• Journal of Soil and Groundwater Environment
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• v.21 no.4
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• pp.50-59
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• 2016

Spatial and temporal changes in nitrification activities and distribution of microbial population of ammonia oxidizing bacteria (AOB) and ammonia oxidizing archaea (AOA) in paddy soils were investigated. Soil samples were collected in March and October 2015 from rice paddy with and without the presence of confined animal feeding operations. Incubation experiments and quantitative polymerase chain reaction showed that AOA's contribution to nitrification kinetics was much higher in locations where organic nitrogen in animal waste is expected to significantly contribute to overall nitrogen budget, and temporal variations in nitrification kinetics were much smaller for AOA than AOB. These differences were interpreted to indicate that different microbial responses of two microbial populations to the types and concentrations of nitrogen substrates were the main determining factors of nitrification processes in the paddy soils. The copy numbers of ammonium monooxygenase gene showed that AOA colonized the paddy soils in higher numbers than AOB with stable distribution while AOB showed variation especially in March. Although small in numbers, AOB population turned out to exert more influence on nitrification potential than AOA, which was attributed to higher fluctuation in AOB cell numbers and nitrification reaction rate per cells.

• Asian Journal of Turfgrass Science
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• v.17 no.4
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• pp.147-154
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• 2003

This experiment was carried out to study an effect of liquid fertilizer contained amino acids(LFcAA) on the growth of bentgrass(Agrostis palustris Huds. penncross) and the change of soil chemicals characteristics. The utilization of nitrogen in soil was increased more 70.6∼90.1％ in the treatment of LFcAA than in control. Fresh weight, dry weight and concentration of T-N, Mg and chlorophyll were increased in grass treated LFcAA. These results suggested that treatment of LFcAA was promoted utilization of nitrogen in soil and growth of bentgrass.

• Journal of the Korean Society of Tobacco Science
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• v.28 no.1
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• pp.17-22
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• 2006

This study was conducted to investigate the effect of soil, cultural practices and climatic conditions on some chemical constituents of flue-cured tobacco. Increasing the nicotine and total nitrogen contents may be useful to reduce the total sugar content of cured leaves in flue-cured tobacco. Delaying the transplanting date and increasing the soil nitrogen($N0_3-N$ and $N0_4-N$) content for 30 days after transplanting by fertilizing are desirable so as to increase the nicotine and total nitrogen contents of cured leaves. Those treatments will delay the ripeness, and elongate the duration of cultivation(day from transplanting to harvesting), and increase the fresh leaf weight. Moderate rainfall in April and May, lower relative humidity in June, and higher mean daily air temperature in June and July seem to be necessary for good leaf of flue-cured tobacco in Korea.

• Journal of The Korean Society of Grassland and Forage Science
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• v.8 no.3
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• pp.152-157
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• 1988

The effect of gypsum application was tested on dry matter yield, sulfur uptaken, composition of Ritrogen compound and sulhr compound and sulfur balance in mixed pasture. Total dry matter yields and sulfur uptake by grasses increased with the increasing of gypsum application rates. The ratios between total nitrogen and total sulfur in masses decreased with the increase of sulfur uptake at 2nd and 3rd cutting times. Cysteine content was little affected by gypsum while methionine content slightly increased an 4.0, 6.0 kg3 per 10a levels at 2nd and 3rd cutting times. The uptake of nitrate nitrogen decreased with gypsum application and dry matter digestibility increased about 1.1 to 3.3%. The soil pHs after experiment become high in surface and subsoil till 6.0 kg.S per 10a, but low at 10.0 kg.S per 10a. The content of sulfur in surface soil was 19.9 ppm after experiment, but very high in subsoi1,ranging from 94 to 143 ppm.S. Sulfur leached from the surface soil by 0.69, 2.39, and 6.24 kg.S per 10a in the plots of 4.0, 6.0, and 10.0 kg.S per 10a, respectively.

