• Korean Journal of Agricultural and Forest Meteorology
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• v.20 no.1
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• pp.18-33
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• 2018

A new eddy covariance-based flux tower has been established since June 2016 in a dry direct-seeding rice paddy field in southwestern Korea - Haenam Paddy field KoFlux site (HPK). To assess the competitiveness of direct-seeding agricultural technique in the context of climate-smart agriculture, we have been monitoring the $CO_2$, $CH_4$ and energy fluxes continuously. In this communication, we (1) introduce the HPK site and (2) explain the structure and processes of the HPK-specific data processing and quality control. The latter consists of 10-steps data processing and quality control procedures following the KoFlux standardized protocol and explained each step in layman's term. The final data produced during the data processing were stored in NCAM-DAPS (National Center for AgroMeteorology-Data Acquisition and Processing System, http://daps.ncam.kr). We hope that the introduction of new HPK KoFlux site would serve as a platform to facilitate transdisciplinary efforts in the research and education associated with climate-smart agriculture toward sustainability.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.45 no.3
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• pp.185-189
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• 2000

The object of this study was to determine the optimum seeding dates of "Donganbyeo", "Daesanbyeo", Hoanbyeo", "Nonghobyeo", and "Gwnganbyeo" for direct seeding on dry paddy in Youngnam region. Dry seeds of these varieties were sown 5 times with 10-day intervals from April 20 to May 30. It took 13 to 14 days from sowing to emergence. It was shortened in the delayed seeding date, but the emerged seedlings per unit area was decreased as the seeding date was advanced before May. Heading date was delayed as seeding was delayed. Culm length, panicle length and number of spikelets per panicle was not affected by seeding date, but number of panicle per $m^2$ and ripened grain ratio were high from April 30 to May 10 seeding date. Consequently, the optimum seeding date for high yield of "Donganbyeo", "Daesanbyeo", "Hoanbyeo", "Nonghobyeo", and "Gwanganbyeo" was estimated May 3, May 2, May 10, May 8, and May 1, respectively and "Gwanganbyeo" was estimated May 3, May 2, May 10, May 8, and May 1, respectively.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.40 no.5
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• pp.574-579
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• 1995

To investigate the effect of the midsummer drainage method on growth and lodging characters, Dongjinbyeo was direct seeded on dry paddy field under 4cm of soil depth at May 1 by seeding machine. Three kind of drainage methods were treated such as, once in 20day, towice in 20, 30 days and 3 times 20, 30, 40 days after flooding. As increase the drainage times, the culm and internode length were shorter, culm wall of 4th internode was thicker, breaking weight was heavier, height of center weight was lower, lodging index was reduced, and dry weight of root was increased. Field lodging occured seriously at none drainage but didn't, with two or three times of drainage. Grain yield was not shown significantly different compared with constant flooding irrespective of midsummer drainage times. Therefore two or three times of midsummer drainage could be recommended as the effective water management for the reduction of lodging occurance in direct seeding culture on dry paddy field.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.46 no.2
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• pp.84-88
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• 2001

Two methods of nitrogen application at the 4th leaf stage were evaluated in direct-seeding rice cultivation on dry paddy soil: one was the top dressing of nitrogen on dry paddy condition before irrigation (TNDP) for labor saving, and the other was the top dressing of nitrogen on dry paddy with mechanical rotavation of the inter-row space (TNDPIR) for increasing the efficiency of nitrogen. To evaluate these two application methods, leaf chlorophyll contents, growth characteristics and yields were compared with two conventional methods, basal application (BA) and top dressing on flooded paddy condition at the 4th leaf stage (TNFP). The SPAD value of rice in TNDP was similar with that in TNFP throughout the whole growth stage of rice. Also, there were no differences in rice growth and yield between the two methods. However, in TNDPIR, the SPAD value was the highest during tillering stage among the four application methods, and the tiller number, LAI at heading stage and the panicle number were higher than the two conventional methods.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.42 no.6
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• pp.752-758
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• 1997

Urea, which is the major nitrogenous fertilizer used in Korea, has been used inefficiently in direct-seeding on dry soil by farmers. This study was conducted to investigate changes in concentrations of basal N within soil layers and its loss during early stage of rice growth. Urea fertilizer was applied in the rates of 7, 5.25, 3.5, 1.75, 0kg- N /10a under direct-seeded rice in dry paddy soil. The concentrations of ammonium and nitrate were determined in soil samples with different depths during period from seeding to the 3rd leaf stage. Futhermore, N leaching was measured in lysimeter designed with pot in greenhouse. ${NH_4}^+ \; and\; {NO_3}^-$ adsorption by soil increased with increasing concentration of added urea and decreased as deeper in soil layers. ${NH_4}^＋$ concentration reached its peak at 7 days after urea application (DAA) and disappeared almostly at 14 DAA. ${NO_3}^-$ reached its peak at 10 DAA and decreased slowly until 14 DAA. ${NO_3}^-$N leaching started next day after urea application and completed until 11 DAA. We concluded that most of basal N applied to direct-seeded paddy was lost by leaching and not useful for rice plant which was in stage of germination. It is urgent need to develop new nitrogen application method for direct-seeding rice on dry soil.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.42 no.4
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• pp.459-465
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• 1997

