• KOREAN JOURNAL OF CROP SCIENCE
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• v.61 no.1
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• pp.25-32
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• 2016

A long-term field experiment under different fertilization treatments had been conducted to explore the effects of rice yield and soil chemical properties from 1978 to 2008 in Suwon, Korea. The paddy was applied eight fertilization treatments which were F0 (no fertilizer), PK (phosphorous and potassium), NK (nitrogen and potassium), NP (nitrogen and phosphorous), NPK (nitrogen, phosphorus and potassium), NPKC (NPK with compost), NPKS (NPK with straw) and NPKL (NPK with lime). Results of 31 years experiment showed that yield index (the ratio of yield in each treatment to NPK) was the lowest in F0 (0.52) and the highest in NPKC (1.18). Yield index was gradually increased in NPKC but decreased in F0 and NK. The yield index of PK, NP, NPKS and NPKL were not changed long-term treatment. Soil acidity of NPKL showed the highest with pH 7.9, and that of other treatments ranged from pH 6.3 to 6.8. Available phosphorous content of soil was increased in all plots by long-term fertilization, was the highest in PK and NPKC. Soil organic matter was higher in NPKC (1.8%) and NPKS (1.8%) than other treatments (1.3~1.4%) in the early experiment, but that was remarkably increased in only NPKC (2.5%) according to annual long-term application. Thus we suggest that annual compost application with optimum NPK could make stable and sustainable rice production.

• Korean Journal of Environmental Agriculture
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• v.33 no.1
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• pp.9-16
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• 2014

BACKGROUND: This study was conducted to investigate the effects of seeding timing and method of rye and/or hairy vetch on seasonal soil and foliar nutrient concentrations as well as fruit quality in a pesticide-free pear orchard. METHODS AND RESULTS: The treatments included as followed: single seeding of rye in September (Sep-Mono), November (Nov-Mono), and January (Jan-Mono), or mix seeding of rye+hairy vetch in November (Nov-Mix) and January (Jan-Mix), or sod culture as a control. Cover crops or vegetation was mown and mulched on the soil surface in April and May for two years. Nov-Mix treatment produced the highest dry matter weight of $12,070kg\;ha^{-1}$, with the lowest dry matter weight for sod culture ($6,520kg\;ha^{-1}$), following Jan-Mix ($7,030kg\;ha^{-1}$). Nov-Mix treatments increased potential amount of N, P, and K from the raw materials of the cover crops as well as improved soil physical properties. Nov-Mix treatments overall elevated soil pH, EC, organic matter, and $P_2O_5$ in May compared to other cover crop treatments or sod culture. The difference of the seasonal nutrient concentrations in leaves or fruit qualities were not consistently occurred amongst treatments. CONCLUSION: Nov-Mix treatments showed playing role in a substitute of a chemical fertilizer. Delayed seeding of cover crops such as Jan-Mix did not increase the potential dry matter production due to the short growing period, and the seeding time would affect the dry matter production of cover crops.

• Journal of The Korean Society of Grassland and Forage Science
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• v.25 no.1
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• pp.1-6
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• 2005

With recent interest organic farming the use of legumes including vetch and clover to provide N to adjacent crops is increasing in Korea. In the present studies, we conducted a trial to investigate the effects of the application of N rate on nitrogen fixation and transfer from vetch to barley in mixed stands. The experiment was arranged in a randomized complete block design with three replications. Four different N rates(0, 75, 113 and 150/ha) was used and vetch+barley was broadcasted manually on 1.5 $\times$2 m plot in Oct. 2001. Half of urea and K$_{2}O, 200 Phosphate and 75 kg potash per ha were applied as basal dressing md half of N md 75 potash were used for topdressing to soil surface on MarctL 2002. The equivalent of 1kg ha$^{-1}$ at($^{15}$NH$_{4}$)$_{2}$SO$_{4}$ solution at 99.8 atom $\%$$^{15}$N excess was applied to the microplot in mid April. Forage was harvested from each plot at ground level and separated into barley and vetch. Total N content and It values of samples were determined using a continuous flow stable isotope ratio mass spectrometry(IsoPrime-EA. Micromass, UK.). The percentage of legume H fixed from atmospheric N2 were 95.0, 93.8, 94.4 and $84.8\%$ with increment of N levels. The percentage of N transfer from vetch to barley by N-difference method with increment of N fertilizer were from 58 to$49\%$ while 39 to $23\%$ in $^{15}$N-dilution method. The amount of transfer from vetch to barley were 87 to 68 kg/ ha with N level by N-difference moth여 and 58 to -56/ha with N application levels by $^{15}$N dilution method. The amount of nitrogen fixation per ha were from 150 kg / ha to 219 kg / ha by different method, but on the other side 49 to 105kg/ha by N$^{15}$-dilution.

