• Korean Journal of Soil Science and Fertilizer
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• v.16 no.3
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• pp.228-234
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• 1983

The effects of subsoiling on improving soil physical properties for increasing yield of rice were studied at different depths and spacings in a clay loam paddy soils. The results are summarized as follows : 1. Working efficiencies of subsoiling at depth 50cm were lower than those at depth 30cm by tractor, while subsoiling ratios at depth 50cm were higher than those at depth 30cm. 2. During cultivation period, water requirement in 50cm depth subsoiling was higher than that in 30cm depth subsoiling. Water requirement in the central part was more rapid about 1.0-2.0mm/day than in the middle between two neighbouring central points. 3. Soil physical properties such as hardness, bulk density and porosity were significantly improved by subsoiling and the subsoiling effects have been continued until the second year. Negative correlations between yield and bulk density or hardness of subsoil were observed. 4. A lograrithmic function was observed between rice yield ($\hat{Y}$) and subsoiling ratio(X) at depth of 20cm. The optimum space for subsoiling in 30 and 50cm depth. was 80 and 120cm, respectively.

• Korean Journal of Plant Resources
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• v.29 no.4
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• pp.393-399
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• 2016

This study was conducted to elucidate the photosynthetic response to the environment and establish optimum cultivation conditions for the Korean endemic plant, Aster koraiensis. Photosynthetic characteristics according to growth stage, light, CO₂, and soil water potential were investigated. During the first year of transplanting, photosynthetic rates were drastically increased until June, after which they slowly declined, During the second year, photosynthetic rates declined throughout the entire growth period. The highest level of light compensation point was shown the early growth stage. Photosynthetic rates affected by intercellular CO₂ concentration were maintained or decreased over the CO₂ saturation point. The lowest CO₂ compensation point was 16.1 μmol·mol⁻¹ during March. The morphological changes of leaves were observed due to shading with chlorophyll contents increasing. Photosynthetic rates were higher at 0% and 50% shading treatments than at 75%. There were rarely any morphological changes of leaves due to soil moisture, however, changes to leaf compactness were observed. Photosynthetic rate, apparent quantum yield, and respiration rate increased, whereas water use efficiency decreased over −25 kPa of soil moisture.

• Korean Journal of Environmental Agriculture
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• v.17 no.3
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• pp.189-194
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• 1998

In order to evaluate the residual effects of bituminous coal fly ash, gypsum, oyster shell as soil amendments, Chinese cabbage was cultivated on acidic sandy loam soils with low boron content. The soils were amended in the upper 15cm with amendments in previous year and the growth and qualities of plants were analyzed. Amendments treated one year before were, in metric tons per hectare, i) none(Check) ; ii) 80 fly ash(FA) ; iii) 4 shell(SH) ; iv) 56 fly ash + 24 gypsum (FG) ; v) 40 fly ash + 24 gypsum + 0.8 shell(FGS). Yield response in fresh weight of Chinese cabbage was in order of 834% for FGS > 780% for FG > 755% FA > 193% for SH plants. Reducing sugar, vitamin-C, and total nitrogen contents of leaves depending on treatments showed the same tendencies as that in yields, whereas crude fibre opposite to them. In particular, FA, FG, and FGS plants showed normal growth without both boron deficiency symptoms which appeared in Check and SH plants and possibilities of accumulation of heavy metals. In any soils treated with the above amendments, however, magnesium was insufficient.

• Korean journal of applied entomology
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• v.14 no.2 s.23
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• pp.71-76
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• 1975

The study has been carried to find a proper site for seed potato production in Jeon Bug Province, Korea. Two fields, one at the alpine area (700-800 m sea level) in Muju county and the other at the plain area in Jeoniu, were chose for this study. Seed potatoes for the experiment were obtained from Alpine Experiment Station and from the traditional sources in Muju area. During the growing season the virus infection (Potato virus X,S,Y, and M) was detected by serolgical method. The average percent of virus infection on the original seed potatoes, which have been used as a seed source in Korea, was $50.5\%$, and the ratio of the infection for each of potato virus, Y, M and X was 34..87, 40.33, 41.00 and $87.10\%$, respectively. Infection percentage of virus at first year in Muju area was $11.7\%$ and those in Jeonju area was $18.95\%$. In case of potato virus Y, the most prevalent virus in Korea, lower Infection percentage $(6.45\%)$ was found in Muju area than in tile Jeonju area $(26.0\%)$ when the seed from Alpine Experiment Station was planted in both areas. The percentage of infected seed potato, Alpine Experiment Station$(41.75\%)$ was almost the same as those from the traditional sources in Muju $(42.17\%)$. The production of seed potato, however, was much better by the seeds from Alpine Experiment Station.

• Korean Journal of Plant Resources
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• v.9 no.1
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• pp.23-29
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• 1996

Chungbuk native Polygnatum stenophyllum Max. for used in this experiment were regional groups that collected at Cheongju and Jecheon, and then classified by seed tuber weights as 15, 30, 45, 60g. Shoot emergency time was faster about $4\sim7$days in Chengju regional group than that of Jecheon. In different seed tuber weights, shoot emergency time was the faster, seed tuber weight was the heavier. All of growth factors such as plant height, stem length and leaf length were worse Cheongju regional group in compared with that of Jecheon but leaf width was not different. Yields per 10a in both of Cheongju and Jechon were 1,600kg. After due consideration to seed tuver cost, approximately 40g is regarded as the most suitable weight for cultivation of Polygnatum stenophyllum Max.

