• Weed & Turfgrass Science
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• v.7 no.1
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• pp.46-53
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• 2018

This study was conducted to establish standard fresh weight data about the minimum amount of occurred weeds at untreated paddy fields, upland fields and orchard fields (including non-cultivated land) in 10 areas. The amount of occurred weeds in each area was compared fresh weight with dry weight. The average percentage for ratio of dry weight to fresh weight in paddy fields was concluded to be 14.8% of Echinochola crus-galli, 12.5% of annual weeds (including Echinochola crus-galli), and 13.9% of perennial weeds. The average percentage for ratio of dry weight to fresh weight in upland fields was concluded to be 20.1% of annual weeds and in orchard fields was concluded to be 18.4% of annual and perennial weeds. According to the research, standard fresh weight about the minimum amount of occurred weeds at untreated paddy fields was proposed to $210g\;m^{-2}$ of Echinochola crus-galli, $400g\;m^{-2}$ of annual weeds (including Echinochola crus-galli), and $220g\;m^{-2}$ of perennial weeds. Standard fresh weight about the minimum amount of occurred weeds at untreated upland fields was proposed to $250g\;m^{-2}$ of annual weeds and at untreated orchard fields was proposed to $550g\;m^{-2}$ of annual and perennial weeds.

• Journal of Bio-Environment Control
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• v.11 no.1
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• pp.35-39
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• 2002

This study was conducted to investigate the effect of early $CO_2$ enrichment during seedling stage on long-term $CO_2$ enrichment after transplanting in the culture of pat-choi (Brassica campesris L), spinach (Spinacia oeracea L.), and leaf lettuce (Lactuca saliva L). During seedling stage, $CO_2$enrichment had significantly higher fresh and dry weight and leaf area of the top parts (above ground) of all three plant species than the control (no $CO_2$ enrichment). About 53%, 70% , and 40% increase in fresh weight of the top parts of pak-choi, spinach, and leaf lettuce were observed, respectively. Also, in seedling stage, dry weights of roots of spinach and leaf lettuce were significantly increased by early $CO_2$ enrichment. Relative fresh weight increment, compared with fresh weight of the control, in the top parts of roll three plants showed the highest values in 10 days after $CO_2$ enrichment treatment. In the long-term $CO_2$ enrichment experiment, early $CO_2$ enrichmented plants had 20% greater leaf area than the control in all three leafy vegetables. Fresh and dry weights of top parts of early $CO_2$-treated plants were also increased from 10 to 20%, as compared with the control plants. However, these increasement rates in the long-term $CO_2$ enrichment were lower than those seedling stage, which had 30-60% increment-rates. After transplanting, photosynthetic rate of each leafy vegetable in the control treatment slowly decreased, but those rates of early $CO_2$ enriched plants rapidly decreased.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.3
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• pp.374-383
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• 2010

Microwave radar can penetrate cloud cover regardless of weather conditions and can be used day and night. Especially a ground-based polarimetric scatterometer has advantages of monitoring crop conditions continuously with full polarization and different frequencies. Kim et al. (2009) have measured backscattering coefficients of paddy rice using L-, C-, X-band scatterometer system with full polarization and various angles during the rice growth period and have revealed the necessity of near-continuous automatic measurement to eliminate the difficulties, inaccuracy and sparseness of data acquisitions arising from manual operation of the system. In this study, we constructed an X-band automatic scatterometer system, analyzed scattering characteristics of paddy rice from X-band scatterometer data and estimated rice growth parameter using backscattering coefficients in X-band. The system was installed inside a shelter in an experimental paddy field at the National Academy of Agricultural Science (NAAS) before rice transplanting. The scatterometer system consists of X-band antennas, HP8720D vector network analyzer, RF cables and personal computer that controls frequency, polarization and data storage. This system using automatically measures fully-polarimetric backscattering coefficients of rice crop every 10 minutes. The backscattering coefficients were calculated from the measured data at a fixed incidence angle of $45^{\circ}$ and with full polarization (HH, VV, HV, VH) by applying the radar equation and compared with rice growth data such as plant height, stem number, fresh dry weight and Leaf Area Index (LAI) that were collected at the same time of each rice growth parameter. We examined the temporal behaviour of the backscattering coefficients of the rice crop at X-band during rice growth period. The HH-, VV-polarization backscattering coefficients steadily increased toward panicle initiation stage, thereafter decreased and again increased in early-September. We analyzed the relationships between backscattering coefficients in X-band and plant parameters and predicted the rice growth parameters using backscattering coefficients. It was confirmed that X-band is sensitive to grain maturity at near harvesting season.

