• Magazine of the Korean Society of Agricultural Engineers
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• v.16 no.1
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• pp.3225-3262
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• 1974

The purposes of this thesis are to clarify experimentally the variation of ground water temperature in tube wells during the irrigation period of paddy rice, and the effect of ground water irrigation on the growth, grain yield and yield components of the rice plant, and, furthermore, when and why the plant is most liable to be damaged by ground water, and also to find out the effective ground water irrigation methods. The results obtained in this experiment are as follows; 1. The temperature of ground water in tube wells varies according to the location, year, and the depth of the well. The average temperatures of ground water in a tubewells, 6.3m, 8.0m deep are $14.5^{\circ}C$ and $13.1^{\circ}C$, respercively, during the irrigation period of paddy rice (From the middle of June to the end of September). In the former the temperature rises continuously from $12.3^{\circ}C$ to 16.4$^{\circ}C$ and in the latter from $12.4^{\circ}C$ to $13.8^{\circ}C$ during the same period. These temperatures are approximately the same value as the estimated temperatures. The temperature difference between the ground water and the surface water is approximately $11^{\circ}C$. 2. The results obtained from the analysis of the water quality of the "Seoho" reservoir and that of water from the tube well show that the pH values of the ground water and the surface water are 6.35 and 6.00, respectively, and inorganic components such as N, PO4, Na, Cl, SiO2 and Ca are contained more in the ground water than in the surface water while K, SO4, Fe and Mg are contained less in the ground water. 3. The response of growth, yield and yield components of paddy rice to ground water irrigation are as follows; (l) Using ground water irrigation during the watered rice nursery period(seeding date: 30 April, 1970), the chracteristics of a young rice plant, such as plant height, number of leaves, and number of tillers are inferior to those of young rice plants irrigated with surface water during the same period. (2) In cases where ground water and surface water are supplied separately by the gravity flow method, it is found that ground water irrigation to the rice plant delays the stage at which there is a maximum increase in the number of tillers by 6 days. (3) At the tillering stage of rice plant just after transplanting, the effect of ground water irrigation on the increase in the number of tillers is better, compared with the method of supplying surface water throughout the whole irrigation period. Conversely, the number of tillers is decreased by ground water irrigation at the reproductive stage. Plant height is extremely restrained by ground water irrigation. (4) Heading date is clearly delayed by the ground water irrigation when it is practised during the growth stages or at the reproductive stage only. (5) The heading date of rice plants is slightly delayed by irrigation with the gravity flow method as compared with the standing water method. (6) The response of yield and of yield components of rice to ground water irrigation are as follows: \circled1 When ground water irrigation is practised during the growth stages and the reproductive stage, the culm length of the rice plant is reduced by 11 percent and 8 percent, respectively, when compared with the surface water irrigation used throughout all the growth stages. \circled2 Panicle length is found to be the longest on the test plot in which ground water irrigation is practised at the tillering stage. A similar tendency as that seen in the culm length is observed on other test plots. \circled3 The number of panicles is found to be the least on the plot in which ground water irrigation is practised by the gravity flow method throughout all the growth stages of the rice plant. No significant difference is found between the other plots. \circled4 The number of spikelets per panicle at the various stages of rice growth at which_ surface or ground water is supplied by gravity flow method are as follows; surface water at all growth stages‥‥‥‥‥ 98.5. Ground water at all growth stages‥‥‥‥‥‥62.2 Ground water at the tillering stage‥‥‥‥‥ 82.6. Ground water at the reproductive stage ‥‥‥‥‥ 74.1. \circled5 Ripening percentage is about 70 percent on the test plot in which ground water irrigation is practised during all the growth stages and at the tillering stage only. However, when ground water irrigation is practised, at the reproductive stage, the ripening percentage is reduced to 50 percent. This means that 20 