• Applied Biological Chemistry
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• v.25 no.3
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• pp.150-154
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• 1982

Top-dressing pot experiment with $^{15}N$ urea was carried out by using three varieties. Two-split application was much better for Tongil line than 4-split. Fertilization efficiency (Fe), use efficiency (Eu) and absorbed fertilizer nitrogen efficiency (Ef) were much greater in 2-split than in 4-split. The order of Fe followed that of Ef. Grain yield and $^{15}N$ excess % among plant parts suggest that Tonsil line uptakes fertilizer nitrogen much in early stage and retranslocated well later. The order of soil nitrogen increment in plant per fertilizer nitrogen in plant $({\Delta}Ns/Nf)$ might be an index of soil nitrogen use efficiency due to fertilizer.

• Journal of The Korean Society of Grassland and Forage Science
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• v.14 no.2
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• pp.88-92
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• 1994

This study was carried out to investigate the effects of lime(0, 250, 500 and 1,000 kg/lOa) and phosphate (0, 17 and 34 kg/lOa) applications on growth and nitrogen fixation of alfalfa (Medicago sativa L.). The phosphate applications improved(p<0.05) shoot, root and root nodule dry weight of Alfalfa and acetylene reduction activity of alfalfa with increasing levels of phosphate in the soil pH 6.2 at 7 and 12 weeks(ear1y bloom) after sowing, but these were not influnced with lime applications. Total nitrogen content of each part of alfalfa was increased with lime application, but was not significantly different by levels of lime application at 7 weeks after sowing. Application of phosphate did not affect total nitrogen content of each part of alfalfa. Total nitrogen contents of each part of alfalfa were not significantly different between lime and non-lime application at 12 weeks(ear1y bloom) after sowing but were decreased(p<0.05) with phosphate application(p< 0.05). These results suggest that lime(250 kg/lOa) and phosphate(34 kg/lOa) applications are effective for the growth and the nitrogen fixation of alfalfa at the soil pH 6.20.

• Korean Journal of Soil Science and Fertilizer
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• v.50 no.6
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• pp.574-587
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• 2017

Excessive application of nitrogen (N) fertilizer to support switchgrass growth for bioenergy production may cause adverse environmental effects. The objective of this study was to determine optimum N application rate to increase biomass yield of switchgrass and to reduce adverse environmental effects related to N. Switchgrass was planted in May 2008 and biomass yield, N uses of switchgrass, nitrate ($NO_3$) leaching, and nitrous oxide ($N_2O$) emission were evaluated from 2010 through 2011. Total N removal significantly increased with N rate despite the fact that yield did not increased with above $56kg\;N\;ha^{-1}$ of N rate. Apparent nitrogen recoveries were 4.81 and 5.48% at 56 and $112kg\;N\;ha^{-1}$ of N rate, respectively. Nitrogen use efficiency decreased into half with increasing N rate from 56 to $112kg\;N\;ha^{-1}$. Nitrate leaching and $N_2O$ emission were related to N use of switchgrass. There was no significant difference of cumulative $NO_3$ leaching between 0 and $56kg\;N\;ha^{-1}$ but, it significantly increased at $112kg\;N\;ha^{-1}$. There was no significant difference of cumulative $N_2O$ emission among N rates in crest, but it significantly increased at $112kg\;N\;ha^{-1}$ in toe. Excessive N application rate (above $56kg\;N\;ha^{-1}$) beyond plant requirement could accelerate $NO_3$ leaching and $N_2O$ emission in switchgrass field. Overall, $56kg\;N\;ha^{-1}$ might be optimum N application rate in reducing economic waste on N fertilizer and adverse environmental impacts.

