第2次世界大戦以前に都市化が終了した中野区中央3・4丁目と,大戦前・後にまたがって都市化が進行した武蔵野市西久保の2地区において,都市化に対応した農民の土地供給形態と,その後,現在に至るまでの旧農民の土地所有と土地利用の変遷を比較した.戦前の住宅は主に借地上に建設されたため,中野区の農民は耕地を貸宅地に転換し,宅地地主となった.ところが,武蔵野市の場合,中野区と同様に終戦までに宅地地主に転じた農民も存在したが,終戦後も農業を継続していた約半数の農民は, 1960年前後から土地を切り売りしはじめ,やがて種々の不動産経営を展開するようになった.現在,両地区とも農業生産は消滅し去った市街地となっているが,旧農家の貸地上に宅地化が進展した中野区では高層・高密度化が進み,一方,武蔵野市では今なお旧農家が所有する駐車場などの土地がオープン・スペースを提供している.つまり,第2次世界大戦の前・後で農民の土地供給が貸地から土地売却へと変質した結果,戦前の都市化地域と戦後の都市化地域では市街地の土地利用パターンも著しい対照を呈するようになった.

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本研究では,農村不況期の青果物産地市場と産地仲買商人の動向を明らかにし,その動向が野菜の産地形成にいかなる影響を及ぼしたかについて検討を試みた.以下,概括すると次のようになる. A-1) 農村不況期の埼玉県北部農村では,繭価の暴落を補うべく野菜・果樹等の商品作物栽培が積極的に推進された. 2)その結果,土壌の理化学的性質の影響を強く受けて,利根川右岸の冬・春野菜地域と洪積台地の果樹,夏・秋野菜地域とが形成された. 3) 両野菜地域の発展に伴い,首都近郊農業地帯の外縁部に適合した独特の流通組織-産地市場の濃密分布と仲買商の集積-が成立した. B-1) 利根川右岸農村における養蚕経営の固定性と肥沃な土壌によって枠組みされた普遍的な経営類型,単純化された作物編成とが,結果的に生産の集中と特産地的性格をもつ濃密産地を形成した. 2) 一方,大正末期の村農会指導の販路拡大策の成果が生産意欲を刺激し,生産の増大は組合組織の市場設立を促し,村農会主管の共同出荷体制を仲買人の参加しやすい産地市場体制に移行させた. 3) 特産地型市場の季節性と相侯って,零細農民の仲買業務への参加が行なわれ,限られた耕地の多角的利用を必要としていた農家との間に,野菜栽培の発展をめぐり,相互補完的な関係が創り出された. 4) 産地市場体制の確立と仲買人の活動とは,出荷組織や交通手段が未発達で,かつ近隣の消費市場も未成熟であった昭和初期の野菜生産農家にとって,かなり効果的な生産拡大要因となった. 5) こうして,産地形成にとって不可欠の流通経済組織を確立した利根川右岸農村の野菜栽培は,おりから進行する地方軍需工業都市化や,東京の急速な膨張に伴う農産物市場の拡大に支えられて,品目的な多様化と栽培期間の通年化を変化の基調に据えながら,発展の過程をたどることになった.

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The present report aims at seeking a possible way to simulate the developmental process of channel networks through the geologic time. Firstly, problems regarding application of the stochastic branching process theory to the networks were briefly reviewed. Kirkby's (1976) conversion or mapping of a network to a path of a random walk was appreciated, but the definition of mapping was expanded for the sake of its application to all possible paths.
The total number of possible paths of 2 n steps is 2²ⁿ. Each path is represented by a binary string of 1's and 0's. In our model, when the walk returns to zero after some steps, a mapped drainage system finishes with its development and another new walk starts at that point. The paths which lie in the negative half-plane are regarded as the same in the positive just like as the reflected ones with the X-axis.
The very few walks only return to zero just after the 2 n steps. In this case, the area having n water sources (or n first-order channels) is divided to drainage basins, the number of which is equal to the times of return to zero in a path of 2 n steps. After the theorems of random walk it can be expected that the area will be divided to nearly _??_2n drainage basins with the most probability.
A great majority of the walks does not finish at zero after 2 n steps. In this case, distance from the X-axis at x=2 n indicates the number of active channels that have possibility to develop to the higher-order ones. Such channels are regarded as inflow channels from the outside to the preliminarily bounded area. All paths of random walk of 2 n steps are thus mapped to a full set of networks.
The theorem of unbiased random walk says that the probability that no return to zero will happen, or only once it will do, is highest, and that the probability becomes lower as the supposed times of return to zero increase. This means that with the most probability the preliminarily bounded area will be embraced by a bigger drainage system, or divided to one independent drainage basin and the remainder which forms a part of a bigger drainage system. This tendency was named as the law of oligopoly of drainage basin occupation.
Entropy defined after the information theory was discussed for the network systems. The cyclic systems have comparatively low entropy because of its limitation which gives the cyclic property to the developmental process of systems. Shreve's (1966) random system has lower entropy than the system which allows the area to be divided to some drainage basins. The system which allows inflow channels from the outside to the area has the maximum entropy because it has not any limitation on generating a new branch channel at each step. Limitation which keeps low entropy from the autogenetic increasing tendency should not be thought to result from the cyclic property or the restraint of a drainage network strictly to an .area, but if there is, it results from geomorphological reasons.
In conclusion, it will become possible to simulate the evolutional process of drainage systems as a branching process with a transition probability defined as a function of location (geologic control) and time (environmental change).

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