우리나라에서 휴경기간에 따른 묵논의 군락분류 및 특성

심인수 ( In Su Shim ),김종봉 ( Hong Bong Kim ),조광진 ( Kwang Jin Cho ) 한국환경농학회 2013 한국환경농학회지 Vol.32 No.3

BACKGROUND: As a result of rural exodus, aging of rural population, development of high-yield rice varieties and so on, abandoned paddy fields of South Korea have generally increased. The phytosociological studies are needed to recommend the effective vegetation management methods of abandoned paddy fields. The current study performed an analysis of vegetation characteristics by classifying plant communities for abandoned paddy fields in South Korea. METHODS AND RESULTS: A comparative analysis of syntaxonomy, synecology, and syndynamics was performed by using the Z.-M. method of phytosociology and vegetation survey which was obtained from an enumeration district of total 203 phytosociological releves of 5 regions in Gangwon-do, 5 regions in Gyeonggi-do, 2 regions in Chungcheong-do, 18 regions in Gyeongsang-do, and 10 regions in Jeolla-do. Alopecurus aequalis community, Juncus effusus var. decipiens community and Salix koreensis community were, respectively, identified as successional plant communities of the early stage, the middle stage, and the late stage in the vegetation of abandoned paddy field. Sere of abandoned paddy field can be classified, developmentally, into annual plant stage, perennial plant stage, shrub plant stage, and forest tree stage. Several kinds of dominant species rather than a distinct species were found in the middle stage of abandoned paddy field. CONCLUSION(S): In this study, changing pattern in vegetational communities of abandoned paddy field were understood. These results will provide important information for restoring and conserving the ecology of fallow ground.

An Empirical Model for Backscattering Coefficients of Vegetation Fields at 5.4 GHz

오이석,Chang Jisung Geba,Shoshany Maxim 한국전자파학회 2022 Journal of Electromagnetic Engineering and Science Vol.22 No.2

A new, simple empirical model for microwave backscattering from vegetation fields at 5.4 GHz is proposed in this paper. First, a modified radiative transfer model (RTM) is used to generate a database of multi-polarized backscattering coefficients of various vegetation fields at 5.4 GHz with wide ranges of vegetation biomasses and soil moistures. Second, we propose a functional form of an empirical model that is a simplified water cloud model (WCM) after closely examining the behaviors of the well-known WCM based on an extensive database that includes the modified RTM outputs, scatterometer measurements, SAR datasets, and in situ measured ground-truth data for various vegetation fields. Finally, the unknown constant parameters of the empirical model are determined for each soil moisture condition based on the extensive database. The new empirical model is verified with the database itself, and also with independent Sentinel-1 synthetic aperture radar (SAR) data and in situ measured ground-truth data.

A Modified Water-Cloud Model With Leaf Angle Parameters for Microwave Backscattering From Agricultural Fields

Soon-Koo Kweon,Yisok Oh IEEE 2015 IEEE transactions on geoscience and remote sensing Vol.53 No.5

<P>This paper presents the development of an accurate and simple scattering model for radar backscatters of agricultural fields. We modified the water-cloud model (WCM) by adding new parameters (the average and standard deviation of leaf angle distribution) to accurately estimate the backscattering coefficients with the angular effect of scattering particles in a vegetation canopy. A relatively accurate radiative transfer model (RTM) and field measurements were used in this modification. The accuracy of the RTM was verified with the C-band ground-based scatterometer data of a cornfield, the X-band synthetic aperture radar data and ground-based scatterometer data of a bean field, and the in situ measured ground-truth data of those fields. The newly modified WCM (MWCM) was also verified with the measurement data. It was found that the root-mean-square errors between the MWCM and the measurements were less than 1.5 dB for all backscatter data from the agricultural vegetation fields.</P>

Development of a Scattering Model for Soybean Fields and Verification with Scatterometer and SAR Data at X-Band

