岡山大学環境理工学部 Acta Medica Okayama 1341-9099 13 1 2008 Neutralizing Capacity of Basic Slag in Acid Sulfate Soils and Its Impacts on the Solubility of Basic Cations under Various Moisture Regimes 67 74 EN Takeo Akae 10.18926/fest/12830 An incubation study was conducted with the topsoils (depth: 0-20 cm) of two different series namely Cheringa (silty clay loam, pHwater 3.6, electrical conductivity = EC 18.5 dS m-1, CEC 17.2 c mol kg-1, organic matter = OM 39.1 g kg-1, and Badarkhali (silty clay loam, pHwater 3.9, EC 19.0 dS m-1, CEC 18.40 c mol kg-1, OM 30.7 g kg-1) acid sulfate soils to evaluate the effectiveness of basic slag (BS) for the neutralization of acidity and solubility of basic cations. These soils received BS at the rate of 0, 11, 22 and 33 t ha-1 under various moisture regimes (moisture at saturated condition, i.e. 100 % moisture, moisture at field condition, i.e. 50 % and wetting-drying cycles of those 50 and 100 % moisture levels). The impacts of these treatments on some selected properties and changes in water soluble bases in these soils were studied at different periods of 180 days of incubation. The application of BS was found to be increased the pH of soils from 3.6 to 5.1 for Cheringa; 3.9 to 5.2 for Badarkhali soils during the 180 days of incubation. These increments were more striking with the highest doses of BS at 33 t ha-1 under saturated moisture conditions in both the soils. The EC of the soils had not much influenced by the application of BS, regardless of time. The treatments were exerted significant (p≤0.05) effects on the solubility of basic cations in different periods of incubation. The maximum release of the bases were recorded during 180 days of incubation under saturated moisture condition and the findings will be supportive for planning of crop production on these soils. No potential conflict of interest relevant to this article was reported.

岡山大学農学部 Acta Medica Okayama 0474-0254 86 1 1997 圃場整備における田園居住空間創出の事例的研究 79 86 EN Kinzo Nagahori Takeo Akae Seiroku Ohta Recently,the environmental situation of rural area has been being degrated.The farm land in Hikawa Town in Shimane prefecture has been sprawled because this area is located between Izumo City and Matsue City.A land Consolidation project conducted by Hikawa Town has a striking feature opposed to this situation.It respects the environment of agricultural production and the inhabitants'lives as well as landscape of the rural area.An integrated rural improbement plan was adoptde to solve all the problems involved.The results of the field research are summarized as follows:(1)To prevent the land sprawl,a large-sized land consolidation plan was adopted and the agricultural infrastructure was strengthened.(2)According to future estimated population decrease,a new settlement stabilization plan was adopted to accept both successors and newly arriving farmers who return from cities.In addition,the project aims to improve the amanity of the rural settlement and rural landscape by consolidation of parks and so on.(3)To debelop employment chances for stable inhabitants,an industrial area was allocated and industrial companies have been invited.(4)Important future issues to be solved are considered to be mainly concerning farming programs.These are adoptation of converted crops such as wheat and soy bean combined with rice as a main crop,the methodology of fertilizers,pesticides and herbicides,the introduction of new crops and highly-valued crops by taking advantage of reduced farming labor time,the establishment of a direct seeding method for rice,the fostering and stabilizing of farming associations,the training of agricultural machinery operators,and the stabilization and strengthening of the farming association's infrastructure. No potential conflict of interest relevant to this article was reported.

