• 대한원격탐사학회지
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• 제37권4호
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• pp.789-802
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• 2021

Synthetic Aperture Radar (SAR) at C-band is an ideal remote sensing system for crop monitoring owing to its short wavelength, which interacts with the upper parts of the crop canopy. This study evaluated the potential of dual polarimetric Sentinel-1 at C-band for monitoring rice phenology. Rice phenological variations occur in a short period. Hence, the short revisit time of Sentinel-1 SAR system can facilitate the tracking of short-term temporal morphological variations in rice crop growth. The sensitivity of SAR backscattering coefficients, backscattering ratio, and polarimetric decomposition parameters on rice phenological stages were investigated through a time-series analysis of 33 Sentinel-1 Single Look Complex images collected from 10th April to 25th October 2020 in Gimhae, South Korea. Based on the observed temporal variations in SAR parameters, we could identify and distinguish the phenological stages of the Gimhae rice growth cycle. The backscattering coefficient in VH polarisation and polarimetric decomposition parameters showed high sensitivity to rice growth. However, amongst SAR parameters estimated in this study, the VH backscattering coefficient realistically identifies all phenological stages, and its temporal variation patterns are preserved in both Sentinel-1A (S1A) and Sentinel-1B (S1B). Polarimetric decomposition parameters exhibited some offsets in successive acquisitions from S1A and S1B. Further studies with data collected from various incidence angles are crucial to determine the impact of different incidence angles on polarimetric decomposition parameters in rice paddy fields.

• 한국토양비료학회지
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• 제42권Spc호
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• pp.57-61
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• 2009

우리나라에서 가축 사육밀도가 가장 높고 오리농법을 가장 대규모로 실시하고 있는 충남 홍성군 홍동면, 장곡면의 흥동저수지 유역을 사례지역으로 선정하여 오리농법에 의한 벼 재배가 지역 환경과 주변 수질에 미치는 영향을 밝히고 이를 바탕으로 친환경농업의 달성을 위한 올바른 발전방안을 제시코자 오리농법에 의한 벼 재배가 토양 환경과 주변 수질에 미치는 영향을 분석하였다. 오리농법 실시 논의 토양화학성은 벼농사를 위한 적정범위 안에 있었지만 일반농법 실시 논보다 유기물 함량과 유효인산 함량이 높아 오리농법 실시 논의 양분투입량이 상대적으로 많은 것으로 추정되어 지속농업의 달성을 위해서는 적정량의 퇴비나 유기질비료의 시용이 요구됨을 알 수 있었다. 조사지역 하천수의 수질은 T-N, T-P, COD 값들이 높아 상당히 인근의 하천들이 오염되었음을 나타내고 있으며, T-N, T-P, COD 등으로 평가한 수질의 오염도가 논으로부터 비료성분의 유출 가능성과 일치한 결과로 볼 때 이 지역의 하천수가 벼재배에 의해 배출되는 오염물질의 영향을 일정부분 받고 있는 것으로 평가될 수 있었다. 오리농법 실시 논의 표면수 수질은 일반농법 실시 논보다 EC는 135.7%, COD는 220.1%, T-N는 172.0%, T-P는 227.9%가 높았으며 특히, COD와 T-P는 2배 이상이 높았으며 오리의 활동에 의해 발생하는 물의 탁도와 유의성 있는 상관관계를 보여 오리농법에 의한 벼 재배는 일반농법에 의한 벼 재배 방법보다 논물유출에 의한 잠재 수질오염 가능성이 큰 것으로 평가되었다. 따라서 오리농법 실시 논은 논물 유출에 의한 주변 수질오염 방지를 위해 더욱 철저한 물꼬관리가 필요한 것으로 판단되었다.

