• Water for future
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• v.6 no.2
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• pp.19-29
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• 1973

The progressive contamination of water resulted from man's activity and the use of fertilizers is not restricted only to surface water, but also the shallow groundwater is affected. This type of groundwater contamination is mainly restricted to areas composed of permeable, nonconsolidated sediments forming a shallow aquifer. The chloride and the sulfate resulted from man's activity and the use of fertilizers were measured to study the variations of the groundwater contamination. In general, (1) When water level rises, the rate of groundwater contamination becomes less and when water level declines, the rate of contamination is increased. (2) The highly contaminated season is the early-summer and the less contaminated season is the winter or after rainy season. (3) The groundwater in weathering zone without covering layer. (4) The degree of contamination of wells is increased with the increase of well depth and lowing the water table, because of increasing contaminated water from enlargement of the area of influence of the well.

• Food Science and Preservation
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• v.5 no.2
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• pp.127-132
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• 1998

In order to fad out an efficient way of topdressing nitrogen fertilizer in mulch-cropping system of onion(Allium cepa L.), solid, slow-release, and liquid forms of nitrogen fertilizers were allied to cv. 'Changnyungdaego' various number of times at different time, with 5 topdress applications of solid fertilizer serving as a control. Whole basal application of conventional solid fertilizer and 2 slow-release fertilizers were labor-saving and showed improved storage quality of bulbs, but resulted in poor plant growth and considerably low yield due to fertilizer shortage from early April. This suggests that topdress application is necessary. Liquid form of nitrogen fertilizer was more effective for plant growth and yield and saving labor than the solid form. Early applications was effective for increasing yield and storage quality of onion bulbs harvested. Thus two applications of liquid form of nitrogen fertilizer in February and March at rome month interval are recommended in mulch crowing system of onion.

• The Korean Journal of Mycology
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• v.49 no.4
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• pp.517-524
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• 2021

Red pepper seedlings were inoculated either alone or with a mixture of all five species of arbuscular mycorrhizal fungi (AMF). After 10 weeks of growth in the greenhouse, the seedlings were transplanted into fields and cultivated without chemical fertilizers and pesticides for 10 weeks. The results showed that plant growth was significantly increased under both greenhouse and field conditions, suggesting that AMF inoculation has a positive effect on the growth of Capsicum annuum and improves the physical properties of the soil by increasing the concentration of glomalin. The application of AMF can positively contribute to sustainable agriculture by reducing the use of chemical fertilizers while increasing crop growth.

• Korean Journal of Agricultural Science
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• v.38 no.1
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• pp.17-23
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• 2011

This research was conducted to investigate the influence of application rate of liming fertilizers on changes in soil chemical properties and growth of 'Red Madness' petunia in plug production. To achieve this, dolomite (DO) with 0, 1.0, 3.5, 8.0 or 13.0 $g{\cdot}L^{-1}$ and calcium carbonate (CC) with 0, 2.0, 2.5, 3.0, 3.5, or 4.0 $g{\cdot}L^{-1}$ were incorporated into peatmoss + vermiculite (1:1, v/v) during the root substrates formulation. The treatments of 3.5 $g{\cdot}L^{-1}$ of DO and 2.5 or 3.0 $gL^{-1}$ of CC had acceptable ranges of pH and EC in soil solution such as 5.6~6.2 and 0.7~1.0 $dS{\cdot}m^{-1}$, respectively. The faster rising of pH was observed in root media containing CC rather than those of DO. This indicates that the solubility of CC is higher than DO. The soil Ca concentrations in all treatments of CC were 1.8 times as high as those of DO. The treatments of 3.5 or 8.0 $g{\cdot}L^{-1}$ of DO had the highest soil Mg concentrations, but all treatments of CC had lower soil Mg concentrations than control treatment indicating that additional application of Mg fertilizers are required. The elevated application rate of DO or CC resulted in the increase of fresh and dry weight. But plant heights were not influenced by application of liming fertilizers. The results of tissue analysis showed that application of DO or CC influenced the $PO_4{^-}P$, Ca and Mg contents, but not influenced the contents of other nutrients such as N, P, Fe, Mn, Zn and Cu.

• Korean Journal of Medicinal Crop Science
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• v.19 no.2
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• pp.83-89
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• 2011

This studies were conducted to investigate the growth responses and yields of Astragalus membranaceus Bunge which were grown with organic cultivation using two organic fertilizers and two green manure crops of hairy vetch and rye in 2008 and 2009. The lengths of stems and roots were not clearly different between organic and conventional cultivations. The root diameters and the branch numbers were slightly thicker and more in all treatments of organic cultivation than that of conventional cultivation in 2008, although they were not significantly different between two cultivating methods in 2009. The dry weights of shoot and root were heavier on organic cultivation than those on conventional cultivation. The T/R ratios were commonly higher in organic culture, showing more clearly in 2008 than 2009. The yields were generally higher in organic cultivation than those in conventional cultivation in 2008 although the effect did not clear on yield in 2009. The organic cultivation using of organic fertilizers and green manure crops would be new method to have safety and qualitative products. The techniques of organic cultivation for Astragalus membranaceus Bunge would be studied more on utilizing the natural organic resources.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1999.06a
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• pp.137-159
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• 1999

