• Korean Journal of Medicinal Crop Science
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• v.27 no.1
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• pp.1-8
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• 2019

Background: This study was conducted to investigate the effects of fertilization with the application of mixed organic matter after cultivating green manure crops on the growth and saponin content of Codonopsis lanceolata Trautv. Methods and Results: Five type of cultivation of green manure crops were done: hairy vetch as a single seedling crop (HV), hairy vetch and rye as a mixture of seedling (HV/R), additional fertilization with mixed organic matter after cultivation of a seedling mixture (HV/R/MO), chemical fertilizer (CF), and a non-treated control (NT). The total nitrogen content was the highest in the HV/R/MO treatment, followed by the HV, CF, HV/R and NT treatments, respectively. Nitrogen fixation was higher in the single seedling treatment with hairy vetch (HV) than in the treatment with a mixture of hairy vetch and rye seedling (HV/R). Moreover, the growth of C. lanceolata was greatly increased by the application of additional fertilizer after treatment with the mixture of hairy vetch and rye seedlings. The HV/R/MO treatment produced the highest total lancemaside content among the treatments, followed by HV, HV/R, CF, and NT, respectively. Conclusions: It was verified that C. lanceolata experienced superior growth with the application of mixed organic matter as additional fertilizer after the cultivation of green manure crops, and the content of its major saponins, lancemasides were also increased by this treatment.

• Journal of Korea Foresty Energy
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• v.22 no.2
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• pp.44-53
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• 2003

This study was conducted to develop new fertilizers which can be applied to various environmental conditions. Fertilizers with different levels of nitrogen, phosphorus and potassium, and different types and amount of combined fertilizers were used on 1-1 seedlings of Pinus densiflora, Larix leptolepis, Quercus acutissima, and Betula platyphylla var. japonica. Biomass, specific leaf area (SLA) and chlorophyll content of foliage were measured. Biomass of foliage, shoot, and root showed no differences among fertilization treatments. Biomass of double treatments of solid-combination fertilizer and UF combination fertilizer increased whereas those of triple treatments decreased. SLA ($\textrm{cm}^2$/g) of P. densiflora fo. the 6:4:1 treatment and L. leptolepis for the 3:4:1 treatment showed the highest with 59.2 and 110.0, respectively, but those of Q. arutissima and B. platyphylla var. japonica for the control showed the higher than other treatments with 207.5 and 202.0, respectively. Chlorophyll contents (mg/g) in the foliage of P. densiflora and L. leptolepis fertilized with the 6:4:1 treatment were 0.222 and 0.127, respectively, and these contents were higher than those of the 3:4:1 treatment with 0.211 and 0.082, respectively. These results suggested that the increased nitrogen fertilization had an effort on increase of chlorophyll contents.

• Journal of Korean Society of Forest Science
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• v.106 no.1
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• pp.19-25
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• 2017

This study was conducted to investigate the effects of nitrogen fertilization on physiological characteristics and growth of Populus sibirica seedlings in a semi-arid area, Mongolia. 2-year-old P. sibirica seedlings were planted in May, 2015 with applications of urea 5 g (N1), 15 g (N2), 30 g (N3) and ammonium sulfate 33 g (NS; same nitrogen amount with N2) to each seedling. Chlorophyll contents were significantly different among treatments in August, but not in June and July. The lower chlorophyll contents in August than those in June and July might be related to leaf senescence. In June and July, net photosynthetic rate was higher in NS and N2 than in the control. Unlike the tendency of photosynthesis, transpiration rate was highest in N2, but lower in NS than in any other nitrogen treatments. Relative growth rate of root collar diameter was significantly higher only in NS than in the control and it of height did not differ among treatments. Leaf area in nitrogen treatments was not significantly different from that in the control. Ammonium sulfate seemed to be more suitable fertilizer than urea for the early growth of P. sibirica seedlings in the study site. However, as the effects of urea and ammonium sulfate on soils and seedlings were different, further studies would be necessary to determine the optimal amount of ammonium sulfate.

• Korean Journal of Soil Science and Fertilizer
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• v.48 no.6
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• pp.641-647
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• 2015

