• KOREAN JOURNAL OF CROP SCIENCE
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• v.62 no.3
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• pp.193-202
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• 2017

This study was carried out in 2014 and 2015 to investigate the effect of transplanting density on panicle production and to analyze the relationship of panicle production with yield traits in the mid-maturing quality rice cultivar 'Haiami' in the mid-plain area of Korea. Number of tillers per square meter increased by reducing planting distance and increasing seedling number per hill. These effects were maintained until maturity and were reflected in the final number of panicles per square meter, although the effect of planting density decreased as rice growth progressed. However, increased panicle number per square meter following dense planting did not improve head rice yield. Panicle number per square meter was negatively associated with spikelet number per panicle and was not correlated with other yield components or head rice yield. Head rice yield was not correlated with head rice percentage but was closely and positively correlated with milled rice yield. Milled rice yield did not increase with grain filling percentage but increased with spikelet number per square meter. Spikelet number per square meter increased with both spikelet number per panicle and panicle number per square meter, although the former had a greater influence. Therefore, we conclude that head rice yield of the 'Haiami' cultivar grown in the mid-plain area of Korea is not improved with an increased panicle number following high planting density but it could be improved with high milled rice yield by increasing spikelet number per unit area.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.67 no.4
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• pp.342-361
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• 2022

In order to evaluate the effect of nitrogen application levels on yield and quality of rice varieties, a field experiment was conducted at National Institute of Crop Science of Korea from 2018 to 2020. Five levels (0, 3, 5, 7, and 9 kg/10a) of nitrogen fertilizer were treated to 21 Korean rice varieties. Yield, yield component, appearance quality, and protein content in rice were analyzed. The average head rice yield for 3 years decreased by 28%, 22%, 11%, and 8%, respectively, when cultivated with 0, 3, 5, and 7 kg/10a nitrogen application compared to cultivation with a standard nitrogen application amount, 9 kg/10a. The number of panicles per hill increased as the amount of nitrogen application increased, but there was no significant change in the number of grains per panicle and 1000-grains weight, and the number of panicles per hill showed relatively small annual variation compared to other yield components. There was no significant difference in the head rice ratio according to the nitrogen application amount, the broken rice ratio slightly decreased, and the floury rice ratio increased. The protein content of rice decreased with increasing nitrogen application in 2018 and 2019, and was the lowest at 7 kg/10a of nitrogen application, and showed a tendency to increase again at 9 kg/10a. In the case of 2020, as the amount of nitrogen application increased, the protein content showed a tendency to continuously increase. In terms of varieties, 13 varieties, including Chilbo, seemed to be capable of low-nitrogen cultivation because loss of the head rice yield was less and the protein content could be lowered to 6% or less according to 7 kg/10a nitrogen application.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.spc1
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• pp.73-76
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• 2006

This study was carried out to investigate the change yield and grain quality in rice caused by damages of brown planthopper (Bph) on major agronomic traits at the ripening stage. A major agronomic traits such as culm length, panicle length, number of panicle and number of grain per panicles was no-significant difference compared hopperburn area (HBA) and moderately damaged area (MDA) by brown planthopper with non-damaged area (NDA). but, the ripeing ratio and yield in HBA and MDA was significantly decreased. The perfect rice of brown rice in HBA and MDA was also lowered than the NDA and the immatured grain among imperfect rice in damaged area by BPH was significantly increased than in the NDA. Among the traits related with palatability of cooked rice, the amylose content was not affected by damage of brown planthopper, whereas, the protein content was significantly increased in the HBA and MDA. additionally, Peak viscosity in HBA and MDA is lower than the NDA, and setback was increased. In most cases, there was negative on yield and grain quality by the damage of brown planthopper at the ripening stage. Thus, the rice product harvested in damaged area should be separated with that in non damaged area for grain market quality of milled rice.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.59 no.2
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• pp.174-180
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• 2014

This study was conducted to know the effect of low radiation during grain filling stage of rice on its grain yield, components, physicochemical properties and palatability, compared to the effect of natural light. Ripened grain ratio, 1000 grain weight of brown rice, milled rice yield of Mipum, Hopum, and Sindongjin were reduced as the shading treatments become higher. After harvest, physicochemical properties of rice influencing eating quality were investigated. Protein content of milled rice was increased, but palatability was decreased by shading treatments. Change of milled rice proteins and palatability due to shading treatments were found to be less in Mipum than that in Hopum and Sindongjin. With regard to amylogram properties, shading treatments resulted in a significant decrease in peak trough final breakdown viscosities of rice flour, though it increased pasting temperature and setback viscosity. The degree of the 55% shading effect was more intensive than the 35% shading effect in changes of ripened grain ratio, 1000 grain weight of brown rice, milled rice yield and milled rice protein.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.50 no.spc1
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• pp.41-45
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• 2005

