• Applied Biological Chemistry
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• v.32 no.2
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• pp.104-108
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• 1989

A 2.5 ton scale of solar energy concentration blast-grain circulation dryer (SECD) was developed in order to shorten the drying time without damaged paddy. Comparative experiments were carried out on performance, drying efficiency, consistency in moisture content, milling recovery, grade of milled rice, and energy requirement and cost against all that of in-bin drying and storage (IBDS) method. The experiments were performed using mixture of several rice varieties of Tongil type(Japonica-Indica breeding type) under the autumn weather in Korea. The circulating air temperature inside SECD was $4{\sim}5^{\circ}C$ higher than that of IBDS. The moisture content of the paddy during the drying period in SECD was uniform while substantially varied in upper, middle or bottom layer in IBDS. By SECD, 24% initial moisture content of paddy was reduced to 15% after only 3 days of drying as compared to 14 days at IBDS. The percentage of cracked kernels in upper, middle and bottom layers in IBDS was 6, 6 and 12%, respectively, whereas 7% in all layers in SECD. Both types of dryers did not significantly affect the milling recovery of dried paddy and grade of milled rice. Energy requirement of SECD(28.8Kw/2.5ton) for paddy drying was much less than that of IBDS(108Kw/2.5ton).

• Korean Journal of Food Science and Technology
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• v.20 no.4
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• pp.576-584
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• 1988

Neutral detergent fiber(NDF) were extracted from the Nampung, Milyang #23, Whasung and Jinhung varieties of rice by neutral detergent fiber method. To determine the properties of NDF three factors were measured : water-binding capacity(WBC), Fe-binding capacity and sodium taurocholate binding with NDF. The average WBC of NDF was $5.60{\pm}0.87gH_2O/g$ NDF, and the average Fe-binding capacity ranged from 24.63% at pH 5.0 to 19.6% at pH 6.0 and 48.98% at pH 7.0. Binding of sodium taurocholate with NDF was determined in vitro using C-14 labeled sodium taurocholate at 100M sodium taurocholate concentrations. NDF binding of Jinhung was 27.87 while Nampung, Milyang #23 and Whasung measured 32% each. When sodium taurocholate concentrations were raised from $40{\mu}M\;to\;240{\mu}M$ the tendency of binding increased as the concentrations increased, but not linearly.

• Korean Journal of Agricultural and Forest Meteorology
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• v.3 no.1
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• pp.22-29
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• 2001

In Korean high yielding varieties developed by crosses between indica and japonica rice, the most limiting factor for yield may be attributed to the less number of the tillers in the unit area. The goals of this study is to find out the effect of the temperature factors as well as cultural practices on the development and increase of tillers of Dasanbyeo, the high yielding indica crossed japonica cultivar. The effect of temperature was examined under controlled phytotron condition with 6 levels of temperature, 15, 17, 19, 22, 24 and 26$^{\circ}C$, respectively, For the experiment, the leading japonica variety in Korea, Hwaseongbyeo, was used for the check cultivar for the comparison with Dasanbyeo. The high temperature also accelerated the initiation and termination of tiller development. The cultivar difference in the speed of tiller development was observed, for example, more rapid development of tiller in Dasanbyeo than in Hwaseongbyeo was observed at the high temperature range of 24-26$^{\circ}C$, while the vice versa phenomena was observed at lower temperature range of 17-22$^{\circ}C$. The first secondary tiller of Dasanbyeo was observed on the 16, 17, 23, 27 and 38 days after transplanting (DAT) at 26$^{\circ}C$, 24$^{\circ}C$, 22$^{\circ}C$, 19$^{\circ}C$, and 17$^{\circ}C$, respectively. Those of Hwaseongbyeo was 19-22, and 26 DAT at 19-26$^{\circ}C$ and 17$^{\circ}C$, respectively. The last effective tiller of Dasanbyeo was observed on 27-33 DAT for the primary tiller, 20-41 DAT for the secondary tiller. Those of Hwaseongbyeo were 23-40 DAT for primary tiller, and 24-40 DAT for the secondary tiller, and 24-40 DAT for the secondary tiller.

