• Applied Biological Chemistry
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• v.43 no.2
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• pp.124-129
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• 2000

Nitrogen and P in surface runoff and eroded sediment from cropland areas can contaminate streams and lakes. Runoff losses of N and P were determined in a small field plot $(14.3{\times}24.8\;m)$ of peach orchard from March to November in 1999. Nitrogen and P were applied in the rate of 172 and 46 kg/ha using chemical fertilizer and mixed oil cake fertilizer. During the season, in 26 rainfall events, $421.5\;m^3/ha$ of runoff including 1,989 kg/ha of soil loss was collected. Concentrations of total-N, $NO_3-N$, $NH_4-N$, total-P and $PO_4-P$ in runoff samples were in the range of $4.7{\sim}171.0,\;0.1{\sim}188.0,\;0.13{\sim}3.36$, $0.58{\sim}4.99$ and $0.05{\sim}3.71\;mg/l$, respectively. Total loss of N was 16.39 kg/ha and 75% of the loss was $NO_3-N$. Total loss of P was 1.04 kg/ha, and $PO_4-P$ and sediment bound P accounted for 47 and 27% of the total loss, respectively. The losses of N and P were about 9.5 and 2.3% of the applied N and P in the plot, respectively. Although the loss of N or P would be relatively small in agricultural aspect, considering the high concentrations of N and P in runoff, loss of N and P from croplands should be controlled to reduce the eutrophication problem of stream waters.

• Korean Journal of Soil Science and Fertilizer
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• v.15 no.2
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• pp.110-116
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• 1982

A water culture was conducted with 5 levels of nitrate-ammonium ratio (NAR: 10:0, 7:3, 5:5, 3:7, 0:10) to study the ionic balance, cation-anion (C-A) in mulberry leaves and to determine the optimum NAR for the greatest leaf yields. The results were as follows: 1. The growth rate of mulberry plants was the greatest at 7:3 NAR. 2. Magesium in the mulberry leaves was not affected by NAR. By lowering NAR, calcium content decreased more than potassium content increased, consequently lowering the sum of cation content (${\sum}C$). However, the sum of anion (${\sum}A$) increased because of increments of sulphate, chloride and especially phosphate. 3. Ionic balance in the mulberry leaves deceased from 727 to 116 me/Kg dry matter with increasing ammonium levels of 0 to 100% in the nutrient solution.

• Korean Journal of Soil Science and Fertilizer
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• v.20 no.3
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• pp.275-283
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• 1987

In order to find out the effectiveness of nitrogen fixation in rhizobia-legume symbiotic relationship, ecological and physiological characteristics of indigenous rhizobia distributed in Korean soils, that is, dissimilatory nitrate reduction patterns of indigenous soybean rhizobia isolated from four different soils, and differences in one-and two-dimensional polyacrylamide gel electrophoretic pattern of proteins among the each subgroups of Bradyrhizobium japonicum and Rhizobium fredii, were investigated. The results were summarized as follows: 1. The indigenous soybean rhizobia isolated from four different soils could be classified into 4 groups depending on growth rate and dissimilatory nitrate reduction pattern, that is, $S_1$ (slow-grower; Bradyrhizobium japonicum and nitrate denitrifier), $S_2$ (slow-grower; Bradyrhizobium japonicum and nitrate respirer), $F_1$ (fast-grower; Rhizobium fredii and denitrifier), and $F_2$ (fast-grower; Rhizobium fredii and nitrate respirer). 2. The population ratio of fast- to slow-growing R. japonicum was 39% to 61%, and the ratio of denitrifier to nitrate respirer was 31% to 69% and 89% to 11% in fast and slow-grower, respectively. Some differences were observed between fast- and slow-growing R. japonicum but no significant difference was observed between denitrifier and nitrate respirer within same growth type by one and two dimensional SDS-polyacrylamide gel electrophoretic patterns.

• Korean Journal of Soil Science and Fertilizer
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• v.19 no.1
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• pp.32-37
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• 1986

Field experiments were carried out to investigate the effect of wollastonite and iron refinery slag on the paddy rice yield insandyloam soil in which available silica level is 56 ppm. The results are as follows: 1. Application of wollastonite and iron refinery slag reduced the tillering and the height of rice plant in the early growth stage, while promoted those in the late growth stage. 2. As the same amounts of wollastonite and iron refinery slag were applied, the effectiveness on yield increase was same between the two silicate fertilizers. 3. The recovery ratio as measured by absorbed $SiO_2$ on rice plant over applied $SiO_2$, was greater in wollastonite than in iron refinery slag. 4. The increasing of the ratio of $SiO_2$ over N absorbed in rice plant trends toward decreasing the infection rate of neck blast. 5. The left-over ratio of available $SiO_2$ in soil over applied $SiO_2$, was greater in iron refinery slag than in wollastonite. 6. As measured by silica soluble in 0.5 N-HCl solution, 1 kg application per 10a of both silicate fertilizers increased about 2.3 ppm in soil silica content after harvest, respectively.