This experiment was carried out to identify the proper transplanting time at reclaimed saline land in the southwestern area of Korea from 2002 to 2004. The rice cultivars tested were Samcheonbyeo(Early maturing one), Nampyeongbyeo (Medium maturing one) and Hwaseongbyeo(Mid-late maturing one). The results are summarized as follows: No. of spikelet per the unit area was higher at transplanting on May 20 than those of the other transplanting time. when Samcheonbyeo was transplanted early, the ripened grain rate was high. But, Hwaseongbyeo and Nampyeongbyeo wasn't differ among transplanting time. The yield of milled and head rice(YMHR) was high transplanted May 20 in Samcheonbyeo, May 30 in Hwaseongbyeo, from May 20 to June 9 in Nampyeongbyeo. Among the varieties YMHR was higher in the order of Hwaseongbyeo, Samcheonbyeo and Nampyeongbyeo. There wasn't different of amylose and protein content among the transplanting time and varieties. But, palatability value was low transplanted early(May 20). Considering the rice growth, the rice good quality, the yield of milled and head rice, the proper transplanting time was May 20 to May 30 in Samcheonbyeo and Hwaseongbyeo, whereas Nampyeongbyeo was from May 20 to-June 9.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.5
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• pp.369-378
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• 2006

For precision farming the influences of site-specific N application on rice grain yield and quality were investigated in 0.5 ha paddy field from 2001 to 2003. In pre-cultured soil, EC, O.M., total nitrogen, phosphate and potassium content showed high spatial variation, ranging from 11.63 to 52.03% of coefficient of variation, while that of pH was relatively low. In rice growth characteristics, tiller number at panicle formation stage was more than 10% in coefficient of variation, but plant height, SPAD figure at panicle formation stage and milled rice yield, protein content in brown rice showed less below 10%. Spatial dependence was over 0.60 in pH, total nitrogen, phosphate and potassium in pre-cultured soil and was over 0.50 in plant height, SPAD figure and protein content, while it was below 0.22 in tiller number at panicle formation. The range of spatial dependence was longer than 20m in all factors except for protein content in brown rice. Basal dressing nitrogen rate was positively correlated with PH, $SiO_{2}$, plant height and SPAD figure. Nitrogen fertilization rate at panicle formation stage was positively correlated with EC and O.M.. Protein content in brown rice was positively correlated with $SiO_{2}$ in pre-cultured soil. Milled rice yield was positively correlated with plant height, tiller number and SPAD figure at panicle formation stage.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.54 no.4
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• pp.339-345
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• 2009

This experiment was carried out to identify the proper transplanting time at reclaimed saline land in the southwestern area of Korea from 2006 to 2007. The rice cultivars tested were Unkwangbyeo(Early maturing one), Gopumbyeo(Medium maturing one) and Samgwangbyeo, Sindongjinbyeo, Cheonghobyeo, Hopyeongbyeo(Mid-late maturing one). The results are summarized as follows. No. of spikelet per the unit area was lower at transplanting on May 20 and wasn't different in those of the other transplanting time. The ripened grain rate was high transplanted May 20 in Unkwangbyeo, but high transplanted from June 1 to June 20 in Mid-late maturing Cultivar. The yield of head rice was high transplanted June 10 and June 20 in Unkwangbyeo, Sindongjinbyeo, Hopyeongbyeo, but June 1 and June 20 in Samgwangbyeo, Cheonghobyeo. The protein content was high transplanted early in Unkwangbyeo, Samgwangbyeo, and late in Gopumbyeo, Sindongjinbyeo, Cheonghobyeo, but wasn't differ among transplanting time in Hopyeongbyeo. Considering the rice growth, the rice good quality, the yield of milled and head rice, the proper transplanting time was June 10 in Unkwangbyeo, Sindongjinbyeo, whereas was June 10 in Samgwangbyeo, Cheonghobyeo, Hopyeongbyeo.