• Korean Journal of Agricultural and Forest Meteorology
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• v.4 no.3
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• pp.151-158
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• 2002

In Korean high yielding varieties developed by crosses between indica and japonica rice, the most limiting factor for yield increase may be attributed to the less number of tillers per unit area. The goal of this study is to find out the effect of the environmental factors as well as cultivation practice on the development and increase of tillers of Dasanbyeo, the high yielding indica / japonica hybrid cultivar. The effect of temperature was examined with 3 different light intensity, 220,600, and 1220 $\mu$㏖/s/$m^2$, respectively. For all the experiments, the leading japonica variety in Korea, Hwaseongbyeo, was used fur the check cultivar for the comparison with Dasanbyeo. The increase of the tillers was more prominent in Dasanbyeo than in Hwaseongbyeo at 220 $\mu$㏖/s/$m^2$ of light intensity, while the similar increase of tiller no. was found at 600 $\mu$㏖/s/$m^2$ of light intensity treatment. However, Hwaseongbyeo showed more rapid increase of tiller at 1220 $\mu$㏖/s/$m^2$ of light intensity. The mean number of the primary tiller ranged 5 to 7 in Dasanbyeo, and 2 to 7 in Hwaseongbyeo, showing greater variation in the latter case. However, the secondary tiller number ranged from 2 to 13 for the former, and 2 to 12 for the latter. The earliest initiation of tiller node of Dasanbyeo and Hwaseongbyeo was observed on 6 and 4 days after transplanting(DAT), respectively, at 600 $\mu$㏖/s/$m^2$ of light intensity, while 10, and 7 DAT, respectively, at 1,220 $\mu$㏖/s/$m^2$. No cultivar difference was observed at 600 $\mu$㏖/s/$m^2$ with the 18 DAT. The ratio of effective tiller was lower in Dasanbyeo, ranging from 47 to 55% than in Hwaseongbyeo, ranging from 72 to 100%.

• Korean Journal of Agricultural and Forest Meteorology
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• v.24 no.4
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• pp.330-336
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• 2022

It is likely that the heading would occur early when air temperature increases. In 2022, however, the heading date was delayed unusually, e.g., by 3 to 5 days although temperature during the vegetative growth stage was higher than normal years. The objective of this study was to identify the cause of such event analyzing weather variables including average temperature, sunshine hours, and day-length for each growth stage. The observation data were collected for medium-late maturing varieties, which has been grown at crop yield experiment sites including Daegu, Andong, and Yesan. The difference in heading date was compared between growing seasons in 2021 and 2022 because crop management options, e.g., the cultivars and cultivation methods, were identical at those sites during the study period. It appeared that the heading date was delayed due to the difference in temperature responsiveness under a given day-length condition The effect of the temperature increase on the heading date differed between the periods during which when the day-length was more than 14.3 hours before and after the summer-solstice.. The effect of the temperature decrease during the period from which the day-length decreased to less than 14.3 hours to the heading date was relatively greater. This merits further studies to examine the response of rice to the temperature change under different day-length and sunshine duration in terms of heading.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.29 no.4
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• pp.366-375
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• 1984