• Journal of Forest and Environmental Science
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• v.28 no.4
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• pp.232-241
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• 2012

We investigated the relationship between vegetation type and soil carbon dynamics in even-aged alder (Alnus hirsuta) and Korean pine (Pinus koraiensis) plantations in central Korea. Both forests were located on the same soil parent material and occupied similar topographic positions. Soil $CO_2$ efflux in the two plantations was determined using a dynamic chamber method accompanied by measurements of soil moisture content and temperature. Mean soil temperature was similar in the two plantations, but mean soil water content was significantly higher in the alder plantation than in the pine plantation. In both plantations, seasonal patterns in soil $CO_2$ efflux exhibited pronounced variation that corresponded to soil temperature. Soil water content did not affect the seasonal variation in soil $CO_2$ efflux. However, in summer, when soil temperature was above $17^{\circ}C$, soil $CO_2$ efflux increased linearly with soil water content in the alder plantation. Estimated $Q_{10}$ was 3.3 for the alder plantation and 2.7 for the pine plantation. Mean soil respiration during the measurement period in the alder plantation was 0.43 g $CO_2\;m^{-2}\;h^{-1}$, which was 1.3 times higher than in the pine plantation (0.33 g $CO_2\;m^{-2}\;h^{-1}$). Higher soil $CO_2$ efflux in the alder plantation might be related to nitrogen availability, particularly the concentration of $NO_3{^-}$, which was measured using the ion-exchange resin bag method.

• Journal of Microbiology and Biotechnology
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• v.30 no.11
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• pp.1688-1696
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• 2020

Soil physical and chemical characteristics, soil potential denitrification rates (PDR), community composition and nirK-, nirS- and nosZ-encoding denitrifiers were studied by using MiSeq sequencing, quantitative polymerase chain reaction (qPCR), and terminal restriction fragment polymorphism (T-RFLP) technologies base on short-term (5-year) tillage field experiment. The experiment included four tillage treatments: conventional tillage with crop residue incorporation (CT), rotary tillage with crop residue incorporation (RT), no-tillage with crop residue retention (NT), and rotary tillage with crop residue removed as control (RTO). The results indicated that soil organic carbon, total nitrogen and NH₄⁺-N contents were increased with CT, RT and NT treatments. Compared with RTO treatment, the copies number of nirK, nirS and nosZ in paddy soil with CT, RT and NT treatments were significantly increased. The principal coordinate analysis indicated that tillage management and crop residue returning management were the most and the second important factors for the change of denitrifying bacteria community, respectively. Meanwhile, this study indicated that activity and community composition of denitrifiers with CT, RT and NT treatments were increased, compared with RTO treatment. This result showed that nirK, nirS and nosZ-type denitrifiers communities in crop residue applied soil had higher species diversity compared with crop residue removed soil, and denitrifying bacteria community composition were dominated by Gammaproteobacteria, Deltaproteobacteria, and Betaproteobacteria. Therefore, it is a beneficial practice to increase soil PDR level, abundance and community composition of nitrogen-functional soil microorganism by combined application of tillage with crop residue management.

• Korean Journal of Soil Science and Fertilizer
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• v.49 no.1
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• pp.7-11
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• 2016

Winter crops have been recognized as an alternative to soil management for fertility and crop productivity in paddy soil. Recently, rape has been produced at winter season and there is little research results on reduction of N fertilizer by adding rape residues for rice cultivation. In this study, we investigated the productivity and quality of rice by applying with 0, 27, 63, $90kg\;ha^{-1}$ of N fertilizer after input of rape residues into soil for two years. The highest yield of rice was average $4.68Mg\;ha^{-1}$ at the treatment applied with the $90kg\;N\;ha^{-1}$ with rape residue. It was reduced to N rate from 31.6 to $43.2kg\;N\;ha^{-1}$ in comparison to $4.53Mg\;ha^{-1}$ of maximum yield in treatment added $90kg\;N\;ha^{-1}$ with rape. Amylose content in rice was similar among treatments with/without rape residue, but protein content was lower in treatment with rape residue than in those without rape residue. In conclusion, input of rape residue in rice cultivation could be alternative to reduction of N fertilization and improvement of quality by adjusting rice productivity in paddy soil under cropping system.

