• Korean Journal of Environmental Biology
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• v.36 no.4
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• pp.439-455
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• 2018

Hanon made in the largest maar crater in Korea, is the only paddy field ecosystem in Jeju Island that has been conducting rice farming, for the past 500 years. Flora surveys were conducted eight times, 2015-2018, to understand floristic characteristics and a restoration plan of the study area. As a result, vascular plants of Hanon paddy fields were listed 225 taxa that consist of 55 families, 151 genera, 194 species, 1 subspecies, 25 varieties, and 4 forms. The taxonomic group including the most species, was Gramineae (36 taxa). The next families were Compositae (29 taxa), Cyperaceae (20), Leguminosae (13), and Polygonaceae (11). Biological type of the Hanon was $Th-R_5-D_4-t$ type. The rare plants revealed 3 taxa; Ottelia alismoides(L.) Pers., Acorus calamus L., Pseudoraphis ukishiba Ohwi. Endemic plant revealed 1 taxon; Saururus chinensis(Lour.) Baill. Forty three taxa were naturalized plants composed of 15 families, 24 genera, 41 species, and 2 varieties. The urbanization index and naturalized index were 13.3% and 16.9%, respectively. The Hanon has high plant diversity, including endemic plant and rare plants, and is the only rice paddy in Jeju Island. So, the Hanon has sufficient values in ecological and socio-cultural aspects, so it should be maintained continuously in the future.

• Microbiology and Biotechnology Letters
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• v.23 no.1
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• pp.36-42
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• 1995

Actinomycetes occur in a wide range of environments and many more actinomycetes remain to be detected in the natural environment. In isolation stages, selection of the environment as a source of useful isolates is important. Two hundred and eighteen strains were isolated on Bennet's agar and 346 strains were on humic acid-vitamin agar from five each paddy field, field, forest, grass land, riverside soil samples. These isolates were identified to the genus level based on morphological and physiological characteristics. Among them, 386 strains were Streptomyces, 49 strain were Nocardia, 35 strains were Microbispora and Micromonospora each, 15 strains were Nocardiopsis, 13 strains were Actinomadura, 10 strains were Streptosporangium, and the others were isolated rarely. According to soil type, Nocardia, Micromonospora, Microbispora and Streptosporangium were dominant in paddy field, Microbispora Nocardia, Nocardioides and Micromonospora were dominant in field, Nocardia, Micromonospora, Microbispora and Actinomadura were dominant in grass land, Nocardia, Micromonospora and Microbispora were dominant in forest, Nocardia, Microbispora and Micromonospora were dominant in riverside. Generally, Nocardia, Micromonospora, Microbispora and Actinomadura were isolated in all kinds of soils, Streptosporangium were paddy field, Dactylosporangium were forest, Nocardiopsis were field, forest and riverside.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.6
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• pp.1314-1319
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• 2011

This study was carried out to investigate the surface soil organic carbon fractions affecting by different land use types, including needle-leaf forest (FN), broad-leaf forest (FB), pasture, annual upland cropping land (upland), and paddy rice land (paddy). We chose seven regions across Korean inland, considering sea level altitude, and measured soil organic carbon content and physico-chemical properties such as bulk density at a depth of 0~15 cm using core samples in April for the each land use type. In addition, labile organic carbon fractions in soil including light fraction and hot water extractable carbon were investigated. From this study, organic carbon storage (Mg C per ha) in the upper 15-cm soils was highest in FB (37.8), and decreased in the order of pasture (29.1), FN (28.8), paddy (21.9), and upland crop (19.9). In forest, more than 20% of soil organic carbon existed as light fraction, the free organic matter. Hot-water extractable carbon contents of soils in five land use types were lower than 7% of their soil organic carbon content.

• Journal of Biosystems Engineering
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• v.6 no.2
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• pp.33-47
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• 1982