岡山大学農学部 Acta Medica Okayama 0474-0254 83 1 1994 斐川町地区用水路の住民による水辺環境機能の評価 53 64 EN Seiroku Ota Kinzo Nagahori Takeo Akae Toshikiyo Maekawa 用水路にどのような水辺環境機能があるかを調べるために,住民に対してアンケート調査を行った.アンケートは回答者の属性と用水路の機能項目の2つに大きく分けて質問し,結果をそれらの問のクロス連関を中心として分析した.また全部で18個の機能項目に関して,因子分析を行い,今回の調査では,住民は水辺環境に対して,景観整備機能,自然-親水機能,および生活的な利水-管理機能の3つの主要な機能要因を意識していることがわかった.また,これらの要因はアンケート結果の解釈の段階で,各機能項目に実際的な影響を与えていることが確められた.次に得られた主要な結果と,それらに対する整備の方針を述べる. (1)物を洗ったり,水を汲んだりする事が用水路利用と強く結びついている.農業従事者の58%,「水路へ毎日のように行く」人々の53%が「物を洗う」ことに「非常に機能している」と高い評価を与えた.農業地域では用水路の水辺環境機能として,「物を洗う」ことを重視し,水質の浄化をはじめとして,洗い場の数や配置等の具体的な問題では住民の意見を取り入れた整備計画が求められる. (2)用水路改修直後の原鹿地区では,「美観」,「水質浄化」および「危険管理」等の項目で他の地区に比較して,高い評価が与えられたが,一方「物を洗う」ことでは,やや低い評価であった.また「自然の生物に親しむ」や「散水」などの自然-親水機能では住民の評価は他の地区に較べて低調であった.水路の改修,新設に当たって,岸辺の構造やデザインに配慮を行い,自然-親水機能や水路へのアクセスが失われないようにすることが大切である. (3)砂川用水路では上流地区と下流地区で意識の違いが見られた.特に,下流部では,水路までの距離が「0-5m未満」の近距離居住者の中の30%以上の人が,「水質浄化」が「機能していない」と低い評価を与えた.今後は農業用水にとっての水質基準とともに,水辺環境に対する水質基準などの検討も必要である. 最後に,本報告では住民が自然-親水機能に対して,一定の強さの潜在的な関心を抱いている事を確認したが,現状では生活的な利水機能に較べて,自然-親水機能に対する評価は低調であった.ただ周りの丘陵的な自然に恵まれた出西高瀬川地区では自然-親水機能が比較的よく保全されていると考えられた.今日,自然への無関心や環境の悪化のために,水路から水辺環境が失われていくことが多い.したがって自然-親水機能に対する保全的で,計画的な整備が今後の重要な課題としてあげられる。 No potential conflict of interest relevant to this article was reported.

岡山大学農学部 Acta Medica Okayama 0474-0254 83 1 1994 土地改良区における維持管理の現状と課題 35 42 EN Kinzo Nagahori Takeo Akae Seiroku Ohta Land improvement districts originally started as organizations after World War II: They are in charge of construction and operation of irrigation and drainage facilities, Development of agricultural land, reclamation from sea water, reclamation by filling, Recovery from disaster, exchange and consolidation of agricultural land and so on. As the Main construction projects were completed, the purpose of land improvement districts Has shifted from facilities construction to operation and maintenance of them. However, the recent social situation has brought great changes in circumstance to land improvement districts. In both urban and agricultural areas around local cities, urbanization has progressed so rapidly and widely that agricultural land has decreased through conversion into urban use. That causes pollution of irrigated water and difficulties in maintenance of land improvement facilities. In rural moutainous areas, on the other hand, excess Depletion in population has occurred, causing difficulties in proper maintenance of Agricultural land and land improvement facilities, which eventually increases the danger of natural disaster. Also, in other agricultural areas, the decline in agriculture of this country has degraded the quality of the production and living environments. This work was conducted to analyze the present situations of land improvement Districts in differing geographical and social conditions, and to discuss the problems Surrounding them. Through such discussion, we pointout some possible remedies which Might improve the situation. No potential conflict of interest relevant to this article was reported.

