• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1996.06c
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• pp.977-986
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• 1996

The uncertainty of rains at the onset of wet season (WS) and the drought risk involved hinder growing more than one rainfed lwoland rice crop per year. Establishing transplanted rice well into the WS leaves insufficient moisture in the soil for subsequent crop. Rice establishment early in the season gives the farmer better opportunities to grow a crop after rice. An experiment was conducted startign in 1993 to evaluate dry seeding of rice through slit soil seeding. It is done utilizing the vertical metering slit seeder for conserving soil moisture coming from the first rains in the early WS to sustain germination and establishment of the seeding at least until the succeeding rains under therainfed lowland (RL) environment. The treatment consisted of slit-seeding the PSBRc 14 into the tilled and nontilled plots at 100kg/ha and at depths of <10 mm (shallow seeding) and 60-70m (deep seeding). The control treatment was broadcast seeded on tilled soil and harrow to cover the seeds The superior crop establishment observed in 1995 WS experiment on nontilled, slit-seeded plots confirmed the results observed in 1993 WS and 1994 WS experiments. Emergence in deep seeding was not significantly different from shallow seeding in nontilled plots giving an average yield of 2.1 t/ha in all slit-seeded plots. This offers an advantage of reduced energy in put in nontilled shallow seeding. However, heavy weed infestation has to be addressed at the early stage of rice in nontilled soil to get the full advantage from slit seeding. The consistently better crop establishment observed in slit seeding over that of broadcast seeding in the WS of 1993, 1994 and 1995 also demonstrates that the slit seeding technology can be adopted with confidence in the rainfed lowland field condition to reduce the risks involved in broadcast seeding.

• Korean Journal of Weed Science
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• v.6 no.1
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• pp.25-32
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• 1986

This experiment was conducted to evaluate effect of various hormones on callus induction, and on plantlet formation on various media, and to detect of Londax [Methyl 2-[[[[[(4,6-dimethoxy pyrimidin-2-yl) amino] carbonyl] amono] sulfonyl) methyl] benzoate] and Basta[Ammonium-(3-amino-3-carboxy-propyl)-methyl phosphinate] on callus growth and reaction of succinate dehydrogenase in callus against TTC, using various species such as Eleocharis kuroguwai, Cyperus serotinus, Oryza sativa (samgangbyeo) and Echinochloa crusgalli P. Beauv. var. caudata Kitagawa. The optimal levels of 2,4-D in MS medium seems to be different among species tested, 2.0 ppm for rice and E. crusgalli, 1.0 ppm for Eleocharis kuroguwai, and 4.0 ppm for C. serotinus derived callus from shoot-tip. In case of combination of 2,4-D with BA, 1.0 plus 0.3 ppm appeared the most appropriate level to induce callus from rice and E. kuroguwai, and I.0 plus 0.1 ppm for C. serotinus and E. crusgalli. When 2,4-D treated with TIBA, 1.0 plus 0.5 ppm appeared the most appropriate rates to induce callus derived from seeds of rice, E. crusgalli, seeds of C. serotinus and E. kuroguwai, 1.0 plus 0.3 ppm for shoot-tip of C. serotinus. Positive reaction of succinate dehydrogenase against TTC was observed regardless of calli and herbicides tested, indicating that they all are alive, and these herbicides were not able to kill the calli tested within the short period of time 20 hrs treatment. Regardless of plant species used, the rate of plantlet formation from callus was very low. However, some plantlet formed from E. crusgalli at 0.8 ppm of 2,4-D plus 8.0 ppm of kinetin, and from E. kuroguwai at 1.6 ppm of 2,4-D plus 16.0 ppm of kinetin, showing effectiveness of 2,4-D with kinetin mixture treatment. No callus was induced from C. serotinus treated with Basta from $10^{-6}M$ to $10^{-3}M$. In general, rice was the least susceptible to Basta among plant species tested, followed by E. crusgalli, and E. kuroguwai. In Londax treatment, rice showed the least inhibition rate in callus growth. Callus was induced from rice even at $10^{-3}M$ of Londax. However, $10^{-3}M$ of Londax completely inhibited callus induction from the test species. Rice showed most tolerant to both herbicides, indicating the existence of different responses among plant species.

• Korean Journal of Weed Science
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• v.16 no.2
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• pp.81-87
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• 1996

Seeds of rice, cv. Ilpoom, and barnyardgrasses(Echinochloa crus-galli, vars. oryzicola, crux-galli, and praticola) were sown for a characterization of their responses to temperature during emergence under a dry direct-seeded condition. A laboratory-made aluminum block apparatus for emergence-temperature control conferred a linear continuous temperature gradient from 10 to $30^{\circ}C$ to the seeds from cooling to heating ends of the apparatus. The lowest temperature for emergence was $12.3^{\circ}C$ for rice cv. Ilpoom, and $11.0^{\circ}C$ for the three varieties of Echinochloa spp.. Percent emergence of rice increased sharply with an increase in temperature by ca. $20^{\circ}C$, then leveled-off, while those of barnyardgrasses increased almost linearly with temperatures up to $30^{\circ}C$. In rice the time required for emergence after seeding was shortened exponentially with increased temperature while those for barnyardgrasses were shortened almost linearly from 11 to $30^{\circ}C$. The temperature-response characteristic of rice in emergence-speed was almost the same among those for the 1st emergence, emergence by 25, 50, 75%, or average emergence time. At $13^{\circ}C$, $346.7^{\circ}C$ days of accummulated temperature(26.67 days) were required for the 1st emergence in rice while 131.7, 136.0, and $138.7^{\circ}C$ days(10.13, 10.46, and 10.67 days) were required for the 1st emergence in E. spp., vars. crus-galli, praticola, and oryzicola, respectively. Greater cold tolerance and increasingly faster emergence of barnyardgrasses than rice below $20^{\circ}C$ seem to render the barnyardgrasses as much more competitive than rice at lower temperatures.