• Journal of The Korean Society of Grassland and Forage Science
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• v.18 no.1
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• pp.43-48
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• 1998

No-tillage silage corn with legume hairy vetch(Vicia villosa Roth, HV) has renewed interest in supply of mineral N, soil erosion control at sloping land and weed control by cover of HV killed. This study was conducted to monitor concentration of soil mineral N ($NO_3^-$ -N + $NH_4^+$-N) and to find out variation of growth, yield and N uptake of silage corn according to quantity of HV cover; HV-removed, 1X-HV, 2X-HV at field of Crop Experiment Station in 1996. HV groM in early spring decreased the mineral N of soil depth 7.5 -22cm before corn seeding. But, killed HV cover increased the concentration of soil mineral N at surface soil (0-7.5cm) up to 45.4mglkg at early growth stage of corn. Dry matter(Dh4) of corn at harvest was lower in W-removed than in Okg FNlha. But DM and N uptake of corn at harvest were increased by quantity of HV-cover increasing liom HV-removed to 2X-HV. Hairy vetch could substitute N fertilizer for silage corn by N mineralized h m HV killed, but reduced early growth and N uptake of corn before silk by reducing soil mineral N of plow layer.

• Horticultural Science & Technology
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• v.17 no.6
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• pp.753-754
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• 1999

Application of compost to vineyards reduced nitrogen absorption into vine roots, increased soil nitrogen content, soil pH, soil organic matter, and fine roots density. Long pruning reduced the growth of 'Campbell Early' of Wakeman's training system. Maintaining proper vine shape was very difficult because long pruning decreased the vine growth. In conclusion, the application of compost to 'Campbell Early', 'Kyoho', 'Sheridan' vineyard decreased vine growth, increased soil organic matter, soil pH and favored the rhizosphere condition and the growth of fine roots increased.

• Journal of Plant Biology
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• v.13 no.3
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• pp.25-31
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• 1970

The ratio of occurrence of azalea (Rhododendron mucromultum T.) was determined on the north and south facing slopes on a mountain in Koyang county, Kyungi Province. Data was actually recorded at the eight aspects facing N, NE, E, SE, S, SW, W and NW on the mountain. In each of the eight aspects, six 10m transect tapes were placed in parallel directly down the slope, each 1m apart, and fifty 1$m^2$ quadrats were constructed between them. Frequency of the azalea in each of these quadrats was determined by counting the central stumps of the bushes Soil samples were also taken from pits dug in each plot to use for determination of the following: Soil pH, soil moisture loss on ignition, total nitrogen, and available phosphorus. The occurrence rate of azalea on the northern slop e was found to be for higher on the northern slope than on the southern slope. The abundance of azalea on the northern slope was found to be partially correlated with soil moisture(r=0.93; 0.01>p) and the amount of humus in the soil (r=0.04;0.01>p). The content of total nitrogen, soil PH, and available phosphorus in the soil, however, were found to have no evident relationship with the abundance of azalea. The conditions for growth in the species of azalea Rhododendron mucronulatum T'. were generally found to be more favorable on the northern slope.

• Korean Journal of Soil Science and Fertilizer
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• v.25 no.3
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• pp.275-280
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• 1992

Inoculation responses of alfalfa[Medicago sativa(L.) Vernal] to Rhizobium meliloti with nitrogen fertilization were characterized by soil populations and plant yields from 1989 to 1991 at cultivated upland soil, which contained $3.1{\times}10$cells of R. meliloti/g.soil. The results obtained accordingly to fertilizing with 8Kg N/10a and differently inoculating the host such as initial and annual inoculation methods were as follows : 1. Soil populations of R. meliloti were increased more at no nitrogen fertilized condition compared to nitrogen fertilized condition to 2nd year experiment from 1st year that came up $1.6{\times}10^3$cells/g.soil, but at 3rd year the trend was reversed. Between inoculation methods, on the whole, the annual inoculation caused more populations, which were $2.0{\times}10^4$cells/g.soil in maximum number. And the populations declined after winter but recovered passing through summer season. 2. Alfalfa yields were mainly influenced by rhizobial populations rather than by fertilizing nitrogen showing a significant correlation(Y=0.36+0.287X, $r^2=0.58^{**}$) with the former. The increased extents of yields obtained by inoculation at no nitrogen and nitrogen fertilized conditions, respectively, were 66 and 10% in 1st : 13 and 20% in 2nd : 19 and 13% in 3rd year experiment with the initial inoculation, and were 66 and 10% in 1st ; 30 and 20% in 2nd : 35 and 36% in 3rd year experiment with the annual inoculation. 3. The results demonstrated the importance of inoculating, if possible, annual inoculating alfalfa to get much yields even at cultivated upland soil.