• Korean Journal of Weed Science
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• v.16 no.2
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• pp.108-113
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• 1996

The experiment was conducted to obtain basic information on occurrence ecology system of Aneilema japonica and to establish its effective control systems in dry seeded rice at National Yeongnam Agricultural Experiment Station in 1995. Total amount of weed in dry seeded rice in the following year('95) as affected by control of barnyardgrass at 70 days after seeding(DAS) in previous year('94) was reduced 47.7% at 30 DAS and 7.8% at 60DAS and also exhibited different weed occurrence as compared with no control plot. Especially in control plot at 60 DAS, occurrence of Echinochloa crus-galli was reduced by 46.9%, But the growth of Aneilema japonica which is one of the problems in weed species was drastically increased by 231 % and Persicaria hydropiper by 11.8%, respectively. Suppressed tillering of rice plant as affected by occurring of A. japonica(300-750 plants/$m^2$) occurred from about 40 DAS and rice grain reduced 74-93% compared with hand weeding due to reduced panicle number. Soil applied Butachlor(EC) at 5 DAS, foliar applied Propanil -Butachlor(EC) at 13 DAS and Lgc 40863+Pendimethalin at 20 DAS were very effective for Aneilema japonica. As considering both weed suppression of Aneilema japonica and yield capacity, middle late foliar application of Lgc 40863+Pendimethalin and systematic application of Butachlor at 5 DAS followed by Propanil/Molinate at 25 DAS were the most effective control systems.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.50 no.spc1
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• pp.29-32
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• 2005

This experiment aimed to estimate the effect of imperfect rice on rice palatability. Rice cultivar, Ilpumbyeo, was cultivated by direct-seeding on flooded paddy surface with 11 kg/10a nitrogen application. Palatability of harvested rice was measured by NIR spectroscope. Brown rice was divided according to their appearance namely, perfect, discolored, green-kerneled, and immature opaque with a composition ratio of $75.7\%,\;11.0\%,\;8.0\%,\;and\;5.3\%$ respectively. When the perfect brown rice was milled, the grain were composed of head, cracked, and white core & belly, at $64.7\%,\;25.3\%\;and\;10.0\%$ respectively. The milled rice of discolored brown rice had similar composition with the perfect rice. The milled green-kerneled vice, on the other hand, had $36\%$ head rice and $64\%$ white core & belly rice. The immature opaque brown rice, when milled, had $25.3\%$ white core & belly and $74.7\%$ damage & opaque rice. With the respect to grain quality, the viscosity of white core at belly rice and damaged & opaque rice was lower than that of head rice. In contrast, their protein content was a little higher than that of head rice. The palatability value of pure imperfect rice was much lower than head rice. The palatability value of damaged & opaque rice was the lowest among the imperfect rices. When mixed with head rice, the damaged & opaque rice impacted on the deterioration of vice palatability. Mixing $1\%$ each of white core at belly rice and damaged h opaque rice decreased the palatability value by $5\%$ as compared with the head rice.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.61 no.1
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• pp.9-16
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• 2016

To investigate the effect of soluble silicate zeolite dressing of the rice against bakanae disease, field trial in reclaimed land and in vitro were carried out. The coated rice seeds (SCS) which were dressed with the mixture of 25% silicic acids (binder), and the zeolite (coating powder). In wet direct seeding, uniform scattering of rice seeds on the soil surface and the better seedling establishment were shown in SCS treatment plots. The incidence of bakanae disease began from the mid tillering stage toward the heading stage. Around heading stage, the ratio of infected tillers reached its highest point by 9.9% in non-SCS treatment plots. While, in SCS treatment plots, the ratio of infected tillers was no more than 0.01%. The vitality of the pathogenic fungi of bakanae disease in the SCS and non-SCS samples were assessed. Samples were incubated for one week keeping proper humidity at $30^{\circ}C$ after inoculated with panicles of infected rice plants from experimental field plots. In non-SCS treatment, pinkish colonies were formed on the grain surface of panicle of infected plants, and mycelium, macro-conidia and micro-conidia were developed actively inside part of infected grain inoculated. While in SCS treatment, micro-conidia and mycelium were not survived and the growth of macro-conidia, mycelia were greatly inhibited and withered. Based on the results, it is concluded that the environmental friendly control of bakanae disease by use of SCS is possible and soluble silicate can be applied as agents for replacement of seed disinfection.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.spc1
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• pp.52-57
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• 2006

