• Asian-Australasian Journal of Animal Sciences
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• v.24 no.6
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• pp.867-874
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• 2011

This paper describes the results of a survey aimed at characterizing smallholder pig production systems in northern Lao PDR. A total of 341 households from five Northern provinces were interviewed in the survey. Village meetings and individual interviews, using a semi-structured questionnaire, were used to collect information. Three main pig rearing systems, free-scavenging, semi-scavenging and confinement (enclosures and pens), were found in the survey areas. These systems were practiced differently by smallholders depending on the level of intensity of crop production, ethnicity and purpose of keeping pigs. The confinement system was mainly practiced by Lao-Tai and Tibeto-Burman groups, who mainly bought piglets and fattened these pigs for sale. In contrast, the Mon-Khmer and Hmong-Mien reared pigs in free-scavenging and semi-scavenging systems, and usually keep sows for piglet production. The main factors that affected the changes in rearing systems were found to be level of intensity of crop production, local regulations and outbreaks of disease. The main constraints found in smallholder systems were outbreaks of disease, high mortality of piglets and the slow growth rate of fattening pigs.

• Agribusiness and Information Management
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• v.6 no.1
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• pp.37-44
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• 2014

This study was conducted to evaluate light intensity and uniformity of two SMD (surface-mount device) type LEDs for protected crop production. A low-power (0.1 W) and a high-power (1 W) LEDs were selected and the intensity and uniformity was evaluated at different vertical (height) and horizontal (distance) intervals. When the horizontal interval of the LED bar was fixed, the light intensity increased and the uniformity decreased as the height decreased. At the 30~40 cm heights, 20~30% of the area showed $200{\pm}20{\mu}molm^{-2}s^{-1}$. As the horizontal distance of the LED bars increased, while the uniformity increased as well, the light intensity decreased. At the distances of 6~10 cm, 17~23% of the area showed $200{\pm}20{\mu}molm^{-2}s^{-1}$. When the LED bars were added to the sides, the light intensity and uniformity were generally improved. Results showed that the light intensity and uniformity depended on the height and interval of the LED bulbs; therefore, optimum arrangement for the crops interested should be determined through experiments.

• Korean Journal of Soil Science and Fertilizer
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• v.50 no.6
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• pp.674-683
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• 2017

The frequency and intensity of soil moisture stress associated with climate change has increasing, and the stability of field crop cultivation has decreasing. This experiment was conducted to investigate the effect of soil moisture management method on growth and yield of corn. Soil moisture was managed at the grade of WSM (wet soil moisture, 34.0~42.9%), OSM (optimum soil moisture, 27.8~34.0%), DSM (dry soil moisture, 20.3~27.8%), and ESM (extreme dry moisture, 16.6~20.3%) during V8 (8th leaf stage)-VT (tasseling stage). After VT, irrigation was limited. The treated amount of irrigation was 54.1, 47.7, 44.0 and 34.5% of total water requirement, respectively. The potential evapotranspiration during the growing period was $3.29mm\;day^{-1}$, and upward movement of soil water was estimated by the AFKAE 0.5 model in the order of ESM, DSM, OSM, and WSM. We could confirm this phenomenon from actual observations. There was no significant difference in leaf characteristics, dry matter, and primary productivity depending on the level of soil moisture, but leaf development was delayed and dry weight decreased in DSM. However, dry weight and individual productivity of DSM increased after irrigation withdrawal compared to that of OSM. In DSM, ear yield and number of kernels per ear decreased, but water use efficiency and harvest index were higher than other treatments. Therefore, it is considered that the soil moisture is concentratedly managed before the V8 period, the V8-VT period is controlled within the range of 100 to 500 kPa (20.3~27.8%), and no additional irrigation is required after the VT.

• Korean Journal of Organic Agriculture
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• v.19 no.1
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• pp.23-38
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• 2011

● The current world is suffering abnormal climate caused by global warming. The main cause of global warming is greenhouse gas such as carbon dioxide. The carbon labeling system and carbon traceability system being pushed ahead in the agricultural sector is the policy for responding to climate change to reduce greenhouse gas emissions. To make this policy more effective and enhanced, the amount of carbon emissions should be calculated based on the kind of crops or the various businesses in the agricultural sector. Therefore, in order to estimate the accurate amount of carbon emissions, it is necessary to establish carbon dioxide emission intensity of various agricultural materials added onto the agriculture, and to calculate the amount of carbon dioxide emission for each crop according to agricultural production. The purpose of this study is to establish the amount of emission, emission per agricultural materials, of agricultural materials being added for crop production as a basic step, and emission intensity which can be used in the future market in order to estimate accurate amount of carbon emission in all the policies being promoted in the agricultural sector. Therefore, in this study, in order to build LCI D/B about organic fertilizers among many organic materials added onto the organic agriculture sector, one leading company in organic fertilizer production was selected and LCA was conducted for this leading company. We had to build the intensity and integrated average concept of intensity upon the two cases once production farmers for their own consumption and farms besides organic fertilizer company were categorized even if it's little amount. But in this study, individually produced organic fertilizers were excluded. Calculated results are following. Carbon emission of mixed expeller cake fertilizer in organic fertilizer was 1,106,966.89kg-$CO^2$ and emission intensity was 0.01606kg-$CO^2$, respectively. Total emission of mixed organic fertilizers was 241,523.2kg-$CO^2$ and emission intensity was 0.01705kg-$CO^2$. And total emission of organic compound fertilizers was 94,592.66kg-$CO^2$ and emission intensity was 0.01769kg-$CO^2$, respectively.

