• Journal of the Korean Institute of Landscape Architecture
• /
• v.25 no.2
• /
• pp.62-72
• /
• 1997

This study was conducted to find out the hydroseeding timing of several herbaceous plants for the slope revegetation works. Four native plants and five introduced grasses were used for this experiment and were seeded on the cut slopes by hands in April, May, June, September and October. To identify the best seeding timing, germination percentage, ground covering rate, number of tillers and plant heights were investigated. There were wide differences in germination and ground covering rates of native plants are lower than those of cool-season foreign grasses and they show different germination rates according to seeding timing. Among them, Arundinella hirta var. ciliata shows the most apparent germinatin pattern according to seeding timing. 2. Seeding timing : Native plants tend to germinate well in May and June and cool-season foreign grasses in May and September. But Native plants show extremely low germination rates in autumn, so it is necessary to adjust the seeding rates when seeding in autumn. When seeding in May, it will be possible to use native plants-seed-mixture without using introduced foreign grasses. In sum, the best seeding timing of cool-season foreign grasses are May and September, and warm-season foreign grass is May and June. The best seeding timing of native plants seem to be in May and June.

• Journal of the Korean Institute of Landscape Architecture
• /
• v.25 no.1
• /
• pp.73-81
• /
• 1997

This study was conducted to find out the hydroseeding timing of woody plants. Five native plants were used for this experiment and were seeded on the cut slopes by hands in April, May, June, September and October. In order to identify the best seeding time, germination percentage, ground cover rate and plant height were investigated. There was a difference in germination percentage and ground cover rate depending on the seeding time. The results are summerized as follows 1. Characteristics of germination : Seeding was best carried out in spring(May, June) or autumn(September). In spring, Lespedeza cyrtobotrya shows quick germination and rapid growing which can be compared with herbaceous plants using in the hydroseeding. As for Pinus thunbergii, there was little difference in germinatin according to different seeding timing. But Evodia daniellii, Parthenocis년 tricuspidata and Alnus hirsuta seem to need seed treatments to improve the seed germination. 2. Ground cover rate : The most rapid growing plant is Lespedeza cyrtobotrya and the next is Amorpha fruticosa. The other plants show extreamly low ground cover rate, so they seem to be surpressed by herbaceous plants which will be mixed for erosion control. 3. Plant height : On 8 weeks later after seeding, the Lespedeza cyrtobotrya which was seeded in June recorded 17.1cm plant height. It will be enouch height to compete with herbaceous plants. As the Parthenocissus tricuspjdata seeded in May shows 27cm plant length, it can be used more frequently on seeding works if the seed germination were improved. In sum, seeding is best carried out in May. When deciding seeding rate for the purpose of hydroseeding, it will be necessary to adjust the woody plants germination percentage according to seeding timing.

• Korean Journal of Optics and Photonics
• /
• v.11 no.4
• /
• pp.265-270
• /
• 2000

We investigate the effects of the power and wavelength of externally injection seeded light on timing jitter and pulse width in a gain-switched $1.55\mu\textrm{m}$ DFB semiconductor laser by numerical simulation based on the transmission line laser model. As external seeding power increases, the timing jitter decreases and the pulse width increases. The lowest timing jitter is observed when the seed wavelength is aligned with the chirped spectrum center. By external seeding, we can decrease the timing jitter up to 1/2.7 without noticeable increase in pulse width. Our simulation results reasonably well agree with our sampled experiment and the other published papers. This proves the validity of our model to analyze a system based on a semiconductor laser. laser.

• Korean Journal of Weed Science
• /
• v.12 no.2
• /
• pp.124-131
• /
• 1992

Not only reducing the carry-over effects of quinclorac [3, 7-dichloro-8-quinoline carboxylic acid] used in paddy field to some following vegetable crops but also rationalizing agro-ecology conservation and farm economy, the reducing feasibility of application rates by various cropping patterns and application timing after rice seeding and transplanting. Four cropping patterns namely dry direct seeding(DDS), flooded direct seed(FDS), transplanting of 8 days old early seedlings(EST) and 25 days old machinery seedling(MST) were experimented with 7 application timings as 0, 5, 10, 15, 20, 25, 30 days after seeding/transplanting and 9 levels of application rates as 0, 75, 150, 225, 300, 375, 450, 525, and 600g ai/ha of the chemical, respectively. Within the maximum permitted limit of rice phytotoxicity, the minimum application rate of quinclorac to complete control of Echinochloa crus-galli as influenced by various cropping patterns with application timing could be evaluated as follows : A. Dry direct seeding : The minimized application rate at application timing upto 10 days after seeding (DAS) was counted 150g ai/ha, and delaying upto 15-30 DAS, the rates were increased upto 225-525g ai/ha. B. Flooded direct seeding and transplanting : The application rates were minimized 75g ai/ha at application timing upto 10 days after seeding/transplanting(DAS/T), 150g ai/haupto 15 DAS/T, and 225g ai/ha at later than 20 DAS/T, respectively.

