• Applied Biological Chemistry
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• v.44 no.2
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• pp.92-96
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• 2001

Soil physical-chemical properties and phosphorous adsorption characteristics were investigated to obtain the informations of the appropriate fertilization and soil management in Baicheng region, China, where agricultural circumstances at present forces to consider the use of land for crop production. Soils were collected from one uncultivated and three cultivated lands on August 1993. Soil $_PH$ was very higher in uncultivated land than in cultivated land, their values were 10.2 and 7.4, respectively. Regardless of cultivation, soil organic matter contents were below 2%, and concentrations of available soil phosphorus expressed as Bray 1 P and Olson P were less than 10 mg P $kg^{-1}$, however, cation exchange capacity was higher than 20 cmol(+) $kg^{-1}$. For uncultivated soil, the values of exchangeable sodium percent and calcium saturation percent were higher than 100%. The major cation of soil saturation paste extracts was Na regardless of land use type. Based on electrical conductivity and sodium adsorption ratio of saturation paste extracts, uncultivated soil was classified as saline-sodic soil and cultivated soil was classified as sodic or normal soil. The maximum adsorption capacity of phosphorus calculated by Langmuir isotherm ranged from 406 to 521 mg P ,$kg^{-1}$. The constraints of soils in Baicheng regions for agricultural cops werw high salt concentration, unfavorable soil chemical composition such as low concentration of available phosphorous, and poor drainage due to soil dispersion by high Na concentration. Therefore, the soil in Baicheng region, need the application of phosphorus fertilizer to increase the soil fertility and the proper soil management to improve the soil physical property especially permeability and soil structure.

• Korean Journal of Environment and Ecology
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• v.14 no.1
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• pp.38-45
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• 2000

This research has been done to investigate influence of soil physical and chemical properties on forest environmental change by fired pine forest in Koseong, Kangwondo. The sample sites were divided by not-fired sites(NF), not-cutting site after fired(FNC), cutting and planting sites after fired(FCP) and cutting and not-planting sites after fired(FC). Soil texture of whole sites was sandy clay loam. Sand content of NF top soil were lower than those of sub soil and clay content were higher, while FNC, FCP and FC sand content of top soil were higher than those of sub soil. Total porosity didn't differ between the sites. Coarse porosity and permeability had the increasing order as NF> FNC> FCP> FC, but fine porosity and bulk density had the opposite trends. Because forest fire removed the vegetation and then soil erosion was accelerated, forest environmental changes by forest fire greatly degraded soil porosity and permeability which were indices for forest water retention, so that soil physical properties were deteriorated. Both top and sub soil pHs of NF and FNC were higher than those of FCP and FC. Organic matter content and total nitrogen content of top and sub soils were high in order as NF> FNC> FCP> FC. Cation exchange capacities and exchangeable cation(K+, Na+, $Ca^2$+, $Mg^2$+) content in top soils were higher than those in sub soils, and in order as NF> FNC> FCP> FC, to be compared by the sites. Those mean that forest fire result from the erosion of top soil layers.

• Korean Journal of Soil Science and Fertilizer
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• v.34 no.2
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• pp.117-121
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• 2001

This study was carried out to investigate the effects of rice cultivation of no-tillage seeding on the physicochemical properties and rice yield in the paddy soil of Milk vetch (Astragalus sinicus L.) established. The number of Milk vetch establishment was 256 per $m^2$ in the before experiment but 440 per $m^2$ in the after experiment. The seed numbers of Milk vetch were sufficient that Milk vetch seed were not sown again in the next year. Soil physicochemical properties of the plot of Milk vetch cultivation were similar to the conventional plot. The amount of weed occurrence was 87g dry weight per $m^2$ in the conventional but not occurrence in the sowing of Milk vetch establishment. Rice yield was 4.9ton per ha in the conventional and 4.5 ton per ha in the soybean seeder sowing of Milk vetch establishment.

• Research in Plant Disease
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• v.12 no.2
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• pp.108-114
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• 2006

This study was conducted to elucidate the interactions among soil microorganisms in a special field where one, two or three of N, P, K fertilizers were continuously not applied for 29 years. Crop yield (barley, soybean), soil chemical properties and microflora and microfauna including nematodes, nematophagous fungi, actinomycetes, bacteria, and fungi were examined for two years. Tylenchorhynchus sp. was the most important plant-parasitic nematode (range $11{\sim}642/300 cm^3$ soil) followed by Pratylenchus sp. and Helicotylenchus sp. Among nematophagous fungi, Monacrosporium spp. was the most frequently found followed by Harposporium sp. and Cystopage sp. In general, plots treated with phosphate fertilizer yielded more, had more nematodes, bacteria and actinomycetes. In contrast, total fungal population densities including nematophagous fungi, Cystopage sp. and Harposporium sp. were in reverse; they were more abundant in the plots with lower phosphate contents. Phosphate and pH are positively correlated and two most important determining factors for the population density of soil organisms under investigation. According to correlation analysis, Ca, Mg, and $SiO_2$ contents in soil and population densities of Tylenchorhynchus sp., saprophitic nematodes, actinomycetes, and bacteria were positively correlated with pH, but were negatively correlated with fungal population densities. We hope that the study will add an additional knowledges to understand our mysterious underworld.