This experiment was conducted to compare the change of growth and canopy photosynthesis between transplanting and direct seeding on paddy surface in rice. Total tiller number by the early vegetative growth stage was significantly higher in the direct seeding flooded paddy surface, while it was reversed from later vegetative growth stage in terms of tillering ability per unit period. But total panicle number was higher in direct seeding on paddy surface. Leaf area index, nitrogen content in leaf blade and canopy photosynthetic ability at later vegetative growth stage were lower in direct seeding on flooded paddy surface than transplanting. Biological yield at harvest stge, leaf area index and conopy photosynthetic activity at heading stage were gradually increasing according to nitrogen level increased both transplanting and direct seeding on paddy surface. Leaf area index, canopy photosynthetic activity, however, were lower in direct seeding on paddy surface than transplanting in the same nitrogen level. Nitrogen content per unit leaf area was high in transplanting.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.41 no.1
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• pp.28-33
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• 1996

This experiment was carried out at National Crop Experiment Station in 1994 to obtain basic information of growth characters and yield of rice under various seeding methods in direct seeding on dry paddy. Hwaseongbyeo sown on April 27 by flat drill seeding, high ridged drill seeding and hill seeding under different seed conditions, soil convering after seeding and irrigation methods. Nitrogen applied 150kg /ha by 3 times split application at rate of 40:30:30％ (basal: 5th leaf stage:panicle initiation stage). Seedling stands were higher in flushed irrigation water after seeding than in irrigation at 3rd leaf stage, and it also was higher in high ridged drill seedings than in flat drill seedings. Days for seedling stand, heading date were shorten 6~10 days, 2~3 days by flushed irrigation water after seeding, respectively. Number of tiller was more in high ridged drill seedings than conventional seedling method(Flat drill seeding ＋ intact seed ＋ soil covering after seeding ＋ irrigation at 3rd leaf stage after seedling stand) at early growth stage, but the most tiller number was highest in developed seeding method(Flat drill seeding ＋ soaked seed ＋ non soil covering after seeding ＋ fulshed irrigation water after seeding) at heading stage among used seeding methods. Lodging index was slightly high in high ridged drill seeding and conventional seeding. Field lodging was degree 1 in high ridged drill seedings and developed seeding, Milled rice yield in developed seeding was increased 7％ compaired with conventional seeding(5.35t /ha).

• Korean Journal of Agricultural and Forest Meteorology
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• v.3 no.2
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• pp.75-80
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• 2001

This study was conducted to identify the optimum proper nitrogen (N) application rate for tillering in ridge direct seeding on dry paddy of rice culture. During 1998, a series of experiments was carried out at paddy field (Chonbuk series) of the National Honam Agricultural Experiment Station, RDA using Dongjinbyeo. Leaf area index and top dry weight increased with higher N levels, especially in the 100 kg/ha seeding rate compared with the 60 kg/ha seeding rate. N use efficiency increased at increased by 50~75% of the N topdressing rate at tillering. Heading date, ripened grain rate, and 1,000-grain weight of brown rice did not vary among the rate of topdressing for tillering and seeding rates. The highest grain number per unit area was at the level of increased by 75% in N topdressing at tillering stage. Milled rice yield increased 5% at the 60 kg/ha seeding rate and increased 16~17% at the 100 kg/ha seeding rate at increased by 50~75% of topdressing N compared with 48 kg/ha topdressed N of 60 kg/ha seeding rate.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.41 no.1
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• pp.115-122
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• 1996

One of the most laborious work in rice farming is transplanting of rice seedling which has been required preparation of nursery bed and care of seedling during one month period. In this research, direct seeding in dry paddy(DS) and direct seeding in wet paddy(WS) were practiced to compare with traditional transplanting(TP) in Suwon. Growth stages in direct seeding were delayed as its planting time was about 21 days later than those of TP. Heading stage of direct seeding at Suwon was delayed about 9 days as compared to transplanting culture. Rice yield was not different between the seeding practises. Working-hour saving was about 17％(DS) and 28％(WS). Production cost of direct seeding was decreased 20％(DS) and 32％(WS), respectively. Amount of rice production per a unit working-hour in direct seeding could increase 14％(DS) and 39％(WS) compared to that of TP, respectively. Therefore, direct seeding could save significantly working hour and production cost without reducing rice yield. WS was more effective than DS in saving labor and production cost. Direct seeding was not efficient method in input of farming energy and agricultural chemicals.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.43 no.1
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• pp.49-53
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• 1998

Direct-seeding has major advantages such as labor and cost saving by eliminating preparation of seed bed and transplanting. But, it required increased input of fertilizers and pesticides because of the extended paddy period. Direct seeding in wet paddy (DSWP) gives faster growth and more uniform seedling emergence than direct-seeding in dry paddy. This research had an objective to develop an efficient N management practices for DSWP with split application of N fertilizer. A paddy field experiment was conducted to evaluate effects of starter N and N-topdressing which was delayed N application until 5-leaf stage, with comparison to transplanting (TP). Total amount of N application were two levels; 110kg and 77kg/ha. The N applications were split four times during rice growth stages; starter, topdressing at 5-leaf stage, top dressing at tillering stage, and topdressing at panicle initiation stage. DSWP had more tillers/$m^2$ than TP, but with the delayed heading. The DSWP plots which received N-topdressing at 5-leaf stage without starter N had higher leaf area index (LAI) and leaf greenness than the TP plot. Also, these DSWP plots had high leaf-N concentration at the heading stage, as calculated from leaf chlorophyll meter readings. Rice yield in DSWP with N-topdressing at 5-leaf stage was significantly higher than that in TP and in DSWP with starter N. Energy and N use efficiency were improved in DSWP with N-topdressing at 5-leaf stage. But, there were no significant differences in grain yield between the two levels of total amounts of N applications, 77kg and 110kg/ha. We concluded that starter N could not be used effectively by rice seedlings, but topdressing N at 5-leaf stage was an efficient N management for rice growth and yield in DSWP system.