This research was carried out to determine the effect of controlling nitrogen application on tiller development, yield, and quality of rice under scanty or excess seedling stands in direct-seeded rice on flooded soil surface. Seedling stand was set to 3 levels: scanty $(60/m^2)$, optimum $(120/m^2)$, and excess $(200/m^2)$. In the scanty plot, additional 4 kg/10a nitrogen was applied at the 3rd leaf stage to promote tiller development. On the other hand, applying 3.3 kg/10a nitrogen at 5th leaf stage in the excess plot was omitted to suppress tillering. Maximum numbers of tillers per plant were 15.2 and 8.6 in scanty and excess plots, respectively, as compared with 9.8 in optimum plot. Productive tiller rate decreased with the increase in number of seedling stands. Regardless of seedling density, the first tiller developed on the 3rd node of rice stem from the bottom. The primary tillers developed at 3, 4, 5, 6, 7 nodes in scanty plot, 3, 4, 5 nodes in optimum plot, and 3, 4 nodes in excess plot. The secondary tillers developed only in some portion of plants in scanty and optimum plots. The order of tiller emergence was negatively correlated to stem length, panicle length, non-productive tiller number, grain number per panicle, and fertility in scanty plot, and to perfect grain ratio in excess plot. In the optimum plot, however, the order of tiller emergence was not correlated to any of the mentioned characteristics. The perfect grain ratio of scanty plot was the highest because green-kerneled rice was a very small portion in the primary tillers as compared with those of optimum and excess plots. Yield indexes of scanty and excess plots were 99%, and 97%, respectively, of the yield (494 kg/10a) in optimum plot. In conclusion, when seedling stands are not at optimum level, rice yield and quality similar to optimum planting density level can be obtained by means of controlling nitrogen application.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.38 no.2
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• pp.128-133
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• 1993

This experiment was carried out to evaluate the germination characteristics of Korean red rice seeds. Ten lines of the long grain and ten lines of the short grain Korean red rices were tested for dormancy, shoot emergence rate at different water and soil depth. Both the long and short grain type seeds of Korean red rice germinated over than 99% immediately after harvest, so that no dormancy was observed in the Korean red rices. Shoot emergence rate of the long grain red rices at 7cm of water depth and that of the short grain red rices at 11cm were 83.3% and 83.5% respectively, while those of the indica check Samgangbyeo and japonica check Seomjinbyeo were 0%. Shoot emergence rates of the long and short grain red rices at 7cm of soil depth were 71.1% and 73.9% respectively, while those of the check varieties Samgangbyeo and Seomjinbyeo were 40.0% and 28.0% respectively. Thus, the Korean red rices were expected to be useful germplasm source for direct seeding.

• Journal of the Korean association of regional geographers
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• v.2 no.1
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• pp.51-67
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• 1996

There are three main rice-growing regions in the United States: the prairie region along the Mississippi River Valley in eastern Arkansas; the Gulf Coast prairie region in southwestern Louisiana and southeastern Texas; and the Central Valley of California. The Central Valley of California is producing about 23% of the US rice(Fig. 1). In California. most of the crop has been produced in the Colusa, Sutter, Butte, Glenn Counties of the Sacramento Valley since 1912, when rice was commercially grown for the first time in the state(Fig. 2). Roughly speaking, the average annual area sown to rice in California is about 300,000 acres to 400,000 acres during the last forty years(Fig. 3). California rice is grown under a Mediterranean climate characterized by warm, dry, clear days, and a long growing season favorable to high photosynthetic rates and high rice yields. The average rice yield per acre is probably higher in California than in any other rice-growing regions of the world(Fig. 4). A dependable supply of irrigation water must be available for a successful rice culture. Most of the irrigation water for California rice comes from the winter rain and snow-fed reservoir of the Sierra Nevada mountain ranges. Less than 10 percent of rice irrigation water is pumped from wells in areas where surface water is not sufficient. It is also essential to have good surface drainage if maximum yields are to be produced. Rice production in California is highly mechanized, requiring only about four hours of labor per acre. Mechanization of rice culture in California includes laser-leveler technology, large tractors, self-propelled combines for harvesting, and aircraft for seeding, pest control, and some fertilization. The principal varieties grown in California are medium-grain japonica types with origins from the cooler rice climates of the northern latitudes (Table 1). Long-grain varieties grown in the American South are not well adapted to California's cooler environment. Nearly all the rice grown recently in California are improved into semidwarf varieties. Choice of variety depends on environment, planting date, quality desired, marketing, and harvesting scheduling. The Rice Experiment Station at Biggs is owned, financed, and administered by the rice industry. The station was established in 1912, as a direct result of the foresight and effort of Charles Edward Chambliss of the United States Department of Agriculture. Now, The station's major effort is the development of improved rice varieties for California.

