• Korean Journal of Agricultural and Forest Meteorology
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• v.3 no.2
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• pp.75-80
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• 2001

This study was conducted to identify the optimum proper nitrogen (N) application rate for tillering in ridge direct seeding on dry paddy of rice culture. During 1998, a series of experiments was carried out at paddy field (Chonbuk series) of the National Honam Agricultural Experiment Station, RDA using Dongjinbyeo. Leaf area index and top dry weight increased with higher N levels, especially in the 100 kg/ha seeding rate compared with the 60 kg/ha seeding rate. N use efficiency increased at increased by 50~75% of the N topdressing rate at tillering. Heading date, ripened grain rate, and 1,000-grain weight of brown rice did not vary among the rate of topdressing for tillering and seeding rates. The highest grain number per unit area was at the level of increased by 75% in N topdressing at tillering stage. Milled rice yield increased 5% at the 60 kg/ha seeding rate and increased 16~17% at the 100 kg/ha seeding rate at increased by 50~75% of topdressing N compared with 48 kg/ha topdressed N of 60 kg/ha seeding rate.

• Proceedings of the Korea Water Resources Association Conference
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• 2009.05a
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• pp.602-607
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• 2009

논에서 수질변화특성에 관한 메카니즘은 매우 복잡하다. 영양물질의 농도특성을 정확히 파악하기 위해서는 영농활동에 따른 체계적인 모니터링을 통한 다양한 측정 자료가 필요하다. 그러나 현재 논에서 토양의 산화환원에 관한 연구 자료는 많지 않기 때문에 그의 특성을 파악하기에는 어려운 실정에 있다. 본 연구의 목적은 충북대학교 부속농장 필지논에서 2008년 영농기간을 중심으로 논에서의 영양물질인 총인(TP), 인산성 인($PO_4-P$) 및 산화환원전위(Eh)의 변화특성을 파악함으로써, 논으로부터의 영양물질 유출제어에 관한 기초 자료를 제공하는데 있다. 이 연구는 2008년 6월부터 10월까지 필지논에서 논 표면수의 TP 와 $PO_4-P$의 농도변화와 토양의 산화환원전위(Eh)와의 관계 특성을 파악하였다. 관개기의 논에서 인은 분얼비 시기에 인성분이 시비되지 않았는데도 불구하고 분얼비 직후와 분얼비 1주일 후에 TP농도가 높게 나타났는데 이는 담수의 영향으로 논이 환원상태로 되어, 논바닥에 침전된 철이온에 흡착되어 있던 인이 철이온의 환원으로 함께 용출하기 때문이라고 생각된다. 산화환원전위(Eh)는 높아지면 산화경향을, 낮아지면 환원경향을 나타낸다. 본 연구기간 동안의 산화환원전위(Eh) 값은 비 관개기에 $201^{\sim}405$ mV로 높게 나타났고, 관개기에는 $93^{\sim}195$ mV로 낮게 나타났다. 필지논 표면수의 인농도는 분얼비 직후 1주일후까지 TP 와 $PO_4-P$ 농도는 같이 상승하다가 TP농도는 약 2주일까지 더 상승하여 2008년 최대값을 나타냈고 $PO_4-P$농도는 하강하였는데 이는 논 토양이 환원상태로 되면서 바닥에 있던 입자성 인이 논 표면으로 떠올랐기 때문으로 사료된다. 그 후에 담수가 끝나는 시점까지 농도는 낮아졌다. 강우량이 적은 관개초기에 인의 농도는 비교적 높게 나타났지만 강우량이 많은 여름에는 작물의 생장에 필요한 영양물질 섭취 등으로 인농도가 낮게 나타나 논은 인의 유출을 억제하고 있는 것으로 나타났다. 이와 같이 인의 유출특성 및 산화환원전위(Eh)의 변화에 따른 논에서의 유출부하 특성이 규명된다면, 환경부하가 적은 효과적인 물관리가 가능해 질 것으로 판단된다.