• Horticultural Science & Technology
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• v.34 no.2
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• pp.269-281
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• 2016

The statistical analyses of coefficient of variation, heritability, and genetic advance were carried out to identify differences in morphological characteristics, such as the stem and inflorescence length, of 10 major commercial cultivars of spray chrysanthemum (Chrysanthemum morifolium). For morphological characteristics, stem lengths ranged from 46.4 cm to 54.9 cm, the maximum diameter of stem was 5.6 to 8.5 mm, the hardness of the stem was 0.17 to $0.70kg{\cdot}m^{-2}$, the fresh weight of stem was 7.5 to 17.5 g, the dry weight of the stem was 1.6 to 3.3 g, the ratio of dry weight/fresh weight of stem was 15.9% to 23.1%. Also, the number of leaves on the stem was 8.4 to 12.2, the stem leaf area was 17.8 to $37.8m^2$, the fresh weight stem leaves was 5.3 to 18.6 g, the dry weight was 0.5 to 1.4 g and the ratio of dry weight /fresh weight of stem leaves was 7.6% to 11.5%. The inflorescence length ranged from 10.1 to 18.6 cm, the fresh weight of inflorescence was 7.3 to 26.7 g, the dry weight of inflorescence was 1.2 to 2.8 g, the ratio of dry weight /fresh weight of inflorescence was 10.4% to 17.1%. For flower, the diameter of the flower center was 8.2 to 13.3 mm, the petal width was 5.7 to 14.0 mm, the petal length was 12.9 to 33.1 mm, and the petal thickness was 157.8 to $354.4{\mu}m$. The mean values of each character in each cultivar were very different, and DMRT and LSD values based on morphological characteristics among 10 cultivars were highly significant. For variability and genetic parameters, the lowest CV (coefficient of variation), PCV (phenotypic coefficient of variation), and GCV (genotypic coefficient of variation) were 4.79% to 5.15% in stem length, and the highest variations were 62.97% to 65.21% in leaf area. ECV (error or environmental coefficient of variation) was the lowest for leaf area (1.71%) and it was the highest for leaf dry weight (19.30%). Heritability also significantly differed among the characteristics, ranging from 68.69% to 99.67%, the lowest value was shown in ratio of dry weight /fresh weight of stem and the highest value was for leaf area of stem. The value for genetic advance was the lowest in hardness of stem at 0.30 and the highest in leaf thickness at 156.65. The lowest genetic advance as percentage of mean of stem hardness was 9.17%, while the highest percentage of stem length was 134.27%. Thus the characters which had the highest values indicated above show the influence of additive gene action and may provide useful resources for selection programs for agronomic improvement.

• Korean Journal of Soil Science and Fertilizer
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• v.40 no.3
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• pp.173-180
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• 2007