• Korean Journal of Plant Resources
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• v.9 no.3
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• pp.279-284
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• 1996

Effects of varieties and cutting lengths of Chinense Martrimony Vine on the growth characteristics and the yield of green shoot were investigated in order to obtain the basic data The Yuseong-2 was observed higher in the number of green shoot per plant, of green shoot, but smaller in the length and the width of leaves than those of Cheongyang native. The number of green shoot was decreased in longer cutting length, but the other growth characteristics were increased. The dry weight of green shoot was $1.01{\sim}0.03g$ and the ratio of stem to leaf in green shoot was higher in leaf than that of stem, and the ratio was 46 : 54. The dry yield of green shoot was $108{\sim}204kg/10a$ in Cheongyang native and $215{\sim}363kg/10a$ Yuseong-2 and the dry yield of green shoot of Yuseong-2 may be expected in this planting year. Each growth characteristic of varieties was highly positive correlation with the yield except the number of green shoot of Cheongyang native. The number of green shoot of Yuseong-2 was nagative correlation with each growth characteristic and the yield except the number of total leaves per plant.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.59 no.3
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• pp.307-311
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• 2014

This study was conducted to evaluate effect of plants number per hill (PNH) on growth and yield of sorghum in drained paddy field for 2 years. Crop growth and development and yield in the field was examined to know the efficiency of proposed cropping system. At seeding after 40 days, leaf number and stem diameter were highest at 1 PNH plot, on the other hands, plant height was at 5 PNH plot the $1^{st}$ and $2^{nd}$, respectively. The harvest stage, 5 PNH plot was highest culm length of 183, 188 cm the $1^{st}$ and $2^{nd}$, however, culm diameter was lowest. Culm length of sorghum was highest by 183, 188 cm at 5 PNH plot also, culm diameter was thickest by 19.18, 20.13 mm at 1 PNH, respectively. Yield components of ear length, seed number per ear and 1000-seed weight were highest at 1 PNH the $1^{st}$ and $2^{nd}$, respectively. As yield of sorghum was highest at 2 PNH plot $344kg{\cdot}10a^{-1}$, $382kg{\cdot}10a^{-1}$ yearly, respectively that it were in order of 1 PNH plot > 3 PNH plot > 4 PNH plot > 5 PNH plot.

• Korean Journal of Environmental Agriculture
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• v.21 no.1
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• pp.31-37
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• 2002

In order to select proper plants for phytoremediation at heavy metal contaminated areas, eight species of non-edible plants were cultivated at the heavy metal contaminated soils near a metal smelter. The content of the absorbed heavy metals (Cd, Cu, Pb and As) at different part of the plants were analyzed. Plants included five tree species (Populus nigra x P. maximowiczii, Euonymus japonica, Acer palmantum, Celtis sinensis, Buxus microphylla), two flower species (Rhododendron lateritium, Calendula officinalis), and lawn (Zoysia japonica). Biomass yield of tree species was higher than those of flower or lawn species. Heavy metals were highly accumulated in roots compared to those In leaves and stems. The concentrations of Cd, Cu, Pb, and As in Buxus microphylla were greater than those in other plant species. Total absorbed Cd and Pb contents, from high to low by each plant in experimental plots were in the order of Populus nigra x P. maximowiczii, Celtis sinensis and Acer palmantum. They were Celtis sinensis, Populus nigra x P. maximowiczii and Buxus microphylla for Cu, and Buxus microphylla, Acer palmantum and Populus nigra x P. maimowiczii for As. It was estimated that among eight plant species used in the experiment Populus nigra x P. maximowiczii, Buxus microphylla, Acer palmantum, and Celtis sinensis were the most effective species for phytoremediation in the heavy metals polluted areas considering biomass yield and heavy metal uptake.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.35 no.5
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• pp.393-402
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• 1990

Studies to obtain a fundamental data to improve the quantity and quality of wheat protein and to select the excellent breeding materials suitable for various uses of it were performed on the focuses of protein content, amino acid composition, and its related quality. The range of seed protein content of crossing block consisted with 319 varieties or lines was from 9.9% to 17.6% with the average of 13.2%. The minimum protein content was showed by Wonkwang, and the maximum by Chungnamjaerae and Suwon 210. Among the Korean native varieties or breeding lines of crossing block, at least twelve lines or varieties were selected as the high-protein wheats. In the effects of environmental conditions, the variations of protein content by cultivating locations and year were showed out to be up to 3.6%, and 3.3%, respectively. But the varietal characteristics of wheat protein were seemed to remain constantly. In the results of amino acid analysis, those related with bread quality, except proline were improved with the increase of seed protein. But the improvement of nutritional quality did not agree with the protein content increase of seed. The total content of amino acid essential to adults was very low with 266.6-273.3mg per one gram of protein compare to the 350mg (free from the amino acid of tryptophan) recommended by FAO/WHO. Especially the limiting amino acid such as methionine, lysine and threonine were critically deficient. The correlation between protein contents and sedimentation values was obtained r=0.656$\^$**/ of average notwithstanding widly different environmental conditions, and in some condition the value was obained about to r=0.956$\^$**/.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.32 no.1
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• pp.112-118
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• 1987

This study was carried out to investigate the effects of early planting and polyethylene film (P.E) mulch on early maturing soybean of Korean native cultivar Kyeonggi No. 114 in the Kyeonggi area. It was planted four times at the ten days interval from April I to April 30 in 1985 and 1986. The average soil temperature was 1-5$^{\circ}C$ higher under the polyethylene film mulch condition than the conventional cultural practice condition. Soil moisture content also was higher under P.E mulch condition. Days to emergence was shortened 5-16 days and days to flowering was shortened 3-5 days. The fresh pod yield was increased 12% more at the planting date of April 1 and April 10. Income was increased 70, 83, more at the planting date of April 1 and April 10 under the polyethylene mm mulch conditions.