Soon-Koo Kweon,Ji-Hwan Hwang,Yisok Oh 한국전자파학회JEES 2012 Journal of Electromagnetic Engineering and Science Vol.12 No.1

This paper presents a scattering model and measurements of backscattering coefficients for soybean fields. The polarimetric radar backscatters of a soybean field were measured using the ground-based X-band polarimetric scatterometer in an angular range from 20° to 60°. The backscattering coefficients were also obtained using the COSMOSkyMed (Spotlight mode, HH-polarization) from July to October 2010. The backscattering coefficients of the soybean field were computed using the 1st-order radiative transfer model (RTM) with field-measured input parameters. The soybean layer is composed of the stems, branches, leaves, and soybean pods. The stems, branches, and pods are modeled with lossy dielectric cylinders, the leaves are modeled with lossy dielectric disks. The estimated backscattering coefficients agree quite well with the field-measured radar backscattering coefficients.

소석회를 이용한 급경사 농경지 토양유실 저감

고일하,유찬,박미정,지원현 한국지하수토양환경학회 2019 지하수토양환경 Vol.24 No.2

The feasibility of using hydrated lime (Ca(OH)2) was assessed in reducing soil loss in sloped land under field condition. During 6-month monitoring from May to October, amendment of hydrated lime (3%, w/w) to a test plot decreased soilloss by 76% as compared to the unamended plot. However, the growth of natural vegetation was hampered by hydratedlime addition due to pH increase. Hydrated lime can be used as an effective agent to prevent soil loss in sloped land, butadditional treatments are needed to preserve vegetation growth, especially in crop fields.

1차 Vector Radiative Transfer 기법을 이용한 옥수수 생육에 따른 후방산란 특성 분석

권순구(Soon-Koo Kweon),황지환(Ji-Hwan Hwang),박신명(Sin-myeong Park),홍성욱(Sungwook Hong),오이석(Yisok Oh) 한국전자파학회 2014 한국전자파학회논문지 Vol.25 No.4

본 연구에서는 위성 SAR 영상을 이용한 초목층 정보 예측을 위해 옥수수의 생육에 따른 후방 산란 계수 변화를 분석한다. 이를 위하여 지상형 산란계 시스템을 이용하여 옥수수 밭의 후방 산란 계수를 측정하였으며, 지표면 정보를 입력변수로 한 1차 VRT(Vector Radiative Transfer) 기법을 이용하여 후방 산란 계수를 계산하여 측정값과 비교/분석한다. 그 결과, 생육 초기에는 옥수수보다 토양에서의 산란이 지배적이었으며, 옥수수의 밀도가 증가하면서 잎의 분포의 영향으로 입사각이 증가하면서 후방 산란 계수가 점차 상승하는 특징을 보였다. 측정 데이터와 1차 VRT 계산 오차는 평균 RMSE (Root Mean Square Error)가 VV-편파에서 1.32 dB이었고, HH-편파에서 0.99 dB이었다. 또한, 1차 VRT 계산을 통해LAI (Leaf Area Index) 변화에 따른 작물과 토양에서의 산란 영향을 분석하였다. In this study, we analyzed the effect of corn growth on the radar backscattering coefficient. At first, we measured the backscattering coefficients of various corn fields using a polarimetric scatterometer system. The backscattering coefficients of the corn fields were also computed using the 1st-order VRT(Vector Radiative Transfer) model with field-measured input parameters. Then, we analyzed the experimental and numerical backscattering coefficients of corn fields. As a result, we found that the backscatter from an underlying soil layer is dominant for early growing stage. On the other hand, for vegetative stage with a higher LAI(Leaf-Area-Index), the backscatter from vegetation canopy becomes dominant, and its backscattering coefficients increase as incidence angle increases because of the effect of leaf angle distribution. It was also found that the estimated backscattering coefficients agree quite well with the field-measured radar backscattering coefficients with an RMSE(Root Mean Square Error) of 1.32 dB for VV-polarization and 0.99 dB for HH-polarization. Finally, we compared the backscattering characteristics of vegetation and soil layers with various LAI values.