• Korean Journal of Soil Science and Fertilizer
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• v.14 no.4
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• pp.201-209
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• 1982

In 1980, the abnormal low temperature was lasted during the late stage of rice growing season, thus low temperature injury occurred severely. The severity of the injury and nutrition absorption were investigated. The result obtained were summarized as follows: 1. It was considered that the severe low temperature injury of rice was caused by the low temperature and shorts of sunshine in the late growing season of rice, especially, the minimum air temperature which was lasted for a few days below critical reproductive growing temperature in the meiosis stage affected high the injury. 2. The low tmperature injury was lightened in the no nitrogen applied plot, and becoming severe with high nitrogen levels, but the balanced application of NPK lessened the low temperature injury. 3. The low temperature injury was more severe in Indica and Japonica hybrid than in Japonica cultivar, and the injury was shown as sterilizing, degraded spiklets, ill emerging of head and inhibition of nutrition absorption, etc. 4. Under the low temperature condition, $SiO_2$ content of rice plant was significantly reduced according to the increase of nitrogen levels. 5. Under the low temperature condition, the optimum application amount of nitrogen for Milyang 23, was 13, 6 kg/10a, this was approximately 10kg/10a smaller than average in usual year. The highly reduced rice yield was resulted from the cool injury, and the reducing rate of yield was larger in Indica and Japonica hybrid cultivar than in Japonica cultivar.

• Korean Journal of Environmental Agriculture
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• v.20 no.1
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• pp.8-14
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• 2001

To investigate the effects of waste sludge from antibiotic fermentation on the growth of young radish and chemical properties of soil, five levels of fertilizer, control (recommended fertilizer, $N-P_2O_5-K_2O=160-59-104$ kg/ha), AS(control + sludge 1,000 kg/ha), AC(control + conventional compost 1,000 kg/ha), SNS(control - subtracting 30% N of sludge + sludge 1,000 kg/ha) and SNC(control - subtracting 30% N of conventional compost + conventional compost 1,000 kg/ha) were applied and radish was grown twice with same treatments on May and August in 1998. Germination rate and early growth of young radish grown with AS and SNS were lower than those grown in control and with AC, SNC. This negative effects by adding the sludge in the early growth seemed to be caused by damage of ammonia gas released during degradation of the sludge in soil. However, yield of young radish showed no significant difference among all the treatments including the AS and SNS at the 1st and 2nd experiment, and these suggested that the latter half of growth of young radish was accelerated by adding the sludge. Contents of T-N in young radish and inorganic N in soil showed a tendency to increase by adding the sludge while antibiotic substance, cephalosporin-C, was not detected in plant material and soils after harvest of young radish in both experiments. Consequently, waste sludge from antibiotic fermentation, which contains high levels of organic matter and nitrogen could be used as an useful resource in agriculture.

• Korean Journal of Medicinal Crop Science
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• v.5 no.4
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• pp.255-259
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• 1997

The effects of slow-release fertilizer, C. D. U. (cyclo-di-urea), vinyl mulching and herbicides in different combinations were tested for weed control as well as the growth and yield of Cnidium officinale and economics were analyzed. Black vinyl mulching, ethalfluralin EC+white vinyl mulching, and ethalfluralin EC controlled weed completely till 60days after planting. When pendimethalin GR was sprayed more than 4.5kg/10a weed control value was $93.7{\sim}97.3%$, so significant difference was recognized with the recommended application rate (3.0kg/10a).