• Korean Journal of Environmental Agriculture
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• v.42 no.2
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• pp.152-158
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• 2023

This study was conducted to evaluate the effects on soil chemical properties and plant growth after applying soldier fly compost (SFC). Treatments were as follows. No fertilizer (NF), control, SFC1 (SFC 250 kg/10a), SFC2 (SFC 500 kg/10a) and SFC3 (SFC 1,000 kg/10a). As compared to control in the pot test, organic matter (OM) and exchangeable sodium (Ex-Na) of SFC3 treatment were increased, and growth and nutrient uptake of young radish were not significantly different. Correlation coefficient between soil chemical factors like total nitrogen (T-N), OM, and CEC and uptake of nitrogen (N) and phosphorus (P) was significantly positive (p≤0.05). Compared to control in the field test, electrical conductivity, T-N, OM, Av.-P₂O₅, and CEC was increased, and lettuce growth was not significantly different. Correlation coefficient between application amount of SFC and T-N, OM, and Av.-P₂O₅ was significant positively (p≤0.05). These results indicated that the application of SFC improved nutrient availability of soil by increasing OM and CEC.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.22 no.2
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• pp.42-47
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• 1977

Experiment was conducted to find out the influence of nitrogen and potassium split application on the yield and physiology of rice plants in a sandy-gravel soil. Nitrogen and potassium mixed application, nitrogen split application, and potassium split application increased yield of rice by 22, 20, and 18%, respectively, compared to conventional fertilizer application. Nitrogen split application increased chlorophyll content and potassium split application increased root activity. Concentration of silica, magnesium, and calcium was increased by the mixed split application of nitrogen and potassium.

• Journal of Korean Society for Atmospheric Environment
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• v.19 no.5
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• pp.529-540
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• 2003

A closed chamber system was used for measuring $N_2$0 fluxes from an agriculturally managed upland soil in Kunsan during the growing season from May to July 2002. It is known that soil is one dominant source of atmospheric $N_2$O, contributing to about 57% (9 Tg y $^{-1}$ ) of the total annual global emission. Hence, its increasing emissions and concentrations are largely associated with agricultural activities. In order to elucidate characteristics of soil nitrogen emissions from intensively managed agricultural soils and to understand the roles of soil parameters (soil moisture, soil pH, soil temperature, and soil nitrogen) in the gas emission, $N_2$O soil emissions were measured at every hour during the experimental period (21 days). Soil $N_2$O fluxes were calculated based on changes of $N_2$O concentrations measured inside a closed chamber at every hour. The analysis of $N_2$O was made by using a Gas Chromatography (equipped with Electron Capture Detector). Soil parameters at sampling plots were also analyzed. Monthly averaged $N_2$O fluxes during May, June, and July were 0.14, 0.05, and 0.13 mg-$N_2$O m$^{-2}$ h$^{-1}$ , respectively. Soil temperature and soil pH did not significantly vary over the experimental period; soil temperatures ranged from 12∼$25^{\circ}C$, and soil pH ranged 4.56∼4.75. However, soil moisture varied significantly from 32% to 56% in WFPS. Relationships between soil parameters and $N_2$O fluxes exhibited positive linear relationships. Strong positive correlation ($R^2$ = 0.57, P< 0.0001) was found between $N_2$O flux and sil moisture. It suggests that soil moisture has affected strongly soil $N_2$O emissions during the experimental periods, while other parameters have remained relatively at constant levels. $N_2$O flux from agricultural soils was significant and should be taken account for the national emission inventory.

• Journal of The Korean Society of Grassland and Forage Science
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• v.7 no.1
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• pp.25-30
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• 1987