• Proceedings of the Korean Society of Crop Science Conference
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• 2000.04a
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• pp.318-319
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• 2000

• Proceedings of the Korea Water Resources Association Conference
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• 2010.05a
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• pp.1661-1666
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• 2010

본 연구의 목적은 충북대학교 부속농장에서 2009년 영농기간을 중심으로 담수된 논에서의 산화환원전위(Eh)의 변화와 시비에 따라 영양물질인 인(P)의 농도변화 특성을 파악함으로써, 논으로 부터의 인의 유출제어에 관한 기초 자료를 제공하는데 있다. 이 연구는 2009년 5월부터 11월까지 논에서 담수의 총인(T-P)과 인산염 인($PO_4$-P)의 농도변화와 토양의 산화환원전위(Eh)와의 관계 특성을 파악하였다. 관개기의 논에서 인은 분얼비 시기에 인성분이 시비되지 않았는데도 불구하고 T-P농도가 0.68 mg/L로 높게 나타났다. 이는 담수의 영향으로 논이 환원상태로 되어, 논바닥에 침전된 철이온에 흡착되어 있던 인이 철이온의 환원으로 함께 용출하기 때문이라고 생각된다. 높은 Eh는 산화경향을, 낮은 Eh는 환원경향을 나타낸다. 본 연구기간 동안의 Eh 값은 연속적으로 담수되었던 7월 중순까지는 74~112 mV 가량 나타냈고, 그 이후에는 담수상태가 아닌 경우가 많아 179~636 mV로 높게 나타났다. 논 담수의 T-P와 $PO_4$-P 농도는 분얼비 직후 1주일후까지 같이 상승하다가 T-P농도는 약 2주일까지 더 상승한 반면 $PO_4$-P 농도는 하강하였는데 이는 논 토양이 환원상태로 되면서 바닥에 있던 입자성 인이 논 표면으로 떠올랐기 때문으로 사료된다. 그 후에는 담수가 끝나는 시점까지인 농도는 낮아졌다. 관개초기에 인의 농도는 비교적 높게 나타났지만, 7월 이후로는 작물의 생장에 필요한 영양물질 섭취 등으로 인 농도가 낮게 나타났는데 이는 7월 이후의 논은 인의 유출을 억제하고 있는 것으로 추정된다. 또한 논 담수위의 증감에 따른 $PO_4$-P 농도와 Eh 값을 회귀분석 한 결과 각각 정의 상관관계와 부의 상관관계가 있는 것으로 나타났다. 이와 같이 논 담수 및 시비에 따른 인의 유출부하 특성과 산화환원전위(Eh)의 변화 특성이 규명된다면, 향후 환경부하가 작은 물관리가 가능해 질 것으로 판단된다.

• Proceedings of the Korean Society of Crop Science Conference
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• 2000.04a
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• pp.200-201
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• 2000

• Proceedings of the Korean Society of Crop Science Conference
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• 2001.09a
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• pp.106-107
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• 2001

• KOREAN JOURNAL OF CROP SCIENCE
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• v.52 no.1
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• pp.104-111
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• 2007

As protein content of milled rice, generally used as a benchmark for rice eating quality, is greatly affected by N fertilization and nutrition status of rice plant, understanding its response to nitrogen rate and plant nitrogen status at different growth stage is important for recommending N fertilizer management for high quality rice production. The responses of milled-rice protein content were compared and quantified under various combinations of basal+tillering and panicle N application levels in 2001 and 2002. Protein content of milled rice was ranged from 6 to 9%, increasing significantly with increasing basal+tillering and panicle N rates. However, milled rice protein content was raised much greater by panicle N than by basal+tillering N fertilization. Even though basal+tillering N increased up to 20 kg/ha, protein content of milled rice was observed less than 7% in case that panicle N was applied below 1.8 kg/10a. Regression analysis revealed that nitrogen accumulated until harvest was partitioned with almost constant rates of 58.3% and 46.5% to panicle and milled rice, respectively. The partitioning rates was slightly but not significantly different between experimental years. Protein content of milled rice showed linear and quadratic responses to the shoot N accumulation until panicle initiation stage (PIS) ant shoot nitrogen accumulation from PIS to harvest, respectively. The increment of milled-rice protein content per unit N increase was much greater in shoot N accumulation from PIS to harvest than in that until PIS. Regardless of shoot N accumulation until PIS upto 8 kg/10a, protein content of milled rice was lower than 7% and ranged from 6.5 to 7.5% in case that shoot N accumulation from PIS to harvest was below 3.0 kg/10a and below 6.0 kg/10a respectively. It would be concluded that even under the same N accumulation until harvest milled rice protein content could be different according to the N fertilizer management and weather condition especially during ripening, providing rooms for controlling protein content by N fertilizer management without damage to grain yield.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.7
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• pp.571-583
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• 2006

