• Title/Summary/Keyword: Rice fields

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A Phytosociological Study on the Weed Communities in the Cultivated and Abandoned Fields of Korea (한국의 경작지 및 휴경지의 잡초군락에 대한 식물사회학적 연구)

  • 송종석
    • The Korean Journal of Ecology
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    • v.20 no.3
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    • pp.191-200
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    • 1997
  • The present study was undertaken to classify and describe the weed communities of the fields in Korea by methods of the ZM school of phytosociology. On the basis of the data obtained, the following vegetation units were recognized: A. summer weed community of rice field A-1. Oryzetea sativae: Sagittario-Monochorietum, A-2. Lemnetea minoris: Lemna paucicostata-Spirodela polyrrhiza community B. spring weed community of rice field B-1. Bidentetea tripartitae: Stellario-Ranunculetum cantoniensis C. summer weed community of arable land C-1. Chenopodietea Pinellio ternatae-Euphorbietum pseudochamaesyceslsynonym: Acalypho australis-Digirietum pectiniformis and Cephalonoploso segetti-Geranietum eriostemonii of North Korea in Dostal다 et al.(1990)] and Phyllantho urinariae-Lindernietum crustaceae D. weed community of fallow field D-1. Erigeron sumatrensis-Erigeron anmus community, D-2. Digitaria adscendens-Portulaca oleracea community, D-3. Chenopodium album community, and D-4. Erigeron canadensis-Erigeron annuus community. Generally compared to the Korean Peninsula, the weed communities in the fields of Cheju Island is much plentiful in their species composition.

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Physical Properties of Hardpan in Paddy Fields (논토양 경반의 물리적 특성)

  • Lee, K.S.;Park, J.G.;Cho, S.C.;Noh, K.M.;Chang, Y.C.
    • Journal of Biosystems Engineering
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    • v.32 no.4
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    • pp.207-214
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    • 2007
  • Based on the profiles of cone index with depth, physical properties of hardpan in selected rice fields were measured and analyzed in the study. An error correction algorithm removing a random measurement error from raw CI profile data was introduced in the study. The properties of hardpan included the shape, the thickness and the rice root growing layer. The analysis of physical properties of hardpan in the rice fields showed that the type of hardpan could be classified into 6 categories. The thickness of hardpan ranged from 6 cm up to 41 cm and the average hardness of hardpan was analyzed to be from 1.1 MPa through 3.2 MPa in Cone index.

The evaluation for soil carbon sequestration with rice straw treatments in paddy fields

  • Seo, Myung-Chul;Cho, Hyeon-Suk;Seong, Ki-Yeong;Kim, Min-Tae;Ryu, Jin-Hee;Lee, Geon Hwi
    • Proceedings of the Korean Society of Crop Science Conference
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    • 2017.06a
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    • pp.340-340
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    • 2017
  • Rice straw is very important to maintain fertility in agricultural soil with several aspects such as carbon and nitrogen cycles in Korea. Recently, concerning about climate change, carbon sequestration in agricultural land has become one of the most interesting and debating issues. Rice straw is most representative source of organic material produced in agricultural sectors. In order to evaluate changes of soil carbon treated by rice straw during cultivating rice in paddy field, we carried out to treat rice straw with 0, 0.5, 1, 1.5, and $2.0ton\;ha^{-1}$ at $50{\times}50{\times}20cm$ blocks made of wood board, and analyze contents of fulvic acid and humic acid form, and total carbon periodically. The experiment was conducted in 2013-2016, and sampled with interval in a month. The organic material was applied to treatment blocks in 2 weeks ago in rice transplanting of each year. Total carbon in beginning time is low as $7.9g\;kg^{-1}$. The contents of total carbon with treatments of rice straw after experiment are recorded as 8.7, 11.2, 9.5, 10.5, and $10.9g\;kg^{-1}$ applied by 0, 0.5, 1, 1.5, and $2.0ton\;ha^{-1}$, respectively. When trend lines were calculated on changes of soil carbon in periods of experiments, The trend equations of soil carbon changes with treatments of 0, 0.5, 1, 1.5, and $2.0ton\;ha^{-1}$ were Y=0.0015X+8.479, Y=0.073X+8.2577, Y=0.0503X+8.4477, Y=0.0822X+8.2103, and Y=0.082X+8.5736. These trends suggested several results. When rice straw was applied in cultivating paddy fields, most carbon in rice straw would be decomposed regardless the amount of rice straw in soil. We calculated sequestration rate of applied rice straw as about 0.1% per year during rice cultivation in paddy fields. It means that if farmer want to increase 1% soil organic matter by using application of rice straw returned after cultivation, famer should apply rice straw continuously for ten years. The change of soil carbon as fulvic acid, humic acid, and humane is showed that only content of carbon as mumine is increased significantly while fulvic acid and humic acid were changed in range of 10 to 30% among total carbon in soil. In conclusion, to sequestrate soil carbon with rice straw, it is important for rice straw to apply continuously every year. The amount of rice straw applied is not much effected to increase soil organic matter.

