• Korean Journal of Soil Science and Fertilizer
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• v.31 no.2
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• pp.177-182
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• 1998

To evaluate the effect of chicken manure compost(CMC) application on nutrient utilization and reduction of N fertilizer application for vegetables such of cabbage, reddish, and eggplant, four different application rates of CMC such as 0, 10, 30. $50Mg\;ha^{-1}$ were amended with three different rates of chemical fertilizer of 0, 15, $300kg\;ha^{-1}$. The efficiency of nutrient utilization on CMC were in the order of N, P, K. For each respective nutrient utilization by cabbage, reddish, and eggplant, N were 29%, 20%, 14%; P were 10%,<1%, and <1% ; K were 5%, 22%, 32%. The greater application of CMC, the less the efficiency, while the efficiency of P was increased with increasing application of CMC. The highest efficiency of nutrient utilization was found in $10Mg\;ha^{-1}$. The amounts of reduction of N fertilizer application in soils amended with $10Mg\;ha^{-1}$ of CMC with respect to maintain the normal production of each vegetables observed in this experiment were as follows: $25kg\;ha^{-1}$ and $15kg\;ha^{-1}$ less, and $13kg\;ha^{-1}$ more than the recommended rate for cabbage, eggplant, and reddish, respectively. For elution of available of N by the application of CMC, there was a gradual increase up to 30 day, then gradually decreased. However, there was increase of N eluted in the application of $50Mg\;ha^{-1}$. For soil chemical properties, pH, T-N, OM, and $P_2O_5$ were increased with increased application of CMC, as well as did cations such as K, Ca, and Mg. Yield and glucose of cabbage was significantly increased at the application of $30Mg\;ha^{-1}$ CMC, but content of nitrate in eggplant and raddish was highly increased with increasing application of N fertilizer and CMC. By the way, the yields of cabbage, reddish, and eggplant were slightly decreased with CMC application greater than $50Mg\;ha^{-1}$.

• Korean Journal of Soil Science and Fertilizer
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• v.38 no.3
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• pp.134-141
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• 2005

Cultivation of winter cover crops and its soil utilization for summer main crops in slope upland is very important at the respects of diminution of soil erosion and non-point pollution source. The effects of cover crop, hairy vetch as no-tillage or conventional tillage on prevention of soil erosion and reduction of chemical nitrogen fertilization were investigated in the slope upland with whiter clover living mulch (partial tillage) in Suwon for three years and with rye (conventional tillage) in Hongcheon for two years, respectively. In Suwon, amounts of soil lost by rainfall runoff decreased as much as 90% by hairy vetch-no tillage (HV-NT), white clover-partial tillage (WF-PT) together with the decrease of rainfall runoff compared to winter fallow with conventional tillage (WF-CT). In addition, amounts of weed also decreased as much as 80-90% by HV-NT and WF-PT. Corn yield decreased much at the plot of WF-PT mainly due to competition for soil water and nutrients between clover and corn at the early corn growth stage. On the contrary, corn yield increased by HV-NT compared to WF-CT regardless of weed control. In Hongcheon, amounts of soil eroded during winter season before corn seeding were reduced as much as 95% by cultivation of hairy vetch and rye compared to winter fallow. Amount of soil eroded during waxy corn growing season was reduced as much as 98% by HV-NT compared to WF-CT. Also, soil incorporation of hairy vetch and rye as green manure with conventional tillage at corn seeding time could reduce soil erosion as much as 70% compared to no soil cover with conventional tillage. Ear yields of waxy corn were increased 10% higher at hairy vetch green manure (HV-CT) without nitrogen fertilizer, 20% higher at HV-NT with standard nitrogen fertilizer, respectively than WF-CT. But ear yields of waxy corn were decreased by rye green manure (R-CT) and HV-NT at the condition of no nitrogen fertilizer. It was concluded that hairy vetch was better as winter cover crop to reduce both soil erosion and chemical nitrogen fertilizer simultaneously in slope upland than other cover crops.