Monitoring of soil fertility by long-term application of fertilizers is necessary to improve the fertility of soil and the productivity of crop. The objective of this study was conducted to investigate the changes of exchangeable Mg by continuous application of fertilizers from 1969 to 2014. The treatments were no fertilization (No fert.) and fertilization (NPK, NPK+C, NPK+S, and NPK+CS). The concentration of exchangeable Mg in No fert., NPK+C, and NPK+S treatments tended to increase from 1965 to 1975, but decrease gradually from 1976 to 1987, and increase again after 1988. Based on these, the changes of exchangeable Mg were divided into period I ('69 ~'75), period II ('76~'87), and period III ('88~'14). Especially, exchangeable Mg decreased in the period II. This was presumed that a significant amount of Mg from topsoil were leached into subsoil by break of plow pan and some of subsoil was incorporated into topsoil according to change of plowing depth by replacement of tillage machinery. It could be possible that exchangeable Mg in NPK, NPK+S, and NPK+CS was accumulated in the depth of 15~20 cm. For the period III, exchangeable Mg in No fert., NPK, NPK+C, NPK+S, and NPK+CS treatments increased at rates of 0.013, 0.018, 0.015, 0.023, and $0.024cmolckg^{-1}{\cdot}yr^{-1}$ respectively. Exchangeable Mg level in NPK+S was lower than the other treatments in the period I and period II, but higher than in the period III. This result was attributed to replacement of silicate fertilizer type from wollastonite (Mg 0.3%) to silicate fertilizer (Mg 3%). Also, exchangeable Mg level of No fert. treatment increased, which showed that Mg concentration of irrigated water had the greatest impact on Mg accumulation of soil. Recently, Mg level of irrigated water tended to increase, indicating that Mg concentration of water will affect greatly the concentration of exchangeable Mg of soil in the future. Like these, the changes of exchangeable Mg were greatly influenced by agricultural environment such as plowing depth, plow pan, content of fertilizer, and quality of irrigated water. Considering these agricultural environment, the proper management of soil is needed for the improvement of soil fertility and crop productivity.

• Journal of The Korean Society of Grassland and Forage Science
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• v.17 no.1
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• pp.19-26
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• 1997

To find out the residual effect of phosphate fertilization on botanical composition, mineral contents and mineral nutrient deprivation of pasture plants, this experiment was arranged as a randomized complete block design with six treatments(0-0, 50-50, 100-65, 150-65, 200-65 and 250-65kg $P_2O_5$/ha), those were composed of three P,O, fertilization level(0, 50 and 65kg P,OJha) after phosphate fertilization trial with six treatments(0, 50, 100, 150, 200 and 250kg $P_2O_5$/ha) from 1989 to 1992, and conducted at hilly land in Kwangju, Kyonggi Province 60m 1993 to 1994. The results obtained are summarized as follows: The botanical composition of pasture plants without phosphate fertilization was very poor. With increasing available phosphate of soil, the percentage of grasses and legumes were remarkably increased and weeds was decreased. With 150-65kg $P_2O_5$/ha application for two years, the average DM yield was composed of 80.6% grasses, 15.4% legume and 4.0% weeds, the percentage was similar to that of 200-65kg $P_2O_5$/ha. As available phosphate of soil increase, P, K and Mg content of pasture plants were increased, but Ca/P ratio was lowed and the other mineral contents tended not to be regular. The mineral nutrient contents deprived by DM yield was increased as available phosphate of soil was increased, but those were not different between 150-65 and 250-65kg $P_2O_5$/ha. However, mineral nutrient of $P_2O_5$,$K_2O$ and MgO were higher in 200-65 and 250-65kg $P_2O_5$/ha. Most of applied mineral elements were accumulated at a subsurface(0-2.5cm) of grasslands, and mineral tended to be decrease than that of soil chemical analysis before the experiment of residual effect of phosphate fertilization.

• Korean Journal of Animal Reproduction
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• v.15 no.1
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• pp.41-47
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• 1991

The ability of fertilization in vitro and subsequent development of superovulated oocytes was assessed in a controlled environment using an in vitro fertilization technique. The in vitro fertilization percentage of oocytes with cumulus mass declined significantly(P<0.05) with increased doses from 4~10 to 16~40IU of PMSG for superovulation. However, the porportion of polyspermic penetration varied from 2.3 to 9.7% and there was no significant difference between treatments in incidence of polyspermy. When morphologically normal ova with cumulus mass were cultured for 66~72h in a plastic mini-straw to undergo fertilization in vitro, the mean percentage of embryos developed to 2-16 and 4-16cell stage was 61.8 and 17.6%; it was slightly(P<0.05) superior to the corresponding results from petri dish. A total of 52 two-cell embryos fertilized in a mini-straw were transferred to seven pseudopregnant rat. Among these recipients, two normal young were born from one recipient which received a total of six embryos. These results suggest that superovulated oocytes are proportionately less competent than normally ovulated oocytes to undergo fertilization in a controlled environment using an in vitro fertilization technique. Also, a plastic mini-straw designed was slightly superior to petri dish as a culture vessel for fertilization and embryo development in vitro.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.3
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• pp.83-87
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• 1965

This experiment was done to observe the morphological change of plant under the cultivation of deep ploughing and heavy fertilization with paddy rice 1963 at Seoul. A seedling of 35 days old was transplanted June 1st, in a galvanized iron pot with botton 20 cm in diameter, which was painted white inside and filled with sand mixed with fertilizers. The treatments were 15cm soil depth of normal fertilization, 30cm of fertilization twice and 45cm of fertilization thrice. Replications were three. The plant was observed on main stem Aug. 6 before heading, Sep. 12 after heading and Oct. 17 at the time of harvest at the same pot. The results are as follows. The length and the width of leaf blades of the upper part on main stem have the tendency to be big and vigorous with the deep ploughing and heavy fertilizations(Fig 1, 2, 3 and 4). The number and the size of vascular bundles of main stem is to increase when the paddy is cultivated with the method of deep ploughing and heavy fertilizations(Fig 5). The number and the weight of roots of main stem increases with deep ploughing and heavy fertilizations(Fig 6).