• Korean Journal of Environmental Agriculture
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• v.34 no.4
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• pp.355-358
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• 2015

BACKGROUND: Changes in Korea's agricultural soil properties were analyzed at a four-year interval from 1999 to 2002 on a national scale and used as basis for the determination of the appropriate agricultural policy on maintaining food safety and soil quality. The scope of this study ideally requires sampling thousands of paddy, greenhouse, upland and orchard land across the country, however, due to limitations in economic and manpower resources, it was deemed necessary to reduce sampling site to greenhouse soil. In this study, we try to investigate the applicability of cultivated crops as criteria for selecting representing fields in greenhouse soils.METHODS AND RESULTS: Soil samples were collected from red pepper, oriental melon, watermelon and strawberry cultivated soil. Principal components analysis (PCA) was performed on soil chemical properties of the selected fields: pH, electron conductivity (EC), available phosphate (Av-P₂O₅), organic matter (OM), and exchangeable cation (Ex.-K, Ca, and Mg). Soil chemical properties of oriental melon cultivated soil was separated from red pepper, watermelon, and strawberry cultivated soil on PC1 and red pepper cultivated soil was separated from watermelon cultivated soil on PC2. Position on PC1 was strongly correlated with pH, Ex.-Ca and Ex.-Mg and position on PC2 was strongly correlated with OM and Av-P₂O₅.CONCLUSION: The soil chemical properties of greenhouse soil was assorted amongst the different crops. Therefore, the cultivated crops as a criteria for the selection of representative field in greenhouse soil would be used in the future.

• Korean Journal of Environmental Agriculture
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• v.3 no.1
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• pp.52-56
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• 1984

In order to evaluate the applicability of two kinds of antibiotic fermentation residues on rice and tomato growth, yield, yield components, and some indicators for plant growing status were checked including analysis of physico-chemical properties of these two antibiotic fermentation residues. The results obtained are as follows: 1) These two antibiotic fermentation residues contain high organic matter ($21.6{\sim}24.2%$), phosphorus ($2900{\sim}4600 ppm$) and exchangeable cations ($55.4{\sim}138.3 meq/100 g$,), showing their pH values of $7.0{\sim}8.0$ range. 2) Both have developed net positive charge rather high and stiffly that exhibits high negative ion adsorption capacities, accordingly showing higher zero point of charges($pH 7.0{\sim}8.0$) than those of common soils. 3) The effect of the two kinds of antibiotic fermentation residues on rice growth was more or less the same comparable to the effect of the other fertilizers applied, showing the maximum yield at the application rate of 40 ㎏/10a. 4) The effect of these antibiotic fermentation residues on tomato growth was also similar to effects on rice plant showing the yield increment upon fertilizer application including two antibiotic fermentation residues but no significant differences among fertilizers. 5) According to the plant growing status, plant height, dry matter, number of effective tillers and grain number per panicle of rice and plant height and fresh weight of plant of tomato showed similar trend with yield of both plants.

• Korean Journal of Environmental Agriculture
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• v.24 no.3
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• pp.295-302
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• 2005

The nitrogen (N) balance in Korea during 1985-1997 was calculated according to the surface balance method of the PARCOM guidelines and compared with Japanese N balance. The some differences were founded in the coefficients used on calculating N balance in two nations. Of the important parameters, which can make a big difference in balance, N input by organic fertilizers was not included in Korea different with Japanese, due to absence of reliable statistics and then made lower the input. Nitrogen destruction rate from livestock manure was adjusted differently with 15% in Korea but 28% in Japan. There was some difference in the conversion factors of livestock number into manure N quantity in two nations, but the gap was ignoble scale except beef cattle. Our manure N production rate of beef cattle might be evaluated to be so lower than Japanese. Biological N fixation by pulses was very higher in Korea than in Japan but scarcely affect the increase of total N input, due to small cultivation area. In contrast, N fixation rate by free-living organisms in Korean and Japanese wet paddies showed the big difference with 7.6 and $37.0kg\;ha^{-1}\;yr^{-1}$, respectively, and therefore $29.4kg\;ha^{-1}\;yr^{-1}$ of nitrogen was estimated to be more inputted in Japan. Although there are many points to be more specified and improved, still, Korean N balance was very high with $250-257kg\;ha^{-1}$ in the mid of 1990s, which was the second highest level in OECD countries and furthermore increased continuously during the investigation. In contrast in Japan, which has similar fanning system with Korea, N balance was lower with $130-158kg\;ha^{-1}$ and has decreased continuously since 1993. This high N balance was mainly due to a high usage of chemical fertilizers in our intensive fanning system and the fast increment of livestock feeding. Therefore, the more active action to decrease chemical fertilizer utilization and reduce livestock feeding density is required in the government and farmer sides.

• Journal of The Korean Society of Grassland and Forage Science
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• v.31 no.4
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• pp.423-430
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• 2011

This study was carried out to examine the nutritive values and quality of agricultural bag (AG-BAG) silage manufactured with corn grown in reclaimed paddy field of Sukmoon at Dangjin Province in Korea. The cultivars of silage corn used in this experiment 1 were both Kwangpyungok and P32B33. The fertilizer were applied with the amounts of customary applications (200 kg N/ha, 150 kg $P_2O_5$/ha and 150 kg $K_2O$/ha). The content of moisture in corn AG-BAG silage ranged from 68 to 79%. The pH in corn AG-BAG silage stages ranged from 3.49 to 3.65 and was not influenced by the harvest time. The contents of crude protein (CP) in corn AG-BAG silage decreased with delayed harvest time. However, the contents of ADF (acid detergent fiber) and NDF (neutral detergent fiber) increased. The content of lactic acid increased with delayed harvest time, but the content of acetic acid decreased. Therefore, we suggest that the system of AG-BAG silage can improve the quality of corn silage and be one of the economical and effective methods to manufacture corn silage.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.15 no.1
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• pp.141-154
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• 2012

This study was launched to verify the effective composition of plant species and its management program most suited for the dredged soiled area near Nakdong River Site 14. The improvement methods of planting base and the composition of plants such as silver grass, reed, and some colonies in aesthetic effect were studied. To search the management methods to decrease the confining pressure risen from the burried seeds which would consequently harm the previously seeded plants, experimental construction process was measured on the site. The purpose of this experiment was to figure out which part of the improvement on the plant base has the most significant effect for the revegetation of infertile, dredged soil, to verify the easily seeded, developing plants among seeded plants, and finally, to find the restoration model using plants near the dredged soil around riverside. 8 seeded plants and 23 invaded species were appeared which among the emerged plants, development of Aster yomena MAKINO, Lotus corniculatus var. japonica Regel, Trifolium repens L, and Dianthus longicalyx Miq were proved to be brought up well. Difference risen from the seed composition were not noticeable until 150day since the germination was proceeded mainly by Aster yomena MAKINO. The experimental plot with dredging sand+organic fertilizer method of construction and dredging sand+soil conditioner method showed most development while the effect of the plot with only the soil base of dredging sand stayed low. Another important method for the management of infertile, dredged soil base would be the removal of disturbing species which the experiment showed the tied relationship between the removal of disturbing species and development of seeding plants. Although this study was carried out focused on the Nakdong River Project, the study suggests the general management program that the removal of disturbing species such as Humulus japonicus Sieboid & Zucc. and Pueraria lobata (Willd.) Ohwi in times around rainy season(60days after seedling) would be effective for the easy growth of revegetation plants.