• Korean Journal of Soil Science and Fertilizer
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• v.47 no.1
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• pp.36-40
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• 2014

Korea's agricultural land is constantly being reduced. The reasons for this are due to the change of agricultural profitability and the policy conditions. The reduction of agricultural land in 2010 showed a decline trend by 14.4 % of paddy fields and 1.2% of uplands compared to areas from 2000. These reductions were mainly due to switch rice paddy fields into upland or greenhouse facility cultivation because of low profitability of rice products compared to farm products. In addition, the permit system of agricultural areas was relaxed in switching paddy fields and this accelerated the reduction of agricultural land. For this reason, more than 1% of agricultural land area has been reduced every year for last five years. Moreover, indiscreet fill and cover materials such as construction wastes were used in agricultural lands and caused land contamination which threatened foundation as sustainable agricultural lands. For these reasons, it is a desperate situation to conserve good agricultural lands. However, the standards of transported soils, filling soils and cutting soils in the Agricultural Land Act are qualitative and have a problem of causing complaints. Therefore, the following criteria (proposals) are proposed in the Agricultural Land Act; (1) Use the proper soils for crops (criterion), (2) Soil components and amounts should be proper as transported soils (range), and (3) Prohibiting usage of improper earth rocks or recycled aggregates in case of filling soils (kinds). The presented criteria (proposals) suggest following; (1) Use physio-chemically proper soils for crops (criterion), (2) In case of transported soils, i, exclude potential acid sulphate soils, ii, gravel content sould be less than 15%, and iii, Heavy metals and other contaminants should be less than the soil contamination warning limit from the Ministry of Environments, (3) In case of filling soils, 13 kinds of recycled wastes specified in the Wastes Control Act should not be used as filling soils, (4) Practice soil conservation technology in case of sloping areas, and (5) Follow proper fertilizer application standards for maturing paddy fields and uplands when cutting soils.

• Korean Journal of Soil Science and Fertilizer
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• v.40 no.6
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• pp.488-494
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• 2007

Highland regions for farming are generally located in slopes higher than 7%, where alpine farming systems rely on highly input agriculture management with great amounts of chemical fertilizer and/or compost. Most of the uplands is thus needed to maintain environmentally friendly soil management due to its impact on soil erosion and runoff during heavy rainfall season. Therefore, the objective of this research is to evaluate the effect of reduction of soil erosion by applying four wild edible greens (fatsia, goat beard, leopard plant, and aster). The lysimeter experiment of slope gradients of 15, 30, and 45% was conducted in an alpine region of Hoengkye, Kangwon, in 2005 and 2006. In 2005, both amounts of soil loss from the experiment plots cultivated with goat beard and aster were lower than one with Chinese cabbage by about 50%. The amounts of runoff of goat beard and aster plots were also lower than those of the others. An increase in the slope gradients was accompanied with an increase in runoff. Of the plots of slope gradient of 15, 30, and 45%, S of goat beard plots was 52.50, 108.33, and 171.50 kg, respectively. Soil loss of Chinese cabbage was 2 to 3 times as high as those of goat beard plots. These results suggest that goat beard and aster plants with minimum tillage reduce soil erosion compared to Chinese cabbage cultivation.

• Korean Journal of Soil Science and Fertilizer
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• v.32 no.3
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• pp.232-238
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• 1999

Effects of animal manure application on the yield of crops were studied. Red pepper (1995) and Chinese cabbage (1996) were planted in pot with chicken, cow and pig manure application at $1.6mg\;ha^{-1}$, $3.2mg\;ha^{-1}$. Silage corn was grown in pot at 100%, 75%, 50% and 0%of recommended chemical fertilization rate among previously manure applied soils to predict the reduction of fertilizer. Results were as follows: Chemical properties of manure applied soils for two years were increased as pH 6.1~7.1, OM $17.1{\sim}23.7g\;kg^{-1}$, $P_2O_5$ $370{\sim}1.058mg\;kg^{-1}$, while those of chemical fertilizer applied soils were pH 5.8. OM $16.9g\;kg^{-1}$, $P_2O_5$ $249mg\;kg^{-1}$. Exchangeable cation and $P_2O_5$ content were increased in chicken manure applied soils than those in manure applied soils. Red pepper yield in manure applied pots was 121~192% compared to that in only chemical fertilizer applied pot. Effects of manure application was in the order of pig, chicken and cow manure. Chinese cabbage yield in manure applied pots was 55%~111% compared to that in chemical fertilizer applied pot. Effects of manure application were higher in red pepper than in Chinese cabbage. Fresh corn yield showed no significance between reducing 0% and 25% of recommend fertilization rate in previously manure applied plots, except in previously cow manure applied plots at $1.6mg\;ha^{-1}$. Fresh corn yield showed a positive correlation ($r=0.75^{**}$) with organic matter content and showed a positive correlation ($r=0.85^{**}$) with total nitrogen in untreated plot among previously manure applied soils.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.4
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• pp.424-429
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• 2010