In order to confirm the effect of climatic consumption index (C C I) on the number of spikelets and yield of rice, 3 levels of shading rates such as 0, 25, 50% of full light were treated during the tillering stage, reproductive growth stage and ripening period, respectively, in a phytotron controlled with day/ night temperature of 20/10$^{\circ}C$ and 30/20$^{\circ}C$, and field at Crop Experiment Station, Suwon, Korea. The results are as follows: 1. As solar radiation decreased during the reproductive growth stage in 30/20$^{\circ}C$ or field condition, the number of spikelets per panicle was decreased due to the decrease of the number of differentiated secondary rachis branches and spikelets as well as the increase of the number of degenerated secondary rachis branches and spikelets. 2. Our results showed slight negative correlation between C C I of the reproductive growth stage and number of panicles per square meter and number of differentiated secondary rachis branches. On the other hand, there was highly significant positive correlation between C C I of the reproductive growth stage and the number of degenerated secondary rachis branches and spikelets, and negative correlation in number of differentiated spikelets. 3. The shading during the reproductive growth stage did not affect on the percentage of ripened grains and 1000 grains weight of hulled rice, whereas those were decreased with shading during the ripened period. 4. Influence of shading in each growing stage on the yield was severe in the order of ripened period, reproductive growth stage, tillering stage. 5. Respiration rate in Jinheung was higher than that of Tongil at low temperature, but reversed above 30$^{\circ}C$. Respiratory coefficients (Q$\sub$10/) of Tongil and Jinheung were 2.74 and 1.96, respectively. Respiration/ photosynthesis ratio in Jinheung was higher than that of Tongil at low temperature, while higher in Tongil above 32$^{\circ}C$. 6. Transportation of $\^$14/C was restricted at 20/10$^{\circ}C$ in Tongil, however, there was no differences at 30/20$^{\circ}C$ in both Tongil and Jinheung. The influence of shading on the transportation of $\^$14/C did not affect at 20/10$^{\circ}C$, but it was hampered with shading at 30/20$^{\circ}C$ in both varieties.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.41 no.5
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• pp.505-513
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• 1996

This study was conducted to investigate the variation of chemical components in stagnant water under different mulching amount of barley straw after combine harvesting and the effect of stagnent water on the germinatidn and seedling elongation at early growth stage in rice. pH was lower in barley straw mulching than non-mulching and decreased with increasing of mulched barley straw but was not different among treatments in stagnant water at 15 days after flooding. Dissolved oxygen decreased with the increasing of mulched barley straw and increased with the passing of time, while saline content increased with the increasing of mulched barley straw, showing significant difference among treatments, was peaked at 15 days after flooding and thereafter, decreased. NH4-N was higher 5 days after flooding with thicker barley straw mulching but was not different at 10 days. N $O_3$-N increased up to 10 to 15 days after flooding and increased with thicker barley straw mulching. Water soluble phosphorus and cation content ( $K^{+}$, $Ca^{2+}$, $Mg^{2+}$)were higher in thicker barley straw mulching and peaked at 10 and 15 days after flooding. Germination rate was decreased by thicker straw mulching and was high in order of medium late, medium and early maturing rice variety. Keumobyeo, Gancheokbyeo, Ilpumbyeo, Dongjinbyeo and Gyehwabyeo showed higher germination rate. Seedling elongation at early growth stage was poorer with increasing of barley. straw mulching. Ilpumbyeo had good seedling elongation in one time amount of barley straw mulching and Shinunbongbyeo, Unjangbyeo, Nonganbyeo and Dongjinbyeo had poorer, in two times.mes.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.68 no.4
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• pp.335-342
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• 2023

To achieve self-sufficiency in domestic wheat (Triticum aestivum L.), an increase in high-quality wheat production is essential. Given Korea's limited land area, the utilization of cropping systems is imperative. Wheat is compatible with a double cropping system along with rice, soybeans, and corn. Data on alterations in wheat quality following summer crop cultivation is required. This study investigated the impact of cultivating preceding crops such as rice, soybeans, and corn in a wheat cropping system. The analysis focused on the influence of these preceding crops on wheat growth, quality, and soil characteristics, elucidating their interrelationships and impacts. While there were no differences in growth timing and quantity during wheat growth, a significant variance was observed in stem length. Protein content, a key quality attribute of wheat, displayed variations based on the intercropped crops, with the highest increase observed in wheat cultivated after soybeans. Soil moisture content also exhibited variations depending on the intercropping system. The wheat-rice intercropping system, which requires soil moisture retention, resulted in greater pore space saturation in comparison to other systems. Moreover, soil chemical properties, specifically phosphorus and calcium levels, were influenced by intercropping. The highest reduction in soil phosphorus content occurred with soybean cultivation. These findings suggest that intercropping wheat with soybeans can potentially enhance wheat quality in domestic varieties.