• 한국유기농업학회지
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• 제19권spc호
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• pp.119-122
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• 2011

Among the developed bio-degradable polymer films as compared with transparent film(White), black polymer film was significantly more effective for controlling weeds in red pepper. Also, we found that white and black polymer mulching had 81.8% and 97.9% of managing weed controlling effects in rice, respectively. Compared to non-mulched rice paddy with water supply, the non-mulched rice paddy without any water supply has stopped its growth at 41 days after transplanting, while polymer-mulched rice paddy without water supply had about 60% of normally growing rice plants. This shows the polymer treatment has a remarkable effect on water and power saving, solution of herbicidal resistance, avoidance of herbicidal influence to eco-system etc. When the naturally decomposing polymer was used, a temperature was elevated as high as $4.7^{\circ}C$ on maximum and $2.6^{\circ}C$ on average. Also the naturally decomposing polymer accelerated rooting by 7 days and lowered a stress level from transplanting. The weed control effect mulched by polymer was remarkable as 98.7%. The polymer now, after 294 days treated on the rice paddy, has been completely decomposed.

• Journal of Biosystems Engineering
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• 제26권3호
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• pp.221-228
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• 2001

Chemical application, one of the most important crop management processes happened to cause spray drift, that would threaten farmers in field as well as dwellers in rural region. Spray drift was affected by micro-meteorological parameters. A study to evaluate short distance drift characteristics of a boom sprayer in paddy fields has been undergoing. This study is the first step of the research. Main purpose of the was conducted to develop a mean wind profile and to get information on turbulence intensities above and within rice canopy. Wind in rice paddy field were measured at every 10cm from 10 to 180cm above the ground using a 2-dimensional probe and a hot wire anemometer system. Main results were summarized as follows. 1. Mean wind profile was modeled as; Equations. see full-text 2. Roughness length and zero-displacement in rice canopy were analyzed to be respectively 0.04 and 0.7∼0.72 times of the canopy height. The values are smaller comparing to those of other crops because rice canopy is flexible and uniform comparing to other crops. 3. Turbulence intensities (Tl) was greater as close to the ground and became constant at heights greater than 1.5Hc. where Tl’s were 0.4 and 0.15 in horizontal and vertical direction respectively.

• 한국작물학회지
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• 제44권2호
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• pp.102-105
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• 1999

Mineralization of organic N is an important factor in determining the appropriate rate of organic matter application to paddy fields. A kinetic analysis was conducted for nitrogen mineralization of rice, barley, Chinese milk Ovetch (Astragalus sinicus L.; MV) and narrow leaf vetch straw in paddy soil. Nitrogen immobilization occurred rapidly and its rate increased in straw with high C/N ratio. The amount of nitrogen mineralization was rapid in the first year of rice-vetch cropping system. The rate constant (K) depended on the C/N ratio of organic matter. Mineralization of straw increased at high temperature. The amount of available N increment resulted in fast mineralization of straw, especially in rice and barley straw. Chinese milk vetch had the greatest mineralization rate at all temperatures and fertilization levels followed by narrow-leaf vetch. However, rice and barley straws with high C/N ratio immobilized the soil N at the initial incubation duration. Chinese milk vetch or narrow leaf vetch was not effectively mineralized in mixed treatments with rice or barley straw. The mineralization rate of organic matter was mostly affected by the C/N ratio of straw and temperature of incubation. Organic matter with low C/N ratio should be recommended to avoid the immobilization of soil N and the increasing mineralization rate of straw.

• 한국환경복원기술학회지
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• 제16권5호
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• pp.19-26
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• 2013

