• Journal of Bio-Environment Control
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• v.25 no.3
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• pp.212-217
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• 2016

This study was conducted to investigate the effect of nursery period on growth and yield attribute of green papaya (var. Red lady). The nursery period was 3, 5, 7, 9, 11 and 13 months and the green papaya was transplanted on 15 April, 2015 in a non-heated greenhouse. The plant height, node number and fresh weight of nursery plant were increased as the nursery periods increased. The growth of green papaya with 13 months nursery period was better than those of other treatments. First harvest after transplanting was increased as the nursery periods were shorten. It took 137 days (18 August) at 13 months treatment, and 184 days (2 October) at 3 months treatment. The fruit length and diameter were smallest at 3 months treatment and there was no significant difference among other treatments. The fruit yield was also influenced by the nursery periods, the commercial yield was also increased as the nursery periods increased. The commercial yield was highest at 13 months treatment (3,172kg/10a), followed by 11 (2,247kg/10a) and 9 months treatment (2,357kg/10a). At 7 and 5 months treatment were 1,942kg/10a and 1,787kg/10a, respectively and the yield was lowest at 3 months treatment (1,443kg/10a). The commercial yield was significantly decreased under 7 months treatment. Although the harvest time of 11 months treatment was earlier than that of other treatments in non-heated greenhouse, 9 month treatment will be more recommendable for green papaya production because of operating costs.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.12 no.1
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• pp.7-11
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• 1979

This study was attempted to establish the basic data for evaluating the processing suitability of Cynthia roretzi which is one of the most tasty sea foods in Korea. The results are as follows: The moisture content was increased from November to January. From this period to March, moisture was decreased and increased again from April. Protein content was high from August to November and lipid content was relatively high from June to February. From March to May the content of glycogen was 7.3 to 7.5 percent. From this period to February glycogen was decreased rapidly. By the results of condition index and chemical composition of Cynthia roretzi, the suitable harvest season as raw materials for processing seems to be from March to June.

• Fisheries and Aquatic Sciences
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• v.6 no.4
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• pp.194-202
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• 2003

Budgets for water, nitrogen, and chemical oxygen demand (COD) were determined in two 0.012 ha earthy-bottom ponds stocked with Israeli strain common carp at an initial stocking density of $20\;fish/m^3$. Total ammonia nitrogen (TAN) concentrations increased continuously but later decreased in pond A as a consequence of high nitrification. COD concentrations increased during the experimental period due to the accumulation of feed input. Nutrient budgets showed that feed represented $94-95\%$ of nitrogen input and about 99% of organic matter input. Fish harvest accounted for $40\%$ of nitrogen and organic matter input. Seepage and water exchange removed $15-17\%$ of nitrogen input but only $1-2\%$ of organic matter. Draining of the ponds removed $20-26\%$ of input nitrogen, mostly in inorganic forms, but removed only minus organic matter. Fish and water column respiration accounted for $39\%$ of organic matter input, and benthic respiration accounted for $7-12\%$ of organic matter input. No significant change of nitrogen and organic matter in both pond bottoms were found during the three-month growth period. The unrecovered input nitrogen, about $6.3-13\%$, was lost through denitrification and ammonia volatilization. On a dry matter basis, fish growth removed $31\%$ of total feed input and left $69\%$ as metabolic wastes.

• Korean Journal of Agricultural and Forest Meteorology
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• v.3 no.1
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• pp.55-70
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• 2001

It was unusual crop weather for 1998 and 1999 compared with normal in Korea. The consecutive days of the optimum ripening period for rice plant that had daily mean temperature 21~23$^{\circ}C$ for 40 days after flowering, increased with long anomalies in 1998~99. The air temperature during ripening period was much higher than the optimum temperature and lower sunshine hour than norm in the local adaptability tests of newly developed rice lines during those years. In response of rice cultivation to warming and cloudy weather during crop season, the yield shall be decreased. Most scientists agree that the rate of heating is accelerating and temperature change could become increasingly disruptive. Weather patterns should also become more erratic. Agrometeorologists could be analyzed yearly variations of temperature, sunshine hour and rainfall pattern focused on transient agroclimate change for last a decade. Rice agronomists could be established taking advantage of real time agricultural meteorology information system for fertilization, irrigation, pest control and harvest. Also they could be analyzed the characteristics of flowering response of the recommended and newly bred rice cultivars for suitable cropping plan such as cultural patterns and sowing or transplanting date. Rice breeders should be deeply considered introducing the characteristics of basic vegetative type of flowering response like Togil rices as prospective rice cultivars corresponding to global warming because of the rices needed higher temperature at ripening stage than japonica rices, photoperiod-sensitive and thermo-sensitive ecotypes.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.37-37
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• 2003

Rice is one of the most important crop in the world and is a major export of Thailand. Optical sensors are not useful for rice monitoring, because most cultivated areas are often obscured by cloud during the growing period, especially in South East Asia. Spaceborne Synthetic Aperture Radar (SAR) such as RADARSAT, can see through regardless of weather condition which make it possible to monitor rice growth and to retrieve rice acreage, using the unique temporal signature of rice fields. This paper presents the result of a study of examining the backscatter behavior of rice using multi-temporal RADARSAT dataset. Ground measurements of paddy parameters and water and soil condition were collected. The ground truth information was also used to identify mature rice crops, orchard, road, residence, and aquaculture ponds. Land use class distributions from the RADARSAT image were analyzed. Comparison of the mean DB of each land use class indicated significant differences. Schematic representation of temporal backscatter of rice crop were plotted. Based on the study carried out in Pathum Thani Province test site, the results showed variation of sigma naught from first tillering vegatative phase until ripenning phase. It is suggested that at least, three radar data acquisitions taken at 3 stages of rice growth circle namely; those are at the beginning of rice growth when the field is still covered with water, in the ear differentiation period, and at the beginning of the harvest season, are required for rice monitoring. This pilot project was an experimental one aiming at future operational rice monitoring and potential yield predicttion.

