• Journal of Korean Society of Forest Science
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• v.105 no.2
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• pp.231-237
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• 2016

This research was conducted in order to examine whether the Woodgrab short-wood logging method, most widely used logging method in Korea, is more favorable than other logging methods in terms of productivity and profitability. For the comparative purposes, whole-tree logging methods with cable yarding system using a swing yarder and a tower yarder were evaluated. The productivity and the profitability of the logging operations by the machine types on a L. kaempferi stand were estimated by simulating logging processes based on bucking patterns and the results were compared. As a result, the Woodgrab short-wood logging system showed the most favorable results in terms of skidding productivity and operating cost. On the contrary, the system was the least profitable among the three logging methods. Main reason is that while the system may be beneficial in terms of operation productivity, it is restricted to produce only short logs mainly for low quality raw materials such as pulp, bolts, etc. which are sold at cheap prices.

• Journal of Bio-Environment Control
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• v.17 no.2
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• pp.176-180
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• 2008

In days to calyx-flex stage test, flower development affected by light intensity, light duration and the prevailing temperature. As, 'Jacaranda' variety shorter in under 46 days of flower bud formation and 13 days of calyx-flex stage than the other variety with 'Queen Elizabeth' control variety. About cut flower only 'Grand Vicki Brown' (as within 46 days of flower formation, 13 days of calyx stage and 'Jacaranda', both with shorter plants than the other varieties produced cut flower classified as short and medium-stemmed cut flowers. 'Jacaranda', 'Vicki Brown', 'Golden Times', 'Champagne', 'Osiana', and 'Queen Elizabeth (control variety)' flowered earlier from 46.7 to 50.8 days from pruning. Flower development was likewise faster in all the above mentioned cultivars; while 'Tineke' had significantly delayed flower development reaching calyx-flex stage from 0.5 cm bud size after 51.0 days. The top ten high yielding varieties were 'American Orange', with a net income of P3,081,676.00; 'Yellow Island' with P1,572,874.00; 'Frosty Pink' with P1,085,183.00; 'Champagne' with P980,620.00; 'Coral Pink' with P959,669.00; 'Lara Pink' with P918,444.00; 'Lara Orange' with P714,252.00; 'Grand Gala' with P705,787.00; 'Golden Times' with P806,489.00; and 'Lady X' with P778,060.00 net returns.

• Journal of Korean Society of Forest Science
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• v.101 no.3
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• pp.426-433
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• 2012

This study was carried out for preliminary feasibility review to consult forest farmer, to make policy and to search improvement for Ligularia fischeri forest farm. The survey for eight Ligularia fischeri forest farmer in Inje-gun was conducted. And the case study was conducted with computing labor input, gross margin, net margin in each planting stages, which is contented each cultivating stage from creating to harvesting. B/C ratio, Net Present Value and Internal Rate of Return were used for profitability analysis. The results applied 3% of discount rate showed IRR 48.6%, B/C ratio 1.5 and NPV 41 million KRW, which means high profitability. Forest farming is early step in Korean forestry so that standard methods of cultivation for that haven't established yet, and differences among farmers in productivity are being. Establishing organized methods of cultivation in each stages and being political supports are essential for income generation to forest households, supply of safe food and rest place for urbanity.

• Journal of Korean Society of Forest Science
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• v.94 no.1 s.158
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• pp.21-25
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• 2005

In order to prevent the pine mushrooms, Tricholoma matsutake, from being damaged by the pine needle gall midges, Thecodiplosis japonensis, and thereby, to increase their production and improve their quality, a sprinkler system was installed on the mushroom field. A low-concentration insecticide (deltamethrin 1% EC, x2,000) was sprayed once at insects' most active time every day during the period of insects' adult occurrence and thereafter, the irrigation by ground water spraying was periodically enforced. Such a test was conducted at Yangyang-Gun, Kwangwon-do, Korea for 2 years from 2000 through 2001. The pine needle gall midges generally emerged for about 40 days from late May to early July. 50% emergence of them was about June 6, and peak emergence (more than 80%) was early or mid-June. Gall formation rate was 3.5% on average with this ground insecticide spraying, while 51.3% when not treated. Control effectiveness of this insecticide spraying was 92.3%, which was higher than 82.5% by the conventional injection of insecticide into tree stems. Pine mushrooms emerged for about 35 days from mid-September through earlier October, and around 80% of them did for about 15 days from late September through early October. As a result of the periodic ground water-spraying (30 mm per week) for 2 months (from August to October), the production of mushrooms increased by 74.3% (110% in terms of weight), with their quality improvement. The mushrooms produced from the treated stand by the spraying system were priced 8,670,000 wons per hectare, and thus, the net income deducting the facility and management cost was 4,310,000 wons, about 5% higher than value from the control stand. It was analyzed that this treatment was significantly cost effective when the facilities are used more than 5 years.

• Horticultural Science & Technology
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• v.29 no.2
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• pp.102-109
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• 2011

This research was conducted to establish efficient methods to control root-zone temperature of tomato plant when cultivated in perlite bag during the summer season. Tomato plants were grown with four selected treatments; covering irrigation pipe by aluminum insulation material (Insulate), discarding nutrient solution inside the irrigation line before each irrigation (Discard), skipping irrigation for two hours from 13:00 to 15:00 (Skip), or no treatment as a control (Non). Based on the analysis of plant development index, all plants with selected treatments grew more vigorous and vegetative in similar growth patterns. The discard treatment exhibited the best root-zone temperature control among the treatments. The discard treatment also resulted in the best root growth and above-ground growth, followed by skip, Insulate and Non. The total yields were obtained by the order of Insulate, Discard, Non and Skip. However the marketable yield was obtained by the order of Discard, Insulate, Skip and Non. The net incomes treated with Discard and Insulate were 9,687,600 and 9,396,000 Korean won per hectare, respectively, exhibiting higher incomes than that of Non. Therefore, it was concluded that insulation of the irrigation pipe and discarding nutrient solution inside the pipe before each irrigation were the most desirable and economical methods in terms of costs and yields.