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Influence of Pesticide Use on Distribution of Waterbirds in Rice Fields at Mid-western Part of South Korea (화학살충제의 사용이 한국 중서부지역 논습지에 도래하는 수조류 분포에 미치는 영향)

  • Nam, Hyung-Kyu;Kim, Miran;Choi, Green;Jang, Dooly;Choi, Seung-Hye;Cho, Kwang-Jin;Choe, Lak-Jung;Na, Young-Eun;Kim, Myung-Hyun
    • Korean Journal of Environmental Biology
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    • v.34 no.4
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    • pp.361-364
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    • 2016
  • Waterbirds using rice fields has increased due to a decline of natural wetlands. The rice field is an essential habitat to supports the waterbird population. Although use of rice field by waterbirds has been widely documented, little information is available on distribution patterns of waterbirds under the pesticide use in rice fields. The current study conducted to understand the relationship between habitat use by waterbirds and pesticide applicatioins in rice fields. We monitored the distribution of waterbirds at Daeho reclaimed area in July 2013 to June 2014 and September 2014 to August 2015. As a results, three heron species (Black-crowned Night Heron Nycticorax nycticorax, Eastern Cattle Egret Bubulcus coromandus and Intermediate Egret Egretta intermedia) are more sensitive to pesticides use than other waterbird species in rice fields. Future studies are necessary to explore the relationship between bird's distribution and management practices including pesticide use at different spatiotemporal scales.

Comparisons of inorganic amounts in paddy fields, rice straw and seed with varying severity of brown spot caused by Cochliobolus miyabeanus

  • Yeh, Wan-Hae;Park, Yang-Ho;Kim, I-Yeol;Kim, Yong-Ki;Shim, Hong-Sik
    • Proceedings of the Korean Society of Plant Pathology Conference
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    • 2003.10a
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    • pp.91.2-92
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    • 2003
  • In order to elucidate influence of nutritional status on rice brown spot caused by Cochliobolus miyabeanus, rice cultivation soils and rice straws were collected from paddy fields where ice brown spot occurred severely, moderately, a little and none respectively. Rice plant materials were analyzed to measure inorganic nutrients in rice straws and rice seeds. Analysis of chemical properties of rice paddy soil showed that EC and contents of available phosphate, cation and silicic acid in soil with severe infections were lower than those in healthy soil. This result suggests that amount and holding capacity of nutrient contents in soils collected from paddy field with infection of C. miyabeanus are relatively low compared to those in soils collected from healthy paddy field. Analysis of inorganic nutrients in rice straws showed that amount of macronutrient elements such as silicic acids, available phosphate and total nitrogen, and micronutrients such as copper, iron and zinc in rice straws from paddy field with infection were lower than those in healthy soil. Especially amount of iron and silicic acid were very low in rice straws from paddy field soils with infection Amount of inorganic nutrients such as iron and zinc in rice seeds was the same trend as those of rice straws. These results showed that one of major factors affecting rice brown spot was amount of nutrient contents in soil and rice straw.

