• Korean Journal of Soil Science and Fertilizer
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• v.51 no.1
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• pp.61-70
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• 2018

This study was carried out to review and compare crop cultivations upon chemical properties of paddy soil and qualitative characteristics of rice in Sejong-city from a point of view of farming extension to rice farmers and to utilize the result of the study as a basic guideline for precise agricultural practice. The pH in soils of Sejong was about 6.1-6.6 and had no difference with an average pH of paddy soils in Chung-Nam with pH 6.1. However, the average of organic matter, calcium (Ca) and available silicate in Sejong was lower than the average of them in Chung-Nam. The yields of rice were higher in 2010 than in 2011 and 2012, and the protein contents of rice were the highest in 2011 while the lowest water contents of rice in 2011. The protein contents upon regions were the highest in 2011 with 6.1%, and the amylose contents were the highest in Yeondong-myun, Jeoneu-myun, and Yeonseo-myun in 2010 while Kumnam-myun and Jeondong-myun were the highest in 2012. With the increase of precipitation, the protein content level in rice was increased while the amylose content level tended to decrease. Correlations between the chemical properties of paddy soil and the quality of rice and between level of organic matter in soil and amylose contents were negative (r = -0.507), and the correlation between the moisture contents and amylose contents (r = 0.419) and between the water contents and whiteness (r = 0.485) were positive. Because the quantity and quality of rice yield is determined by the soil characteristics, the consultation to farmers for the proactive soil analysis and for the maintenance of stable level of pH, organic matter and available silicate based on historical results of analysis is highly recommended. Also, the analysis on the effect of the weather and the soil characteristics affecting the quality and quantity of rice would be another good way.

• Korean Journal of Soil Science and Fertilizer
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• v.41 no.6
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• pp.415-418
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• 2008

The application of sludge wastes into agricultural fields has been increasing annually in Korea. In particular, sewage sludge application has been widely accepted in decades. Sewage sludge application aid in the recycling of essential nutrients and act as a source of organic matter improving the structure and water-holding properties of the soil. The efficient use of sludge wastes, however, requires an individual assessment of waste products. This study assessed the biological characteristics of organic waste-treated lysimeter soils and develop its indicator to assess the soil health of organic waste-treated lysimeter soils. Several analytical techniques more recently developed such as restriction fragment length polymorphism (RFLP), phospholipid fatty acid (PLFA), and community level substrate utilization (CLSU) fingerprints allow for detailed analyses of soil microbial communities. PLFA and RFLP was, therefore, used in the study to characterize the microbial communities in soil without the need to isolate individual fungi and bacteria. PLFA, RFLP and CLSU have been utilized to assess microbial characteristics of the lysimeter soils with four different sludge wastes for eight consecutive years. Each of these methods was analyzed for a different aspect of soil microbial characteristics. The study would disclose those methods yielded highly reproductive results for each soil and allow distinguishing the soils based on the structures of specific geneand PLFA-pools more than CLSU fingerprints. PLFA methods, especially, revealed the same relative similarities of the treated soils based on cluster analysis of the biological characteristics. Pig manure compost-treated soil, however, was only the same relative resemblance among the three methods. These results indicated that PLFA easily assessed the biological soil characterization.

• Agricultural and Biosystems Engineering
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• v.4 no.2
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• pp.45-49
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• 2003

Achievements in the real-time soil spectro-photometer are: an improved soil penetrator to ensure a uniform soil surface under high speed conditions, real-time collecting of underground soil reflectance, getting underground soil color images, use of a RTK-GPS, and all units are arranged for compactness. With the soil spectrophotometer, field experiments were conducted in a 0.5 ha paddy field. With the original reflectance, averaging and multiple scatter correction, Kubelka-Munk (KM) transformation as soil absorption, its 1st and 2nd derivatives were calculated. When the spectra was highly correlated with the soil parameters, stepwise regression analysis was conducted. Results include the best prediction models for moisture, soil organic matter (SOM), nitrate nitrogen ($NO_3-N$), pH and electric conductivity (EC), and soil maps obtained by block kriging analysis.

