• Korean Journal of Weed Science
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• v.18 no.3
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• pp.186-190
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• 1998

To establish weed control method in no-tilled and rice straw-covered wheat sown coincidentally with rice harvest using combine-attached drill seeder, several herbicides and their combination were tested for 2 years. Similar number of panicle to hand-weeding plot was secured at sprayed plot with Buta EC + Glyphosate SL mixture just after seeding. Water-foxtail(Alopeculus aequalis) and broadleaf weeds were controlled effectively by Buta EC + Glyphosate SL mixture, showing the control efficacy of 92 percent. In the 1st cropping year, weed species occurred was simple and water-foxtail predominated nearly half. However, weed species was diversified and water-foxtail predominated 83.5 percent in the 2nd cropping year. Wheat yield of Buta EC + Glyphosate SL plot showed no difference with hand-weeding plot. Dry weight of water-foxtail showed closer linear relationship with wheat yield reduction than that of broadleaf weed.

• Korean Journal of Weed Science
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• v.15 no.4
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• pp.254-261
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• 1995

The nationwide weed survey was conducted in lowland rice fields over whole country of Korea in 1992 in order to determine a change of weed community and to identify a major dominant weed species and/or problem weed. Based on morphological characteristics of weeds, population ratio of broad leaf weed was 42.6%, grasses weed-9.0%, sedges-33.4% and others were 15.0%. Annual weed was 33.4% while perennial weed was 66.6% in terms of life cycle of weeds. Meanwhile, there was different weed occurrence as affected by planting method of the rice plant. In hand transplanted paddy fields predominant weed species was Sagittaria trifolia L., Monochoria vaginalis Presl., and Aneilema japonica Kunth. In machine transplanted rice fields of infant and young rice seedling Eleocharis kuroguwai Ohwi. and S. trifolia L. were more predominant. There was high occurrence of M. vaginalis, Echinochloa crus-galli L., and Leesia japonica Makino in water seeding while E. crus-galli and Cyperus serotinus Rottb. were predominant weed species in dry seeded rice. Monoculture of the rice plant would cause to high occurrence of E. kuroguwai, S. trifolia, M. vaginalis, E. crus-galli, and Sagittaria pygmaea Miq and there was higher population of S. trifolia, S. pygmaea, M. vaginalis, E crus-galli, and E. kuroguwai in double cropping system based on rice culture. In particular, there was high different weed occurrence under different transplanting times. E. kuroguwai, S. trifolia, S. pygmaea, M. vaginalis, and C. serotinus were higher population at the transplanting of 25 May and S. trifolia, E crus-galli, C. serotinus, and M. vaginalis at 10 June and S. pygmaea, E. kuroguwai, M. vaginalis, S. trifolia, and E. crusgalli at 25 June in Korea, respectively. Autumn tillage in terms of tillage time would cause more predominant weed species such as S. trifolia, E. kuroguwai, M. vaginalis, and S. pygmaea while spring tillage was higher population of E. kuroguwai, S. trifolia, E. crusgalli, M. vaginalis, and S. pygmaea. In plain area of paddy field there was higher occurrence of E. kuroguwai, S. trifolia, M. vaginalis, E. crus-galli, and S. pygmaea and in mid-mountainous area S. trifolia, E. kuroguwai, M. vaginalis, E. crus-galli, and Ludwigia prostrate Roxb. while in mountainous area S. trifolia, M. vaginalis, Potamogeton distinctus Ben., E. kuroguwai, and E. crus-galli were. In 1992 the most ten predominant weed species at the rice field of Korea based on summed dominant ratio(SDR) were E. kuroguwai > S. trifolia > E. crus-galli > M. vaginalis > S. pygmaea > C. serotinus > L. prostrate > P. distinctus > A. japonica > Scirpus juncoides Roxb.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.56 no.2
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• pp.140-145
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• 2011

In order to establish the application method of slurry composting & biofilteration liquid fertilizer (SCB LF) in rice cultivation, experiments were studied on split application method of it and effects of it on soil chemical properties and rice yields. Land leveling by rotary tillage within 2 days after application of SCB LF, $NH_4$-N concentration in soil was maintained uniformly in all paddy field. Initial concentrations of $NH_4$-N and $NO_3$-N in soil were high at standard fertilization and 100% application of SCB LF as basal fertilization, however, after tillering stage they maintained similar concentrations in all experimental plots. $NO_3$-N content in infiltration water was slightly lower at 70% application of SCB LF as basal fertilization and 30% application of SCB LF as fertilization at panicle initiation stage than at standard fertilization. Yields of rice by split application of SCB LF were lower at 100% application of SCB LF as basal fertilization, however, those of the other application of SCB LF were similar with that of standard fertilization. In case of rice quality, perfect kernel rates were high and protein contents were lower at non-application and 100% application of SCB LF. Rice quality of 70% application of SCB LF as basal fertilization and 30% application of SCB LF as fertilization at panicle initiation stage were similar with that of standard fertilization.