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DISCRIMINATION OF EARLY MATURING PADDY RICE CROPS USING MULTI-TEMPORAL SAR IMAGES

  • Hong, Suk-Young;Jang, Min-Won;Kim, Yi-Hyun;Park, No-Wook
    • Proceedings of the KSRS Conference
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    • 2007.10a
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    • pp.243-245
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    • 2007
  • This study was begun to classify the paddy fields by the rice varieties and to monitor the temporal change in rice growth using SAR backscatter coefficients $({\sigma}^{circ})$. For nine fine-beam mode images of Radarsat-1 SAR, a growing period time-series of backscatter coefficients was set up from April to October in 2005, and was compared with the field-measured rice growth parameters such as LAI (leaf area index), plant height, fresh and dry biomass, and water content in grain and plant for 45 parcels in Dangjin-gun, Chungcheongnam Province, South Korea. The average backscatter coefficients for early-maturing rice varieties (13 parcels) were ranged from -18.17dB to -6.06dB and were lower than for medium-late maturing rice varieties during most of the growing season. At around the heading stage (July 30) for early-maturing rice, both rice crops showed the highest backscatter coefficient values and the difference was the greatest before harvesting early-maturing rice. The temporal difference in backscatter coefficients between rice varieties was expected to play a key role to identify early-maturing rice fields. On the other hand, comparison with field-measured rice growth parameters showed that the backscatter coefficients decreased or stayed on the plateau after heading stage even though the growth of rice canopy advanced.

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Occurrence of Major Insect Pests in Machine Transplanted and Direct Seeded Rice Paddy Field (벼 기계이앙 및 직파재배에 따른 수도 주요해충의 발생.피해)

  • 이승찬;마경철
    • Korean journal of applied entomology
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    • v.36 no.2
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    • pp.141-144
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    • 1997
  • Studies were conducted to investigate the incidense of insect pests in transplanted and direct seeded paddy fields in southern region of Korea. Population dencities of the rice green leafhopper (RGLH: Nephotettix cincticeps Uhler) and rice leaffolder (RLF: Cnaphalocroch medinalh Guenee) were higher in machine transplanted than in direct seeded, but the brown planthopper (BPH: Nilaparvata lugens Stal) and smaller brown planthopper (SBPH: Laodelphax striatellus Fallen) were abundant in direct seeded. However, no significant difference was found between machine transplanted and direct seeded fields in the incidense of rice stem borer (RSB: Chilo suppressalis Walker), whiteback planthopper (WBPH: Sogatella furcifera Horvath), and rice stem magot (RSM: C'hlorops oryzae Matsumura). Occurrence of rice key pests were affected more by transplanting time than other cultural practices. Later transplanting induced higher populations of BPH, WBPH, SBPH, RGLH. However, RSB and RLF caused higher damage in earlier transplanted paddy field.

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Application of Drone Images to Investigate Biomass Management Practices and Estimation of CH4 Emissions from Paddy Fields (드론영상을 활용한 논 유기물 관리 인자 조사 및 메탄가스 배출량 산정)