연안역의 토사 및 영양염류 유출에 관한 현지관측

이국진,김인수,池田俊介 한국항해항만학회 2005 한국항해항만학회지 Vol.29 No.1

본 연구는 강우에 기인한 연안역의 토사 및 영양염류 유출에 관한 현지관측과 대안[(沖縄石頭島)오끼나와 이시가키섬]이며, 이를 통한 유출지형분석, 강우강도·조석과의 영향, 유출입자의 특성(탁도, 입도, 영양염류)등을 확인하였다. 연안부의 토사 유출과 영양 염류의 농도는 강우강도와 조수간만의 시간적 변화에 따라 지역적 차이를 보였으며, 하천유역 주변 토지 이용형태와 주변 식생의 분포비율에 따라 변화되어지고 있음을 확인할 수 있었다. We studied field observation and countermeasure about the effluent of sediment and nutrient materials on the Okinawa Ishigaki coast according rainy season though this observation, we found out the analysis of outflow topography, intensity of rainfall and effects on the tide, the property of effluent materials etc. The sediment and nutrient concentration of the Okinawa Ishigaki coast are different on the regional sites according to vary with time variation of intensity of rainfall and the ebb and flow. We could confirm to vary with utilized waterways land area and distribution of surrounding vegetation.

Soil Water Flow Patterns due to Distance of Two Emitters of Surface Drip Irrigation for Horticultural Crops

Soon Hong Kwon,Dong Hyun Kim,Jong Soon Kim,Ki Yeol Jung,Sang Hun Lee,Joon Kook Kwon 한국원예학회 2020 원예과학기술지 Vol.38 No.5

Surface drip irrigation is one of the most efficient systems for irrigating vegetables. The patterns of soil water distribution formed under the emitter are important for designing an optimal drip irrigation system. This study aims to evaluate the soil water patterns between two emitters using field experiments and numerical simulations. Field experiments were conducted using two emitters with different lateral spacings (20, 40, and 60 ㎝). Frequency domain reflectometry (FDR) sensors were used to measure the soil water content. HYDRUS-2D software was used to simulate water infiltration in the field experiments. At a short lateral spacing (20 ㎝), the water content started to increase at 30 min and saturated at 200 min. These values became significantly larger as the lateral spacing increased—300 min and saturated at 700 min at 40 ㎝ and 900 min and longer than 22 hours at 60 ㎝, respectively. The simulated water contents were in satisfactory agreement with the experimental values (R² = 0.97, RMSE = 0.009 ㎤ ㎝<SUP>-3</SUP>, E (coefficient of efficiency) = 0.959). These results provide valuable information that can be used to design an efficient surface drip irrigation system for vegetables, thereby improving crop productivity and quality.