• Korean Journal of Weed Science
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• v.11 no.1
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• pp.32-49
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• 1991

Residual period and carry-over effect of some herbicides were determined using a bioassay method in five winter crops (chinese cabbage, radish, spinach, onion and garlic). The effects were measured at regular time intervals after applling different rates of the herbicides. There were no great differences in residual period and carry-over injury between the soils and kinds of crops used. However, the residual period varied with the herbicides studied and the carry-over injury was rate of the herbicide application, sampling depth of soil, and kind and seeding date of the test plant. When the residual herbicides were applied, the carry-over injury could be minimized by selecting tolerant crops, delaying seeding of the crops after application of the herbicides, and regulating the cultivation depth. Herbicides which showed no residual effect by the end of the cropping period (200-240 days for winter crops) and no carry-over effect were alachlor, trifluralin, ethalfluralin and prometryn. When pendimethalin, metolachlor, linuron and methabenthiazuron were applied at the recommended rate or less, there was no carry-over injury at harvesting time. With doubling the recommended rate, however, the carry-over effect was found in sensitive crops. Napropamide applied in winter crops at rate of 150-300g a.i./10a brought about carry-over injury for such Gramineae as Italian ryegrass, direct-seeded rice and barley, whereas the injury was not found in lowland-transplanted rice, Cruciferae, Cucurbitaceae and Solanaceae. Long residual herbicide nitralin applied at the rate of 75g a.i./10a caused the carry-over injury for Italian ryegrass, direct-seeded rice, baley and lowland-transplanted rice at 275 days in winter crops. In addition, a slight injury occurred in sesame, perilla and spinach, However, there was no injury for Cruciferae, Cucurbitaceae and Solanaceae.

• Korean Journal of Agricultural Science
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• v.42 no.1
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• pp.15-22
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• 2015

This study was conducted to evaluate the phytotoxicity of imazosulfuron+fentrazamide mixture in rice field. It is recommended that safe herbicide application was obtained at 3 cm of transplanting depth and in sandy loam or loam soil type. In the direct water seeding of rice, imazosulfuron+fentrazamide SC should be applied at least 10 days before sowing land ower than 25+100 g ai/ha. In case of imazosulfuron+fentrazamide SC application after sowing, If we use the herbicide 15 days after sowing, no herbicide symptoms will be detected even though the amounts of the herbicide increase. In the rice transplanting, it is recommended that imazosulfuron+fentrazamide GR is applied 5 days after transplanting. In case of sequential herbicide application, the imazosulfuron+fentrazamide SC application at 75+300 g ai/ha 15 or 20 days after transplanting after the application at 25+100 g ai/ha or 50+200 g ai/ha 3 days before sowing increases weed control efficacy and gives no phytotoxicity in the rice growth.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.53 no.4
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• pp.440-446
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• 2008

Successful germination and establishment of seedlings in flooded paddy are critical in direct seeding cultivation of rice. In this study, we examined the relationship between antioxidant enzymes and alcohol dehydrogenase (ADH) activities and coleoptile elongation under submergence of deep water with two rice cultivars, Iksan429 and Woodrose, which show characteristic coleoptile elongation under hypoxic condition. The growth of shoot under submerged in water was faster than the root. The survival duration was longer in Iksan429 than in Woodrose under submerged in water. The alcohol dehydrogenase (ADH) activities were significantly increased under hypoxia compared to in aerated condition. The ADH activity was increased in Iksan429 more than in Woodrose under hypoxia. The superoxide dismutase (SOD) activity in Iksan429 was gradually increased up to 5 days after treatment (DAT) then decreased slowly till 14 DAT under water, whereas in Woodrose it was dramatically decreased after 5 DAT. The peroxidase (POX) activity in Iksan429 was significantly increased until 7 DAT under hypoxia, whereas it was not significantly different in Woodrose during hypoxic treatment. However, in non-treated condition, POX activity in Woodrose was increased more than Iksan429. The changes of catalase (CAT) activities showed no differences in both cultivars. We suggest that the overexpression of ADH, SOD and POX activities is responsible for the hypoxic tolerance and plays an important role in the surviving of rice seedling.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.41 no.3
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• pp.308-317
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• 1996

These experiments were conducted to investigate variation of physical characteristics of the culm related to lodging resistance by nitrogen levels under direct seeding on flooded paddy surface. The number of seedling per m$^2$ were from 103 to 110 plants, and seedling ratios were ranged from 66.7% to 71.2%. The lodging occurrence were increased in order to the nitrogen levels 15 kg, 10 kg, 5 kg /10a, and the lodging resistant varieties ; Dongjinbyeo and Cheongmyungbyeo showed less values of field lodging than those of lodging susceptible varieties ; Daecheongbyeo, Palgongbyeo and H waseongbyeo. The lodging resistance was decreased in semidwarf varieties compare with long culm varieties, but Dongjinbyeo, long culm variety has lodging resistance. The occurrence of lodging decreased with lower values in top moment, but with higher values in the breaking moment with leaf sheath. The root dry weight positively correlated with weight of culm base, but modulus of section was negatively correlated with bending curvature, respectively.