• Korean Journal of Weed Science
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• v.30 no.3
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• pp.258-265
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• 2010

The effects of organic-compound fertilizer on weed control and rice growth in the transplanting rice cultivation were researched in this article. The results showed that the growth of transplanted rice was promoted (the increased rate was 10.3~27.2%), but the plant number for Echinochloa crus-galli was controlled (the inhibition rate was 50.3~89.2%), besides, small amount of organic-compound fertilizer in controlling Aneilema keisak was highly effective when the transplanted rice was treated with 125~250 kg $10a^{-1}$ organic-compound fertilizer. Moreover, E. crus-galli, Monochoria vaginalis and A. keisak were inhibited largely by increasing the water depth (1~5 cm), whereas Eleocharis kuroguwai and other sedges weeds were not effected by water depth. Compared with the temperature of $20{\sim}35^{\circ}C$, the plant occurrence of E. crus-galli and M. vaginalis at high temperature was inhibited (the inhibition rate were 75.4~92.2% and 49.5%~81.6%, respectively). When the transplanted rice was treated with the above organic-compound fertilizer after 10day, the inhibition rate of plant occurrence for E. crus-galli and M. vaginalis was 33.7% and 23.3%, respectively. Similarly, in the later period of rice growth, the plant height and the numbers of tiller grew slowly in conventional soil in comparison with the soil treated with organic-compound fertilizer. It has been found that the rice yield in experimental soil was decreased by 4%. This result in the field experiment showed that organic material contents in conventional soil were lower than that in soil which used the organic-compound fertilizer. Weed control in experimental soil showed 60.5% lower effects than that in conventional soil.

• The Korean Journal of Ecology
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• v.23 no.5
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• pp.369-375
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• 2000

Although urban soils must be well understood in order to ensure their conservation and optimum use, these intensively managed and disturbed soils have not been extensively investigated up to now. Urban soils from forest, lawn, streetside, and bare ground and under pavement in Inchon had high bulk density as a result of widespread trampling-induced soil compaction. The various urban soils including forests showed lower water content and higher temperature as compared with rural forest soil. Chemically, soils from urban areas had an unusual neutral pH and low organic matter content. Total bacterial numbers in urban soils was only 5∼50% of that in the rural forest soil. An analysis of stepwise multiple regression revealed that soil organic matter was the most important predictor variable on total bacterial number. The dehydrogenase activity of most urban soils was not significantly different from that of rural forest soil, whereas the microbial activity of soils under pavement was lower. Our investigations show that inadequate organic matter of highly compacted soils has adversely affected the abundance of microorganisms involving nutrient cycling in urban soils.

• Journal of Plant Biology
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• v.7 no.2
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• pp.1-8
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• 1964

Cha, Jong Whan (Dept. of Biology, Graduate School, Dong Kuk Univ.) The changes of chemical properties of forest soils in dry and wet seasons. Kor. Jour. Bot. VII(2): 1-8, 1964. Soil selected for the present investigation was collected from a mountain of the Forestry Experiment Station of the vicinity of Seoul. The forest communities studied were three forest and a unplanted soils. The soil samples were obtained from each forest type during dry and wet seasons. And these samples were collected from four horizons of all communities respectively. It was showed that exchangeable hydrogen was increased by rainfall, and total exchangeable base decreased in the same way. The content of nitrogen is washed away by rainfall, especially ammonium nitrogen was highly significant between dry and wet season. On the contrary, organic matter and available phosphorus were of no significant difference between dry and wet seasons. The values of pH appeared a different response in dry and wet seasons according to the plant communities. The needle-leaved forest soils showed more acidity than the broad-leaved forest soils, and the least acidity in open places. All nutrients in soil studied gradually decreased down the profiles. According to statistical analyses of the soil components among all soil horizons, total exchangeable bases in wet season indicated only significant at 1%. Exchangeable hydrogen and organic matter of the soil in dry season was particularly very low with increased depth in the profile. The fertility level of most forested soils selected for the present investigation is low according to chemical tests for available nutrient elements.