Reclaimed tidal area is a great agricultural resource in the world. Improvement and utilization of reclaimed soil is an important measure for expanding land resource. This study was conducted to evaluate relative salt-tolerance of plants and its effect for improving saline soil. Eighteen tolerance plants were selected from China, Pakistan and Korea the climate of which is different. The emergence of different varieties in reclaimed soil was in order as FL478>Barnyard grass>Pokkali>Atriplex>Sesbania>Rumex>Alfalfa>Tall Fescue>Ryegrass>Sudan grass. Four varieties, Barnyard grass, Sesbania, Atriplex and Limonium were selected for soil improvement in reclaimed land. Cultivation of Sesbania, Barnyard grass and Atriplex were good to soil physico-chemical quality. Also these plants increased soil organic matter contents and reduced soil salt concentration. Organic matter contents of cultivated soils of Sesbania, Barnyard grass and Atriplex were $4.10g\;kg^{-1}$, $4.60g\;kg^{-1}$ and $2.81g\;kg^{-1}$ respectively. On the other hand organic matter content of uncultivated soils was $2.65g\;kg^{-1}$. As Sesbania and Barnyard grass were applied to cultivated soil like green manure, bulk density improved from $1.42Mg\;m^{-3}$ to $1.39Mg\;m^{-3}$.

• Journal of Bio-Environment Control
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• v.15 no.2
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• pp.196-203
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• 2006

Objective of this research was to determine the effect of application level of fused superphosphate (FSPP) in root media containing granular micronutrient fertilizers (MF) on growth of marigold 'Orange boy' in plug culture. To achieve this, three granular micronutrient mixes such as MF 1, MF 2, and MF 3 were produced and incorporated into three root media, peatmoss+composted pine bark (1:1, v/v, PB), peatmoss+composted rice-hull (1:1, v/v, PR), and peatmoss+composted saw-dust (1:1, v/v, PS), at a rate of $0.3g{\cdot}L^{-1}$. Elevated application level of FSPP in PS medium containing each of MF resulted in increase of plant growth such as plant height, plant width, stem diameter, fresh weight and dry weight at 35days after sowing. The dry weight in the treatment of MF 1, MF 2, MF 3, and control fertilized with $9.0g{\cdot}L^{-1}$ of FSPP were 0.066g, 0.103g, 0.077g, and 0.095g per plant, respectively. These results indicated that each of MF affected marigold plug seedlings differently. The application level of FSPP resulted in the heaviest fresh and dry weight in PR medium were $9.0g{\cdot}L^{-1}$ in MF 1, $3.0g{\cdot}L^{-1}$ in MF 2, $9.0g{\cdot}L^{-1}$ in MF 3, and $6.0g{\cdot}L^{-1}$ in control. Elevated application level of FSPP in PB medium containing each of the micronutrient mix increased fresh and dry weight. The general trends in response of plant growth to elevated FSPP were linear and quadratic. The dry weight in the treatment of MF 1, MF 2, MF 3, and control fertilized with $9.0g{\cdot}L^{-1}$ of FSPP in PB medium were 0.131g, 0.104g, 0.137g, and 0.111g per plant at 35days after sowing. These results indicated that MF 1 and MF 3 performed better than MF 2 and control treatments in growth of marigold plug seedlings.

• Horticultural Science & Technology
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• v.28 no.5
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• pp.777-782
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• 2010

This research tested five modified Hoagland solutions for proper fertility management of nitrogen in 'Seolhyang' strawberry cultivations. The changes of nutrient solutions were in total nitrogen concentrations ($meq{\cdot}L^{-1}$) such as 0 (${NO^-}_3$), 2.5 (${NO_3}^-$), 5 (${NO_3}^-$), 10 ($7.5{NO_3}^-$ + $2.5{NH_4}^+$) and 15 ($10{NO_3}^-$ + $5{NH_4}^+$). The fresh weight and $NO_3$-N concentrations in petiole sap responded to the elevated nitrogen concentrations in fertilizer solution in quadratic (y=7.10+2.668x-$0.115x^2$, $R^2=0.7983^{***}$) and linear (y=26.14+5.245x, $R^2=0.6083^{***}$), respectively. The dry weight and N content of the above ground plant tissue responded to the elevated nitrogen in quadratic (y=2.140+0.492x-$0.022x^2$, $R^2=0.6110^{***}$) and linear (y=0.569+0.033x, $R^2=0.6952^{***}$), respectively. In our experiment the solution with $5meq{\cdot}L^{-1}$ of ${NO_3}^-$ showed positive results in both dry and fresh weight productions. However, a future research about modification of this solution and growth and nutrient uptake response is necessary to achieve better growth of 'Seolhyang' strawberry.