percent reduction in the ripening percentage by using ground water irrigation at the reproductive stage. \circled6 The weight of 1,000 kernels is found to show a similar tendency as in the case of ripening percentage i. e. the ground water irrigation during all the growth stages and at the reproductive stage results in a decreased weight of the 1,000 kernels. \circled7 The yield of brown rice from the various treatments are as follows; Gravity flow; Surface water at all growth stages‥‥‥‥‥‥514kg/10a. Ground water at all growth stages‥‥‥‥‥‥428kg/10a. Ground water at the reproductive stage‥‥‥‥‥‥430kg/10a. Standing water; Surface water at all growh stages‥‥‥‥‥‥556kg/10a. Ground water at all growth stages‥‥‥‥‥‥441kg/10a. Ground water at the reproductive stage‥‥‥‥‥‥450kg/10a. The above figures show that ground water irrigation by the gravity flow and by the standing water method during all the growth stages resulted in an 18 percent and a 21 percent decrease in the yield of brown rice, respectively, when compared with surface water irrigation. Also ground water irrigation by gravity flow and by standing water resulted in respective decreases in yield of 16 percent and 19 percent, compared with the surface irrigation method. 4. Results obtained from the experiments on the improvement of ground water irrigation efficiency to paddy rice are as follows; (1) When the standing water irrigation with surface water is practised, the daily average water temperature in a paddy field is 25.2$^{\circ}C$, but, when the gravity flow method is practised with the same irrigation water, the daily average water temperature is 24.5$^{\circ}C$. This means that the former is 0.7$^{\circ}C$ higher than the latter. On the other hand, when ground water is used, the daily water temperatures in a paddy field are respectively 21.$0^{\circ}C$ and 19.3$^{\circ}C$ by practising standing water and the gravity flow method. It can be seen that the former is approximately 1.$0^{\circ}C$ higher than the latter. (2) When the non-water-logged cultivation is practised, the yield of brown rice is 516.3kg/10a, while the yield of brown rice from ground water irrigation plot throughout the whole irrigation period and surface water irrigation plot are 446.3kg/10a and 556.4kg/10a, respectivelely. This means that there is no significant difference in yields between surface water irrigation practice and non-water-logged cultivation, and also means that non-water-logged cultivation results in a 12.6 percent increase in yield compared with the yield from the ground water irrigation plot. (3) The black and white coloring on the inside surface of the water warming ponds has no substantial effect on the temperature of the water. The average daily water temperatures of the various water warming ponds, having different depths, are expressed as Y=aX+b, while the daily average water temperatures at various depths in a water warming pond are expressed as Y=a(b)x (where Y: the daily average water temperature, a,b: constants depending on the type of water warming pond, X; water depth). As the depth of water warning pond is increased, the diurnal difference of the highest and the lowest water temperature is decreased, and also, the time at which the highest water temperature occurs, is delayed. (4) The degree of warming by using a polyethylene tube, 100m in length and 10cm in diameter, is 4~9$^{\circ}C$. Heat exchange rate of a polyethylene tube is 1.5 times higher than that or a water warming channel. The following equation expresses the water warming mechanism of a polyethylene tube where distance from the tube inlet, time in day and several climatic factors are given: {{{{ theta omega (dwt)= { a}_{0 } (1-e- { x} over { PHI v })+ { 2} atop { SUM from { { n}=1} { { a}_{n } } over { SQRT { 1+ {( n omega PHI) }^{2 } } } } LEFT { sin(n omega t+ { b}_{n }+ { tan}^{-1 }n omega PHI )-e- { x} over { PHI v }sin(n omega LEFT ( t- { x} over {v } RIGHT ) + { b}_{n }+ { tan}^{-1 }n omega PHI ) RIGHT } +e- { x} over { PHI v } theta i}}}}{{{{ { theta }_{$\infty$ }(t)= { { alpha theta }_{a }+ { theta }_{ w'} +(S- { B}_{s } ) { U}_{w } } over { beta } , PHI = { { cpDU}_{ omega } } over {4 beta } }}}} where $\theta$$\omega$; discharged water temperature($^{\circ}C$) $\theta$a; air temperature ($^{\circ}C$) $\theta$$\omega$';ponded water temperature($^{\circ}C$) s ; net solar radiation(ly/min) t ; time(tadian) x; tube length(cm) D; diameter(cm) ao,an,bn;constants determined from $\theta$$\omega$(t) varitation. cp; heat capacity of water(cal/$^{\circ}C$ ㎥) U,Ua; overall heat transfer coefficient(cal/$^{\circ}C$ $\textrm{cm}^2$ min-1) $\omega$;1 velocity of water in a polyethylene tube(cm/min) Bs ; heat exchange rate between water and soil(ly/min)

