土壌の物理性
Online ISSN : 2435-2497
Print ISSN : 0387-6012
73 巻
選択された号の論文の9件中1~9を表示しています
  • 太田 健, 谷山 一郎, 草場 敬, 森 昭憲, 荒谷 博
    1996 年 73 巻 p. 3-10
    発行日: 1996年
    公開日: 2021/12/02
    ジャーナル フリー
    In hilly and mountainous areas, many terrace paddy fields have been abandoned due to lack of the successor to the farmer, difficulty of irrigation and so on. To clarify the changes of the soils after abandoned, the terrace paddy fields that were 3,12 and 20 years after farmers give up cultivation were investigated. The neighboring cultivated paddy fields, as the controls, were also investigated in Ohshima village, Niigata prefecture. The soil three years after abandoned had little differences in soil morphology and property compared with the control. In the cultivated paddy fields, the soils were classified into Gley or Gray Upland soils. On the well-drained sites (dominated by Miscanthus sinensis), the soils 12 and 20 years after abandonment had been desiccated and classified into Brown Forest soils. The surface (plow) and subsurface (plowsole) layers of these soils had changes in soil color from reduced gley or gray to oxidized brown and had weakly developed granular structure. In contrast, the soils 12 and 20 years after abandoned on the poorly drained sites (dominated by Phragmites communis) were classified into the same taxa as the controls. Basic intake rate, hydraulic conductivity and macro pore were increased, and exchangeable bases were decreased with the years after abandoned in the surface and subsurface layers of the soils on the welldrained sites. There, however, were not significant differences in these properties of the soils on the poorly drained sites. After abandoned, soil morphological features and physical properties were remarkably changed on the well-drained sites. The changes of the soils have been influenced by microtopography and drainage conditions.
  • 谷川 寅彦, 矢部 勝彦, 福田 勇治, 衣裴 隆志
    1996 年 73 巻 p. 11-18
    発行日: 1996年
    公開日: 2021/12/04
    ジャーナル フリー
    This study was conducted to make clear the groundwater environment and the influences to the vegetation of forest land under the subway construction. The former was investigated by using the distributions of water table and. the cross sections. The latter was investigated by using the daily fluctuations of soil moisture tension in the planting site of higher trees and the observations of growth along the subway construction. Consequently, the groundwater environment was not influenced so much by the shield tunnel-ing of the subway construction, but much influenced by the excavation works. Because the excavation works are considered to cause the sudden change of groundwater environment. On the other hand, the sudden change of ground water influences to the soil moisture environment of the vegetation, so it is found that much higher dead trees and higher weakened trees were observed along the route of the excavation works.
  • 張 玉龍, 郭 玉文, 加藤 誠, 安富 六郎
    1996 年 73 巻 p. 19-24
    発行日: 1996年
    公開日: 2021/12/04
    ジャーナル フリー
    This report describes the change of soil water properties of SHENYNAG Agricultural Universi-ty Experimental Farm for 6 months, from May to October in 1993. In order to study the properties, soil moisture suction was measured in the depth of 10 cm, 20 cm, 30 cm, 50 cm and 70 cm from ground surface at 6 : 00 PM every day. After the soil suction in the farm was measured, soil samples were obtaind in the each depth from ground surface. Soil moisture characteristic curves were determined by soil moisture external method and the soil gravity and the soil grain size distribution were measured from the samples. By scaling the data of each soil moisture characteristic curves , scaling factors were calculated. The following results were obtained : (1) The water retentivity was influenced by not only the depth but also soil properties, for examples, the grain size distribution and the dry density. (2) Rainfall during summer in 1993 was ordinary level. Rainfall of some months were very different from the normal year. Conditions in the soil water were very good for the growth of some vegetables in the field. (3) The soil layer in the depth of 20cm and 30cm was very important for the vegetables growth, while it was found that the soil water supply layer under the 30 cm was also important. (4) Soil moisture extraction pattern in the field was classified in all layer soil moisture extraction pattern.
  • 三原 真智人, 中川 英, 安富 六郎, 成岡 市, 穴瀬 真
    1996 年 73 巻 p. 25-30
    発行日: 1996年
    公開日: 2021/12/04
    ジャーナル フリー
    The objective of this study is to investigate the effect of soil structural changes on raindrop erosion processes. Disturbed and undisturbed soils are sampled in embanked slope of Memanbetu, Hokkaido. According to the results of raindrop erosion test, splash ratio decreased after the repetition of freezing-melting process. Soil saturated hydraulic conductivity increased after the repetition. It was concluded that percolation mechanism is important to understand the raindrop erosion processes. Percolation volume was simulated on the bases of rheological properties of percolated suspen-sion and pF-moisture distribution curves. Results of the simulation represented observed changes in permeability due to the repetition of freezing-melting process in this study.
  • 平野 繁, 田辺 猛
    1996 年 73 巻 p. 31-35
    発行日: 1996年
    公開日: 2021/12/04
    ジャーナル フリー
    The relationship between change in soil structure induced by application of cow’s compost and yield of paddy rice was investigated in 1/2000 a pot trials. Three fertilization treatment were set up by compost application at the rate of 100%,50% or 0%,and adjusted to the total concentration of three major nutrients (NPK) with application of chemical fertilizer. Compost application gave considerable increase in rice yield. The increase in rice yield can be explained by the following effects. One was slower mineralization of compost than chemical fertilizer, hence, the nutrient-absorption pattern of rice in this situation increased yield. The other effect was the decrease in the solid phase of the soil induced by compost application. This study showed the difficulty of dividing the effects of compost application into chemical and physical effects.
  • K.L. Zhang, K. Hosoyamada
    1996 年 73 巻 p. 37-44
    発行日: 1996年
    公開日: 2021/12/04
    ジャーナル フリー
    本研究では,人工模擬降雨の実験のもとに,傾斜度がシラス土におけるリル間侵食に及ぼす影響が検討された。リル間侵食の変動および表面流出の発生を評価するために,強度が62mm/hrである降雨を実験槽に30分間与え。斜面傾斜度は6°,9°,12°, 15°, 20°の5種類の実験を行った。結果として,6°の斜面の他は,いずれの斜面においても,流亡土,流出水ともに降雨実験の最初の10分間に急に増加し,実験経過時間の後半では,12°, 15°, 20°の傾斜度において,流出水が実験の経過にほぼ無関係に一様に発生するが,流亡土の方は傾斜度によって異なることが認められた。流亡土および流出水と傾斜度の関係を見ると,いずれも三次元の関係式が導かれ,変動の傾向が異なることが指摘された。ここで行った実験条件の場合では,流出水は15°付近でピークに達して,更に増加すると,減少することがみられた。しかし,流亡土が傾斜度の増大に伴って増加し,特に9°から15°までの間に顕著な増加の傾向があり,15°を越えると,流亡土の増加は減衰する傾向が現れた。
  • 花山 奨, 中野 政詩
    1996 年 73 巻 p. 45-52
    発行日: 1996年
    公開日: 2021/12/04
    ジャーナル フリー
  • 松川 進, 富田 平四郎, 鈴木 敬
    1996 年 73 巻 p. 53-58
    発行日: 1996年
    公開日: 2021/12/04
    ジャーナル フリー
  • 取出 伸夫
    1996 年 73 巻 p. 59-61
    発行日: 1996年
    公開日: 2021/12/04
    ジャーナル フリー
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