Hydro-geomorphological study for the formation of soil water chemistry in hilly grassland within small watershed

小流域丘陵草地土壤水化学形成的水文地貌研究

• 批准号: 16500654
• 负责人: YAMAMOTO Hiroshi
• 金额: $ 1.98万
• 依托单位: National Agricultural and Bio-oriented Research Organization
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2004
• 资助国家: 日本
• 起止时间: 2004 至 2005
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-16500654/
• 关键词: Hydrological landform; Formation of water chemistry; