Assessment of N Topdressing Rate at Panicle Initiation Stage with Chlorophyll Meter-Based Diagnosis in Rice

다국어 초록 (Multilingual Abstract)

This study was conducted to determine N topdressing rate at panicle initiation stage by using chlorophyll meter (SPAD-502)-based
N nutritional diagnosis in rice plant for high quality production of the Chucheongbyeo variety. Field experiments were carried for 3
years from 2003 to 2005 in Gyeonggi, Hwaseong. To confirm the method of measuring the leaf color with SPAD-502, leaf position
of rice plant and measuring point on the leaf were studied. And the proper period to examine the leaf color and growth characteristics
of rice plants was suggested at panicle initiation stage, from the results of the correlation between SPAD value and both content of
chlorophyll and nitrogen in rice leaves. The multiply value of plant height, number of tillers per m2 and SPAD value could explain
well the effect of nitrogen fertilization on the growth of rice plants, and was used to determine an equation for on-site determination
of nitrogen fertilization rate for Chucheongbyeo variety at the panicle initiation stage. Nitrogen fertilization increased number of
tillers and rice yields, and affected the increase in protein content in rice grain resulting in loss of quality, such as taste value, and
decreased the percentages of both ripened and whole rice grains. Based on the response surface statistical methodology using the
SAS program, the relationship equation among protein content of brown rice (PROT), plant growth value (plant height × number of
tillers × SPAD value, PGV), and nitrogen fertilization rate at the panicle formation stage (NF) was developed. That is, PROT (%) =
7.379403 - (5.27E-7) a - 0.013291 b + (3.025355E-13) a2 + (3.222997E-8) ab + (6.781E-05) b2, where a means PGV and b is NF
(%), and the equation's coefficient of determination (R2) was 0.967. From this equation, to recommend the optimum N fertilization
rate at panicle initiation stage easily to produce high quality rice of Chucheongbyeo variety, which contains the target protein content
of brown rice.

다국어 초록 (Multilingual Abstract)

This study was conducted to determine N topdressing rate at panicle initiation stage by using chlorophyll meter (SPAD-502)-based
N nutritional diagnosis in rice plant for high quality production of the Chucheongbyeo variety. Field experiments were carried for 3
years from 2003 to 2005 in Gyeonggi, Hwaseong. To confirm the method of measuring the leaf color with SPAD-502, leaf position
of rice plant and measuring point on the leaf were studied. And the proper period to examine the leaf color and growth characteristics
of rice plants was suggested at panicle initiation stage, from the results of the correlation between SPAD value and both content of
chlorophyll and nitrogen in rice leaves. The multiply value of plant height, number of tillers per m2 and SPAD value could explain
well the effect of nitrogen fertilization on the growth of rice plants, and was used to determine an equation for on-site determination
of nitrogen fertilization rate for Chucheongbyeo variety at the panicle initiation stage. Nitrogen fertilization increased number of
tillers and rice yields, and affected the increase in protein content in rice grain resulting in loss of quality, such as taste value, and
decreased the percentages of both ripened and whole rice grains. Based on the response surface statistical methodology using the
SAS program, the relationship equation among protein content of brown rice (PROT), plant growth value (plant height × number of
tillers × SPAD value, PGV), and nitrogen fertilization rate at the panicle formation stage (NF) was developed. That is, PROT (%) =
7.379403 - (5.27E-7) a - 0.013291 b + (3.025355E-13) a2 + (3.222997E-8) ab + (6.781E-05) b2, where a means PGV and b is NF
(%), and the equation's coefficient of determination (R2) was 0.967. From this equation, to recommend the optimum N fertilization
rate at panicle initiation stage easily to produce high quality rice of Chucheongbyeo variety, which contains the target protein content
of brown rice.

참고문헌 (Reference)

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