• Korean Journal of Agricultural Science
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• v.38 no.4
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• pp.747-752
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• 2011

Wireless technology has enabled farmers monitor and control protected production environment more efficiently. Utilization of USN (Ubiquitous Sensor Network) devices also brought benefits due to reduced wiring and central data handling requirements. However, wireless communication loses signal under unfavorable conditions (e.g., blocked signal path, low signal intensity). In this paper, performance of commercial wireless communication devices were evaluated for application to protected crop production. Two different models of wireless communication devices were tested. Sensors used in the study were weather units installed outside and top of a greenhouse (wind velocity and direction, precipitation, temperature and humidity), inside ambient condition units (temperature, humidity, $CO_2$, and light intensity), and irrigation status units (irrigation flow and pressure, and soil water content). Performance of wireless communication was evaluated with and without crop. For a 2.4 GHz device, communication distance was decreased by about 10% when crops were present between the transmitting and receiving antennas installed on the ground, and the best performance was obtained when the antennas were installed 2 m above the crop canopy. When tested in a greenhouse, center of a greenhouse was chosen as the location of receiving antenna. The results would provide information useful for implementation of wireless environment monitoring system for protected crop production using USN devices.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.168-168
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• 2022

According to the 5th Climate Change Report, global average temperature in 2081~2100 will increase 1.8℃ based on RCP 4.5 and 3.7℃ based on RCP 8.5 from the current climate value (IPCC Working Group I AR5). As temperature is expected to increase due to global warming and the intensity and frequency of rainfall are expected to increase, damage to crops is expected, and countermeasures must be taken. This study intends to evaluate rice growth in terms of nitrogen utilization efficiency according to future climate change conditions. In this experiment, Oryza sativa cv. Shindongjin were planted at the SPAR facility of the NICS in Wanju-gun, Jeollabuk-do on June 10, and were planted and grown according to the standard cultivation method. Cultivation conditions are high temperature, high CO₂ (current temperature+4.7℃·CO₂ 800ppm), high temperature (current temperature+4.7℃·CO₂ 400ppm), current climate (current tempreture·CO₂ 400 ppm). Nitrogen was varied as 0, 9, 18 kg/10a. The N content and C/N ratio of all rice leaves, stems, and seeds increased at high temperature, and the N content and C/N ratio decreased under high temperature and high CO₂ conditions com pared to high temperature. Compared to the current climate, NUE increases by about 8% under high temperature and high CO₂ conditions and by about 2% under high temperature conditions. This seems to be because the increase in temperature and CO₂ induced the increase in biomass. ANUE related to yield decreased by about 70% compared to the current climate under high temperature conditions, and decreased by about 45% at high temperature and high CO₂, showing a tendency to decrease compared to high temperature. This appears to be due to reduced fertility and poor ripening due to high temperature stress. However, as the nitrogen increased, the number of ears and the number of grains increased, slightly offsetting the production reduction factor.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.40 no.5
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• pp.543-547
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• 1995

This study was conducted to light intensity and night interruption on leaf production in perilla. Using two cultivars ; og-dong and Yeup-sil. The present studies were conducted to investigate effect of the light intensity and night interruption for prolongation of vegetative growth by flowering inhibition in the National Honam Crop Experiment Station, R. D. A, Iri, Korea. The results are summarized as followes, varietal differences of days to flower initiation were not significant by the light intensity and night interruption, however differences of days to flower initiation light intensity or night interruption treatment were higly significant. Flowering of perilla was prolongated in high light intensity and in long night interruption. Between the factors treated flowering of perilla was more influenced by light intensity than night interruption. Days to flower initiation of perilla were light intensity(0.5∼1 Lux) in 30 mins night interruption, however 3∼10 light intensity in 60 mins night interruption and 30∼100 Lux light intensity in 10, 30, 60 mins night interruption treatment were not flowering. Plant height, leaf area and dry weight of perilla were the highest in 30∼100 Lux light intensity treatment than in the other treatments. The results would be avaliable establish year-round production methods for low cost of perilla leaf.