• Korean Journal of Soil Science and Fertilizer
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• v.50 no.5
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• pp.472-481
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• 2017

Agricultural field near at the abandoned metal mine and industrial area has a high possibility to be polluted by heavy metals. However, concern about chemical properties including heavy metal concentration has been increased and biological properties such as soil respiration has been minimal in heavy metal polluted field. Therefore, main objective of this research was to evaluate soil respiration as an indicator of heavy metal pollution in agricultural field. Total of 60 sampling sites including each 30 sites of abandoned metal mine and industrial area were selected and heavy metal concentration, soil respiration, and chemical properties were measured. Results showed that heavy metal concentration in metal mine area was ranged Cu: $6.21~85.23mg\;kg^{-1}$, Pb: $23.84{\sim}1,044.72mg\;kg^{-1}$, As: $1.88{\sim}691.44mg\;kg^{-1}$, Zn: $18.72{\sim}527.55mg\;kg^{-1}$, Cd: $0.58{\sim}4.27mg\;kg^{-1}$, and Cu: $0.29{\sim}30.62mg\;kg^{-1}$, Pb: $4.41{\sim}19.77mg\;kg^{-1}$, As: $2.23{\sim}11.76mg\;kg^{-1}$, Zn $39.98{\sim}109.59mg\;kg^{-1}$, Cd $0.29{\sim}0.57mg\;kg^{-1}$ for industrial area respectively. While no sampling site was exceed the threshold value of each heavy metals in industrial field, metal mine area was highly polluted with Pb, As, Zn, and Cd. Soil respiration in the metal mine and industrial area was ranged $12.05{\sim}299.80mg\;O_2\;kg^{-1}$ and $27.68{\sim}330.94mg\;O_2\;kg^{-1}$, respectively. Correlation analysis between heavy metal concentration in soil and soil respiration showed that negative correlation was observed in metal mine area while no correlation was observed in industrial area. This result might indicate that as heavy metal concentration was increased, microbial activity in soil was decreased resulting decrease of soil respiration rate. Overall, soil respiration can be used as indicator of heavy metal pollution in soil and more biological properties need to be evaluated to better understand heavy metal pollution in soil.

• Korean Journal of Soil Science and Fertilizer
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• v.3 no.1
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• pp.29-34
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• 1970

This experiment was conducted to investigate the influence of amounts of lime dressed on the growth of rice by the treatment of percolation and nonpercolation in the acid sulphate soil. And also analysis of soil chemical components after treatment was carried out. The results obtained were summarized as follows: 1. In the initial stage of growth, number of tillers and plant length showed no distinct differences between the treatments of percolation and nonpercolation, but after August the effect of lime appeared and the percolation treatment was more effective than the nonpercolation. 2. Lime dressing affected good influence on the panicles, grain per panicles and the rate of grain formation, and the treatment of percolation showed better results than nonpercolation. 3. If the yield of rough rice in the control (nonpercolation and lime dressing) was 100, it was 194 in the treatment of nonpercolation 12me/100gr of lime dressed, 268 in the treatment of percolation-4me/100gr of lime and 315 in the 8me/100gr-percolation. 4. Lime dressing affected good influence on the control of Helminthosporium leaf spots. 5. In the case of lime dressing, amounts of available phosphate and soluble silicon dioxide were increased, but ferrous ion ($Fe^{{+}{+}}$) were decreased.

• Korean Journal of Soil Science and Fertilizer
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• v.34 no.2
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• pp.85-91
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• 2001

To find diagnosing method of nitrogen status in tomato plant for determining optimum application rate of side dress, chlorophyll reading values were measured by portable chlorophyll meter(SPAD 502, Minolta), and compared with nitrogen supplying capability of soils. Regression between dry weight, amount of nitrogen uptake, and chlorophyll reading at stalk positions of tomato grown on the condition of no fertilization were evaluated For 6 green house soils with different nitrate concentrations ranged from $55mg\;kg^{-1}$ to $306mg\;kg^{-1}$. The chlorophyll reading of tomato leave was significantly correlated with amount of nitrogen per unit area of leave suggesting that chlorophyll content is useful for nitrogen diagnosis of tomato plant. The chlorophyll reading showed peak at the 15th leaf of stalk position on the 45th days after transplanting and this suggested that below or near the 15th leaf and before or near the 45th days after transplanting is the critical stalk position and time for diagnosing nitrogen status of tomato by chlorophyll test. The chlorophyll reading at the 14th leaf on the 40th days after transplanting was significantly correlated with soil nitrate status, dry weight and amount of nitrogen uptake by tomato grown with no fertilization. From the above correlation, the chlorophyll reading value of 57.1 at the 14th leaf of tomato was estimated as the critical level for maximum dry weight and amount of nitrogen uptake by tomato grown with no fertilization. Consequently, chlorophyll reading of tomato leaves measured by portable chlorophyll meter was thought to be available as a rapid plant test for predicting the nitrogen supplying capability of green house soils.