• KOREAN JOURNAL OF CROP SCIENCE
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• v.53 no.spc
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• pp.31-36
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• 2008

This study was carried out to clarify the effect of silicate application on rice grain quality and storage characteristics in Ilpumbyeo cultivar. In yield and yield components, panicles and spikelet numbers were increased and ripened grain rate was also increased by 2%. Head rice yield was increased by $7.7{\sim}9.5%$ in silicate application. Protein content of milled rice was reduced by $0.2{\sim}0.3%$ and head rice rate was increased by $2.9{\sim}6.7%$ in silicate application due to decrease of chalky and damaged rice rate. In milling characteristics, color separation rate was improved by $4.2{\sim}7.2%$ and colored rice rate was decreased by $5.5{\sim}16.6%$ in silicate application. Acid value of stored brown rice were increased slowly in low temperature and silicate application, but that in room temperature and no silicate application was increased remarkably. The best degree rate of stored brown rice (over than 7.5 of pH) measured by the pH of grain was increased by the silicate application in both low and room temperature. Therefore, it was suggested that the storage characteristics of rice grain was improved by the silicate application.

• The Plant Pathology Journal
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• v.22 no.3
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• pp.278-282
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• 2006

Bacillus vallismortis EXTN-1, a biocontrol agent in cucumber, tomato and potato was tested in rice pathosystem against rice fungal pathogens viz. Magnaporthe grisea, Rhizoctonia solani and Cochliobolus miyabeanus. Apart from increasing the yield in the bacterized plants (11.6-12.6% over control), the study showed that EXTN1 is effective in bringing about disease suppression against all the tested fungal pathogens. EXTN-l treatment resulted in 52.11% reduction in rice blast, 83.02% reduction in sheath blight and 11.54% decrease in brown spot symptoms. As the strain is proven as an inducer for systemic resistance based on PR gene expression in Arabidopsis and tobacco models, it is supposed that a similar mechanism works in rice, bringing about disease suppression. The strain could be used as a potent biocontrol and growth-promoting agent in rice cropping system.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.53 no.spc
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• pp.15-18
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• 2008

This study was conducted to analyze the rice yield and grain quality of viviparous germinated seeds caused by long period rainy days. In the yield characteristics, the milled/brown rice rates in two cultivars, Unkwangbyeo and Gopumbyeo were 86.0 and 80.9%, respectively, in viviparous germinated seeds, showing the decreased rates by 3.2 and 6.2%, respectively, as compared to 89.2 and 87.1% in normal seeds. Rice yield in Unkwangbyeo and Gopumbyeo also decreased by 5 and 7%, respectively, in viviparous germinated seeds as compared to normal seeds. Peak viscosity and set back of viviparous germinated seeds were decreased, and the hardness of them was increased compared to normal seeds. Color value (a) of viviparous germinated seeds was 0.90, showing lower value than that (1.65) of normal seeds of Gopumbyeo. The results demonstrated that as the viviparous germinating rate was increased, the grain quality was deteriorated.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.1 no.1
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• pp.26-31
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• 1963

1. This experiment was conducted with paddy rice in replicated field plot of clay load in Chung Puk College. This experiment has been intended to find out the suitable polt for increasing the yield of rice plant among the 36 plots which consist of 3 factors; deep plowing, heavy fertilizer and thick planting. 2 According to the standard and the heavy fertilizer applications, spikes and grains per phyung have been compared. It has been find out that the higher yield can be obtain in such plots as these; (1) the plot with standard fertilizer application, 15cm plowing depth and 400 hill per phyung, (2) the plot with two times as much fertilizer application, 30 cm plowing depth and 300 hills per phyung, (3) the plot with three times as much fertilizer application, 30cm plowing depth and 300 hills, or 45cm plowing depth and 400hills per phyung. 3. In the yield of brown rice, there has been significant difference in each main factor: hills per phyung, the plowing depth and the amount of fertilizer, and in the first order interaction; depthxfertilizer, depthxhills and hillsxfertilizer, and in the 2nd order interaction; depthx hillsxfertilizer. 4. In the plots with 30cm plowing depth, thick, planting of 200∼300 hills per phyung and two times as much fertilizer, the yield of rice has been superior to others.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.10
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• pp.61-71
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• 1971