This study was carried out to provide preliminary data for increasing biodiversity in agricultural ecosystem and investigate availability of using Tubificidae spp. for environment-friendly agriculture through the survey of growth of Tubificidae spp. in flooded paddy fields during winter. We estimated the number of Tubificidae spp. in rice paddy where had been flooded during the previous winter in Ganghwa-gun, Suwon-si, and Hwaseong-si (Bongdam-eup and Paltan-myeon) between March and April from 2010 to 2012. During growing period of rice, the number of Tubificidae spp. was compared between flooded and non-flooded paddy field in Ganghwa-gun. As results, mean density of Tubificidae spp. in winter flooded paddy field was 7,235.5 $ind./m^2$ in Ganghwa-gun, 14,347.5 $ind./m^2$ in Suwon-si, 59,989.9 $ind./m^2$ in Bongdam-eup, and 2,610.6 $ind./m^2$ in Paltan-myeon. Mean density of Tubificidae spp. was the highest in flooded paddy fields of Bongdam-eup that was kept wet until rice harvest time and had shallow water. While mean density was the lowest in Paltan-myeon where had deep water and later flooded paddy field than others. In Ganghwa-gun, during growing period of rice, mean density of Tubificidae spp. in flooded paddy fields (171,109.0 $ind./m^2$) and flooded fallow paddy fields (321,084.2 $ind./m^2$) was much higher than non-flooded paddy fields (1,006.6 $ind./m^2$). Flooded paddy field during winter can help increase the number of Tubificidae spp. which can control weeds and enhance biodiversity in paddy fields for environment-friendly agriculture. Early flooding and shallow water of paddy fields could be a good agriculture practice to encourage the growth of Tubificidae spp..

• 한국토양비료학회지
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• 제50권3호
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• pp.150-161
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• 2017

This study was conducted with the data of monitoring on soil chemical properties of rice paddy soils in Gyeongbuk Province. The selected soil chemical properties were analyzed every 4 year from 1999 to 2015. The soil pH measured in 2015 was higher than pH 6.0, which was 0.3-0.4 pH unit higher than data until 2007 survey year. The mean content of organic matter was greater than $24g\;kg^{-1}$ since 2003, but 35% of soil samples remained below the recommended level ($20-30g\;kg^{-1}$) in 2015. The mean concentration of available phosphate was maintained at $40mg\;kg^{-1}$ higher than the upper recommendation level ($80-120mg\;kg^{-1}$), and more than 40% of paddy soils tested were found to have less than the recommendation level during the survey period. The exchangeable K concentration ranged from 0.25 to $0.39cmol_c\;kg^{-1}$. Exchangeable Ca showed an average at the optimum range ($5.0-6.0cmol_c\;kg^{-1}$) during the monitoring period. Exchangeable Mg decreased linearly ($0.02cmol_c\;kg^{-1}\;year^{-1}$) from $1.55cmol_c\;kg^{-1}$ as of 1999 to below the lower level of the recommendation range ($1.5-2.0cmol_c\;kg^{-1}$). The amount of available $SiO_2$ was increased significantly from 2011 to over the recommendation level (${\geq}157mg\;kg^{-1}$). It was revealed that the soil chemical properties of rice paddy fields was influenced by topology, soil texture, type and region as result of principal component analysis or cluster analysis. Therefore, an assessment on chemical properties of rice paddy soils should be performed to consider various soil physical conditions and agronomic practices such as fertilization, cropping system, and so on. Because of the high variability of nutrient levels across Gyeongbuk Province, nutrient management based on soil fertility test is required by respective farm land unit.

• 한국잡초학회지
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• 제16권3호
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• pp.176-180
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• 1996

지속적 농업을 구현하는 차원에서 제안된 논 무경운체계에서 이앙전 발생한 둑새풀을 효과적으로 방제하기 위하여 제초제의 종류와 처리시기 및 처리약량을 달리하여 둑새풀 방제가, 재생정도 및 전년도 탈립된 벼의 발생정도를 조사한 결과는 다음과 같다. 1. 둑새풀은 4월중순부터 생육이 급격히 진전되었으며, 무경운 경관년수가 깊어질수록 그 발생량은 많아졌다. 2 둑새풀 방제를 위하여 Glyphosate를 이앙전 20일경에 살포하는 것이 적당하였다. 3. 벼 이앙시 결주율은 비선택성 제초제 처리시기가 늦을수록 높아졌으며, 이앙후 생육은 처리시가가 빠를수록 양호하였다. 4. 잡벼 발생은 비선택성 제초제를 살포하지 않을 경우 1,600개체/10a 정도 발생하였으며, 제초제 처리시기가 늦을수록 적게 발생하였다.