There are differences in opinion as to whether nitrogen fertilizer should be used when establishing alfalfa (Medicago sativa L.). Various reports show that under a hot environment, rhizobia (Rhizobium meliloti) are not as effective in fixing atmospheric nitrogen as they are under moderate temperatures. It is also believed that the addition of nitrogen fertilizer inhibits nodulation of alfalfa seedlings. A replicated experiment was conducted under controlled environmental conditions at the University of Nevada-Reno, Reno, Nevada, USA, to determine the effects of nitrogen application on seedling growth and nodulation of alfalfa grown in a hot environment. Sterile sand was used as the growing media to which a complete nutrient solution minus nitrogen was applied volumetrically to each pot daily. In addition, half of the pots received NH4-$NO_3$, at the rate of 11.2 kg per ha at seeding and at two and four weeks after planting giving a total nitrogen application rate of 33.6 kg per ha during the seven-week experimental period. Rhizobia inoculant (R-12) consisted of a mixture of strains 171-15a, 1682c and 80 PI 265 of (Rhizobium meliloti). Inoculant was applied to the seeds prior to planting and to the sand media at two and four weeks after seeding. Twenty seeds were planted in pots 14.0 cm in diameter and 11.5 cm deep. Plants were thinned to ten plants per pot after emergence and were grown in a controlled environment chamber with a 16-hour light period. Soil temperature at 6 cm depth ranged from 17.4^{\circ}C.$ to 31.1^{\circ}C.$ and had a daily mean of 26.5^{\circ}C.$. Plants were harvested at weekly intervals for seven weeks. Root, shoot and total length, dry weight, volume and number of nodules per plant were determined. Root, shoot, and total length were greater in seedlings grown in soil where nigrogen was applied than that grown in soil to which no nitrogen was applied. The average size of the seedlings as determined by volume and weight was more than two times greater where plants were fertilized with nitrogen. Nodule number per seedling was also greater when nitrogen was applied compared to those which received no nitrogen. The differences were greater as the plants became older. The rhizobia did not fix enough nitrogen for adequate growth of seedlings. This is probably due to high temperature growing conditions that caused the rhizobia to become relatively ineffective as compared to cooler growing conditions. Data suggests it would be desirable to apply nitrogen at seeding when alfalfa is established under hot conditions that occur in mid- or late summer.

• Korean Journal of Environmental Agriculture
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• v.36 no.3
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• pp.147-153
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• 2017

BACKGROUND: Soil water content strongly depends on weather condition and irrigation, and it could influence on crop nutrient use efficiency. This study was performed to assess nutrient uptake of soybean by soil water condition. METHODS AND RESULTS: In this study, nutrient leaching and crop uptake as affacted by water management practice was investigated using weighing lysimeter which is located in National institute of agricultural science, Wanju, Jeonbuk province from June 2015 to October 2016. Water supply for soybean (cv. Daewon) was managed with irrigation and rainfall. Nitrate leaching was greatest in the rainfall treatment at early July 2016. Yield of soybean in the rainfall treatment was only 25% compared to the irrigation due to the drought at flowering and podding period. The uptake of nitrogen was considerably reduced by drought whereas the uptake of phosphorus and potassium was less affected by drought. CONCLUSION: It was proven that nitrogen loss and uptake were dependent on soil water condition. Therefore, irrigation water management to maintain available soil moisture capacity is critical to nitrogen uptake and yield of soybean.

• Korean Journal of Organic Agriculture
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• v.21 no.1
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• pp.69-78
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• 2013

This study was carried out to evaluate nitrogen availability of applied fertilizer and to investigate yield and growth of Korean kimchi cabbage as affected by amount of fertilizer and soil fertility in organic farming applied various fertilizers in rainshelter. The head weight of Korean kimchi cabbage cultured in infertile soil (sand loam) with no amendments was very low. and that in fertile soil (clay loam) was higher than in infertile soil (sand loam). The head weight of Korean kimchi cabbage as affected by amount of fertilizer was more variable in infertile soil (sand loam) than in fertile soil (clay loam). Nitrogen availability of applied fertilizer by Korean kimchi cabbage was lower in fertile soil (clay loam) than in infertile soil (sand loam) and the lower that was, the more fertilizer applied. By application of poultry manure compost 20Mg ha-1 and natural mineral materials such as guano, phosphate rock, and potassium magnesium rock equal to amount of fertilizer recommended in conventional farming, the yield of Korean kimchi cabbage in infertile soil (sand loam) with 1% organic matter came up to 90% of the yield in fertile soil (clay loam) with 6% organic matter. Therefore natural mineral materials such as guano for N source, phosphate rock for P source, and potassium magnesium rock for K source may be able to use as environmental-friendly fertilizers in organic Korean kimchi cabbage production in highland.