• Horticultural Science & Technology
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• v.31 no.1
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• pp.103-109
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• 2013

Estimating the high tuber solids needs a simulation system on potato growth, and its development should be obtained by using agricultural elements which analyze the relationship between crop growth and agricultural factors. An accurate simulation to predict solids level against climatic change employs a calculation of in vivo energy consumption and bias for growth and induction shape in a slight environmental adaptation. So, to calculate in vivo energy consumption, this study took a concept of estimate of the amount of basal metabolism in each tuber. In the validation experiments, the results of measuring solid accumulation of potatoes harvested at dates suggested by simulation agreed with the actual measured values in each regional field during the growth period of years from 2006 till 2010. The mean values of tuber solids level and inter-annual level variation in validation experiments were predicted well by the simulation model. And also, the results of validation experiments represent that concentration of tuber solids were due mainly to the duration of sunshine, above 190 hours per a month, and the cumulative amount of radiation, above 2,200 $MJ{\cdot}m^{-2}$, of the effective growth period.

• 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.

• Journal of Bio-Environment Control
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• v.12 no.1
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• pp.1-6
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• 2003

This study was conducted under the condition of greenhouse to investigate the relationships between the period of long day (LD) treatment before short day treatment, the dry matter production and flower quality of cut chrysanthemum (Indicum group) cv. Reagan Improved at Wagenigen University in the Netherlands. Rooted cuttings of chrysanthemum (Indicum group) cv. Reagan Improved were transplanted on 6th, 13th, loth of September and all of them were treated with short-days (SD) on 21th September. The periods from planting until final harvest were 70, 77, 84 days after being planted for 1, 2, and 3 week-LD period, respectively. The time of flower initiation was similar in all treatments. The number of flowers per plant was greater in the plot of 3 week-LD period than that in the plot of 1 or 2 week-LD period. The fresh weight and dry weight of flowers also increased more in the plot of 3 week-LD period than that in the 1 week-LD period by 4g and 0.4g, respectively. The final dry matter production ($g{\cdot}m$^{-2}$ ) was greater in the treatment of 3 week-LD period than 1 or 2week-LD period. In this study, LD period before short day treatment did not affect the time of flower initiation and flower quality. As a result, 3 week-LD period before short day treatment was strongly recommanded for producing high quality cut flowers of greenhouse-grown chrysanthemum.

• Journal of Bio-Environment Control
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• v.11 no.4
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• pp.205-216
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• 2002

This study was conducted to examine the effect of long-day (LD) period before short-day (SD) treatment on the vegetative growth of greenhouse-grown cut chrysanthemum cv. Reagan Improved at Wageningen Agricultural University, The Netherlands. Rooted cuttings of cut chrysanthemum cv, Reagan Improved were transplanted on 6th, 13th, 20th of September and all of them were treated with LD before SD treatment on 27th of September, The periods from transplanting until final harvest were 70, 77, and 84 days for 1, 2, and 3 week-LD treatment, respectively. The final plant height increased in the plot of 3 week-LD period and decreased in the plot of 1 week-LD period before the SD treatment. Total fresh weight and the leaf area were increased more in the plot of 3 week-LD period than that of 1 week-LD period, but the absolute growth rate after SD treatment was the same on plant growth rate and increase of the number of leaves in all treatments. The final dry matter production (g.m$^{-2}$ ) was increased more in the plot of 3 week-LD period than that of 1, 2week-LD period before SD treatment. Plant height and fresh weight were followed by the condition of LD period. In addition, dry mass production was highest in 3 week-LD period.

• Korean Journal of Agricultural Science
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• v.41 no.4
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• pp.265-274
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• 2014

Physiological characteristics of two Korean golden kiwifruit cultivars, 'Halla Gold' and 'Haehyang', were compared to determine the storage potential of fruit. The soluble solid levels of the fruit were 8.9 and 6.9 oBrix in 'Halla Gold' and 'Haehyang' at harvest, respectively but increased up to 15.4 in 'Halla Gold' and 17.5 oBrix in 'Haehyang' after 2 months of storage. Major sugars were fructose and glucose, and sucrose content was relatively low regardless of cultivar. The edible quality of 'Haehyang' was better than 'Halla Gold' because of higher amount of sugars. Firmness of the fruits gradually decreased as the increase of storage period in 'Halla Gold' in both flesh and core tissue. Th firmness loss of 'Haehyang' fruit was faster in the first 2 months and then became slow. After 75 days of storage, the firmness of 'Haehyang' fruit was only 5.2% at harvest. Core tissue was soften enough to eat at ripe stage. Wall modifying enzyme activities including xylanase, ${\alpha}$-L-arabinofuranosi-dase and ${\beta}$-galactosidase were consistently higher in 'Haehyang' and the activity of pectate lyase was more increased than 'Halla Gold' after 2 months of storage. Respiration rate of 'Haehyang' was higher than 'Halla Gold' and further increased after 2 months of storage. Weight loss was much higher in 'Haehyang' which showed higher rate of the firmness loss. The storage potential of golden kiwifruit was estimated to be about 2 months for 'Haehyang' and 3 months for 'Halla Gold' when determined on the basis of the fruit firmness.