occurred with nine species in conventional. Also the dry weight of weed was decreased by 82 and 75% in hairy vetch and crimson clover fields compared to conventional. On the other hand, after harvest of corn, occurred weed in hairy vetch, crimson clover and conventional was five, four and five species, respectively. Dry weight percentage of occurred weed in conventional was 23.5%, and the value was higher than 13.8 and 14.7% in hairy vetch and crimson clover fields, respectively. Stellaria aquatica L. as winter annual weed only occurred in cover crop field during corn growing season. It is these possibilities that low soil temperature and light interception by soil cover of legume cover crop.

• Journal of The Korean Society of Grassland and Forage Science
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• v.36 no.2
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• pp.81-88
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• 2016

This study was conducted to find out the effects of Improvement of Botanical Composition Technology (IBCT) on the forage production and ecological characteristics in a Rumex acetosella-dominated hilly pasture in Pyeongchang, in a period from August 2013 to the end of growing season in October 2015. $2MT\;ha^{-1}$ limestone was applied in August 2013 and April 2014. Liming significantly increased soil pH from 4.69 to 5.47 and then the soil pH consistently hovered at 4.91~4.98. For every grazing time, plant height was found to be higher with the application of IBCT as compared with the control. After grazing, no significant difference in plant height was found between the IBCT group and the control. Changes in the botanical composition of grassland can be affected by a lot of circumstances, but application of IBCT decreased Rumex acetosella from 12% to 2%, while also increasing the proportion of pasture. In relation to the botanical composition of grass, orchardgrass and timothy showed the highest percentages throughout the whole study period. The proportion of Kentucky bluegrass increased over time while tall fescue steadily decreased. The totals for grazing days were 58 in 2014 and 55 in 2015. Average herbage dry matter intake was $7,848kg\;ha^{-1}$ in 2014 and $6,941kg\;ha^{-1}$ in 2015. Due to the application of IBCT, dry matter productivity showed a significant increase of 59% during the first grazing period in 2014 (3,437 kg ha and 5,460 kg ha in control and IBCT). In 2015, the total dry matter yield of the IBCT group was 51% greater than the control ($5,742kg\;ha^{-1}$ and $8,685kg\;ha^{-1}$ in control and IBCT). Under acidic soil conditions, red sorrel can grow more strongly than grasses because it has better tolerance in dry and acidic conditions. Therefore, constant management is required in order to keep red sorrel from dominating the hilly pasture. In this study, the application of IBCT was able to effectively control weeds at all points. As a result, total management, including improvement of soil, overseeding, and application of selective herbicide and fertilizer, is needed to maintain excellent grassland conditions due to the limiting effects of environmental factors on grassland productivity.

• Journal of Korean Society of Forest Science
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• v.12 no.1
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• pp.1-11
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• 1971

The present study was carried out in order to investigate seasonal variation in tannin, sugar and protein contents of persimmon fruits, Five varieties of Diospyros kaki Thunberg, i. e, Buyoo, Wolha, Kapjubackmok, Pyungmuhek, Heuksi, and Goyom (Diospyros Lotus Linne var. typica Makino) growing in Jeonbug area were used as the experimental material. The result are summarized as follow; 1. Maximum tannin contents were 4% in Buyoo, 5.46% in Wolha, 5.4l% in Kapjubackmok, 5.1 % in Pyungmuhek, 9.2% in Heuksi, and 26.1% in Goyom, respectively. Therefore, Heuksi and Goyom were considered to be the most useful as tannin material. 2. The most suitable season for tannin extraction was thought to be July with most varieties but it was August with Goyom. 3. The total sugar contents seemed to increse linearly. Linear regressions are as follows. Buyoo ; $\hat{Y}=0.2394x+3.861$ Wolha ; $\hat{Y}=0.3093x-1.148$ Kapjubackmok ; $\hat{Y}=0.3173x-1.3708$ Pyungmuhek ; $\hat{Y}=0.2796x+0.982$ Heuksi ; $\hat{Y}=0.3233x-3.242$ Goyom ; $\hat{Y}=0.1555x-4.780$ 4. Average crude protein contents of fruits through the year were 5.32% in Buyoo, 4.97% in Kapjubackmok, 4.49% in Goyom, 4.11% in Wolha, 4.02% in Heuksi, and 3.6% in Pyungmuhek, respectively. 5. The crude protein contents tend to decrease gradually after fruit setting.