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      • 湖南地方의 畓土壤特性과 水稻收量性에 關한 硏究

        蘇在敦 圓光大學校大學院 1980 學位論叢 Vol.5 No.-

        Studies were conducted to investigate the morphological and physico-chemical characteristics of wetland rice soils occurring in Honam area, and to find out a method for the evaluation of productivity of wetland rice soils by relating the observed soil characteristics with the experimentally obtained rice yield data. The results are summarized as following. 1. Morphological characteristics of wetland rice soils in Honam area. ˚ Topography: Rice soils occur mostly in flat plain(40.3%), local valley of hill or mountain(21.2%), and local valley of low hills(24.2%). The remainder occurs in river site(1.3%), low undulating terraces(4.8%), and low flat plain(8.2%). ˚ Slope distribution: Alomost of the wetland rice soils are found in slopes of less than 7%(0-2%;44%, 2-7%;38.7%). Around 17% of total rice soils are found in the areas with the slope of 7-15%. In the areas with 15-30% slope, only 0.7% of total rice soils are found. ˚ Soil parent materials: More than 55.7% of wetland soils are derived from local alluvium. Remainders are derived from fluvio-marine deposits(20.9%), alluvium(17.7%) and marine deposits(2.7%). ˚ Available soil depth: More than 70% of wetland rice soils have the available depth of more than 100cm. Sizeable area of them have the available depth of 20-50cm. There are soils with even less than 20cm of available depth. ˚ Soil drainage: Most widely occurring is the imperfectly drained soils(59.8%). The remainders are classified as moderately well drained (28.0%) and poorly drained(12.2%). 2. physico-chemical characteristics of wetland rice soils. ˚ Soil texture distribution: Major soil texture families are fine loamy(38.2%), coarse loamy(35.1%) and fine silty(l4.5%). ˚ Soil reaction: Most of the soils being distributed in the range of pH 5.0-6.5, in general, no problem is expected due to soil pH. However there are the soils of which pH is lower than 5.0(2.7%) and higher than 7.0(1.8%), In these soils, it is expected that the productivity of soils can be increased by correcting the pH through proper means. ˚ Organic matter contents: Majority(66.3%) of rice soils contain 2-3% of organic matter; similar to country average. However, 25% of rice soils are found to be too low in organic matter contents(2.0%). No soils with too much organic matter are found in this area. ˚ Cation exchange capacity: It is found that the cation exchange capacity of rice soils occurring in the area is generally lower than that of country average. In majority of them(71.3%), the cation exchange capacity is lower than 1Ome/100g. ˚ Exchangeable cations and base saturation ratio: In case of exchangeable Ca, the average figure being 4.5me/100g, no difference from country average is found. However, the exchangeable Mg shows unique distribution pattern. In the soils distributed in coastal and plain regions, exchangeable Mg contents are relatively higher than in other regions. Exchangeable K is high in coastal and plain regions and low in mountainous region. The soils with 60-80% of base saturation ratio occupy around 48.1% of total rice areas. In some parts of coastal region, there are the soils with the base saturation ratios of 80-100%. ˚ Available phosphate: It is found that the average content of available phosphate is high enough for rice cultivation in general. However, in 13.2% of total rice soils, available phosphate is lower than 30ppm, which is considered not to be sufficient for the elevated yield of rice. ˚ Available silica: The distribution pattern of available silica is rather peculiar; In about 28.5% of soils the available silica content is 40-70ppm, while in another 30.8% of soils it is more than 130ppm, and the remainder(40.7% of soils) is evenly distributed in the ranges of 70-100ppm and 100-130ppm. 3. The relationships between the soil characteristics and rice yield. ˚ Morphological characteristices and rice yield; Rice yield is generally high in the local valley of low hills and low in river sites. This fact is also reflected in that with the yield of rice is higher in the lands with 2-7% of slopes than in the lands with 0-2% slopes. It is found that the available soil depth influences the yield of rice strikingly. On the soils with the available depth of less than 20㎝ the yield is extremely low. However, if the available soil depth is more than 50㎝, there is no significant difference in yield along with the increase of depth. It seems that the drainge status of soils does not influence the yield of rice if the drainage grades are in the range of moderately well to poor. However, the highest yield is observed in imperfectly drained soils. Soil parent material also influences the yielding potentials of rice soils. The highest yield is observed in the soils derived from local alluvium and lowest in soils derived from marine deposits. In Honam area where the light textured soils prevail, it is observed that the heavier the texture, the higher the yield of rice. It is also observed that in soils with extremely high in silt content the rice yield is relatively low. ˚ Chemical characteristics and rice yield: The chemical characteristics have more clear relationship with rice yield are organic matter content, CEC and available silica content. Other factors such as soil pH, contents of exchangeable cations and base saturation ratio do not show significant correlations with the yield of rice. Between the organic matter and available silica contents and CEC and rice yield, there are positive correlations, while between the pH and base saturation ratio and rice yield, although no significant statistically there are trends that the higher the pH(above 7.0) and the higher the base saturation ratio(above 80%), the lower the yield of rice. 4. Suggestion of a soil productivity classification method for wetland rice soils and evaluation of productivity of rice soils of Honam area. ˚ Derivation of soil productivity index. A new approach was made to derive a soil productivity index(PI), using the relative yield contribution coefficients(RC) and the relative suitability ratings(RR) of individual soil characteristics, as shown in following equation. ◁수식 삽입▷ (원문을 참고하세요) ˚Evaluation of soil productivity of rice soil in Honam area. Using the soils productivity index suggested above, the productivity classification for the soils occurring in Honam area in tried. The result shows that out of 138 soil units(mapping units), 34, 58, 32, and 14 soils are found to be in the productivity classes of I, II, III, and IV, respectively. It is also found that in Honam area, as a whole, the soil factor of lowest suitability rating is CEC. In coastal region low organic matter content and low CEC of soils should be considered at the first place to elevate the productivity of rice soils. In other regions, CEC is the lowest suitability factor.