To modernize the conventional rice post production technology and reduce grain losses, a transition toward the wet-paddy threshing system has been strongly demanded. The head-feeding type thresher with pneumatic separation has been used dominantly for threshing dried-paddy, but some adverse effects in separation performance for threshing wet-paddy is encounterred. In order to solve the problems, the development of thresher with an additional oscillating sieve to the conventional pneumatic separation has been recommanded. This study was intended to evaluate the separating performance of thresher with oscillating sieve which was attached additionally to the conventional auto-thresher equipped with separation system of blower and suction fan. For different feed rates and rice varieties, wet-and dry-material were tested with threshers attached with and without oscillating sieve. Results of the study are summarized as follows: 1. When the feed rates were 480 and 640 kg/hr, there was no statistically significant difference in power reqirements between the threshers with and without an additional sieve device for both dry-and wet-threshing. However, when the feed rate was 960 kg/hr, power requirements of thresher without sieve were greater for wet-paddy threshing than the thresher with the additional sieve separator by about 20% points. 2. With additional oscillating sieve device, the ratios of total weights of whole grains including grains with branch let and damaged grains to the total output did not show statistical difference among the feed rates. However, with pneumatic separation the ratio was decreased as the level of feed rate increased. 3. The total amount of grains with branchlet (including broken panicle) increased with the moisture content. For both the wet-and dry-material threshing with the additional oscillating sieve, the percent of grains with branchlet to the total output decreased greatly as the feed rate increased. 4. The output of the damaged grains increased as moisture content decreased. Especially, for the dry-paddy threshing, the additional sieve separating device produced more damaged grains than the pneumatic separation at all feed rates. 5. Generally, for dry paddy threshing, the separating performance of the thresher with the additional sieve device was better at all feed rates, showing greater difference with increasing feed rates. 6. Separating losses were greater with the pneumatic than sieve separation for both the wet-and dry-threshing. 7. The overall comparison of separating performance of threshers tested with and without an additional sieve device showed that the former was more effective than the latter for the dry-material threshing. However, for the wet-paddy threshing, the separation performance with a sieve device was better than the pneumatic only when the feed rate was high.

• Journal of Biosystems Engineering
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• v.2 no.1
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• pp.55-55
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• 1977

This experimental work was conducted in order to find out the optimum time of harvest of Japonica-type(Akibare) and Indica-type(Tong-il) rice variety for three harvesting systems by investigating the harvestirg losses and milling quality. The study was also concerned atout the nature and amount of grain losses incurred during the each sequence of post-harvest technologies, and based on these results, a modification of existing systems giving a minimum grain loss was attempted. Binder, combine, and traditional harvesting systems were tested in this study and five grain moisture levels were disposed according to the decrease of grain moisture. The results are summarized as follows: 1. The total losses of Akibare variety were ranged from 1.1 to 1.5 per cent for the traditional harvesting system, 2.1 to 4.8 percent for the harvesting system by use of binder, and 2.8 to 4.3 percent for the harvesting system by use of combine as the grain moisture content was reduced from 24 to 15 per cent. Milling recovery of the harvesting system by use of binder, 74.8~ 75.7 percent, was a little higher as it was compared to that of traditional harvesting system, 74. 3~75. 0 percent, and that of the harvesting system by use of combine, 73.8~ 75.0 per cent. Head rice recovery of mechanically dried paddy samples was higher than that of sun-dried paddy samples. 2. The total losses of Tong-il variety were ranged from 3.8 to 5.0 per cent for the traditional harvesting system, 5.2 to 10.0 percent for the system by use of binder, and 3.0 to 5.0 perent for the system by use of combine as the grain moisture was reduced from 28 to 16 percent.

• Journal of Biosystems Engineering
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• v.2 no.1
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• pp.56-80
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• 1977

This experimental work was conducted in order to find out the optimum time of harvest of Japonica-type (Akibare) and Indica-type(Tong-il) rice variety for three harvesting systems by investigating the harvesting losses and milling quality. The study was also concerned about the nature and amount of grain losses incurred during the each sequence of post-harvest technologies, and based on these result, a modification of existing systems giving a minimum grain loss was attempted. Binder, combine, and traditional systems were tested in this study and five grain moisture levels were disposed according to the decrease of grain moisture . The results are summarized as follows ; 1. The total losses of Akibare variety were ranged from 1.1 to 1.5 per cent for the traditional harvesting system , 2.1 to 4.8 per cent for the harvesting system by use of binder, and 2.8 to 4.3 per cent for the harvesting system by use of combine as the grain moisture content was reduced from 24 to 15 percent. Milling recovery of the harvesting system by use of binder, 74.8 ∼75.7 percent, was a little higher as it was compared to that of traditional harvesting system, 74.3 ∼75.0per cent, and that of the harvesting system by use of combine, 73.8 ∼75.0 per cent. Head rice recovery of mechanically dried paddy samples was higher than that of sun-dried paddy samples. 2. The total losses of Tong-il variety were ranged from 3.8 to 5.0 per cent for the traditional harvesting system, 5.2 to 10.0 percent for the system by use of binder, and 3.0 to 5.0 per cent for the system by use of combine as the grain moisture was reduced from 28 to 16 per cent. 3. Milling recovery of Tong-il variety harvested by the traditional harvesting system was 72.3 ∼73.6 percent and it was lower when compared to that of 72.3∼75.0 per cent harvested by binder, and 73.0∼74.6 percent harvested by combine. 4. Head rice recovery of Tong-il variety harvested by the traditional harvesting system (58.

