• Korean Journal of Soil Science and Fertilizer
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• v.45 no.5
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• pp.779-786
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• 2012

Many farmers have been seeking alternatives to chemical fertilizer for successful organic fruit production. This experiment was carried out to investigate the replaceability of chemical fertilizer by cover crop and slurry composting biofiltration (SCB) liquid manure (LM) application in pear orchard. Three treatments were contained in this experiment; cover crop only and cover crop + LM treatment, and control (chemical fertilizer application). Dry weight and mineral contents of gramineous cover crops were significantly increased in LM-combined treatments than that of leguminous species. Bulk density of soil was decreased in rye + LM and hairy vetch + LM treatments, compared with each cover crop treatment. Soil pH was lowest in fertilizer treatment and soil nitrate content became similar between treatments after rainy season. Available soil phosphate was lower in cover crop and cover crop + LM treatmemts than control, but exchangeable Mg was higher. The mineral content and net assimilation rate of leaves showed no difference between the treatments. As a result, it is suggested that the application of SCB liquid manure in pear orchard managed by cover crops is desirable to maintain the productivity by improving soil physical properties and potential nutrient recovery.

• Journal of Mushroom
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• v.13 no.4
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• pp.282-287
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• 2015

Physiological activities of 70% methanol, fermented ethanol and hot-water extracts of Pleurotus eryngii were investigated. Free radical scavenging activities of P. eryngii extracts were determined according to the elimination of DPPH radicals. Their nitrite scavenging activity and total polyphenol content were also determined. Amino acid analysis showed that phenylalanine (Phe) and glutamic acid (Glu) are most abundant essential and non-essential amino acids in the analyzed extracts. The hot-water extract of ASI 2394 represented the highest antioxidant activity with the DPPH radical scavenging rate value of $40.97{\pm}1.65%$. ASI 2820 displayed the superior capacity to eliminate nitrate regardless of extraction solvents. The hot-water extract of ASI 2887 had the highest content of polyphenol. Our results showed that P. eryngii is well qualified as a functional food.

• Korean Journal of Environmental Biology
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• v.37 no.2
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• pp.136-143
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• 2019

This study investigates the effect of denitrified biofloc water on changes in the water quality parameters and the physiological characteristics of shrimps. Biofloc rearing water contains a large number of microorganisms and can rapidly stabilize the water quality and energy saving if reusable due to high water temperatures. Rearing water contain floating bacteria with both aerobic and anaerobic bacteria. Therefore, when the carbon source is added in limited air supply, the anaerobic state is activated and the denitrification process is possible. In this study, the denitrification water had the following properties: ammonia (6.9 mg L^-1), nitrite (0.3 mg L^-1), nitrate concentration (9.2 mg L^-1), high pH (8.42) and alkalinity (590 mg L^-1). The experimental group consisted of seawater (SW, control), a mixture of Seawater and denitrified biofloc water (DNW) in the ratio of 3:1, 1:1 and DNW only. All experiments were done in triplicate. As a result, the survival rate never changed even when 100% of the denitrification water was utilized. However, a body fluid analysis showed that creatine and BUN were increased due to index of stress and the tissue damage resulting from the high denitrified water content. Body fluid ions (Na⁺, K⁺, and Cl^-) significantly decreased as the denitrified water content increased. It was recommended that the denitrification water be mixed with a certain ratio (less than 50%) in the future as it may affect the osmotic pressure control in shrimps.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.39 no.5
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• pp.412-419
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• 1994

This study was carried out to investigate changes of chemical composition in seed, germination percentage, and seedling growth of two F$_1$ hybrid rices(V20A/Cheongcheongbyeo, IR62829A/Cheongcheongbyeo) during germination compared with their parents (V20B, IR62829B and Cheongcheongbyeo) and check variety(Samgangbyeo). F$_1$ hybrid rice showed higher content of free amino acid, inorganic elements, ($P_2O_5$, $K_2$O, MgO) and total sugar, and higher a-amylase activity in brown rice than those of their parents and check variety during germination. Therefore$F_1$hybrid rices showed hybrid vigor in germination percentage at 33 hour and 48 hour after sowing. $F_1$ Hybrid rices also showed /heterosis in seedling growth was different between V20A/Cheongcheongbyeo and IR 62829A/Cheongcheongbyeo. There were positive significant correlation between a-amylase activity and germination percentage, and seedling growth.

