• Proceedings of the Korean Society of Crop Science Conference
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• 1994.10a
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• pp.64-65
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• 1994

• 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.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.122-122
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• 2022

In order to investigate changes in rice yield and quality according to phosphate and potassium fertilization levels when nitrogen fertilizer was applied at 7 kg·10a^-1, a field experiment was conducted at National Institute of Crop Science of Korea in 2021. Three Korean rice varieties were grown in paddy fields, and phosphate and potassium fertilizer were treated at three levels(N-P-K 7-4.5-5.7 kg·10a^-1, 7-3-3 kg·10a^-1, 7-0-0 kg·10a^-1). When phosphate and potassium fertilizers were not treated, the yield of Ilpum and Chilbo was significantly reduced, and there was no significant difference in Hopyung. The head rice ratio was significantly lower in the untreated plot of Hopyung and Chilbo, but there was no significant difference in the Ilpum. Protein content was significantly decreased in the untreated plot of Chilbo, and there was no significant difference in other varieties. As a result of this study, it was confirmed that yield, head rice ratio, and protein content were lowered when phosphate and potassium fertilizers were not treated, and the degree of decrease was different depending on the variety.

• Journal of Animal Environmental Science
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• v.13 no.2
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• pp.139-146
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• 2007

Field experiment was conducted to assess the influence of liquid compost supplemented with chemical fertilizer on the rice growth and yield in 2005. Treatments consisted of liquid compost supplemented with chemical fertilize.(LCSC), liquid manure(LM), chemical fertilizer(CF), LCSC 50% + 50%CF, LCSC 75% + 25%CF. The plant height and tiller's number in plots of 100% basal application plot by LCSC and LM plot were lower than that of chemical fertilizer. But in the plot of basal application by LCSC and top dressing by chemical fertilizer, the height and tilters of rice were significantly difference with LM application plot. And the leaf color the plots by LCSC and chemical fertilizer was darker than that of the LM application plot. In plots by LCSC treatment, number of panicles per hill was higher that of LM plot. As the plot of 100% basal application by LCSC was fertilized, the yield of rice was decreased compared with chemical fertilizer. But the rice yield of basal fertilization by LCSC and top-dressing by chemical fertilizer was 7% increased compared with LM plot. The application plots by LCSC + chemical fertilizer plot were maintained productivity of rice, the rice should be fertilized with the basal application of LCSC and top-dressing of chemical fertilizer. The quality of brown rice was best in LM and LCSC plot, whereas in chemical fertilizer plot, it was the worst by increased of protein content. The results indicates that the application of LCSC + chemical fertilizer improves quality of rice rather quantity.

• Korean Journal of Organic Agriculture
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• v.24 no.2
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• pp.221-234
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• 2016

The application of animal manure on farm fields is one of the most economical ways. However, the continuous application of manure in paddy fields might change soil properties influencing the growth of rice plant. Thus, this study was conducted to investigate the changes in selected chemical and biological properties of soils and rice production as affected by the applications of two different fertilizer sources, which were the consecutive applications of liquid swine manure (LSM) and chemical fertilizer (CF), during the three experimental years, from 2012 to 2014. Application amount of LSM was based on 100% of nitrogen fertilizer recommendation rate for rice cultivation estimated by soil testing. Plant height and tiller number in rice at the first year of liquid swine manure manure plot were lower than those of chemical fertilizer plot. Height and tillers of rice in liquid swine manure plot were higher than those of rice in chemical fertilizer plot after consecutive application for 3 years. Rice yield In the first year of application was decreased by 7% than that of chemical fertilizer, but the yield of rice in the third year of application in LM 100% plot was increased by 8% compared to the chemical fertilizer. Toyo-taste value of milled rice in LM 100% was decreased by increasing of protein contents and decreasing rate of perfect grain. The K and Zn contents in the soil were increased in the plots of consecutive LSM application. The results implied that the liquid manure may neither decrease the yield of rice and nor increase soil properties except K and Zn in the soil, and decrease rice quality.

• Korean Journal of Organic Agriculture
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• v.20 no.4
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• pp.631-642
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• 2012

This study was carried out to determine the effect of SCB compost leachate on the growth and yield of rice. Field experiment was conducted on sandy loam soil under the different fertilizer management; 80%, 100%, 130% N level of SCB leachate based on 13kg N/10a of conventional farmer application level and chemical fertilizer as control. The plant height and tiller's number of 80 and 100% N levels of SCB leachate were lower than that of the chemical fertilizer plot. But in the plot of 130% N level of SCB leachate the plant height and tillers was higher than that of chemical fertilizer. And the SPAD reading value of leaf in plot of 130% N level was higher than that of the chemical fertilizer. Rice yield in the 80% and 100% SCB leachate was increased from 12 to 13% that of plot of chemical fertilizer. But rice yield of 130% N-level was decreased 7% compared with chemical fertilizer. Rice quality of the application levels of 80 and 100% SCB leachate levels was significantly better than those of chemical fertilizer and 130% level of SCB leachate. In conclusion, the 100% N application of SCB leachate was improved yield and quality of rice.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.49 no.3
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• pp.194-198
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• 2004

This study was conducted to identify the appropriate nitrogen fertilizer application rate for improving rice quality in tidal reclaimed area, at the Gyehwado substation of the Honam Agricultural Research Institute during 2002-2(103. The experimental fields contained 0.1% (low salinity) and 0.3-0.4% (medium salinity) Nacl in soil solution. Plant height at panicle formation stage was tall ay heavy nitrogen level and the effect of heavy nitrogen was higher in low than in high soil salinity condition. Heading date was not affected by applied nitrogen levels from 8 to 16 kg/10a in low soil salinity condition but it was one day later in 24 kg/10a nitrogen level when compared with the standard nitrogen level,20 kg/10a. In middle soil salinity condition, the heading date was one day earlier in 8 to 16 kg/10a and similar in 24 kg/10a, when compared with 20 kg/10a nitrogen level. And also it was four days later in middle than in low soil salinity condition. In low soil salinity condition, grain number $\textrm{m}^2$ increased but ripened grain ratio decreased as the nitrogen application increased and finally, milled rice yield was not different among heavy nitrogen application levels compared with 12 kg/10a. Head rice ratio was high and protein content was low in 12 kg/10a or lower nitrogen level. In middle soil salinity condition, grain number $\textrm{m}^2$ increased and ripened grain ratio was not affected as the nitrogen application increased. And finally, milled rice yield increased with increasing nitrogen application levels, Head rice ratio was high and protein content was not affected by nitrogen application levels. Therefore, on the basis of milled rice yield and rice grain quality inreclaimed land, the appropriate nitrogen application level would be 12 kg/10a in low soil salinity condition and 20 kg/10a in middle soil salinity condition.

• Journal of Crop Science and Biotechnology
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• v.10 no.1
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• pp.33-38
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• 2007

Nitrogen management at the panicle initiation stage(PI) should be fine-tuned for securing a concurrent high yield and high quality rice production. For calibration and testing of the recommendation models of N topdressing rates at PI for target grain yield and protein content of rice, three split-split-plot design experiments including five rice cultivars and various N rates were conducted at the experimental farm of Seoul National University, Korea from 2003 to 2005. Data from the first two years of experiments were used to calibrate models to predict grain yield and milled-rice protein content using shoot fresh weight(FW), chlorophyll meter value(SPAD), and the N topdressing rate(Npi) at PI by stepwise multiple regression. The calibrated models explained 85 and 87% of the variation in grain yield and protein content, respectively. The calibrated models were used to recommend Npi for the target protein content of 6.8%, with FW and SPAD measured for each plot in 2005. The recommended N rate treatment was characterized by an average protein content of 6.74%(similar to the target protein content), reduced the coefficient of variation in protein content to 2.5%(compared to 4.6% of the fixed rate treatment), and increased grain yield. In the recommended N rate treatments for the target protein content of 6.8%, grain yield was highly dependent on FW and SPAD at PI. In conclusion, the models for N topdressing rate recommendation at PI were successful under present experimental conditions. However, additional testing under more variable environmental conditions should be performed before universal application of such models.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.50 no.spc1
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• pp.56-61
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• 2005

This study was carried out to elucidate the proper nitrogen application level considering rice quality in Honam plain area from 2002 to 2004 at the paddy field of Honam Agricultural Research Institute. The rice cultivars tested were Samcheonbyeo (Early maturing one), Hwaseongbyeo (Medium maturing one) and Nampyeongbyeo (Mid-late maturing one). The results are summarized as follows: The higher amount of nitrogen application resulted in greater number of panicle and grain in per unit area, but the rate of ripening and the 1,000-grain weight of brown rice decreased. The protein contents showed a tendency of increase with higher nitrogen level. The head rice yield increased by the higher nitrogen application up to 7 kg/10a for Samcheonbyeo and Hwaseongbyeo, and 9 kg/10a for Nampyeongbyeo respectively. The appropriate nitrogen application amounts, with respect to the yield of head rice, the rate of ripening and the quality of rice were found to be in range of 7 to 9 kg/10a.

• International Journal of Contents
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• v.13 no.3
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• pp.1-8
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• 2017

Rice plant numbers and density are key factors for yield and quality of rice grains. Precise and properly estimated rice plant numbers and density can assure high yield from rice fields. The main objective of this study was to automatically detect and count rice plants using images of usual field condition from an unmanned aerial vehicle (UAV). We proposed an automatic image processing method based on morphological operation and boundaries of the connected component to count rice plant numbers after transplanting. We converted RGB images to binary images and applied adaptive median filter to remove distortion and noises. Then we applied a morphological operation to the binary image and draw boundaries to the connected component to count rice plants using those images. The result reveals the algorithm can conduct a performance of 89% by the F-measure, corresponding to a Precision of 87% and a Recall of 91%. The best fit image gives a performance of 93% by the F-measure, corresponding to a Precision of 91% and a Recall of 96%. Comparison between the numbers of rice plants detected and counted by the naked eye and the numbers of rice plants found by the proposed method provided viable and acceptable results. The $R^2$ value was approximately 0.893.