콩 포장에서 잡초 밀도 차이에 따른 초분광 특성 변화

황혜린,정재경,홍세실,송기은,홍선희,심상인 한국잔디학회 2022 Weed & Turfgrass Science Vol.11 No.3

This study was conducted to investigate the effect of competition with various weed densities on crop plants in soybean fields. As the density of weed decreased, the biomass production of soybeans increased, and the soybean yield was also high in plots with low weed occurrence density. The weed species that were dominant in the field were Cyperus iria, Eclipta prostrata, Portulaca oleracea , Mollugo pentaphylla , Galinsoga parviflora , Acalypha australis , and Amaranthus retroflexus. The diversity of weeds was lower in the plot in which weed density was lowered. The hyperspectral reflectance by weed density was different not only in soybean but also in weeds and was affected by the time of the investigation. At 21 days after flowering (DAF) at which water requirement is high in soybean, the hyperspectral reflection was lower than that of weeds, and at 42 DAF, the hyperspectral reflection of weeds was lower than that of soybeans. The carotenoid indicators (CI), known to be related to water stress in plants, was higher than that of weeds at 21 DAF, and at the higher weed density, weeds are higher than soybeans, and it is estimated that the more weeds occur, the more weeds are superior to soybeans in competition for water. When comparing the pigment specific simple ratio (carotenoids) (PSSRc) related to carotenoid level by the weed densities, the index of soybean at the low weed density and medium density decreased at 42 DAF compared to the value at 21 DAF. 본 연구는 콩 밭에서 잡초발생밀도에 의한 잡초 경합이 콩 작물에 미치는 영향을 조사하였다. 잡초발생밀도가 낮아짐에 따라 콩의 건물중은 높아졌으며, 콩 수확량도 잡초발생밀도가 낮은 처리구에서 높았다. 잡초발생밀도에 따른 잡초종및 건물중을 조사한 결과, 주요 발생 잡초종들은 쇠비름, 참방동사니, 한련초, 석류풀, 별꽃아재비, 깨풀, 털비름이었고, 잡초발생저밀도구보다 고밀도구에서 잡초종이 다양하였다. 잡초종 건물중은 개화 후 21일차보다 42일차 조사에서 줄어들었으나 깨풀과 한련초는 증가하였다. 잡초발생밀도에 의한 초분광 반사율은 콩과 잡초, 조사 시기에 영향을 받았다. 특히 작물의 생육단계에 따라 반사율의 변화가 일어났다. 수분요구도가 높은 개화 후 21일에는 콩의 반사율이 잡초의반사율보다 낮았으나 개화 후 42일에는 잡초 반사율이 콩 반사율보다 낮았다. 식물 수분스트레스와 관련 있다고 알려진CI은 콩이 잡초보다 높았기 때문에 수분 경쟁에 있어 콩이 잡초보다 우위에 있는 것으로 보인다. 카로티노이드와 관련된 PSSRc은 잡초발생 고밀도구의 콩에서 감소폭이 잡초 감소폭보다 높은 것으로 보아 콩과 잡초간 수분 경합이 일어나는 조건에서 발생하는 산화적 스트레스에 대한 대응을 위해 카로티노이드가 중요한 역할을 하는 것으로 보인다.

유기농업(有機農業)을 위한 리초방제기술(離草防除技術)의 현재(現在)와 미래(未來)

權容雄 ( Kwon Yong-woong ) 한국유기농업학회 1998 韓國有機農業學會誌 Vol.6 No.2

Organic farming excludes any use of the herbicide. The present paper reviews what can be done for effective weed control with existing weed control technology by farmers cropping paddy rice. field crops. vegetables. and fruit trees. If condition of the crop-Iand allows diversified rotational use of the paddy land as paddy and upland field would minimize weed problem. Practising this is limited in acreage due to extremely limited governmental investment to the land for the purpose. Secondly. rotation of crops in the upland field breaking life cycles of various weeds adapted to each crop should reduce the weed problem. This is also limited as only a few crops are making the farmer profitable. In addition climate and tolerance of crops to high and low temperature. Monsoon rains and poor drainage restrict the freedom of choice. For any crop land year-round multiple cropping in denser planting shalllessen the weed problem. this multiple cropping practiced by 1960s has been abandoned due to laborshortage and increased production cost. Deep flooding the rice is impractical at present in Korea. Mulching crop with transparent. black. or combinated polyethylene sheet has been increasingly used. Progresses in development and use of mulch with allelopathic crop residues. inexpensive paper mulch. allelopathic crop cultivar development. recently developed experimental weeding machinaries. flamers. microbial herbicides. biological control organisms. soil sterilization techniques have been critically reviewed for their adoption into existing integrated weeding system. Unfortunately. information on cost-benifit. and labor-benefit for the various methods above mentioned are lacking. Urgent need for the research on rational weeding in organic farming, and herbicide low-input farming is emphasized.