• Korean Journal of Organic Agriculture
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• v.9 no.2
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• pp.83-99
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• 2001

This experiment was conducted to develop liquid fertilizer for leaf vegetable using the agricultural by-products such as dry chicken dropping, bone meal, rice bran, soybean oil cake and fish meal. Combination of 50% dry chicken dropping, 30% bone meal and 20% rice bran among several combinations of by-products was selected as materials for liquid fertilizer of head lettuce and cabbage. 50kg of materials with combination selected got mixed to 200ι of water, which kept under room temperature in greenhouse. EC and pH of fertilizer was stabilized after 35 days. On the decrease of bad smell during fermentation, addition of materials such as bioceramics, woody vinegar and active charcoal was not effected. And on rapid fermentation, addition of microorganisms and sugar had a little effect, but decreased the content of inorganic nutrients. Fertigation of liquid fertilizer developed on cabbage by dropping made head weight increased by 0.9kg per plant and nitrate content decreased by 276ppm in comparison with chemical fertilizer which was 3.5kg, and 2,426ppm, respectively. By use of organic liquid fertilizer developed in this experiment, yield of cabbage could be more obtained by 26% than in use of chemical fertilizer and income by 24%.

• Korean Journal of Soil Science and Fertilizer
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• v.39 no.5
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• pp.298-302
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• 2006

This study was carried out to establish low-input fertilization and seeding technique using the simultaneous with seeding and fertilizer application machine and band spotty applicator which were manufactured for experiment during cultivation of mulching for peanut(Arachis hypogaea L.). The labor hour for seeding by simultaneous with seeding and fertilizing machine was appeared over 90% reduction effect compared with control plot($17.3hr\;10a^{-1}$). In band spotty fertilization plots, the emergence date was delayed about 4 days and the seedling stand rate was decreased 11~18% compared with control plot(man power). The content of total nitrogen of soil after experiment was increased while the contents of organic matter, available phosphate and exchangeable potassium were decreased than before experiment. The content of nitrogen forming nitrate was increased in band spotty fertilization(BSF) plots by increasing the amount of applied fertilizer from early growth stage till the middle growth stage. Growth rate was increased in band spotty fertilization plots and the absorbed amount of phosphate and potassium for peanut were increased in 70% band spotty fertilization plot compared with control plot. Yield of peanut was increased 70% in band spotty fertilization plot due to high pod kernel ratio and ripened pod rate compared with control plot($3,150kg\;ha^{-1}$). It was found that 70% band spotty fertilization was more effective as fertilization method to reduce both environmental pollution and chemical nitrogen fertilizer in plastic film mulching cultivation of peanut.

• Korean Journal of Soil Science and Fertilizer
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• v.38 no.4
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• pp.222-229
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• 2005

A simplified one-dimensional model STELLA was used to predict soil water movement in lllinois corn fields using soil water balance sheets. It offered the potential to increase understanding of soil nitrate and agrochemical leaching process. The model accounted for aU possible annual inputs and outputs of water from a closed ecosystem as represented by corn fields. Water inputs included precipitation, while outputs included runoff, transpiration, evaporation and drainage. To run the model required daily inputs of two climatic data measurements such as daily precipitation and pan evaporation. Vertical water flow through the soil profile was calculated with first order equation including the difference in hydraulic conductivity and matric potential at the various soil types. The output results included daily changes of water content in the soil layers and daily amount of water losses including run-off, percolation, transpiration. This model was verified using Illinois corn field data for the soil water content measured by neutron scattering methods through 1992 to 1994 growing seasons. Approximately 22 to 78% of simulated water contents agreed with the measured values and their standard deviation, depending on soil types, whereas 30 to 70% of simulated water values agreed with the measured values and their standard deviations depending on soil layers.