To solve the problems with excessive accumulation of soil inorganic N and resulting saline soils from overuse of nitrogen fertilizer, the effect of sucrose application on decrease of soil inorganic N content and electrical conductivity (EC) was studied. Sucrose treatment greatly reduced ${NH_4}^+$-N content in soil. The amount of reduction was greater as the amount of sucrose treatment was increased. When ${NH_4}^+$-N content was reached the lowest point (about 10 mg $kg^{-1}$or lower), the C/N ratio, which determines the amount of sucrose treatment, was around 10 regardless of initial ${NH_4}^+$-N content. For the rate of ${NH_4}^+$-N reduction 15~36 hours was required to reduce the initial ${NH_4}^+$-N content to half, and 36~69 hours to lower ${NH_4}^+$-N content to the lowest point (about 10 mg $kg^{-1}$or lower). In addition, sucrose treatment greatly lowered ${NO_3}^-$-N content. In case of C/N ratio above 10, initial ${NO_3}^-$-N content of 348 mg $kg^{-1}$ was reduced to the lowest of 14~21 mg $kg^{-1}$. As for the rate of ${NO_3}^-$-N reduction by sucrose treatment, it took 36~60 hours for ${NO_3}^-$-N content to reach the lowest point for C/N ratio of 10 or higher, and it took 3 weeks, comparably longer time, for C/N ratio of 5. Lowering soil EC from sucrose treatment showed the same trend as ${NO_3}^-$-N content. As an important energy and carbon source for humankind, sugar should not be wasted and must be carefully applied to soil. In principle, the best way of preventing salt accumulation in soil is to optimize the fertilizer input. However, when over-fertilization should be dealt with, the sucrose treatment would be a possible and effective counter-measure to reduce overdosed nitrogen sources in soil.

• Proceedings of the Korean Society of Environment and Ecology Conference
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• 2003.10a
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• pp.105-126
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• 2003

In Korea most of annual rainfall is concentrated in several episodic heavy rains during the season of summer monsoon and typhoon. Because of uneven rainfall distribution many dams have been constructed in order to secure water supply in dry seasons. The Han River system has the most dams among Korean rivers, and the river is a series of dams now. Reservoirs need different strategy of water quality control from river water. Autochthonous organic matter and phosphorus should be the major target to be controlled in lakes. In this Paper some problems are discussed that makes efforts of water quality improvement ineffective in lakes of Korea, even after the substantial investment to wastewater treatment facilities.1) Phosphorus is the key factor controlling eutrophication of lakes and the reduction ofphosphors should be the major target of water treatment. However, water quality management strategy in Korea is still stream-oriented, and focused on BOD removal from sewage. Phosphorus removal efficiency remains as low as 10-30%, because biological treatment is adopted for both secondary treatment and advanced treatment. The standard for TP concentration of the sewage treatment plant effluent is 6 mgP/l in most of regions, and 2 mg/l in enforced region near metropolitan water intake point. TP in the effluents of sewage treatment plants are usually 1-2 mg/1, and most of plants meet the effluent regulation without a further phosphorus removal process. The generous TP standard for effluents discourages further efforts to improve phosphorus removal efficiency of sewage treatment. Considering that TP standard for the effluent is below 0.1 mg/l in some countries, it should be amended to below 0.1 mg/l in Korea, especially in the watershed of large lakes.2) Urban runoff and combined sewer overflow are not treated, even though their total loading into lakes can be comparable to municipal sewage discharges on dry days. Chemical coagulation and rapid settling might be the solution to urban runoff in regard of intermittent operation on only rainy days.3) Aggregated precipitation in Korea that is concentrated on several episodic heavyrains per year causes a large amount of nonpoint source pollution loading into lakes. It makes the treatment of nonpoint source discharge by methods of other countries of even rain pattern, such as retention pond or artificial wetland, impractical in Korea.4) The application rate of fertilizers in Korea is ten times as high as the average ofOECD countries. The total manure discharge from animal farming is thought to be over the capacity of soil treatment in Korea. Even though large portion of manure is composted for organic fertilizer, a lot of nutrients and organic matter emanates from organic compost. The reduction of application rate and discharge rate of phosphorus from agricultural fields should be encouraged by incentives and regulations.5) There is a lot of vegetable fields with high slopes in the upstream region of the HanRiver. Soil erosion is severe due to high slopes, and fertilizer is discharged in the form of adsorbed phosphorus on clay surface. The reduction of soil erosion in the upland area should be the major preventive policy for eutrophication. Uplands of high slope must be recovered to forest, and eroded gullies should be reformed into grass-buffered natural streams which are wider and resistant to bank erosion.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.2
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• pp.118-122
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• 2006

This experiment was carried out on plastic pots ($40cm{\times}25cm{\times}30cm$) filled with sand soil at greenhouse using two soybean cultivars with small seed; one was Pungsannamulkong (PSNK) recognized as a tolerant cultivar against excessive water stress and the other one was Sobaeknamulkong (SBNK) recognized as a susceptible cultivar. Seed was sown with 30 plants of 2 hills, and the amount of applied fertilizer was N; 3.0 g, P; 3.0 g, and K; 3.4 g per $m^2$ with all basal fertilizations. Plants were grown under photoperiod of natural light with day temperature of $31{\pm}5^{\circ}C$ and night temperature of $22{\pm}1^{\circ}C$. The flooding treatment was done for 3, 5, 7 and 10 days by filling pots with tap water up to 1 cm above the level of the soil surface when plants were 2 days after emerging. Nitrogen uptake by leaves of soybeans decreased significantly by the flooding after 6 days. This significant reduction of N uptake by flooding was evidently recognized from the chlorosis of leaves. The dry matter of flooded soybean seedlings significantly decreased compared to non-flooded soybean seedlings at 10 days. The dry matter of roots also showed similar result of the shoot. Shoots had more N reduction than roots under the flooding. This N reduction was more pronounce in SBNK than in PSNK. Chlorophyll content of flooded soybeans showed decreasing or non-increasing tendency, and the reduction of chlorophyll content was more in SBNK than in PSNK from the flooding stress. Nitrate content of soybean seedlings with flooding stress showed decreasing tendency in shoot and root parts. Ammonium content, however, was higher in flooding stress compared to the non-flooding. Flooding caused a remarkable change in the AA (amino acid) composition and TAA (total amino acid) concentration in the leaves of soybean seedlings.

• Korean Journal of Soil Science and Fertilizer
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• v.19 no.2
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• pp.139-145
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• 1986

In order to study the influence of nitrate reduction to ionic balance in tissue of tobacco plant, differneces in amounts of those cations and anions were determined and these balances were compared with contents of organic acids and activities of nitrate reductase, while they were fertilized with different nitrogen sources ($NO_3-N$, $NH_4-N$, $NO_3+NH_4-N$) in water culture. The results of studies are summerized as follows; 1. Total uptake of inorganic cations was the highest in nitrate-fed plants, whereas that of inorganic anions showed the highest level in the plants grown with the mixture ($NO_3+NH_4$). The amounts of inorganic cations and anions were comparable in two treatments containing $NH_4-N$, but in plants treated with nitrate only had much higher level of inorganic cations than others. 2. Deficiency in the amount of inorganic anions in nitrate-fed plants was balanced with organic acids, dominantly with malic acid among them. But another two $NH_4-N$ fed plant sustained equilibrium between inorganic cations and anions. 3. Reduction of nitrate was raised in tissues of nitrate-fed plants. By the results of nitrate reduction, cations maintained equilibrium with nitrate ion were let loose. The replacement of inorganic anions with organic anions could be a compensation process for the loss of uptaken nitrate ions which must be reduced to be incorporated into organic N compounds.

• 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.