• Korean Journal of Agricultural Science
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• v.38 no.4
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• pp.753-759
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• 2011

Protected crop production has been popular in Korea as well as in other countries. Intensive and continuous monitoring and control of the environment, which is labor- and time-consuming, is critical for stable crop productivity and profitability, otherwise damage could be happened due to unfavorable ambient and soil conditions. In the study, potential utilization of smartphone and remote access application in protected crop production environment was investigated. Tested available remote access applications provided functions of mouse click (left and right buttons), zooming in and out, and screen size and color resolution control. Wi-Fi data communication speeds were affected by signal intensity and user place. Data speeds at high (> -55 dBm), medium (-70~-56 dBm), and low (< -71 dBm) signal intensity levels were statistically different (${\alpha}=0.05$). Means of data communication speed were 6.642, 4.923, and 2.906 Mbps at hot spot, home, and office, respectively, and the differences were significant at a 0.05 level. Smart phone and remote access application were applied successfully to remote monitoring (inside temperature and humidity, and outside precipitation, temperature, and humidity) and control (window and light on/off) of green house environment. Response times for monitoring and control were less than 1 s at all places for high signal intensity (> -55 dBm), but they were increased to 1 ~ 10 s at home and office and to 10 ~ 30 s at hot spot for low signal intensity (< -71 dBm) for Wi-Fi. Results of the study would provide useful information for farmers to apply these techniques for their crop production.

• Journal of Biosystems Engineering
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• v.36 no.4
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• pp.279-284
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• 2011

Protected vegetable production area is greater than 26% of the total vegetable production area in Korea, and portion of protected production area is increasing for flowers and fruits. To secure stable productivity and profitability, continuous and intensive monitoring and control of protected crop production environment is critical, which is labor- and time-consuming. Failure to maintain proper environmental conditions (e.g., light, temperature, humidity) leads to significant damage to crop growth and quality, therefore farmers should visit or be present close to the production area. To overcome these problems, application of remote monitoring and control of crop production environment has been increasing. Wireless monitoring and control systems have used CDMA, internet, and smart phone communications. Levels of technology adoption are different for farmers' needs for their cropping systems. In this paper, potential of wireless remote monitoring of protected agricultural environment using CDMA SMS text messages was reported. Monitoring variables were outside weather (precipitation, wind direction and velocity, temperature, and humidity), inside ambient condition (temperature, humidity, $CO_2$ level, and light intensity), irrigation status (irrigation flow rate and pressure), and soil condition (volumetric water content and matric potential). Scenarios and data formats for environment monitoring were devised, tested, and compared. Results of this study would provide useful information for adoption of wireless remote monitoring techniques by farmers.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.65 no.4
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• pp.468-476
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• 2020

This study was performed to establish light intensity conditions for producing stem cuttings for aeroponic systems suitable for seed potato production using a closed-type plant production system. Shoot tip cultured plantlets of 'Sumi' and 'Chubaek' potato (Solanum tuberosum L.) were acclimatized, cuttings were collected, and stem cuttings were planted. The seedlings were raised for 40 days at different LED light intensities (60, 120, 180, and 240 μmol·m^-2·s^-1), and were cultivated in an aeroponic system for 80 days. When stem cuttings were raised at 60 μmol·m^-2·s^-1 LED light intensity, the plant height was the longest, at 17.3 cm for 'Sumi' and 16.1 cm for 'Chubaek', and the number of nodes was the highest in both cultivars. The higher light intensities, produced smaller plants with fewer nodes. The leaf areas, SPAD values, and Fv/Fm values differed slightly between cultivars. The fresh weight of stem cuttings, and the production rate of healthy stem cuttings were the highest at 60 μmol·m^-2·s^-1. In the aeroponic system, seedlings raised at 60 μmol·m^-2·s^-1 with LED light intensity showed a difference between the cultivars, but the fresh weight of stems and leaves above the planting plate was the heaviest. In addition, below the planting plate the stem cuttings were longest and the root weight was heaviest at 60 μmol·m^-2·s^-1 LED light intensity. The number of stolons also differed between cultivars, but was greatest for seedlings raised at 60 μmol·m^-2·s^-1 LED light intensity, at 4.2/plant for 'Sumi' and 7.7/plant for 'Chubaek'. At 60 μmol·m^-2·s^-1 LED light intensity, the tuber number and total tuber weight were the best, but the higher the light intensity, the smaller the total tuber number and total tuber weight for both cultivars. In conclusion, when producing potato stem cuttings for aeroponic systems using a closed-type plant production system, the most suitable LED light intensity for raising seedlings was found to be 60 μmol·m^-2·s^-1.