• Korean Journal of Weed Science
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• v.31 no.3
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• pp.250-259
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• 2011

This study was conducted to assess the possibility of 5,8-dihydroxy-1,4-naphthoquinone (DHNQ) as a environmental friendly herbicide candidate. Foliar application of DHNQ showed excellent herbicidal effect to the 3 grasses and 5 broad-leaved weeds. Among them, Digitaria sanguinalis and Solanum nigrum were completely controlled by $250{\mu}g\;mL^{-1}$ of DHNQ with main symptoms of desiccation or burndown within 24 hours. Aeschynomene indica was also sensitive to DHNQ treatment. All of the eight weed species were controlled by 90~100% at a concentration of $1000{\mu}g\;mL^{-1}$. However, soil application of DHNQ to Digitaria sanguinalis did not show any herbicidal symptoms. DHNQ strongly inhibited KAPAS activities in vitro and the $IC_{50}$ was $4.4{\mu}M$. Cellular leakage from cucumber leaf squares treated with DHNQ increased depending on the concentrations increased from 6.25 to $100{\mu}M$ after 24 hours incubation with or without light. However, chlorophyll loss in cucumber leaf squares was negligible. Biotin supplements significantly rescued the inhibition of germination rate of Arabidopsis thaliana seeds previously inhibited by the DHNQ. According to above results, DHNQ is a good natural herbicide candidate having a new target KAPAS, which is involved in biotin biosynthesis pathway, with environmental friendly.

• Korean Journal of Environmental Biology
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• v.39 no.4
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• pp.581-589
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• 2021

Using visible-near infrared(Vis-NIR) spectra combined with machine learning methods, the feasibility of quick and non-destructive classification of Convolvulaceae species was studied. The main aim of this study is to classify six Convolvulaceae species in the field in different geographical regions of South Korea using a handheld spectrometer. Spectra were taken at 1.5 nm intervals from the adaxial side of the leaves in the Vis-NIR spectral region between 400 and 1,075 nm. The obtained spectra were preprocessed with three different preprocessing methods to find the best preprocessing approach with the highest classification accuracy. Preprocessed spectra of the six Convolvulaceae sp. were provided as input for the machine learning analysis. After cross-validation, the classification accuracy of various combinations of preprocessing and modeling ranged between 43.4% and 98.6%. The combination of Savitzky-Golay and Support vector machine methods showed the highest classification accuracy of 98.6% for the discrimination of Convolvulaceae sp. The growth stage of the plants, different measuring locations, and the scanning position of leaves on the plant were some of the crucial factors that affected the outcomes in this investigation. We conclude that Vis-NIR spectroscopy, coupled with suitable preprocessing and machine learning approaches, can be used in the field to effectively discriminate Convolvulaceae sp. for effective weed monitoring and management.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.50-50
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• 2022

Recently, the use of mulching film has increased in soybean cultivation. Polyethylene (PE) films and biodegradable films (BF) have the advantages of improving soil moisture retention, geothermal maintenance, and CO2 maintenance as well providing weed control. Furthermore, BFs are a material that can compensate for the shortcomings of PE because it has the ability to decompose naturally by soil microorganisms, sunlight, and geothermal heat. Many researches have been carrying out studies regarding the development of BFs for these very reasons. This study was conducted better understand which films are optimal for soybean cultivation after evaluations of soybean growth and film characteristics of various BFs. BFs Farmsbio (Farm Hannong), Heulgro Film (Sejin Bio), Vonto Film (Eco-Hansung), two unnamed biodegradable films (Seojin Bio and Taesung), and a PE film were used in this study. For the control plots, no mulching was used. Experimental fields were fertilized according to conventional cultivation methods, tilled, and then covered with either BFs or PE films. After 1 week, soybean (cv. Daechan) seeds were seeded. Germination rate and plant height were measured at weekly intervals after seeding. In addition, pH, EC, and decomposition and light transmittance levels of films were measured during the experimental period. Daily average temperatures and relative humidity in soils was measured during the experimental period. There was no significant difference in germination rates and plant height in both crops grown with BFs and PE films, but crops grown in the control plot had significantly lower germination rates and growth. Soil pH was not significantly different regardless of treatments (BF, PE, and non-mulching) at 14, 28, and 42 days after seeding. In general, the EC contents in the control plots was lower than in crops grown using BFs and PE films. With the exception of some BFs, light transmittance and decomposition levels of films did not, in general, increase up to 70 days after soybean seeding. Since this study is ongoing, we are continually investigating these parameters. The average daily moisture in soil was higher in crops grown with BFs and PE films than in the control plot. However, the daily average soil temperature was not consistent regardless of treatments. Therefore, the BFs used in this study can be used without negative impacts on soybean growth.