Over the last three decades, Korean farming system has been directed to maximum agricultural production and to increase farmer's income through adoption of high-yielding crop varieties and high input of agrochemicals . These farming practices have resulted in problems of water-quality deterioration, soil degradation , and food safety. At present, over 40 million tones of animal waste are bing produced annually, which amounts to disposing the waste at the annual rate of 20 tones per ha in the total area of farming land in Korea. Nearly a half of total available water resources is used as irrigation water predominantly for rice paddy field. Thus, non-point source contamination of the water resources has been linked to agriculture across the nation. However, the extent to which agriculture contributes to the water quality is not fully known. Recently, Korean government provided various institutional measures to reduce the negative impacts of agricultural practices on the environ ental quality, and the Agricultural Environment Act was also passed by the legislature in 1998 and became effective January 1999. This Act does not cover the broad spectrum of the sustainable agriculture ; thus, the limited incentives within this Act are arguably ineffective to control the non-point source pollution. Recently new bulk blending of fertilizers(BB fertilizer) are bing produced (100, 000 tones in 1998) with Government subsidies. The BB fertilizers are to balance N-P-K ratio in the soils . Although the use of the BB fertilizers are encouraged with Government subsidies, non-point source pollution is still serious and will become worse. Precision farming is regarded as a new means for sustainable agriculture. It is a new technology that modifies the existing techniques and incorporates new one such as GIS, GPS , differential applicator to produce a new set of tools for the farmer to use. Precision farming, however, has constraints for individual farming practices. For exam le , farm size or parcel unit of each farmer is too small to adopt the precision agriculture on farmhouse-hold bases and farmer's ability to adopt the new technology is limited. However, it would be appropriate to establish local or regional cooperatives to operate such a precision farming system. It is recommended that Government provide sufficient incentives to help establish local and/or regional cooperatives.

• Applied Biological Chemistry
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• v.20 no.2
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• pp.255-261
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• 1977

Using tracer technique of Zn-65, a pot experiment has been carried out in order to evaluate the efficiency of zinc fertilization on two paddy soils; an acidic from Kimpo and an alkaline from Yeongweol. The sources of zinc were zinc sulfate, zinc carbonate, zinc chloride and zinc oxide. Two rates of zinc were applied to the soils and control treatment was also included for this study. The methods of zinc application were uniform mixing throughout the soil, applying to the soil surface and irrigation water, and root dipping with zinc oxide at transplanting. In general, Yeongweol soil had higher efficiency of zinc fertilizers than Kimpo soil. The results showed that zinc fertilizer application should be required to improve the rice growing conditions in Yeongweol soil especially at early stage of growth after transplanting. As to the application method of zinc fertilizers, mixing treatment appeared to be most superior to any other methods in both soils. In addition, it is found that root dipping in the zinc oxide suspension would be a rather effective method of zinc application. In aspect of fertilizer efficiency there was no superiority or inferiority among the zinc sources used in this experiment.

• The Korean Journal of Mycology
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• v.22 no.2
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• pp.172-183
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• 1994

The productions of arbuscular mycorrhizal fungal(AMF) spores were observed by adding three different commercial fertilizers on AMF inhabiting soils. Various morphological features, vesicles, arbuscles, sporulations of spore, and flower-like-structures, were also found in the mycorrhizal roots during 80 days after transplanting. Spore prodcutions of the employed AMF were observed to be periodically increased with the intervals of 40 days. Sorghum, green onion, hot pepper, and wild legume plants were appeared to be a good plant for productions of AMF and as the host of AMF. The productions of AMF spores was inversely related to phosphate fertilizer, and also observed to be low in the plant pots added with whole balanced fertilizers.

• The Korean Journal of Mycology
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• v.22 no.2
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• pp.160-171
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• 1994

Microscopic observations of arbuscular mycorrhizae (AM) were done with the colonizations of AM and the determinations of chitin in the plant roots of Sorghum bicolor, Cassia mimosoides, Capsicum annuum and Allium fistulosum. The intercellular and intracellular hyphae, arbuscules and vesicles were microscopically observed, according to increases of colonization of AM in the roots of four plants. The growth of AM fungi appeared sigmoid with the cultivation days after inoculation. The growth of AM fungi were inversely influenced by the additions of commercial fertilizers, P

• Korean Journal of Soil Science and Fertilizer
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• v.49 no.2
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• pp.194-199
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• 2016

In an experiment conducted at the research field of the National Institute of Agricultural Science, we investigated the effects of mineral fertilizer and rice straw compost on exchangeable potassium and K balances, and rice grain yield under a rice single system. The treatments were no fertilization (No fert.), inorganic fertilization (N), inorganic fertilizer (N, P, K) plus rice straw compost at rates of 7.5, 15.0, 22.5, and $30.0ton\;ha^{-1}$ (NPKC7.5, NPKC15.0, NPKC22.5, and NPKC30.0, respectively). The inorganic fertilizers(N, P, K) were added with standard fertilizer application rate in which nitrogen (N), phosphate ($P_2O_5$), and potassium ($K_2O$) were applied with $75{\sim}150kg\;ha^{-1}$, $70{\sim}86kg\;ha^{-1}$, $75{\sim}86kg\;ha^{-1}$, respectively. Exchangeable potassium for NPKC15.0 NPKC22.5, and NPK30.0 treatments was higher by $0.05{\sim}0.19cmol_c\;kg^{-1}$ than that of NPKC7.5 treatment. Increasing levels of rice straw compost resulted in an increase in the K balance from - $19.9kg\;ha^{-1}yr^{-1}$ (No fert.) to $41.9kg\;ha^{-1}yr^{-1}$ at NPKC22.5 treatment and $62.9kg\;ha^{-1}$ at NPKC30.0 treatment. Continuous application of rice straw compost with NPK fertilizers affected significantly the rice grain yields. The result of the study imply that the application of more than $22.5ton\;ha^{-1}$ of rice straw compost with NPK fertilizers are recommended as the best fertilization practice for enhancement of crop production and K supplying power of soil in the continuous rice cropping system.