• Journal of The Korean Society of Grassland and Forage Science
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• v.41 no.3
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• pp.205-209
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• 2021

Barnyard millet (Echinochloa esculenta) can be processed through soiling, hay, and silage, depending on the weather conditions during harvesting. However, research on barnyard millet is insufficient, and standards for cultivar, seeding density, and fertilizers have not been established. This study was conducted to examine the effects of seeding density and seeding methods on dry matter yields. For this, we used the early-maturing (Shirohie millet) variety of the barnyard millet. The experimental design included different seeding density (10 kg/ha, 15 kg/ha, 20 kg/ha (standard seeding density), 25 kg/ha and 30 kg/ha), and different methods of seeding (drill seeding and broadcast seeding). The seeding date was May 13, 2021, and the harvest date was July 13, 2021. Harvesting was carried out when the heading reached 40 %. Lodging occurred at 5, 9 and 7 at 20, 25 and 30 kg/ha densities in the broadcast seeding, but not in the drill seeding. With decreasing density of seeding, tillage number showed an increasing trend in both drill seeding and broadcast seeding (p>0.05). The plant heights were comparable in both drill seeding and broadcast seeding (p>0.05). The heading stage of barnyard millet was checked July 7 for drill seeding, and, on July 8 for broadcast seeding. It took 62 days, i.e., till July 13 for the heading to reach 40 % of the output. The dry matter yield of barnyard millet was significantly higher at the seeding density of 30 kg/ha, for both the methods of seeding (p<0.05). There was no difference in the chemical composition of grain, based on the seeding method and seeding density. However, as the seeding density increased, the CP, NDF, ADF, and TDN contents increased in both drill seeding and broadcast seeding. We found that, the dry matter content was the highest at the seeding density of 30 kg/ha for both the methods of seeding, but this was only 1.3 times higher than that of 10 kg/ha. Considering the seed price and labor force involved in seeding, it is advisable to have a seeding density of 15-20 kg/ha.

• Proceedings of the Korean Society of Near Infrared Spectroscopy Conference
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• 2001.06a
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• pp.1263-1263
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• 2001

The amounts of organic matter present in soil and the rate of soil organic matter (SOM) turnover are influenced by agricultural management practice, such as rotation, tillage, forage plow down direct seeding and manure application. The amount of nutrients released from SOM is highly dependent upon the state of the organic matter. If it contains a large proportion of light fractions (low-density) more nutrients will be available to the glowing crops. However, if it contains mostly heavy fractions (high-density) that are difficult to breakdown, then lesser amounts of nutrients will be available. The state of the SOM and subsequent release of nutrients into the soil can be predicted by NIRS as long as a robust regression equation is developed. The NIRS method is known for its rapidity, convenience, simplicity, accuracy and ability to analyze many constituents at the same time. Our hypothesis is that the NIRS technique allows researchers to investigate fully and in more detail each field for the status of SOM, available moisture and other soil properties in Alberta soils for precision farming in the near future. One hundred thirty one (131) Alberta soils with various levels (low 2-6%, medium 6-10%, and high >10%) of organic matter content and most of dry land soils, including some irrigated soils from Southern Alberta, under various management practices were collected throughout Northern, Central and Southern Alberta. Two depths (0- 15 cm and 15-30 cm) of soils from Northern Alberta were also collected. These air-dried soil samples were ground through 2 mm sieve and scanned using Foss NIR System 6500 with transport module and natural product cell. With particle size above 150 microns only, the “Ludox” method (Meijboom, Hassink and van Noorwijk, Soil Biol. Biochem.27: 1109-1111, 1995) which uses stable silica, was used to fractionate SOM into light, medium and heavy fractions with densities of <1.13, 1.13-1.37 and >1.37 respectively, The SOM fraction with the particle size below 150 microns was discarded because practically, this fraction with very fine particles can't be further separated by wet sieving based on density. Total organic matter content, mechanical texture, ash after 375$^{\circ}C$, and dry matter (DM) were also determined by “standard” soil analysis methods. The NIRS regression equations were developed using Infra-Soft-International (ISI) software, version 3.11.