• Journal of Bio-Environment Control
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• v.13 no.1
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• pp.61-66
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• 2004

To investigate the effect of charcoal on the physico-chemical characteristics in the growing media and the growth of oriental melon, six treatment, 0%, 10%, 20%, 30%, 40%, and 50% charcoal, were added into the growing media, Baroker. The value of pH in the charcoal contained growing media (CGM) was recorded higher and further increased by raising the charcoal ratio and by growing period. In 20% CGM, the range of pH was adequate to grow crop as 5.2${\sim}$5.8. Contents of Ca and K in CGM increased by raising the ratio of charcoal, while contents of Mg and Na decreased. The growth of oriental melon seedlings in 20% and 30% CGM was better than in other treatments, in terms of fresh and dry weight of shoot, plant height, leaf area, lear width and relative growth rate. Both the physico-chemical properties of growing media and the growth of oriental melon seedlings were changed by the addition of charcoal. These results suggest that charcoal can be used as mixing material with other potting media for producing the seedling of good quality.

• Korean Journal of Soil Science and Fertilizer
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• v.40 no.5
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• pp.412-417
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• 2007

This study was to elucidate the effects of layered double hydroxides(LDHs) application on the chemical properties of the soils along with the fate of the applied LDHs. The effects of LDHs application were compared with those of calcium carbonate widely used for the neutralization of acidic soils. Incorporation of LDHs into the soil resulted in higher pH value and $Mg^{2+}$ content in soil leachate than that of $CaCO_3$ treatment. There was no significant difference in water-soluble P content in both the treatments. However, $Al^{3+}$ and $Si^{4+}$ contents were decreased by LDHs and $CaCO_3$ treatment, even though a large amount of $Al^{3+}$ was released into soil solution with the disintegration of LDHs framework. LDHs structure in soil was gradually disintegrated from the its original layered structure under acidic condition of soil. Therefore, this study suggests that LDHs could be utilized as a carrier of functional substances to enhance the efficiency of various ago-chemicals without any ill effects on the soil environments.

• Korean Journal of Soil Science and Fertilizer
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• v.34 no.4
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• pp.278-283
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• 2001

The overall objective of this research was to show a NIR soil analyzer assessing soil fertility by measuring soil properties rapidly. A total of 140 soil samples were used to obtain calibrations and validation estimating soil properties. The soil samples were ground to pass 0.2mm sieve openings. Partial least square regression analysis was used to develop a calibration for soil analysis. The results indicated that NIR soil analyzer could be used as a routine method for quantitatively determining pH, OM, total nitrogen, CEC, extractable Ca, Mg, K, available $SiO_2$ and soil moisture simultaneously within one minute. Therefore, the NIR soil analyzer may be suitable for quick estimation of soil fertility estimation in fertilizer assessments.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.45 no.3
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• pp.167-170
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• 2000

This study was conducted to investigate the changes of potato growth and soil properties in highland mounding-soil. Experimental plot was designed with control, chemical improvement and zeolite+chemical improvement plots. Mounding-soil was low in organic matter and phosphate contents, and that soil texture was loamy sand soil. The growth and yield of potato were highest in the zeolite treatment plot. Yield of that increased by 3.7% than control plot. Increasing ratios of potato tubers decreased at 60-70 days after planting. Increasing ratio of zeolite plot was higher or than other treatment plots. After harvesting, the contents of soil organic matter increased by 12-125%, and those of phosphate were by 29-73% respectively. The manurial value of fused and superphosphate was higher than that of potassium chloride.

• Journal of the Korean Society of Tobacco Science
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• v.13 no.1
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• pp.74-81
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• 1991

This study was conducted to find out physical and chemical characteristics of burley and flue-cured tobacco leaves followed by location, growing season and leaf position during the period 1985 to 1989. The locations of flue-cured tobacco were 7(65farms) and burley tobacco were 4(40 farms). 1. Flue-cured tobacco leaves The locations of Ch'unch'on and Suwon were higher nicotine and ether extract content, Taegu and Chinju were higher total nitrogen content but Chiniju was lower red color of cured leaves than that of other location. Nicotine content increased but total sugar content decreased during the period 1985 to 1989. Nicotine and total nitrogen content increased but crude ash decreased from lower leaf position to higher leaf position. Total sugar and ether extract content were variable followed by leaf position. 2. Burley tobacco leaves. The location of Ch'onju was higher ether extract content than that of others location, but there was no significant difference the others chemical component among location. Nicotine content and red color of cured leaves increased during the period 1985 to 1989. Nicotine, total nitrogen and ether extract content increased but decreased crude ash content and brightness of cured leaf from lower leaf position to higher leaf position.

• Journal of the Korean Society of Tobacco Science
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• v.21 no.1
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• pp.10-16
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• 1999

Leaves harvested were separated with visual characters into 2 classes such as immature and mature leaves. In the curing process, the prolonged yellowing treatment during yellowing stage was automatically controlled at the different stalk position, and condition of curing process after this period was all the same with conventional ones. In case of prolonged yellowing in immature leaves, increase of price per kg reached to 8 % compared with those of conventional ones. In physical properties, filling capacity and shatter index was decreased with the degree of maturity, and it was equal level in filling capacity of immature leaves between curing method, while shatter index was decreased in prolonged yellowing treatment than that of conventional ones. There was no difference in chemical components between immature leaves of prolonged yellowing and conventional ones. As to the prolonged yellowing of immature leaves, there was decreased in citric and malic acid contents of the nonvolatile organic acids, and it was equal level in all higher fatty acids content of leaves cured by prolonged yellowing treatment compared with in that of conventional curing method. The contents of key compounds such as solanone, damascenone, damascone in the essential oil were lower in prolonged yellowing of immature leaves than those of mature leaves cured by conventional ones.