• Journal of Bio-Environment Control
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• v.29 no.1
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• pp.1-8
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• 2020

The influence of growth regulators (NAA and BA) and sucrose concentrations (0, 3, 5, 7, 9%) on in vitro rapid-propagation of virus-free sweet potato [Ipomoea batatas (L.) Lam.] was investigated with single-node or shoot-tip culture of two cultivars ('Matnami' and 'Shinhwangmi'). The survival rate and growth of shoot-tip explant was also investigated under the presence or absence of light (blue and red LED = 7:3, 150±5 μmol·m^-2·s^-1 PPFD) during minimal-growth in vitro conservation at 15℃. Vine length, vine diameter, fresh weight and dry weight were enhanced without callusing of explant in the MS medium supplemented with 0.2-0.5 mg·L^-1 BA. The growth of single-node and shoot-tip explants were significantly enhanced with the increase of vine length, number of leaf, number of root, fresh weight, and dry weight in the solid medium containing 5% sucrose and 0.2 mg·L^-1 BA. Vine elongation of shoot-tip explants were highest in the liquid medium containing 3% sucrose than the solid medium. The survival rate of minimal-growth in vitro conservation was 100% in 5 months under the presence of light (LED, 150±5 μmol·m^-2·s^-1 PPFD) at 15℃, but the explants in dark condition died in 3 months. The light was absolutely necessary for the in vitro conservation under minimal-growth conditions of virus-free sweet potato plantlets at 15℃, and the high density of explants (10 plantlets per Petri Dish) was increased the efficiency of mass conservation.

• Journal of Bio-Environment Control
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• v.12 no.2
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• pp.72-76
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• 2003

This study was conducted to estimate stimulation of plant growth of green and red leafy lettuces (Lactuca sutiva L. cv. Chungchima and Jugchima) at affected by covering method and time with protected film materials containing concentrated PO film and GA$_3$ foliar spray. Plants were covered with ‘Pasraido’ material from October 26 to November 31 (direct 1), from November 5 to November 31 (direct 2), or with a tunnel, or direct 2＋ tunnel. Mean air temperature and relative humidity under the covering were higher in direct and tunnel, direct and non-covering, in that order. The fresh weight and dry weight of red and green lettuces increased in direct and tunnel followed by direct 1, direct 2, tunnel and the control. GA$_3$ treatment promoted the growth in all covering methods, but decreased the chlorophyll contents. Fresh weight and dry weight were higher in red lettuce than in green lettuce in the control.

• Korean Journal of Weed Science
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• v.13 no.2
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• pp.138-150
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• 1993

Experiments were carried out to understand how much do the environmental factors affect growth and tuber formation of arrowhead, Sagittaria trifolia L. The more the light transmittance decreased, the more the numbers of leaves and floral axes decreased. The dry matter weight of tops and the number and the fresh weight of formated tuber were significantly different between the light transmittance of more than 50% and that of less than 30% at the 5% level of DMRT. Plant height, number and width of leaves, and number of floral axis were affected by the Light spectra. And the degree of their effects on growth of arrowhead was different form the light spectrum. The natural light and the clear cellophane film were the most effective to increase the number and the fresh weight of formated tuber and the green spectrum was the least effective to do those. Plant height grown at 0-5cm water depth was shorter than that at 10-20cm water depth. The deeper the water depth was, the lower the leaves number was. The fresh weight and the number of arrowhead tuber were most produced at 0cm water depth and theose were least at 20cm water depth. The shoot growth and the tuber formation of arrowhead was much increased with increase of the application rate of fertilizer. The difference of the transplanted tuber size was not affected at the shoot growth, but tuber formation of arrowhead was increased with increase of the transplanted tuber size. From viewing the effect of temperature after rice heading, the shoot growth and the tuber formation at $35^{\circ}C$ were also higher than those at $25^{\circ}C$.