• Journal of Animal Environmental Science
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• v.5 no.3
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• pp.157-170
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• 1999

This study was conducted to investigate the effects of Scoria, Quartz porphyry and Oak charcoal powder feeding by 1% level of concentrate on the fattening cross bred bulls(5/8 Korean Native Cattle, 2/8 Charolais, 1/8 Brahman germ plasma) Feeding trial was conducted with 4 treatment groups which were T1(Full feeding of concentrate and roughage for 12 months), T2(T1 and Scoria addition), T3(T1 and Quartz porphyry addition) and T4(Oak charcoal addition) for 360 days, consisting of 32 heads whose initially weights were about 299.7kg. The results obtained are summarized as follows; 1. During the over-all period, average daily gains by T3, T4, T2 and T1 were 1.024, 0.987, 0.977kg and 0.964, respectively, without a significant difference by treatments. 2. Concentrate intakes per body weight and TDN intakes required per unit of kilogram gain were lower in addition agent groups than in control, and in all the treatments feed efficiency was higher at early stage for 360 fattening day than at end stage. 3. Carcass weight, dressing percent, back-fat thickness and loin eye muscle area by treatments were 330.9 to 348.4kg(average 340.3kg), 55.2~56.2(average 55.8%), 0.41~0.55(average 0.46cm)and 76.0~80.9$\textrm{cm}^2$(average 77.6$\textrm{cm}^2$), respectively, and were improved in addition agent groups than in control. 4. Meat quality grade is higher in addition agent groups than in control, and heads of 1st grade by treatments was 3, 2, 1 and none in T4, T2, T3 and T1, respectively. 5. Incidence heads of diseases by treatment were not apparently different, but diseases of digestive system was decreased in addition agent groups than in control. 6. The nitrate nitrogen content of fattening bull dung which collected in rectum were 0.082~0.089% (average 0.084%), and the content in addition agent groups was smaller than in controll. 7. Income was higher in order of T4, T3, T2, and T1 and incomes of treatment groups were grater than that of control group by 21.4 to 33.5 percent. According to the above results it may be concluded that fattening bulls may be required to feed no more than 1% of Scoria, Quartz porphyry and Oak charcoal powder based on the concentrate feeding level during the fattening period(12 to 24 month of age) to produce high quality meat and increase income.

• Korean Journal of Soil Science and Fertilizer
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• v.38 no.2
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• pp.78-84
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• 2005

This study was conducted to investigate the effects of chemical treatments and electric and magnetic field treatments on germination and seedling growth of onion (Allium cepa L.). Germination ratios of the onion seed were not much different among the tested species. However, germination ratio was much higher in species of small and medium size seed than that of large one. Moisture content of the seeds was shown to be more suitable in the range of 10-15% for seed germination compare to that of 20%. The germination ratio of onion seeds was found to be increased by the chemical treatments in the order of GA<$NaNO_3$<$KNO_3$. In particular, the treatments with 0.1 and 0.2% $KNO_3$ increased the germination ratio by 13 and 15% compared to that of the non-treatment. The seeds treated with electric or magnetic field resulted in much higher germination ratio and better initial growth. Germination ratios of 86 and 88% were found in the 10 kV and 4 Gauss treatments, respectively. The length and weight of the seedlings grown for 40 days after transplanting were increased by 23-45% with 8 kV and 12 Gauss treatments compared to those of non-treatment.

• Korean Journal of Environmental Agriculture
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• v.37 no.3
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• pp.166-171
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• 2018

BACKGROUND: Nitrogen leaching depends on the drainage pattern and nitrate content, and those are influenced by soil hydraulic properties and fertility. The purpose of this study was to confirm how soil texture contributed to leaching and balance of nitrogen, as well as to drainage. METHODS AND RESULTS: This study was performed using undisturbed weighing lysimeters which were piled up with clay loam (Songjung series) and sandy loam (Sanju series) soils in National Institute of Agricultural Science experimental field. Chinese cabbage was cultivated from August 30 to October 31, 2017. The application rates of N, $P_2O_5$, and $K_2O$ were 21.5, 7.8, and $15.0kg\;10a^{-1}$, respectively, and irrigation was supplied at -33 kPa in 30 cm soil depth. Drainage in clay loam was not noticeable, although it was increased by rainfall in early September. By contrast, the trend of drainage in sandy loam was strongly dependent upon rainfall pattern. Owing to different drainage patterns between both soil textures, nitrogen leaching was 5-fold higher in sandy loam than in clay loam. Nitrogen use efficiencies in clay loam and sandy loam were represented as 43% and 52%, respectively. CONCLUSION: The pattern of drainage and nitrogen leaching were greatly depended on clay content in soil. From this study, we carefully suggest that soil texture should be considered as an incidental factor to estimate nitrogen balance.