• 한국농공학회논문집
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• 제56권3호
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• pp.47-53
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• 2014

We investigated the effect of straw mat cover and soil amendments on the reduction of runoff, non-point source pollution load and yield of a Chinese cabbage from alpine fields. Two plots on sandy loam soil were prepared. Experimental treatments were control and rice straw mat cover (3,300 kg/ha)+Polyacrylamide (PAM) (5 kg/ha)+Gypsum (1 ton/ha) (SPG). A variety of Chinese cabbage was cultivated and runoff was monitored during a growing season in 2012. Monitoring was conducted to seven times. Runoff rate of SPG plot was lower than those of control plot. The reduction rate of runoff from SPG plot was 29.4 % compared to control plot. The reduction rate of suspended solids (SS), total nitrogen (TN) and total phosphorus (TP) load of SPG plot was 86.5 %, 34.7 % and 39.1 %, respectively. Yield of a Chinese cabbage from SPG plot (39,646 kg/ha) was greater than that of control plots (28,482 kg/ha). It was concluded that the use of SPG on soil surface could not only reduce the NPS pollution loads in receiving waters but also help increase the crop yield.

• 한국농공학회논문집
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• 제55권2호
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• pp.29-36
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• 2013

The objective of the research was to describe the effect of straw mat cover and soil amendments on the reduction of runoff and non-point source load from steep sloped highland agricultural fields. Four $5{\times}30$ m plots on sandy loam soil with 28 % slope were prepared. Experimental treatments were bare (control), rice straw mat cover (3,000 kg/ha) (S), PAM (5 kg/ha)+Gypsum (1 ton/ha) (PG) and rice straw mat cover+PAM+Gypsum (SPG). A variety of lettuce was cultivated and runoff was monitored during a growing season in 2011. Natural monitoring was conducted to three times. Runoff rate of S, PG and SPG plots were significantly lower than those of control plot. Especially, the runoff rate is zero in SPG plot at a first rainfall events. The reduction rate of runoff from the S, PG and SPG plots was 30.8 %, 29.0 % and 81.8 % compared to control plots, respectively. The reduction rate of NPS pollution load of S, PG and SPG was ranged of 50~90 %, 30~70 % and 90~100 %, respectively. Yield of lettuce from S, PG and SPG plots was respectively 400 (567 kg/ha), 320 (453 kg/ha) and 760 (1,067 kg/ha) that of compared to control plots greater than that from control plots (140 kg/ha). We speculated that the experimental treated plots could hold more nutrients and moisture than the control and helped the crop grow healthier. When analyzing the above results, in terms of reduction of runoff and NPS pollution load and crop yields, SPG experimental treatment had the best effect. It was concluded that the use of rice straw mats cover and soil amendments on soil surface could not only reduce the NPS pollution loads in receiving waters but also help increase the crop yield.

• 한국작물학회지
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• 제67권2호
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• pp.77-84
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• 2022

일품등 9품종을 대상으로 경북 남부 평야지역 봄 가뭄 대응 벼 품종별 재배안정성을 평가하기 위해 분얼초기 인위적으로 수분 부족 스트레스를 유도한 결과는 다음과 같다. 1. 일품등 9품종 대상으로 수분 부족 스트레스에 따른 결과는 평균적으로 관행대비 출수기는 약10일 빠르고 쌀수량은 약 18.6% 감소, 담백질 함량은 20.2% 증가, 식미치는 8.3% 감소하였다. 2. 본 연구에서 수량에 가장 영향을 미치는 인자는 2차 지경 분화기에 가장 영향을 받는 영화수와 천립중으로 나타났다. 3. 잎마름이 50%에 도달할때까지 소요일수가 가장 긴 품종은 새누리, 가장 짧은 품종은 대보였다. 4. 재관개 후에도 대보와 삼광은 수량감소가 가장 컸을뿐 아니라 F_V/F_M 관행 초기값으로 회복하지 못하여 가뭄의 광생리학적 지표의 가능성을 확인하였다. 따라서 경북 남부 평야지역에서는 봄 가뭄 대응 내건성 벼 품종은 새누리와 하이아미가 가장 적합하고 내건성이 약한 품종들은 재관개 후에도 광합성 효율이 낮아 수량감소로 이어져 이러한 결과에 따라 관행대비 쌀 수량감소율과 단백질 함량이 낮고 식미치가 높은 품종으로 새누리, 하이아미가 내건성 적합품종으로 선발되었다.

• 한국작물학회지
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• 제47권4호
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• pp.273-278
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• 2002

An efficient low-input system (LIS) for fertiliser use in rice cultivation is necessary to reduce fossil energy use and pollution. Japanese people like Japonica rice, especially cv. Koshihikari. However, it has very low lodging resistance in Japanese weather condition. Our objective was to develop a LIS with the minimum sacrifice of grain yield in rice. Koshihikari was grown using conventional fertilization as a control (CON) with 4 g N $m^{-2}$., 8g $P_2$ $O_{5}$ $m^{-2}$ and 8 g $K_2$O $m^{-2}$ as a basal fertilizer dressing. It was compared with a low fertilizer treatment (LF) with only 4 g $P_2$ $O_{5}$ $m^{-2}$ as a basal dressing in the first year and no basal phosphorus fertilizer in the second year. Chopped rice straw was incorporated into the soil before the cropping season in both years. Fertilizer of 4 g N $m^{-2}$ was top-dressed at 15 days before heading in CON plots and 30 days before heading in LF plots in both years. Lodging was significantly less in LF than in CON plots, however, no rice straw effect was found in low fertilized condition. Grain yields in LF plots were reduced by 15-16% below those of CON plots. Lower yields in LF plots were associated with a reduced number of spikelets per unit area. However, big spikelet size was acquired in LF by 10 days earlier N top dressing than CON plots. A close relationship was found between spikelet numbers and N content of the plant at heading, and between grain yield or shoot dry weight and N content of the plant at maturity. Regardless of the fertilizer application methods, N use efficiency for the number of spikelets, final total dry matter and grain yield was essentially identical among fertilizer treatments. The reduced growth and yield in the LF plots resulted from low absorption of nitrogen. Conclusively, LIS can drastically reduce chemical fertilizer use and facilitate harvest operations by reducing lodging with some yield reduction..

• The Plant Pathology Journal
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• 제22권3호
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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.

• 한국작물학회지
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• 제36권2호
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• pp.112-126
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• 1991

The atmospheric carbon dioxide concentration is ever-increasing and expected to reach about 600 ppmv some time during next century. Such an increase of $CO_2$ may cause a warming of the earth's surface of 1.5 to 4.5$^{\circ}C$, resulting in great changes in natural and agricultural ecosystems. The climatic scenario under doubled $CO_2$ projected by general circulation model of Goddard Institute for Space Studies(GISS) was adopted to evaluate the potential impact of climate change on agroclimatic resources, net primary productivity and rice productivity in Korea. The annual mean temperature was expected to rise by 3.5 to 4.$0^{\circ}C$ and the annual precipitation to vary by -5 to 20% as compared to current normal climate (1951 to 1980), resulting in the increase of possible duration of crop growth(days above 15$^{\circ}C$ in daily mean temperature) by 30 to 50 days and of effective accumulated temperature(EAT=∑Ti, Ti$\geq$1$0^{\circ}C$) by 1200 to 150$0^{\circ}C$. day which roughly corresponds to the shift of its isopleth northward by 300 to 400 km and by 600 to 700 m in altitude. The hydrological condition evaluated by radiative dryness index (RDI =Rn/ $\ell$P) is presumed to change slightly. The net primary productivity under the 2$\times$$CO_2$ climate was estimated to decrease by 3 to 4% when calculated without considering the photosynthesis stimulation due to $CO_2$ enrichment. Empirical crop-weather model was constructed for national rice yield prediction. The rice yields predicted by this model under 2 $\times$ $CO_2$ climatic scenario at the technological level of 1987 were lower by 34-43% than those under current normal climate. The parameters of MACROS, a dynamic simulation model from IRRI, were modified to simulate the growth and development of Korean rice cultivars under current and doubled $CO_2$ climatic condition. When simulated starting seedling emergence of May 10, the rice yield of Hwaseongbyeo(medium maturity) under 2 $\times$ $CO_2$ climate in Suwon showed 37% reduction compared to that under current normal climate. The yield reduction was ascribable mainly to the shortening of vegetative and ripening period due to accelerated development by higher temperature. Any simulated yields when shifted emergence date from April 10 to July 10 with Hwaseongbyeo (medium maturity) and Palgeum (late maturity) under 2 $\times$ $CO_2$ climate did not exceed the yield of Hwaseongbyeo simulated at seedling emergence on May 10 under current climate. The imaginary variety, having the same characteristics as those of Hwaseongbyeo except growth duration of 100 days from seedling emergence to heading, showed 4% increase in yield when simulated at seedling emergence on May 25 producing the highest yield. The simulation revealed that grain yields of rice increase to a greater extent under 2$\times$ $CO_2$-doubled condition than under current atmospheric $CO_2$ concentration as the plant type becomes more erect.