• Korean Journal of Soil Science and Fertilizer
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• v.47 no.5
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• pp.374-380
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• 2014

To estimate greenhouse gas (GHG) emission, the inventory of rice cultivation at the farming without agricultural chemicals was established from farmers in Gunsan, Jeonbuk province in 2011~2012. The objectives of this study were to calculate carbon footprint and analyse the major factor of GHGs. To do this, we carried out a sensitivity analysis using the analyzed main factors of GHGs and estimated the mitigation potential of GHGs. Also we suggested agricultural methods to reduce GHGs that can be appled by farmers at this region. At the farming system without agricultural chemicals, carbon footprint of rice production unit of 1 kg was 2.15 kg $CO_2.-eq.kg^{-1}$. Although the amount of carbon dioxide ($CO_2$) emission was the largest among GHGs, methane ($CH_4$) emission had the highest contribution to carbon footprint on rice production system when it was converted to carbon dioxide equivalent ($CO_2-eq.$) multiplied by the global warming potential (GWP). Main source of $CO_2$ emission in the rice farming system without agricultural chemicals was combustion of fossil fuels used by agricultural machinery. Most of the $CH_4$ was emitted during rice cultivation practice and its major emission factor was flooded paddy field in anaerobic condition. Also, most of the $N_2O$ was emitted from rice cultivation process. Major sources of the $N_2O$ emission was application of fertilizer such as compound fertilizer. As a result of sensitivity analysis in energy consumption, diesel had the highest sensitivity among the energy inputs. With the reduction of diesel consumption by 10%, it was estimated that $CO_2$ potential reduction was about 2.0%. With reducing application rate of compound fertilizer by 10%, the potential reduction was calculated that $CO_2$ and $N_2O$ could be reduced by 0.5% and 0.9%, respectively. At the condition of 10% reduction of silicate and compost, $CO_2$ and $CH_4$ could be reduced by 1.5% and 1.6%, respectively. With 8 days more drainage than the ordinary practice, $CH_4$ emission could be reduced by about 4.5%. Drainage and diesel consumption were the main sources having the largest effect on the GHG reduction at the farming system without agricultural chemicals. Based on the above results, we suggest that no-tillage and midsummer drainage could be a method to decrease GHG emissions from rice production system.

• Weed & Turfgrass Science
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• v.2 no.4
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• pp.358-361
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• 2013

This study was conducted to determine the weed control effect of false seedbed in organic rice paddy field. False seedbed is one of the preventative weed control method, especially effective in upland vegetable field. False seedbed frequency and methods were examined by varying the processing time in greenhouse and field condition in 2012 and 2013. In greenhouse experiment, shallow recultivation and harrow surface soil was effective to control weed up to 70%. Optimal processing time of false seedbed was when the weed was two or three leaf stages. Under field condition, one-time treatment of false seedbed was 61% of weed suppression rate and two-times of false seedbed treatment was 79% of weed suppression rate. Monochoria vaginalis was still troublesome weed after false seedbed treatment, but the occurrence of Echinochloa oryzoides was decreased after false seedbed treament. Results indicated that false seedbed treatment was very effective to lower early weed occurrence in rice paddy field especially Echinochloa spp. Weed control efficiency of shallow recultivation by weeder hollow and rotary tillage by tractor were 68%, 13% respectively.

• Weed & Turfgrass Science
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• v.5 no.3
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• pp.177-180
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• 2016

This study was conducted to identify problematic weed species in grape orchard fields to establish basic information for suitable weed control. Surveys of weed species occurring in grape orchards were conducted in Chungnam province including Daejeon and Sejong of Korea from April to June and from September to October in 2015. From the surveys, 50 weed species belonging to 23 families (33 annuals and 17 perennials) were identified. In the first survey, the most dominant weed species by the importance values was Poa annua (7.07) followed by Echinochloa crus-galli (6.56), Digitaria ciliaris (6.43) and Capsella bursapastoris (5.63). In the second survey, Rorippa palustris (9.59), Eclipta alba (9.13), Digitaria ciliaris (7.68) and Poa annua (7.68) were dominant. Different weed species and dominance patterns were detected according to weed control methods in the grape orchards. Seven weed species belonging to six families were identified in the field in which herbicides were being used as a weed control method. However, most weed species (21 species belonging to 9 families) were occurred in the mowing + tillage fields. These surveys provide information about seasonal variations of weeds species occurred in grape orchards and impact of different weed control methods on the weed occurrence.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.425-425
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• 2015