This study was conducted in order to investigate the effects of slaked lime and borax on the Akiochi paddy field. The pot trial(slaked lime was treated 0, 6, 10, 15g and borax 0, 0.75, 1.5g per pot) and the field trial(slaked lime was treated 0, 100, 200kg and borax 0, 10, 30, 50kg per 10are) respectively. The results are summarized as fo11ows. I. Pot Trial: 1. In a heavy treated of borax, appeared chlorosis on whole leaves(bottom) in early growing stage, However, in about 25 days after transplanting, these chlorosis were disappeared gradually. And in proportion to close by maturity after the ear-heading, changed to dark brown color and rolled at the end of upper leaves, finally withered. At the same time the part of the end of grains was also colored to dark brown. 2. Slaked lime effected to increase the ti1lering, hence increased the number of ear, on the other hand, borax showed the tendency of repression the tillering, conversely. 3. Borax effected to hurried up to heading date of rice plant, to which borax had been the plot of B$_1$ to 3 days and B$_2$ to 5 days, hurried up than control respectively, regardless of the quantities of slaked lime application. 4. According to the application of borax, the length of culm were shortened, otherwise the length of panicle were longished, then no recognized the. independent effect of slaked lime. 5. The number of grains per panicle were seemed like increased by treatment of slaked lime, but the grain were decreased in the heavy treatment of slaked lime and borax. These phenomena were showed in ratio of maturity likely tendency as above. 6. In the 1, 000 grains weight of brown rice, in the case of slaked lime was almost no significant, otherwise by increase the application of borax, increased the weight of 1, 000 grains and the size of the grains was greater. 7. The weight of rough rice and straw were showed the same tendency as the number of grains and maturity ratio. particularly, showed the phenomenon of the reduction by the heavy application of borax. II. Field trial: 1. In a heavy treated of borax, appeared chlorosis in a early growing stage, according to close by maturiting date after the ear-heading changed to dark brown the end of upper leaves, finally dried. 2. Slaked lime application accelerated the growth and increased the number of ear, but borax showed the tendency of repression the tillering. 3. Borax effected to hurried up to heading date of rice plant, according to heavy treatment of borax quickened heading date for 4 to 5 days. 4. As a whole, culm length was repressed by borax treatment. 5. Borax application 10kg per 10are advanced progress the maturity, but in the case of above 30kg per 10are of borax showed the tendency obstruction the maturity. 6. The yield of rough rice and brown rice recognized the independent effect of slaked lime and borax, respectively. the yield was decreased by the abundant of borax.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.339-339
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• 2017

The long grain rice varieties adaptable to South-east Asia tropical regions were tried to develop in Cambodian Agriculture Research and Development Institute (CARDI), Cambodia. The final goal is to develop rice varieties which can culture in diverse environmental conditions of tropical regions of South-east Asia under climate change. We collected and evaluated for agronomic traits of 131 rice germplasm from Cambodia, China, India, Indonesia, Myanmar, Philippines and Vietnam in CARDI. We selected core germplasm including leading varieties of target countries and made 813 F1 cross combinations between leading varieties of each country and promising germplasm of high yield potential, resistance to biotic/abiotic stresses, aromatic rice, and so on. Out of 607 F1s evaluated to heading date, plant type, agronomic traits, and grain type, 106 F1s selected and advanced to F2 populations. 106 F2 populations were evaluated to major agronomic traits, grain type and yield-component traits, and selected 2,560 plants in 62 F2 populations. During six seasons in 2014~2016, the lines of F3 subsequent-generation were cultured a total of 6,256 lines. In yield trial for promising lines in F5 generation, the growth duration from sowing to harvesting was 97~114 days. These lines were 88~129 in number of grain per panicle, an average of 84.6% in the range of 79.3~91.9% in the percentage of ripened grain and 17.5~22.8g in 1000-brown rice weight. The rough rice yields were in the range of 4.33~6.06 ton/ha with an average of 5.23 ton/ha. The yield was increased to 5~47% than Chulsa and 12~41% than IR66. Five lines, KR54-28-1, KR55-14-2, KR57-5-2, KR67-57-2 and KR128-19-1 were 5.33~6.06 ton/ha in rough rice yield. These high yield potential lines would be evaluated to adaptability in Cambodia, Laos, Myanmar and Vietnam during 2017.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.155-155
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• 2017

The long grain rice varieties adaptable to South-east Asia tropical regions were tried to develop in Cambodian Agriculture Research and Development Institute (CARDI), Cambodia. The final goal is to develop rice varieties which can culture in diverse environmental conditions of tropical regions of South-east Asia under climate change. We collected and evaluated for agronomic traits of 131 rice germplasm from Cambodia, China, India, Indonesia, Myanmar, Philippines and Vietnam in CARDI. We selected core germplasm including leading varieties of target countries and made 813 F1 cross combinations between leading varieties of each country and promising germplasm of high yield potential, resistance to biotic/abiotic stresses, aromatic rice, and so on. Out of 607 F1s evaluated to heading date, plant type, agronomic traits, and grain type, 106 F1s selected and advanced to F2 populations. 106 F2 populations were evaluated to major agronomic traits, grain type and yield-component traits, and selected 2,560 plants in 62 F2 populations. During six seasons in 2014~2016, the lines of F3 subsequent-generation were cultured a total of 6,256 lines. In yield trial for promising lines in F5 generation, the growth duration from sowing to harvesting was 97~114 days. These lines were 88~129 in number of grain per panicle, an average of 84.6% in the range of 79.3~91.9% in the percentage of ripened grain and 17.5~22.8g in 1000-brown rice weight. The rough rice yields were in the range of 4.33~6.06 ton/ha with an average of 5.23 ton/ha. The yield was increased to 5~47% than Chulsa and 12~41% than IR66. Five lines, KR54-28-1, KR55-14-2, KR57-5-2, KR67-57-2 and KR128-19-1 were 5.33~6.06 ton/ha in rough rice yield. These high yield potential lines would be evaluated to adaptability in Cambodia, Laos, Myanmar and Vietnam during 2017.