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.4
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• pp.597-599
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• 2011

This study was conducted to find out the optimum nitrogen application rate for the stable production of rape in the newly reclaimed land located at Gangwhal region of Saemangum reclaimed land in which the soil is sandy loam (Munpo series). There were five treatments of nitrogen fertilization from zero to 60% increment based on the standard fertilization of $150kg\;ha^{-1}$. The growth of rape (Sunmang) was not affected by salt content while soil salinity was increased at blossoming season of rape. Compared to yield of standard fertilization the yield and the content of oleic acid of rape were increased by 4~26% with the increasing additional nitrogen fertilizer. The results obtained from the growth and yield of rape in this study indicated that it was possible to cultivate rape in a newly reclaimed land if soil salinity was kept below $3dS\;m^{-1}$.

• Journal of The Korean Society of Grassland and Forage Science
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• v.42 no.3
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• pp.176-182
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• 2022

The aim of this study was to investigate dry matter productivity and nitrate nitrogen content in the growth stages of barnyard millet (Echinochloa esculenta) cultivated for feed, which was treated with different nitrogen fertilization levels. An early variety of barnyard millet (cv. Shirohie) was used for the test, and the different treatments with nitrogen fertilizer were as follows: 50% (N-40 kg/ha, T1), 100% (N-80 kg/ha, reference amount, T2), 150% (N-120 kg/ha, T3), 200% (N- 160 kg/ha, T4), 250% (N-200 kg/ha, T5), and 300% (N-240 kg/ha, T6). Sowing was done on May 13, 2021 and plants were harvested for four stage; vegetative stage, elongation stage, heading stage, and milk stage. The length of the millet increased significantly as the amount of nitrogen fertilization increased during the harvest period (p<0.05), but the difference was insignificant during the milk stage (p>0.05). Moreover, barnyard millet dry matter yield increased significantly as the levels of nitrogen fertilization increased (p<0.05), but there was no significant difference in dry matter yield among nitrogen fertilization levels during the heading stage (p>0.05). Chlorophyll also was significantly higher in T5 (250%) at all harvesting times, whereas nitrate nitrogen content was highest at the vegetative stage, gradually decreased as growth progressed, and lowest at the milk stage. Finally, as the nitrogen fertilization levels increased, the nitrate nitrogen content was significantly higher in all treatment groups (p<0.05). Therefore, our results suggest that the most appropriate nitrogen fertilizer levels is between 150%-200%, considering the dry matter yield, feed ingredients and nitrate nitrogen content in barnyard millet for feed.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.65 no.4
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• pp.436-446
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• 2020

In this study, we verified the effects of organic amendment application based on soil testing in potato cultivation. The application rate of organic amendments was determined based on the inorganicization rate of nitrogen, phosphoric acid, and potassium in the organic amendments. There was no significant difference in the length, stalk number, stalk diameter, and leaf color of potato plants under organic amendment application compared with those under chemical fertilization. The quantity of potato tubers and yield of marketable tubers under organic amendment application were higher than those under chemical fertilization. The top fresh weight and top-to-root ratio were the highest under organic amendment application, followed by those under chemical fertilization and the control. The inorganic nitrogen content in the leaves and stems of potato plants was the highest under chemical fertilization. There was no difference in the phosphoric acid content between the potatoes under chemical fertilization and those under organic amendment application. The potassium content in potatoes was higher under chemical fertilization than that under organic amendment application. While the change trend of inorganic nitrogen content in the roots was similar to that in the leaves and stems, the potatoes under organic amendment application, with the highest yield, showed the highest dry weight. The tuber weight showed a positive correlation with plant length, stalk number, and stalk diameter. The higher the weight of the tuber, the higher the weight of the marketable tuber, and the higher the top fresh weight, the higher the yield. Therefore, to increase yield, it is necessary to supply nutrients to improve the top fresh weight to the optimal level. There was no difference in the utilization efficiency of nitrogen and potassium between the potatoes under chemical fertilization and those under organic amendment application. The utilization efficiency of phosphoric acid was increased by 0.1% in potatoes under organic amendment application compared with that under other treatments. Regarding soil chemistry after harvest, the soils under organic amendment application showed a higher electrical conductivity and higher nitrogen and phosphoric acid content than those under other treatments. Therefore, the organic amendment method used in this study can be an alternative to chemical fertilization. It is also advantageous for the cultivation of subsequent crops in potato fields.