본 연구는 밭에서 발생하는 비점오염원의 저감 효과를 분석하기 위하여 최적관리기법(BMPs) 중 경운방법과 침투짚단을 하여 효과를 분석하고자 하였다. 시험포 1개의 면적은 $150m^2$ (폭 5 m, 경사장 30 m)이며, 모두 사질토의 특성을 가진 토양이다. 시험포는 총 8개(경사도 3% 4개, 8% 4개)로 각각 무경운 시험포 2개와 경운 시험포 1개 그리고 침투 짚단을 설치한 경운 시험포 1개로 경사도와 영농방법을 다르게 조성하였다. 실험의 오차를 줄이기 위하여 강우지속시간과 강우량 그리고 강우강도가 일정한 인공강우 실험을 수행하였으며, 실험시 바람에 의한 강우량의 오차를 줄이기 위해 날씨가 맑은 날에 실시하였다. 또한, 선행무강우일수 7일로 유지하여 토양의 함수비를 동일한 조건이 되도록 하였다. 총 3회의 인공강우실험에서 강우강도는 30 mm/hr 이였으며, 강우로 인해 발생한 유출수는 수위를 측정한 뒤, 수위-유량곡선식을 이용하여 유량으로 환산하였으며, 이때 수질시료를 채취하였다. 채취된 수질시료는 $BOD_5$, $COD_{Cr}$, $COD_{Mn}$, TN, TP, DOC 등의 6개 항목을 분석하였다. 연구결과 경사도 3%의 침투짚단 시험포에서 오염부하는 경운 시험포 대비 $BOD_5$는 25.4%, $COD_{Cr}$은 20.5%, $COD_{Mn}$은 2.1%, DOC는 40.8%, 영양염류인 TN과 TP는 각각 23%와 8.7%가 저감되는 것으로 나타났다. 또한 경사도 3%의 무경운 시험포에서 오염부하는 경운 시험포 대비 $BOD_5$는 57.5%, $COD_{Cr}$은 59.8%, $COD_{Mn}$은 65%, TN과 TP는 65.4%와 75%로 저감되었다. 그리고 경사도 8%에서 경운 시험포대비 침투짚단 시험포의 오염부하는 $BOD_5$ 19.6%, $COD_{Cr}$과 $COD_{Mn}$은 각각 7.8%와 10% 그리고 영양염류인 TN은 15.5%, TP는 11.2%가 저감되는 것으로 나타났다. 경사도 8%에서 무경운 시험포에서는 경운 시험포 대비 $BOD_5$ 70.9%, $COD_{Cr}$과 $COD_{Mn}$은 각각 74.9%와 81.3% 그리고 영양염류인 TN은 70.2%, TP는 70.1%가 저감된 것으로 나타났다. 본 연구결과와 같이 경운을 하는 관행방법에 비해 토양의 침투능이 유지할 수 있는 무경운 방법이나 침투짚단을 활용하는 방법이 밭에서 발생하는 비점오염원을 저감할 수 있는 것으로 나타났다. 그러나, 본 연구의 결과는 3번의 인공강우 실험을 통해 분석된 결과로써 추가적인 연구를 통해 다양한 경사도와 영농방법에 따른 비점오염물질의 저감효과를 분석해야 할 것으로 보여진다.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.5
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• pp.725-732
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• 2012

There is relatively high vulnerability of soil erosion in slope highland agriculture due to a reclamation of mountain as well as low surface covering during early summer with high rainfall intensity. Especially, in soybean cultivation, soil disturbance by conventional tillage and exposure of topsoil at the early stage of soybean have intensified soil loss. The aim of this study was to evaluate various surface covering methods for reducing soil loss in highland soybean cultivation. The experiment was conducted in 17% sloped lysimeter ($2.5m{\times}13.4m$) with 8 treatments. Amount of runoff water and eroded soil, and soybean growth were investigated. Surface covering through sod culture and plant residue showed 3.4~45.0 runoff water amount with $177{\sim}2,375m^3\;ha^{-1}$ compared with control ($5,274m^3\;ha^{-1}$). And the amount of eroded soil was also reduced by 95% in surface covering treatment with $0.02{\sim}1.94Mg\;ha^{-1}$ than control with $40.72Mg\;ha^{-1}$. Yields of soybean pod showed $0.3Mg\;ha^{-1}$ in rye sod culture, $1.3Mg\;ha^{-1}$ in Ligularia fischeri var. spiciformis Nakai, $0.7Mg\;ha^{-1}$ in Aster koraiensis Nakai, $0.2Mg\;ha^{-1}$ in red clover and $2.0Mg\;ha^{-1}$ in non-covering, on the other hand, covering with cut rye showed $3.8Mg\;ha^{-1}$. Conclusively, covering the soil surface with cut rye were beneficial for reduction of soil loss without decreasing soybean yield in highland sloped fields.