• Korean Journal of Organic Agriculture
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• v.17 no.2
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• pp.151-170
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• 2009

The objectives of this study were to analysis the nutrient cycles of agricultural by-products. The region, in which agricultural by-products are circulated for use within the agroecosystem for minimizing the input of artificial nutrients as well as generation of wastes, and where ecologically industrial diversity is formed, was defined as the regional agriculture focused on eco-industrial approach. Plan in stages for promoting ahead with the regional agriculture focused on eco-industrial approach is as follows: First of all, "The Consultation Body for Circulating & Using By-products" should be formed. Secondly, usage of agricultural by-products is identified to select the facilities of recycling and its location including the type and amount. Thirdly, the facilities for recycling of resources and infrastructure are installed. Finally, the facilities for recycling and resource circulation system within the area are efficiently managed.

• Korean Journal of Organic Agriculture
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• v.8 no.2
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• pp.97-110
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• 2000

An organic agriculture should be managed by mixed farming in farm unit as a closed recycling system. Due to restricted purchased of fertilizers from outside, organic farmer has to deal with limited amount of nutrient source in farm unit. Especially the supply of the essential nutrient, nitrogen, mostly depends on legumes fixing nitrogen optimizing the site-adapted crop rotation. Dynamics of humus and metabolic plant carbon and active soil carbon compartment in active and passive humuspool by rotation system was explained, and dynamics of potentially mineralizable nitrogen in organic nitrogen and biomass was discussed. It was also discussed comparison of ammonia emission, potential greenhouse effect, primary energy input, acidification potential, CO2 emission between organic and conventional farming, the nitrate-nitrogen dynamic in the soil profile by organic, integrated and conventional farming system. In conclusion, it was suggested for Korean Organic Agriculture that the importance of legumes and green manures in rotation system for increase/maintenance of soil ferfility, and was pointed out the need of investment for environment impact of Korean organic farming implement.

• Animal Bioscience
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• v.36 no.4
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• pp.529-539
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• 2023

The beef cattle industry in China has advanced remarkably since its reform and opening up; consequently, China has become the world's third-largest beef cattle producer. China is also one of the countries with the most substantial research input and output in the field of beef cattle feed and nutrition. The progress and innovation by China in the research field of beef cattle feed and nutrition have undoubtedly promoted the development of the domestic beef cattle industry. This review summarizes recent advances in feed resource development, nutrient requirements, and nutritional regulation of beef cattle in China. Limitations in current research and perspectives on future work are also discussed.

• Korean Journal of Soil Science and Fertilizer
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• v.33 no.5
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• pp.347-355
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• 2000

To determine nitrogen balance (Input-Output) of Korea that was asked by Joint Working Party of the Committee for Agriculture and the Environment Policy Committee, OECD, nitrogen input and output were separately investigated as followings: nitrogen input included the amounts of chemical fertilizer consumption, cattle manure production, and biological nitrogen fixation in the national scale, and nitrogen output summed amounts withdrawn by crop and pasture harvesting, and crop residue removal, and lost by denitrification. In 1997, nitrogen balance of Korea was $158kg\;ha^{-1}$ and $211kg\;ha^{-1}$ on including and excluding denitrification loss, respectively. N balance excluded N loss by denitrification and N withdrawal by crop residues on nitrogen output was $250kg\;ha^{-1}$, which OECD asked to except two items from N balance determination because participants were not enough their data. Nitrogen balance was increased to 1.7~2.3 times in 1997 compared with 70 and $162kg\;ha^{-1}$ in 1985, which calculated on the condition of including denitrification and excluding denitrification and removal of crop residues in nitrogen output, respectively. This increase was caused mainly by increasing livestock manure production and chemical fertilizer consumption together with agricultural land area decrease. Nitrogen input was composed with 59% of chemical fertilizer. 42% of cattle manure and 5% of others in 1997, and output was with 73% of crop production, 23% of crop residue withdrawal and 4% of pasture production. Average nitrogen balance excluded N loss by denitrification and N withdrawals by crop residues in 1995~1997 calculated by OECD was $253kg\;ha^{-1}$, which was the second highest rank in OECD participants following $262kg\;ha^{-1}$ of Netherlands. Japanese N balance that has similar farming system with us was $135kg\;ha^{-1}$.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.17 no.4
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• pp.252-261
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• 2012

To determine the temporal variations of submarine groundwater discharge (SGD) and SGD-driven nutrients inputs, we measured the seepage rate and the nutrient concentrations of pore water/groundwater in Bangdu Bay of Jeju Island at two and three month intervals from September 2009 to September 2010. The seepage rate of groundwater ranged from 0 to 330 cm/day (average ~170 cm/day) during the five sampling periods, which increased sharply from high tide to low tide due to changes in hydraulic pressure gradient between water table in land and water sea level in the coastal ocean by the tidal cycles. The submarine inputs of groundwater were also relatively higher in summer than in winter. The nutrient fluxes from SGD were about 90~100%, 70~95%, and 65~100% of the total input (except from open ocean waters) for dissolved inorganic nitrogen (DIN), phosphorus (DIP), and silicate (DSi), respectively, potentially supporting about 0.9~33 g $carbon/m^2/day$ of new primary production in Baugdu Bay. Thus, our study suggests that SGD-driven nutrients may play an important role in the eutrophication and biological production in the coastal ocean of Jeju Island.