• Korean Journal of Weed Science
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• v.3 no.1
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• pp.75-99
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• 1983

The herbicidal properties of perfluidone [1,1,1-trifluoro-N-2-methyl-4-(phenylsulponyl) phenyl methanesulfonamide] were investigated in pots and paddy fields. At the rate of 2.0kg prod./10a, perfluidone did not cause any injury to the 4 leaf stage (LS) rice seedlings. Although the crop injury increased with increasing the application rate, the injury caused by 16kg prod. perfluidone/10a gave rise to only 30% yield reduction. The crop injury was greatest when perfluidone was applied 2 days before transplanting and decreased as the application time delayed. Perfluidone showed greater crop injury to the 3 LS seedlings, at more than 7cm water depth, and at high temperature than to the 4 LS seedlings, at 3-5cm water depth, and at low temperature. Indica and indica ${\times}$ japonica rice varieties were generally more sensitive to perfluidone than japonica rice variety. Perfluidone effectively controlled most of annual weeds and such perennial weeds as Sagittaria pygmaea MIQ., Potamogeton distinctus A. BENN, Cyperus serotinus ROTTB, Scirpus maritimus L., Eleocharis kuroguwai OHWL, and Scirpus hotarui OHWL, whereas Sagittaria trifolia L. and Polygonum hydropiper SPACH. were tolerent to perfluidone. The weeding effect decreased with increasing the leaching amount of water and the overflowing of irrigated water within 24 hours after the herbicide application. When the application time was done later than 8 days after transplanting, the perennial weeds were shown at deeper soil layers, and the standing water was deeper than 7cm, the effect tended to decrease. However, there was no difference in the weeding effect between soil types. Downward movement of perfluidone in flooded soil ranged from 2 to 8cm deep. The movement increased with increasing the leaching amount of water and the application rate and at a sandy loam soil which possessed less adsorptive capacity. Residual effect of perfluidone was found at 35 to 80 days after application, which varied such factors as Soil types. Increase in the leaching amount of water resulted in decrease in the period of the residual effect. The period was shorter at non-sterilized soil than at sterilized soil. The 0.75kg ai perfluidone + 1.5kg ai SL-49 (1,3-dimethyl-6-(2,4-dichlor-benzoyl)-5-phenacyloxy-pyrazole)/ha and 1.5kg ai perfluidone + 1.05kg ai bifenox (2,4-dichlorophenyl-3-methoxy carbonyl-4-nitro phenyl ether)/ha showed less crop injury than 1.5kg ai/ha perfluidone alone. However, the weeding effect of the former was similar to that of the later.

• Korean Journal of Soil Science and Fertilizer
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• v.6 no.4
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• pp.231-237
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• 1973

Eeffect of temperature (3-day or 7-day treatment under $15^{\circ}C$, $20^{\circ}C$ and $25^{\circ}C$) on chlorophyll, nitrogen and potassium content in the second leaf blade from top of IR667 line (Suwon 213 and 214) and leading local varieties (Jinheung and Paldal) was investigated at the end of nursery, maximum tillering and flowering stage using phytotron. 1. Chlorophyll content was higher in IR667 line than in the local at $25^{\circ}C$ but reversed at $20^{\circ}C$ or $15^{\circ}C$ and chlorophyll a/b value was always high in the local. 2. Chlorophyll content per fresh weight decreased with growth and low temperature effect was greater at the end of nursery and on chlorophyll a than on chlorophyll b. 3. Chlorophyll a/b value increases with the increase of chlorophyll content and the increasing rate of chl. a/b value per chlorophyll increment tends to decrease under unfavorable condition. This decrease is greater in low temperature sensitive IR667 than local varieties. 4. According to chlorophyll retention value IR667 line was weaker at low temperature. 5. The content of total nitrogen or soluble nitrogen (methanol soluble) was decreased by low temperature. 6. Chl. (a+b)/S-N value decreased with growth and seemed not to be greatly affected by temperature and always higher in the local. 7. Potassium content (total or methanol soluble) tends to decrease at low temperature and soluble K increased with chlorophyll content. 8. High yielding ability of IR667 seems to be attributable to its high chlorophyll content at high temperature and easy leaf discoloration by low temperature or by nitrogen depression of IR667 seems to be attributable to the low Chl./S-N value.