• 한국작물학회지
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• 제38권4호
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• pp.304-311
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• 1993

답전윤환에 의한 논 고도이용과 이에 적합한 작목선정 및 작부양식을 검토하기 위하여 1989년부터 4년간 수도, 콩, 옥수수, 율무를 1년, 2년, 3녀 윤환의 작부양식으로 시험한 결과는 다음과 같다. 1. 수도수량은 윤환재배에 의하여 7～12% 중수되었으며 밭1년윤환답보다 밭2년대두답의 증수복이 더 컸으며, 윤환형태별로는 대두2년윤환답이 가장 유양시 되었으며, 미질은 윤환재배에 dlm하여 저하되는 경향이었다. 2. 대두는 밭연작기간이 길어질수록 수량도 크게 감소되는 경향이었으며 1년 윤환 및 매년윤환의 작부양식이 가장 유이하였다. 3. 식용옥수수 GCB70은 3년윤환재배에서, 사료용옥수수 수원19호는 2년윤환재배에서 가장 수량이 많았다. 4. 율무는 밭연작기간이 길어질수록 감수되었으며 1년윤환재배가 가장 수량이 많았다. 5. 담전윤환재배에 의하여 논ㆍ밭상태 모두 잡초발생량 및 초종수가 감소하였고 밭상태 보다 논상태에서의 잡초감소효과가 더 컸으며, 윤환작물별 우점잡초양상도 달라서 콩 3년연작 재배에서는 광엽잡초 명아주가 36%나 발생하였다. . 토양물리성은 답전윤환에 의하여 논ㆍ밭토양 모두 기상율 및 공극율 등 전반적읜 토양물리성이 개선되었고, 밭 작물기간이 길수록 기상률은 증가하는 경향이었으며 매년윤환 밭토양에서 보다 2년간 밭 전역이 있는 논토양의 심토에서 3.4% 증가하는 효과를 보였다.

• 한국작물학회지
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• 제51권3호
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• pp.199-203
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• 2006

벼 깨씨무늬병 발병 원인을 구명하기 위하여 경북지역 상습발생지 토양을 대상으로 토양특성, 식물체의 양분함량 및 이병정도에 따른 벼 수량감소 정도를 조사하고 깨씨무늬병 발생에 영향을 주는 인자를 분석한 결과는 다음과 같다. 1. 발병포장의 토양유형은 양분보유력이 낮은 사질습답 50%, 사질답이 28.3%로 전체 78.3%였고, 배수불량 토양이 67.4%를 차지하였다. 2. 병 발생이 심한 영남내륙산간 및 동해안 중, 남부지역에서 강수량이 많았고, 평균기온, 최고기온, 최저기온 및 습도와 깨씨무늬병 발병과는 관계는 부의 상관이 있었고, 강수량과는 정의 상관이 없었다. 3. 발병포장의 토양 화학성은 경북지역 논토양의 화학성에 비해 유기물, 치환성양이온, 유효규산 함량이 매우 낮은 편이며, 특히 정상지에 비해 유효규산, 아연함량이 유의하게 낮았다. 4. 이병주의 양분함량은 정상주에 비해 질소, 규산의 함량이 매우 낮았다. 5. 피해가 심한 벼는 정상 벼에 비해 간장 및 수장이 짧았고, 등숙비율은 27.9% 감소되었으며, 쌀 수량은 약 37% 정도 감수되었다. 6. 벼 깨씨무늬병 발병에 따른 미질 특성은 피해가 심할 수록 쇄미 및 심복백미의 증가로 완전미율이 11.5% 정도 더 떨어졌으며, 단백질 함량은 현저히 높아져 식미치는 피해가 높을수록 현저히 저하되었다. 7. 따라서 깨씨무늬병 발생은 양분보유력이 낮고 양분의 용탈이 심하며 유효규산 함량이 낮은 사질토양에서 주로 발생되며 생육후기 양분결핍에 의해 주로 발생되는 것으로 사료되었다.