• 한국농림기상학회지
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• 제15권1호
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• pp.26-39
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• 2013

신 기후변화 시나리오에 따라 예상되는 미래환경조건에서 기존의 작부체계로는 여러 작목 및 품종에서 수량 감소가 예상된다. 본 연구에서는 기후변화에 대처할 수 있는 재배기술 중 하나인 파종시기 이동이 주요 식량작물의 수량 변동과 어떤 관계가 있는지 작물모형에 의해 전망하였다. 현재기후조건에 맞는 기존 재배기술을 고수하였을 때 예상되는 미래의 생육 및 수량추세를 대조구로 두고, 파종 혹은 이앙시기를 7, 14, 21일씩 단축 및 지연하여 모의한 결과를 서로 비교하였다. 벼의 경우 조생종은 조기파종에 의해, 중만생종의 경우 지연파종에 의해 수량저하 현상을 어느정도 완화시킬 수 있었다. 기존 작부체계에서도 지구온난화에 의해 증수가 예상되는 겨울보리의 경우 조기파종에 의해 추가적인 증수효과를 기대 할 수 있다. 콩은 조기파종으로 인한 증수효과를 기대할 수 있었으나, 그 정도는 보리에 비해 적었으며, 파종일 지연 시감수현상이 발생하였다.

• 한국농공학회논문집
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• 제53권4호
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• pp.67-74
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• 2011

The objectives of this study were to assess the rice yields and evaluate fertilizer reduction effect of reclaimed wastewater irrigation in paddy fields using the Decision Support System for Agrotechnology Transfer (DSSAT) v4.5 model. The experimental plots were designed, which was located near the Suwon wastewater treatment plant in Gyeonggi-do, Korea. The rice yield, irrigation amount, irrigation water quality and soil data were monitored and collected between 2006 and 2009. The DSSAT model was calibrated and validated with observed data. The methods that were used to evaluate this model were the root mean square error (RMSE), normalized root mean square error (nRMSE), and index of agreement (d). The values of RMSE, nRMSE, and d ranged from 145 to $789\;kg\;ha^{-1}$, 3.0 to 13.3 %, and 0.90 to 0.95 for the calibration period, respectively and represented from 91 to $538\;kg\;ha^{-1}$, 2.0 to 10.4 %, 0.94 to 0.98 for the validation period, respectively. Overall, this model showed good agreement with observed data of rice yields irrigated with reclaimed wastewater. The fertilizer reduction effect in paddy field of reclaimed wastewater irrigation was assessed about 60 % in 2008 and 40 % in 2009.