• Korean Journal of Soil Science and Fertilizer
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• v.28 no.3
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• pp.241-248
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• 1995

This experiment was conducted to obtain basic information for the management of soil and fertilization for plastic-house soil cultivated Khwari green pepper in Dang Jin area of Chung Nam Province. The range of pH with highest frequency for 36 sites investigated was 6.1~6.5, OM 1.6~2.5%, available phosphorous 601~800mg/kg, CEC 12.1~14.0 c mol/kg, clay 16.1~18.0% and below 2.0ds/m for electical conductivity of soil. Fesh fruit weight of green pepper showed very high significant positive correlation with organic matter, clay content and cation exchange capacity, while negaive correlation with electrical conductivity. Electrical conductivity showed highly significant negative correlation with CEC, clay content and organic matter in soil, respectively. To decrease below 2.0 dS/m of electrical conductivity in plastic-house soil, the content of clay and organic matter could be maintained at above 1.8% and 2.3%, respectively.

• Korean Journal of Environmental Agriculture
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• v.4 no.2
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• pp.71-77
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• 1985

Soil samples collected from paddy field adjacent to zinc-mining sites were sequentially extracted to assess chemical fractions of Cd, Zn, Cu and Pb. The purpose of this study was two fold; (i) to examine the chemical forms of heavy metal in soils by sequential extraction. and (ii) to determine relationships between the chemical distribution of heavy metal in the soil and the heavy metal content of the brown rice. The results are summarized as follows. The content of exchangeable, organically bound and carbonate Cd and residual Zn was 73.9% and 63.8% of total Cd and Zn in the soil, respectively. The content of exchangeable Cd, Zn and Pb in soil showed highly negative correlations with pH, organically bound Cd, carbonate Cd, sulfide Cd, Zn and Pb in soil showed highly positive correlations with pH. The content of organically bound Cd, Zn, Pb and carbonate Cu in soil showed highly positive correlations with organic matter content, while the content of sulfide Cu and residual Cd in soil showed highly negative correlation with organic matter content. The content of carbonate Cd, Zn, Pb and residual Cu in soil showed highly positive correlations with CEC, but the content of exchangeable Cd, Zn, Cu, Pb and organically bound Cu in soil showed highly negative correlations with CEC. The content of total, organically bound, carbonate, sulfide and residual Cd in soil were highly correlated with that of Cd in brown rice. The content of any Pb fractions in soil were not correlated with that of Pb in brown rice. The content of water soluble and exchangeable Zn in soil were highly correlated with that of Zn in brown rice.

• Korean Journal of Soil Science and Fertilizer
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• v.18 no.2
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• pp.134-139
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• 1985

This study was designed to understand the relationships among the soil physical and chemical properties and to obtain the useful regression to calculate the cation exchange capacity, field capacity, wilting point moisture content and organic matter content. Fourteen soil properties were collected from 315 representative soil series in Korea. Simple and multiple regression were analyzed with the data by grouping land use, drainage class and soil depth. The multiple regression equations which can be calculated the cation exchange capacity from clay and organic matter content were found out. Cation exchange capacity of clay was 22me/100g, and that of organic matter was 103.3me/100g. Moisture retentions, both of wilting point moisture content and field capacity, were closely related to clay and organic matter content. The coefficient of clay was increased with drainage class changed more poor but the coefficient of organic matter was highest at moderately well drained soil. Organic matter content can be calculated by soil texture and pH. Organic matter content was decreased by in creasing the pH. The highly significant regressions were found between base saturation and pH.

• Korean Journal of Soil Science and Fertilizer
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• v.12 no.1
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• pp.35-41
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• 1979

A study was conducted to investigate the status of organic phosphorus in soils originated from different parent materials and under different uses(Virgin, rice soil, upland). The results are summarized as a following. 1. Regardless of parent materials and land uses, the contents of different forms of organic phosphorus are in the order of unidentified organic-P>Inositol-P>Sugar-P>Lipid-P. 2. In case of Inositol-p, the contents were in the order of rice soil>upland>virgin soil. 3. The contents of Sugar-P and Lipid-P in cultivated soils are higher than in uncultivated soil. 4. RNA and DNA are not identified in any soil when detected by ultra-violet absorption method. 5. There is highly significant correlation between the content of soil organic matter and that of organic phosphate. However, there is remarkable difference in the pattern of correlation between cultivated soils and uncultivated soils. 6. Comments were made on the factors on plant availability of various organic phosphorus.