To secure high yield and good quality of rice, plant growth and nitrogen (N) nutrition status should be taken into account for managing panicle N topdressing (PN). This research aimed at investigating the rice yield response to PN under different plant growth and N nutrition status that was conditioned by different rates of basal and tillering N fertilizer (BTN). Stepwise multiple regression (SMR) was used for the analysis of yield response to (i) BTN and PN, and (ii) shoot N content at PIS (BTNup) and shoot N uptake from PIS to harvest (PNup). Rice yield increased significantly as BTN and PN Increased, but there was no significant interaction between BTN and PN. Yield increased almost linearly with the increasing BTN and PN up to $10{\sim}12$ and $6{\sim}7\;kgN/10a$, and with the increasing BTNup and PNup up to $6{\sim}7$ and $5{\sim}6\;kgN/10a$, respectively. But yield increment tended to decrease above those levels. These declines resulted from the decreased ripened grain ratio and 1000 grain weight even though spikelet number per unit area increased more at above those N levels. Spikelet number per unit area had the linear relationships with the shoot N uptake until heading, and with yield. Like most yield response curves, yield response in this experiment followed the diminishing return function with BTNup, PNup, and plant N uptake from seeding to harvest. Regardless of the degree of BTNup and PNup, yield had a quadratic relationship ($R^{2}$>0.88) with whole shoot N accumulation until harvest, suggesting that the yield determination was closely related with the whole shoot N uptake until harvest regardless of the differences in seasonal shoot N uptake.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.33 no.3
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• pp.222-228
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• 1988

This experiment was carried out to investigate the effects of N levels (0,10,20,30kg/10a) and N split rates [the rates of basal＋top dressing 15 days after transplanting (DAT) : top dressing 25 days before heading (DBH) was 100 : 0, 80 : 20, 60 : 40 ] on the growth, yield, yield components, and N uptake of Seomjinbyeo (J) and Samgangbyeo (I${\times}$J). The maximum tillering stage occurred in the middle of July in both varieties, but Samgangbyeo showed the second maximum tillering stage in the middle of August probably due to the retarded early growth caused by low temperature in the tillering stage and to favoring temperature in August. Grain yield of Seomjinbyeo was similar among the N levels from 10 to 30 kg/10a without occurrence of rice blast and lodging, but that of Samgangbyeo increased as N level increased upto 30 kg/10a. Grain yield of Seomjinbyeo was higher when N was applied three times (basal and two top dressings 15 DAT and 25 DBH) compared with two times (basal and top dressing 15 DAT), but that of Samgangbyeo was not different among the N split rates. Total N uptake and the proportion of fertilizer N to the total N uptake increased as N level was higher. N uptake tended to be higher as proportion of basal＋top dressing 15 DAT increased in early growth stage, but it was higher as proportion of N applied 25 DBH increased in the late growth stage. The N efficiency to produce grain per absorbed N unit decreased as N level decreased in Seomjinbyeo, but similar in Samgangbyeo.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.47 no.3
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• pp.221-225
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• 2002

This study was conducted to identify the effects of slow release fertilizer (LCU) on ridge direct seeding on dry paddy of rice as an irrigation water-saying cultural system. During 1999-2000, a series of experiments was carried out at field (Chonbuk series) of the National Honam Agricultural Experiment Station, RDA using Dongjinbyeo. Plant height and culm length during the total growth duration were the longest and panicle umber per $m^2$ was the highest in 100% LCU application rate. Leaf area index and top dry weight were the highest in the 100% LCU application rate. They increased as more LCU was applied. Nitrogen uptake was the highest in 100% LCU application, and N use efficiency was the highest in LCU 60% + FP (fertilization at panicle formation stage) 20% application. Milled rice yield was 7% higher in 100% LCU application rate than that of conventional N application. Ripened grain rate and 1,000-grain weight of brown rice did not differ, but panicle number per $m^2$ and grain number per m2 were the highest at 100% LCU application.