岡山大学農学部 Acta Medica Okayama 0474-0254 83 1 1994 圃場整備における墓地移転の事例的研究 27 34 EN Kinzo Nagahori Takeo Akae Seiroku Ohta To modernize agricultural and rural areas, what is needed is not only infrastructure Improvement which enables mechanized farming, but also comprehensive improvement of inhabited areas. An agricultural land consolidation project should be planned to solve Both of these problems. Recently, in view of more effective land use, a larger scale land consolidation is orientated. In planning the project, houses and graveyards present here and there in the project area sometimes hinder ideal allocation of roads, channels and fields. Therefore, it is crucial in order for rational Planning, to obtain lots for non-agricultural use which enable those impeding objects to be shifted. One of the most feasible ways to obtain the lots is by making use of converted substitute lots in the process of the land consolidation project. In particular, removal of graveyards and reuse of former graveyard sites is sometimes Very difficult to handle, because they are subject to religious restrictions. In this paper, The authors investigated old customs and religious backgrounds of the graveyards in the Research area. Then they investigated the examples of successful treatment of the Converted substitute lots in shifting the graveyards. No potential conflict of interest relevant to this article was reported.

岡山大学農学部 Acta Medica Okayama 0474-0254 83 1 1994 圃場整備における非農用地創設の事例的研究 17 25 EN Kinzo Nagahori Toshikiyo Maekawa Takeo Akae Seiroku Ohta Modernizaion of rural regions and their agriculture is completed by a comprehensive rural project which includes both large scale farming land consolidation and improvement of rural settlement. The comprehensive project must include not only a settlement improvement project to match the settlement to her rich environmental nature, taking advantage of climatic, historical and cultural aspects, but also a project to develop comfortable modern institutions such as cultural education and welfare of the inhabit-ants. Furthermore, enhancement of economic and social activity is also needed, such as attracting technology factories for assuring the employment of the inhabitants, aiming to prevent the population from flowing out of the area. In accomplishing such a project successfully, larger converted substitute lots for non-agricultural use have been more keenly required than ever before. To convince the inhabitants of the necessity for establishment of converted lots and to obtain their cooperation, it is considered to be most important to investigate and develop a reasonable and understandable processing method. This study reports a successful example of converted substitute lots for non-agricultural use in the process of the agricultural land consolidation project which was conducted in Hikawa town, Shimane prefecture. The reasons for the success were analyzed in each case. In addition, some issues and countermoves are discussed for problems which are encountered in promoting converted substitute lots for non-agricultural use. No potential conflict of interest relevant to this article was reported.

岡山大学農学部 Acta Medica Okayama 0474-0254 73 1 1989 Practical Studies on Soil Conservation in Reclaimed Sloping Land : Establishment of Study Plots and Some Basic Soil Properties 35 44 EN Kinzo Nagahori Takao Amaya Manas Losirikul Tadashi Adachi Takeo Akae In order to control soil erosion in reclaimed sloping lands among the mountains, first of all the important thing in case of the establishment of plot for repeating various experiments may be the interrelated uniformity of a study plot. The location of a study plot is inside of the development project area where there consists of most general and average slopes. 　Due to the interior study plot was on the same slope and soil property, each of the divided A. B, C, and D sub-plots was thought of having the same conditions, and the aim of this experiment was to estimate whether the sub-plots could be regarded as an uniformity or not from their soil characteristics. 　Soil samples were collected at the upper-, middle-, and lower points of four sub-plots and mixed together so as to evaluate their properties at large. The samples were analyzed to clarify such soil physical properties as specific gravity, porosity, soil structure, particle-size distribution, water retentivity (pF), erodibility, and so on. We then made clear of the general soil characteristics as well as investigated their uniformity among four sub-plots from these obtained results. 　The results obtained can be summarized as follows : l) The soil of study plot is an undeveloped structure, low in degree of aggregation which shows resistivity toward dispersion action, and low in porosity of supporting Permeability and water retentivity. The pF values also substantiate these results. 2) Distribution of particle sizes indicates the property peculiar to Masa soil consisting of the uniform mixture of gravel to clay particles. 3) The study soil showed erodibility resulting from its high ratios of dispersion and erosion. Therefore, it was clarified that some proper erosion control practices have to be devised for the use of soil in the future and for agricultural activities. 4) According to the foregoing results, the differences in soil physical properties were not found among four sub-plots, thus they could be regarded as the same experimental plot and be used for carrying the further experiment. No potential conflict of interest relevant to this article was reported.