• Journal of the Korea Organic Resources Recycling Association
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• v.27 no.1
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• pp.5-14
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• 2019

The objective of this study was investigated the effect of organic fertilizer(OF) application on the grain yield, protein content, and soil chemical properties in rice cultivation to evaluate the replacement ratio of OF based on basal fertilization of inorganic(nitrogen) fertilizer, In case of soil 1 with optimum range of organic matter for rice growth, the grain yield of rice in 70% and 100% treatments of OF were higher than the other treatments. In soil 2 with higher than the optimum range of soil organic matter, the grain yield of rice of NPK, 30%, 70%, 100%, and 300% treatments of OF showed no significant difference. When the protein criteria of rice quality was below 7%, the treatment of 30%, 70%, and 100% using OF in soil 1 were satisfied with protein criteria of rice. In case of soil 1, ammonium nitrogen content, electrical conductivity, and the organic matter in 30%, 70%, 100%, 300% treatments of OF showed similar tendency to NPK treatment. These results suggested that the substitution ratio of OF 70~100% could be appropriate to increase the yield and commercial quality for rice.

• Korean Journal of Soil Science and Fertilizer
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• v.35 no.5
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• pp.296-305
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• 2002

Rice yield and grain guality were investigated with treatments of silicate fertilizer, straw compost and NPK fertilizer in the paddy soil of silty clay loam from 1975 to 2001. Rice yield of the treatments of silicate fertilizer. $1,500kg\;ha^{-1}$ and straw compost $10,00kg\;ha^{-1}$ were increased by 15%, 10%, respectively, for 27years average yield in comparison with NPK plot. In the plots of NPK+silicate fertilizer $1,500kg\;ha^{-1}$, NPK+silicate fertilizer $2,500kg\;ha^{-1}$, taste value(Toyo instrument) of cooked rice and quality assessment were higher than those in NPK control plot and NPK+straw compost $10,000kg\;ha^{-1}$ plot, but the contents of crude protein, amylose of milled rice grain were lower than those in other treated plots. Nitrogen and phosphorous contents of rice plant were lower, but $SiO_2$ content were higher in the treatment of silicate ferti lizer 1,500, $2,500kg\;ha^{-1}$ than straw compost $10,000kg\;ha^{-1}$ plot. Rice quality assessment was positively correlated with taste value, but it was negatively correlated with crude protein and amylose content of milled rice grain. Ratios of Mg/N, $Mg/N{\cdot}K_2O$, $SiO_2/N$, $SiO_2/P_2O_5$ and $SiO_2/K_2O$ were positively correlated with taste value and quality assessment of rice grain, but negatively correlated with crude protein, amylose and fatty acid content. In soil chemical characteristics related with rice quality after experiment in 2001, soil pH and $SiO_2$ content were positively correlated with taste value and quality assessment of rice grain, but contents of soil $P_2O_5$, ex-K were negatively correlated with them.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.40 no.4
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• pp.437-443
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• 1995

Concerns on use of excess amount of chemical fertilizier and pesticide in current farming system turns both of the producer and consumer of agricultural products to an organic farming which use a less chemicals and more natural manure. Rice-duck farming system is one of the strategy to meet the purpose and this experiment was carried out to find the effect of the rice-duck farming system on the quality and yields of rice. 20day-old rice seedling were mechanically transplanted in sandy-loam paddy field and 21 day-old ducks were raised from 3 weeks after transplanting with population of 30 heads per 10a. The plots were consists of reduce fertilizer(70%) with and without duck-raising. The conventional fertilizer treatment without duck-raising was used as check. The results obtained are summarized as follows. The weeds population of test plots which were raised with duck for 3 consecutive years was less than that of test plots without duck-raising, though a speciffic population of Echinochola crusgallis were increased. The weed control effect was higer in duck-raising than in check at the maximum tillering stage but, not at later stages of rice plant. It was found that the small animals and insects inhibiting in the rice field were reduced by duck-treatment, however, there were also damages of grass leaf roller at booting stage in the plots of duck-raising. In rice-duck plot, dark green leaf color were found: 41.8 of SPAD value than 38.6 of SPAD in check plot. Higher root activity and surface soil oxidation were also observed in rice-duck plot than check plot. 3% of the increase in yield was observed by duck-treatment. However, the expected increase of the palatability wsa not observed. This may be due to the unfavorable weather conditions during the rice growing in this expriment.