• Journal of Practical Agriculture & Fisheries Research
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• v.26 no.1
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• pp.16-21
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• 2024

Green manure crops have a variety of benefits, including improving soil fertility, removing soil salinity, enhancing soil aeration and moisture regulation, reducing the use of chemical fertilizers, reducing nitrous oxide emissions, reducing herbicide use through weed-suppressive effects, promoting agricultural ecosystem protection and carbon dioxide absorption capacity. To find ways to increase the germination rate of legumes and green manure crop seeds, which are imported in large quantities every year. It was carried out that two seed priming methods, osmotic priming and heat treatment, and compared their effects. Heat treatment was treated for 10 minutes at 40℃ or 60℃, followed by rinsing with water. Osmotic priming was applied for 30 seconds in a saline solution with a specific gravity of 1.13. Overall, there was no significant difference in the final germination rate, but it was found that osmotic priming and heat treatment affected the germination speed. However, applying heat treatment and osmotic priming simultaneously did not affect the germination characteristics. Therefore, it is suggested that heat treatment and osmotic priming can increase the germination speed of soybean and green manure crops.

• Korean Journal of Weed Science
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• v.9 no.2
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• pp.97-102
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• 1989

1. IAA showed no significant growth of root primordia and then lateral root emerged at 2 days after IAA treatment. BA treatment, however, strongly inhibited the formation of root primordia and a few lateral roots, if any, emerged about 5 days after treatment. 2. Treatment of BA and Indol-B on the water retaining ability sampled 1, 3, 5 days after chemical treatment was apparent on the soybean sprouts sampled 5 days after treatment while the difference among the treatments was negligible when sampled 1 and 3 days after treatment. 3. BA stimulated ABA content in the hypocotyl while inhibited ABA content in the root of soybean sprouts. ABA may relate with water retaining ability. 4. Soaking the soybean seeds to several seed disinfectant chemical solution had no effect on the growth and elongation of soybean sprouts. 5. It can be recommended that container of soybean sprouts should be shut tight during growing period except irrigation because the ethylene accumulation in the container may stimulate hypocotyl swelling and inhibit length of soybean sprouts.

• Journal of Animal Science and Technology
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• v.45 no.5
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• pp.865-874
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• 2003

Red sorrel, as one of exotic weeds in Korea, was introduced along with imported cereals for concentrate feed or within the seed for forage production. The plant was dominated in grassland and reduced the quality of forage. In particular, this weed cause severe problem in alpine grassland. This study was carried out to investigate the effect and response of red sorrel and forage crops by foliar and soil applied herbicide application. Mecoprop(MCPP) and pendimethaline were selected by pre-field experiment trials and applied to control the red sorrel in grassland. Herbicidal activity of MCPP was 77.2% at 500$m\ell$/10a level and 82.8% at 750$m\ell$/10a level. However, seeds of red sorrel from bare land formed after foliar applied herbicide treatment were germinated and covered bare land. Pendimethalin was not reduced the rhizome growth grown from red sorrel root but retarded seedling growth of germinated red sorrel. The herbicidal activity of pendimethalin to the red sorrel seedling was 83.0%. 2 times application of MCPP at the rate of 750$m\ell$/10a was effective to control of red sorrel regrown from root and herbicidal activity was 93.2%. MCPP and pendimethaline treatment was not reduced growth of grass and have no herbicidal injury to forage crop seedling. Amount of MCPP and pendimethalin remained in grass plant was decreased from 20 days after herbicide treatment and could not be problem in livestock feeding.

• Korean Journal of Weed Science
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• v.7 no.1
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• pp.35-44
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• 1987

Differing in water conditions, the dry matter weight per plant was highest at 0 cm flooding depth, and was decreased at above 2 cm flooding depths. The shoot and spikes per pot developed best at flooding depths of 0 and 2 cm, but worst at -5cm or above 4cm flooding depths. The dry matter weight of shoots was linearly increased, but the weight of roots was sharply decreased according to high temperature after flower initation. The shoots and spikes per pot developed more effectively at 25$^{\circ}C$ than at 35 or 15$^{\circ}C$. The number of shoot and spike per pot were decreased according to higher shading. The effects of shading of 25-45% were not significantly small. The natural white and yellow spectra were the most effective to increase dry matter weight, shoots and spikes per pot. The dry matter weights of shoot and root per plant were not significantly different among at: 50 and 75% clay. The number of shoots were best and continuously increased at 75% clay, and the increments at 0 and 100% clays showed the lag period at early stage. The pattern of spikes was similar to shoots with less difference in various clay composition. The dry matter weight per plant in paddy field and upland field was basically similar. The numbers of shoot and spike were increased in response to increased fertilizer levels up to 20Kg per 10a of each component.