• Korean Journal of Environmental Agriculture
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• v.27 no.4
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• pp.373-381
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• 2008

To select of optimum rice species and germanium (Ge) application method for production of functional rice with Ge, the growth characteristics, Ge absorption and grain quality of rice plant were investigated under different rice species (Hopyungbyeo, Junambyeo, Ilmeebyeo and Dongjinbyeo) and Ge application method (soil application and foliar spray). The rice yield by soil application was higher in the order of Hopyungbyeo $\fallingdotseq$ Junambyeo > Ilmeebyeo >> Dongjinbyeo. On the other hand, the rice yield by foliar spray was higher in the order of Junambyeo >> Ilmeebyeo > Dongjinbyeo > Hopyungbyeo. The rice yield by soil application was higher than that by foliar spray regardless of rice species. For soil application, the Ge absorption in various parts of the rice was higher in the other of rice bran > brown rice > polished rice regardless of rice species. The Ge absorption of brown rice in Hopyungbyeo, Ilmeebyeo, Dongjinbyeo and Junambyeo by soil application was 14.5, 8.0, 11.6 and $10.4\;mg\;kg^{-1}$, respectively. In leaf, stem and root, the Ge absorption by foliar spray was higher than that by soil application, whereas, in rice bran, brown rice and polished rice, the Ge absorption by soil application was higher than that by foliar spray. The optimum rice species and Ge application method were demonstrated to be Hopyungbyeo and soil application, respectively, which provided suitable conditions for production of functional rice with Ge.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.34 no.1
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• pp.60-73
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• 1989

Two field experiments were carried out to assess the applicability of a central composite design (CCD) in determining optimum culture condition of an early rice cultivar, Unbongbyeo in southern Korea. A central composite design with two replicates was applied to five levels of five factors such as the number of hills per 3.3m2, the number of seedlings per hill, the levels of nitrogen, the transplanting date and the seedling age (Experiment 1). The levels of planting density were ranged from 30 hills to 150 hills per 3.3m2 ; the number of seedlings per hill from 1 seedling to 9 seedlings per hill; the levels of nitrogen application from 1 kg/l0a to 21 kg/l0a; the transplanting date from June 15 to July 5; the seedling age from 25 days to 45 days. A fractional factorial design was applied to three levels of five factors tested in CCD (Experiment 2). Yield per hill and per unit area were examined and the results obtained from both experiments were compared. The benefits from the central composite design were discussed. Maximum yield of brown rice per unit area was obtained at the combination of the central levels of one of five factors when the other four factors were fixed at central point. Furthermore, brown rice yield per unit area affected by interaction of two factors was maximized at the central point when the remain three factors being fixed at the central level. The responses of five factors to brown rice yield per hill and unit area were found to be a saddle point in both designs. Actual values of the stationary points were 107 hills per 3.3 m2, 4 seedlings per hill, 10 kg nitrogen per l0a, transplanting date of rice on June 26 and 33 days of seedling age in the central composite design. Brown rice yield per unit area at the stationary points were estimated 439 kg/l0a in the central composite design and 442 kg/l0a in the fractional factorial design. Considering the number of experimental treatment combinations, the central composite design was rather convenient in reducing the number of treatment combinations for similar information. It was more convenient for an experimenter to present the results from the central composite design than those from the fractional factorial design. Considering the optimum yields of brown rice per unit area at the stationary points being verified as saddle points in both designs. inter-heterogeneity of each of the factors should be avoided in setting up factors in pursuit of inducing unidirectional response of the factors to yield. Even though both the lower and higher levels in the central composite design being beyond the region of an experimenter's interest. they were considered highly valued in interpretation of the results. Conclusively. the central composite design was found to be more beneficial to optimize culture condition of paddy rice even with several levels of various factors were involved.