• Journal of agriculture & life science
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• v.45 no.4
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• pp.95-103
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• 2011

Ninety five Hanwoo steers averaging 226kg of body weight were used to investigate the effect of dietary type on feed efficiency, carcass characteristics and economical analysis in Hanwoo feeding over 22 months. Treatments were composed of commercial formula feed (formula feed), TMR and Fermented-TMR (F-TMR). Intakes of dry matter and TDN were greater in the F-TMR than the other treatments during each growing and fattening phase (p<0.05). Although daily body gain of the F-TMR was lowest during the growing phase, but was 48% greater than those of other treatment during the finishing phase (p<0.05). Feed efficiency of the F-TMR was maintained constantly during whole growing and fattening phases. Carcass weight and rib-eye area of the F-TMR were greatest (p<0.05) among treatments. However, meat yield index and the rate of grade A in meat yield were highest in the formula feed having the thinnest back fat. Marbling score was hugely (p<0.05) increased when steers fed F-TMR, and therateofgrade 1+andoverinmeatqualitywas96%intheF-TMR. Although feed cost in the F-TMR was increased by 40% compare to the formula feed, but net income was increased by 29% due to improvement of meat quality and body gain.

• Journal of Internet of Things and Convergence
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• v.9 no.6
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• pp.93-98
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• 2023

In paddy rice farming, water management is a critical task. To suppress weed emergence during the early stages of growth, fields are deeply flooded, and after transplantation, the water level is reduced to promote rooting and stimulate stem generation. Later, water is drained to prevent the production of sterile tillers. The adequacy of water supply is influenced by various factors such as field location, irrigation channels, soil conditions, and weather, requiring farmers to frequently check water levels and control the ingress and egress of water. This effort increases if the fields are scattered in remote locations. Automated irrigation systems have been considered to reduce labor and improve productivity. However, the net income from rice production in 2022 was about KRW 320,000/10a on average, making it financially unfeasible to implement high-cost devices or construct new infrastructure. This study focused on developing an IoT-Based irrigation valve that can be easily integrated into existing agricultural infrastructure without additional construction. The research was carried out in three main areas: Firstly, an irrigation valve was designed for quick and easy installation on existing agricultural pipes. Secondly, a power circuit was developed to connect a low-power Cat M1 communication modem with an Arduino Nano board for remote operation. Thirdly, a cloud-based platform was used to set up a server and database environment and create a web interface that users can easily access.

• Korean Journal of Organic Agriculture
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• v.24 no.4
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• pp.759-771
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• 2016

We compared the fruit set and the quality of the 'Niitaka' pear (Pyrus pyrifolia Nakai) among flowers pollinated by two bee species (Apis mellifera and Bombus terrestris) and pollinated artificial. The artificial pollination rate was 1.3 to 1.9 times higher than the bee pollination rate. Moreover, the artificially pollinated flowers produced fruit that was 5 to 10% higher in weight, 2 to 3% larger in size, and had a higher fruit shape index (L/D) than fruit pollinated by the bees. On economic analysis, net profit from insect pollinator was 93.5 to 97.1% of net profit from artificial pollination. Therefore, artificial pollination is more efficient than bee pollination in 'Niitaka' pear. However, regarding fruit quality and net profit, these results suggest that bee pollination can be an good alternative to artificial pollination in 'Niitaka' pear.

• Korean journal of food and cookery science
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• v.7 no.2
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• pp.89-95
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• 1991

The effects of lactic acid bacteria on the chemical and microbial changes of fermented kimchi at various temperatures were studied. Kimchi was homogenized and was sterilized by ultra violet (UV), then Lactobacillus plantarum, Leuconostoc mesenteroides, Pediococous acidilactici, Lactobacillus brevis and the mixture of these bacteria inoculated on sterilized kimchi, respectively. The measurement of alcohol by gas chromatography, and changes of sugar content and total viable count were investigated and palatability test was carried while inoculated kimchi was fermented at $30^{\circ}C$, $21^{\circ}C$ and $7^{\circ}C$. Ethyl alcohol was detected by GC in sample I (original Kimchi homogenate), III(inoculated Leu. mesenteroides), V(inoculated with Lac. brevis), then especially, more content were detected at $14^{\circ}C$. Sugar content reduced in accordance with fermentation proceeding. Total viable count increased at early fermentation stage, but thereafter decreased slowly. In the result of palatability test, sample I was the highest at all temperatures, sample III and IV (inoculated with mixed lactic acid bacteria) was the following in that kimchi odor and taste and the temperature.

• Journal of the Korea institute for structural maintenance and inspection
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• v.20 no.4
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• pp.59-67
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• 2016

Concrete is a very useful construction material for the sealing disposal of hazardous substances. In general, mass concrete is applied to these structures. And, the mineral admixtures are recommended for the long term performance. Calcium leaching could be happened due to the contact with pure water in underground structures. Thus, it is needed to evaluate the resistance of calcium leaching for concrete mixed with mineral admixtures. From the test results, the mineral admixtures are effective to the improvement of long term compressive strength and chloride diffusion coefficient in concrete members. When calcium leaching is happened, however, the reduction of compressive strength and chloride penetration resistance is severe than OPC case, the micro pore distribution is adversely affected. Consequently, when the mineral admixtures are applied to underground structures which is exposed to calcium leaching environment, it is desirable to reduce water-to-binder ratio, to expose after the sufficient pozolanic reaction, and to use BFS than FA.