• Korean Journal of Environmental Biology
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• v.31 no.4
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• pp.471-477
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• 2013

Biochar amendment to agricultural soil is regarded as a promising option to mitigate climate change and enhance soil quality. It could sequester more carbon within the soil system and increase plant yield by changing soil physicochemical characteristics. However, sustainable use of biochar requires comprehensive environmental assessment. In this sense, it is important to measure additional greenhouse gas emission from soils after biochar addition. We investigated emissions of $CO_2$, $N_2O$, and $CH_4$ from incubated soils collected from rice paddy and cultivated grassland after amendment of 3% biochar (wt.) produced from rice chaff. During incubation, soils were exposed to three wet-dry cycles ranging from 5~85% soil gravimetric water content (WC) to investigate the changes in effect of biochar when influenced by different water levels. The $CO_2$ emission was reduced in biochar treatment compared to the control at WC of 30~70% both in rice paddy and grassland soils. This indicates that biochar could function as a stabilizer for soil organic carbon and it can be effective in carbon sequestration. The $N_2O$ emission was also reduced from the grassland soil treated with biochar when WC was greater than 30% because the biochar treated soils had lower denitrification due to better aeration. In the rice paddy soil, biochar addition resulted in decrease in $N_2O$ emission when WC was greater than 70%, while an increase was noted when WC was between 30~70%. This increase might be related to the fact that available nutrients on biochar surface stimulated existing nitrifying bacterial community, resulting in higher $N_2O$ emission. Overall results imply that biochar amendment to agricultural soil can stabilize soil carbon from fast decomposition although attention should be paid to additional $N_2O$ emission when biochar addition is combined with the application of nitrogen fertilizer.

• Journal of Korean Society on Water Environment
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• v.23 no.4
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• pp.518-526
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• 2007

There have been serious soil erosion and water pollution problems caused by highland agriculture practices at Doam-dam watershed. Especially agricultural activities, chemical and organic fertilizer and pesticide applications, soil reconditioning to maintain soil fertility are known as primary causes of soil erosion and water qaulity degradation in the receiving water bodies. Among these, soil reconditioning can accelerate soil erosion rates. To develop soil erosion prevention practices, it is necessary to estimate the soil erosion from the watershed. Thus, the Universal Soil Loss Equation (USLE) model has been developed and utilized to assess soil erosion. However, the USLE model cannot be used at watershed scale because it does not consider sediment delivery ratio (SDR) for watershed application. For this reason, the Sediment Assessment Tool for Effective Erosion Control (SA TEEC) was developed to assess the sediment yield at any point in the watershed. The USLE-based SA TEEC system can estimate the SDR using area-based SDR and slope-based SDR module. In this study, the SATEEC system was used to estimate soil erosion and sediment yield at the Doam-dam watershed using the soil properties from reconditioned agricultural fields. Based on the soil sampling and analysis, the US LE K factor was calculated and used in the SA TEEC system to analyze the possible errors of previous USLE application studies using soil properties from the digital soil map, and compared with that using soil properties obtained in this study. The estimated soil erosion at the Doam-dam watershed without using soil properties obtained in the soil sampling and analysis is 1,791,400 ton/year (123 ton/ha/year), while the soil erosion amount is 2,429,900 ton/year (166.8 ton/ha/year) with the use of soil properties from the soil sampling and analysis. There is 35 % increase in estimated soil erosion and sediment yield with the use of soil properties from soil reconditioned agricultural fields. Since significant amount of soil erosion are known to be occurring from the agricultural fields, the soil erosion and sediment yield from only agricultural fields was assessed. The soil erosion rate is 45.9 ton/ha/year without considering soil properties from soil reconditioned agricultural fields, while 105.3 ton/ha/year after considering soil properties obtained in this study, increased in 129%. This study shows that it is very important to use correct soil properties to assess soil erosion and sediment yield simulation. It is recommended that further studies are needed to develop environment friendly soil reconditioning method should be developed and implemented to decrease the speed of soil erosion rates and water quality degradation.