  • Park, Jinseok;Jang, Seongju;Kim, Hyungjoon;Hong, Rokgi;Song, Inhong
    • Journal of The Korean Society of Agricultural Engineers
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    • v.62 no.3
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    • pp.39-49
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    • 2020
  • Rice paddy cultivation is one of the major sources in methane (CH4) emission of which accurate assessment would be a prerequisite for agricultural greenhouse gas management. Biomass treatment in paddy fields is an important factor that affects CH4 emissions and thus needs to be taken into account. The objectives of this study were to apply drone images to investigate organic matter practices and to incorporate into the estimation of CH4 emissions from paddy fields. Three study areas were selected by one from each of the three different regions of Yeongnam, Honam and Jungbu, which are the most active region in paddy cultivation. The eBee drone was used to take images of the study sites twice a year; Jul mid-season for identifying rice cultivation area; Jan for investigating rice straw management and winter crop cultivation. Based on biomass management practices, different emissions factors were assigned on an individual paddy field and CH4 emmisions were estimated by multiplying respective areas. The ratios of rice straw application and winter crop cultivation were 1.4% and 37.2% in Hapcheon, 1.3% and 19.8% in Gimje, and 0.0% and 0.5% in Dangjin, respectively. The CH4 emissions estimates for respective sites were 0.40 ton CH4/year/ha, 0.34 ton CH4/year/ha, and 0.29 ton CH4/year/ha. On average, estimated CH4 emissions of this study were 28.5% less than the current Tier 2 CH4 emission estimation method.

Risk assessment of genetically engineered rice Bt-9 resistant to Cnaphalocrocis medinalis: influence on above-ground arthropods in Korea

  • Oh, Sung-Dug;Bae, Eun Ji;Park, Soo-Yun;Lee, Bumkyu;Yun, Do Won;Suh, Sang Jae
    • Korean Journal of Agricultural Science
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    • v.46 no.4
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    • pp.827-841
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    • 2019
  • The effect of genetically engineered rice Bt-9 on the diversity and abundance of plant-dwelling insects and spiders was tested under field conditions. Genetically engineered rice Bt-9, expressing mCry1Ac1 from Bacillus thuringiensis, confers resistance to rice leaf roller (Cnaphalocrocis medinalis) and provides tolerance to the herbicide glufosinate (PPT). The study compared Bt-9 and two non-GM reference varieties, Ilmi-byeo and Dongjin-byeo, at LMO isolated fields in Gunwi (Kyungpook National University) and Jeonju (National Institute Agricultural Sciences) in Southern Korea in 2016 - 2017. A total of 40,817 individuals from 62 families and 11 orders were collected from the two living modified organism (LMO) isolated fields. From the three types of rice fields, a total of 13,982, 14,105, and 12,730 individuals from the Bt-9, Ilmi-byeo and Dongjin-byeo were collected, respectively. Throughout the study, the analysis of variance indicated no significant differences (p < 0.05). Multivariate analysis showed that the abundance and diversity of plant dwelling insects were similar. The data on insect species population densities were subjected to principal component analysis (PCA), which did not distinguish among the three varieties, Bt-9 and the non-GM, reference cultivars, during the cultivation years. However, the results of the PCA analysis were completely divided into four groups based on the yearly survey areas. Therefore, there was no evidence for a negative impact of Bt-9 on the above-ground insects and spiders.

Model for Transport of Accidently Released Radionuclides onto Rice-Fields and its Comparison with Experimental Data (사고시 논으로 유출된 핵종 이동 모델 및 실험결과와의 비교)

  • Keum, Dong-Kwon;Lee, Han-Soo;Choi, Heui-Joo;Kang, Hee-Suk;Lim, Kwang-Muk;Choi, Young-Ho;Lee, Chang-Woo
    • Journal of Radiation Protection and Research
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    • v.29 no.2
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    • pp.117-127
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    • 2004
  • A dynamic compartment model was developed to evaluate the transport of accidently released radionuclides onto rice-fields. In the model, the surface water compartment and shoot-base absorption were introduced to account for the effect of irrigation, which is essential to a rice cultivation. The soil mixing by plough and irrigation before transplanting rice was also considered, and the rate of root-uptake and shoot-base absorption were modeled in terms of the function of biomass. In order to test the validation of the model, it was applied to the analysis of some simulated $^{137}Cs$ deposition experiments that were performed while cultivating rice in a greenhouse using soils sampled from rice-fields around Kori, Yonggwang and Ulchin nuclear power plants. The model prediction was generally agreed within about one order of magnitude with experimental data.