• 한국농공학회지
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• 제28권2호
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• pp.31-41
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• 1986

Knowledge of the degree of yield reduction due to water stress at different crop growth stages in rice production is important for rational scheduling of irrigation during periods of insufficient water supply. Previous studies to determine the degree of yield reduction duo to water stress suffered from interruptions by rain during experiment. Also the findings did rot relate the degree of water stress to the soil water potential and water deficit status of rice plants. In this study, two years experiments were conducted using the high yielding rice varieties, an Indica x Japonica (Nampoong) and a Japonica variety(Choochung). These were grown in 1/200$^{\circ}$ plastic pots placed under a rainfall autosensing, sliding clear plastic roof facility to control rainfall interruptions. The results obtained were as follows. 1.The two varieties differed in the growth stage most sensitive to water stress as well as the degree of yield reductions. When rice plants were stressed to the leaf rolling score 4 and soil water potential of about - 20 bar at major crop growth stages which included heading, booting, non-effective tillering, panicle initiation and early tillering stages, the yield reductions in the Indica x Japonica variety were 58%, 34%, 27%, 22%, and 21%, respectively, whereas in the Japonica vairety they were 23%, 36%, 1%, 13% and 22%, respectively. This result show that the recommended drainage during non-effective tillering is valid only for the Japonica variety. Sufficient irrigation at booting, heading and early tillering stages are necessary for both varieties. 2.The two varieties showed visible wilting symptoms when the soil water potential dropped to about - 3.0 bar. The Japonica variety showed more leaf rolling than the Indica X Japonica. However, it had a higher retention of leaf water content and greater stomatal diffusive resistance. When the soil water potential dropped, the Japonica variety showed leaf rolling score (LRS) 1 at 0 soil-5. 0 bar and LRS 2 at 0 soil -6.0 bar while the Indica X Japonica showed LRS 1 at 0 soil - 5.5 bar and LRS 2at 0 Soil - 9.0 bar. The stomatal diffusive resistance was maximum at the second top leaf blade in both varieties at intermediate water stress of 0 soil - 4.5 bar. 3.The number of days that was required for the soil water potential to drop to-3. 0 bar and to - 20.0 bar after drainage of irrigation water from the 20cm deep silty clay loam soil in the pots were 6 and 13 days, respectively for booting stage, and 7 and 11 days, respectively for heading stage, 9 and 12 days, respectively for panicle initiation stage, and 12 and 19 days, respectively for early tillering stage. 4.Water stress during the early tillering stage recorded the longest delay in beading time, the largest reduction in panicle numbers and a substantial yield decrease of 20%. This calls for better water management to ensure the availability of water at this stage, particularly during drought periods. In addition, a reexamination of the conventional inter-drainage practice during the non-effective tillering stage is necessary for the high yielding Indica X Japonica varieties.

• 한국작물학회지
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• 제33권2호
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• pp.195-200
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• 1988

벼를 보통기에 동일하게 이앙하여 추앙후 20일, 유전형성기, 감수분열기 및 출수기의 생육시기별로 포장상태에서 3일간씩 관수처리한 경우와 품종, 이앙기 및 재배조건이 다양한 농가포장에서 태풍 'Thelma 호'('87년 7월 16~18일)에 의해 3일간 관수된 경우에 생육단계별 피해상태와 피해주의 고립분얼이삭의 발생에 의한 수량 보상력을 검토한 결과는 다음과 같다. 1. 보통기 이앙된 벼의 생육시기별 관수처리에서는 생육이 진전될수록 관수된 수온이 높아져 피해가 컸으나 고온기에 여러 생육단계를 갖는 농가포장이 일시에 관수되면 어린 생육단계일수록 피해가 컸다. 2. 생식생장 관수 피해수의 수량보상은 고립절분얼이삭에 의존하였고 고립절분얼이삭이 9월 15일 출수되어 등숙적산온도가 69$0^{\circ}C$, 등숙일조시간이 210시간이 확보되었을 때 쌀 230kg/10a을 보상하였다.0a을 보상하였다.