• Proceedings of the Korean Society of Crop Science Conference
• /
• 2001.05a
• /
• pp.124-125
• /
• 2001

• Proceedings of the Korean Society of Crop Science Conference
• /
• 2001.05a
• /
• pp.128-129
• /
• 2001

• Korean Journal of Environmental Agriculture
• /
• v.33 no.1
• /
• pp.9-16
• /
• 2014

BACKGROUND: This study was conducted to investigate the effects of seeding timing and method of rye and/or hairy vetch on seasonal soil and foliar nutrient concentrations as well as fruit quality in a pesticide-free pear orchard. METHODS AND RESULTS: The treatments included as followed: single seeding of rye in September (Sep-Mono), November (Nov-Mono), and January (Jan-Mono), or mix seeding of rye+hairy vetch in November (Nov-Mix) and January (Jan-Mix), or sod culture as a control. Cover crops or vegetation was mown and mulched on the soil surface in April and May for two years. Nov-Mix treatment produced the highest dry matter weight of $12,070kg\;ha^{-1}$, with the lowest dry matter weight for sod culture ($6,520kg\;ha^{-1}$), following Jan-Mix ($7,030kg\;ha^{-1}$). Nov-Mix treatments increased potential amount of N, P, and K from the raw materials of the cover crops as well as improved soil physical properties. Nov-Mix treatments overall elevated soil pH, EC, organic matter, and $P_2O_5$ in May compared to other cover crop treatments or sod culture. The difference of the seasonal nutrient concentrations in leaves or fruit qualities were not consistently occurred amongst treatments. CONCLUSION: Nov-Mix treatments showed playing role in a substitute of a chemical fertilizer. Delayed seeding of cover crops such as Jan-Mix did not increase the potential dry matter production due to the short growing period, and the seeding time would affect the dry matter production of cover crops.

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.41 no.3
• /
• pp.168-175
• /
• 2021

The optimal determination of seeding rate is critical to minimizing uncertainties about the large variations observed in forage quality and productivity when alfalfa is cultivated under different geographical areas and growing conditions. The objective of this investigation was to provide information about the proper seeding rate according to harvest timing for alfalfa cultivation in the Northern regions of Korea. Alfalfa was sown in September 2018 at a seeding rate of 20, 30 or 40 kg/ha and harvested four times in 2019: May 3, July 2, September 11, and October 13. Regardless of seeding rate, alfalfa plant height was longest at the third harvest (113 cm) and the shortest in the last annual harvest (43.8 cm). However, seeding rate had no effect on alfalfa plant height at any harvest. Forage relative feed value was increased in the first cutting but decreased in the third cuttings as seeding rate increased. However, seeding rate had slight effect on alfalfa forage quality components at the second and fourth cuttings. Total annual DM and crude protein production (in 4 harvests) was greater at higher seeding rates. Plots seeded at a rate of 40 kg/ha produced on average 1,257 and 2,620 kg/ha more forage (DM basis) than those seeded at a rate of 30 or 20 kg/ha, respectively. Forage DM production at the first, second, third, and fourth harvests accounted for 36.1, 24.0, 27.1, and 12.8 % of total annual DM production, respectively. Overall, small differences were seen when alfalfa seeding rate was different but maximum forage DM production (in four harvests) was detected when seeding rate was 40 kg/ha. These data could be useful to the alfalfa growers by allowing them to make more accurate trade-offs between seed price and the expected magnitude of forage yield gains in order to select the best seeding rate.

• Weed & Turfgrass Science
• /
• v.4 no.1
• /
• pp.44-48
• /
• 2015

This study was conducted to evaluate the efficacy of weed control and phytotoxicity of oxyfluorfen using a transgenic rice line (CPPO06 event) resistant to protoporphyrinogen oxidase (Protox) inhibiting herbicides in the direct-seeding flooded rice. Five annual weeds including Echinochloa oryzoides and two perennial weeds were occurred in the test field. Oxyfluorfen at 120 g a.i. $ha^{-1}$ in the application timing of two days before sowing and 0 and five days after sowing showed more than 90% weed control value except for Juglans mandshurica. Total weed control value was more than 95% in any application timing indicating a highly effective herbicide in the direct-seeding flooded rice. When compared with untreated control, no visual injuries were detected at single and double dosage of oxyfluorfen. The agronomic characteristics and yield components of CPPO06 event was reasonable in any time of application in this study. Based on these data, oxyfluorfen application before and after sowing can be applied to provide effective weed management in the direct-seeding flooded field.

• Korean Journal of Agricultural Science
• /
• v.44 no.3
• /
• pp.400-408
• /
• 2017

This experiment was conducted to estimate the livestock carrying capacity per unit area of Hanwoo heifer with determine the quality of the forage by evaluating the productivity and nutritive value of spring seeding oats (Avena sative L.) according to different seeding and harvesting timings. Dry matter yields were the highest at 13.62 tons per ha when oat was seeded on March 15 and harvested on June 8 (p < 0.05), while the lowest yield of 6.29 tons per ha was obtained when seeded on February 25 and harvested on May 19 (p < 0.05). The highest crude protein yield of 1.27 tons per ha (p < 0.05) was obtained when seeded on March 5 and harvested on June 8. The total digestible nutrient yield was the highest at 7.38 tons per ha when harvested on June 8, the last harvest of the experiment (p < 0.05). In the northern part of Gyeongbuk province, spring seeding oats at the beginning of March, rather than in the middle of March, showed good annual livestock carrying capacity per unit area. According to harvest timing, the plot harvested on June 8 showed the highest livestock carrying capacity with an average of 6.53 heads (p < 0.05). In conclusion, in the northern part of Gyeongbuk province in spring, it is better to seed oat early in March and to harvest early in June to increase the livestock breeding capacity, considering dry matter productivity and feed value.