• The Korean Journal of Ecology
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• v.25 no.3 s.107
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• pp.131-137
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• 2002

This study was conducted to clarify the characteristics of bird community and habitat types in Mangyeong River area from Aug. 1999 to Jun. 2000. Paddy field was the most dominant land use type. Water area, mudflat, shrub field, urban area and green house were also dominant land use types in study area. Eighty-eight bird species were recorded during study period. Maximum number of species and individuals were shown as 58 species and 7,084 individuals in Oct. and Jan., respectively. There were low number of diving ducks and clumped pattern of waterfowl distribution of bird community in Mangyeong River area. Dabbling ducks distributed at upper reaches near Samrye Bridge, and plovers and sandpipers at lower reaches near estuary. Those results suggest that creation of pools over one meter water-depth and restoration of paddy field into riparian zone with diverse shrubs are required to increase the bird diversity in the Mangyeong rived.

• The Korean Journal of Ecology
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• v.25 no.2
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• pp.61-67
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• 2002

This study was conducted to clarify the characteristics of bird community and habita types in Mangyeong River area from Aug. 1999 to Jun. 2000. Paddy field was the most dominant land use type. Water area, mudiflat. shrub field, urban area and green house wee also dominant land use types in study area Eighty-eight bird species were recorded during study period. Maxiamum number of species and individuals were shown as 58 species and 7,084 individuals in Oct. and Jan. respecitvely. There were low number of diving ducks and clumped pattem of waterfowl distribution of bird community in Mangyeong River area. Dabbing ducks distributed at upper reaches near Samrye Bridge, and plovers and sandpipers at lower reaches near estuary. Those results suggest that creation of pools over one meter water-depth and restoration of paddy field freld into riparian zone with diverse shrubs are required to imcrease th bird diversity in the Mangyeong rived.

• Journal of The Korean Society of Agricultural Engineers
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• v.62 no.4
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• pp.63-73
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• 2020

The area of paddy fields for upland crop cultivation is gradually increasing. In this context, we developed a chain type mole drainer that can be attached to a tractor to prevent the wet injury of crops. To conduct a field test, we formed underdrains at 2 m intervals in a paddy field wherein soybeans are cultivated, and we investigated the status of the soil moisture, groundwater level, and soybean growth during the cultivation period. The soil moisture content decreased by 22.3~26.8% in the test plot and by 5.9~6.9% in the control plot during a period of 57~88 hour after a rainfall of 41.5~157.0 mm. The effect of underdrainage was clear as the hourly groundwater level decreased approximately 2.8 times faster in the test plot compared with the control plot. Moreover, the soybean yield was greater by 78.6 kg/10a in the test plot than in the control plot. Therefore, for soybean cultivation in paddy fields, the use of the developed mole drainer is expected to help in improving the drainage and increasing the soybean yield.

• Atmosphere
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• v.29 no.4
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• pp.355-365
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• 2019

Based on in-situ monitoring data produced by National Institute of Meteorological Sciences, we evaluated the performance of Joint UK Land Environment Simulator (JULES) on the surface energy balance for rice-paddy and cropland in Korea with the operational ancillary data used for Unified Model (UM) Local Data Assimilation and Prediction System (LDAPS) (CTL) and the high-resolution ancillary data from external sources (EXP). For these experiments, we employed the one-year (March 2015~February 2016) observations of eddy-covariance fluxes and soil moisture contents from a double-cropping rice-paddy in BoSeong and a cropland in AnDong. On the rice-paddy site the model performed better in the CTL experiment except for the sensible heat flux, and the latent heat flux was underestimated in both of experiments which can be inferred that the model represents flood-irrigated surface poorly. On the cropland site the model performance of the EXP experiment was worse than that of CTL experiment related to unrealistic surface type fractions. The pattern of the modeled soil moisture was similar to the observation but more variable in time. Our results shed a light on that 1) the improvement of land scheme for the flood-irrigated rice-paddy and 2) the construction of appropriate high-resolution ancillary data should be considered in the future research.