      • KCI등재

        갈대사상(砂床) 여과법을 이용한 축산폐수정화 : Ⅰ. 처리일수 및 계절별 변화 Ⅰ. Retention Period and Seasonal Variation

        김종구,소재돈,김선관,이덕배,강종국,이경수 한국환경농학회 1994 한국환경농학회지 Vol.13 No.2

        축산폐수의 경제적 정화기술을 개발하고자 砂床濾過漕(모래층 20㎝+자갈층 30㎝)에 갈대를 재배한 뒤 혐기발효된 양돈폐수의 투입 1, 3, 5, 7일 후 정화 효과를 계절별로 분석한 결과는 다음과 같다. 1. 축산폐수 처리일수가 길수록 갈대에 의한 질소 및 인산의 흡수 이용량이 많아지고 근부에서 발생된 산소로 BOD, COD도 낮아져서 정화 효과가 향상되었다. 2. 갈대의 건물생산량은 7일 처리가 가장 높았고 양분흡수량도 처리기간이 경과할수록 중가하는 경향이었다. 3. 갈대사상여과조는 사상여과조 보다도 오염 물질제거율이 높아 여름의 경우 T - N : 30%, PO₄^(-3): 37%, COD : 42%, 부유물은 30% 더 높은 정화율을 나타내었다. 4. 계절별 축산폐수정화율은 여름철이 가장 높고 가을, 봄 순이었다. A reed-sand-filter system was used to purify swine wastewater economically. Reeds (Phragmites communis Trin) were planted on the sand / gravel bed of a 20/30㎝ layer depth. After the input of waste-water up to a depth of l0㎝, the effluent was monitored for pollutants on the 1st, 3rd, 5th and 7th day thereafter. As swine wastewater stayed longer, the pollutants in the effluent such as T-N, PO₄^(3-), COD and BOD were removed more effectively. The sand-filter system with reeds showed a superior removal efficiency to that without reeds. Especially in summer, the former showed greater purification rates than the latter, being 30% greater in T-N, 37% in PO₄^(3-), 42% in COD and 30% in suspended solids. The seasonal purification efficiency was in the decreasing order of July, October and April. Reeds took up 40.1g N, 10.8g P₂O_5, 38.9g K₂O, 2.8g CaO, 2.1g MgO per square meter of the above surface area.

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