• The Korean Journal of Ecology
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• v.15 no.1
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• pp.35-46
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• 1992

To elucidate nutrient cyclings such as nitrogen, phosphorus and potassium in mongolian oak(quercus mongolica) forest, nutrient elements of precipitation, throughfall, outflow, soil, various plant organ and litter were determined at mt.nambyeongsan, pyeongchang-gun, gangwon province in central part of korean peninsula. Annual precipitation input, throughfall and outflow of nutrientswere 10.3, 8.6 and 4.2 kg/ha for the N, 0.11, 0.24 and 0.02 kg/ha for the Pand 1.3, 10.9 and 1.2 kg/ha for the K, respectively. Inseasonal changes of nutrient concentrations, N, P and Kconcentrations which were rich in young leaves decreased steadily until autumn and decreased abruptly during autumnal yellowing. The standing N, P and K concent were 565, 37 and 257 kg/ha for standing phytomass of overstory, 33, 3 and 18 kg/ha for understory, 132, 3.6 and 14 kg/ha for litter on ground including deadwood and 20, 752, 14 and 420 kg/ha for the soil, respectively. The amounts of annual uptake, reture and retain were 174.2, 57.2, 117.2 kg/ha for the N, 9.9, 3.5, 6.4 kg/ha for the P and 73.2, 30.3, 42.9 kg/ha for the K, respectively. Reabsorption efficiency, ratio of the nutrient amount reabsorbed into woody organs to that in the mature leaves before shedding, was 71%(or 99.8 kg/ha in the amount), 69%(or 5.1 kg/ha) and 57%(or 33.1% kg/ha) and recycling coeffciently made with which the large amount of nutrients is absorbed through roots during growing season(UPTAKE) and reasorbed from the leaves before shedding(RETAIN) but the small amount of nutrients is returned through litterfall(RETURN).

• Journal of Bio-Environment Control
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• v.21 no.2
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• pp.108-113
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• 2012

This study was conducted to evaluate soil nutrient concentrations and fertilizer recovery of sorghum- sudangrass hybrid (Sorghum bicolor (L.) Moench) as affected by organic nutrient sources. The treatments included livestock compost, alfalfa hay, oilcake, and chemical fertilizer. Nutrient applications were made at the rates equivalent to approximately 210 kg N per hectare. The oilcake and alfalfa materials had the lowest C : N ratio, but the livestock compost had the highest C:N ratio such as 33.7 : 1. The livestock compost resulted in the highest input to ground surface, which increased nutrient concentrations in soil. The oilcake and alfalfa materials with low C : N ratios increased N-mineralization rate in soil compared to livestock. The N uptake efficiency in plants treated by alfalfa or oilcake was approximately 60% of those treated with chemical fertilizer; but those with livestock compost had N uptake efficiency lower than 20%. The $P_2O_5$ uptake efficiency was the highest in the plants treated with the alfalfa hay, but the lowest in those with livestock compost. Recommendation of organic material selection should consider C:N ratio of the raw materials based on the individual crop requirement.

• Journal of Plant Biotechnology
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• v.48 no.3
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• pp.193-200
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• 2021

Barley (Hordeum vulgare cv. Hangmaeg) sprouts are important microgreens that contain high levels of polyphenols and flavonoids, as well as minerals, vitamin and chlorophyll. Barley sprouts were grown for 9 days and growth was checked every 3 days. In this study, the cultivation efficiency according to the nutrient solution treatment was evaluated by analyzing the length of barley sprouts, fresh weight, chlorophyll, and the yield by growth period. In addition, we tried to increase the industrial applicability of germinated barley through analysis of inorganic component, total polyphenol and total flavonoid content of the extract, and functional substance analysis using HPLC. As a result, the growth rate of the nutrient solution treatment group was faster than that of the control group. When harvested on the 9th day of sowing, the nutrient solution treatment group showed a significant increase in yield compared to the control group. And the barley sprout extract of the nutrient solution treatment group had higher total flavonoid content and luteolin content. Also, the efficiency of water was higher than that of ethanol when extracting phenolics from barley sprouts. Therefore, this study suggests that nutrient input is effective for increasing polyphenol content and increasing production in barley sprout hydroponics.

• Journal of Korean Society of Water and Wastewater
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• v.12 no.3
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• pp.41-47
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• 1998

Doam Lake is located around the pasture area and Yongpyung Resort. Because of the waste load of domestic animals, nutrient concentration of the stream is high. In this study, waste load of Doam Lake watershed is calculated, and QUAL2E model is applied to the upper part of the Songcheon to calculate the input boundary concentration of Doam Lake. And WASP5 model is applied for the water quality modeling of Doam lake. The results indicate that advanced treatment of domestic animal wastes is necessary for the lake water quality management.

• Journal of the Korean Data and Information Science Society
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• v.15 no.3
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• pp.531-542
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• 2004

Principal component analysis and cluster analysis were conducted to comprehensively evaluate the water quality of Busan coastal area with the data collected seasonally by the analysis of surface water at 10 stations from 1997 to 2003. We noted that the first principal component was regarded as a factor related with the input of nutrient-rich fresh water and the second principal component as meteorological characteristics. Also we obtained that water qualities of station 4 and 9 were different from those of other stations in Busan coastal area.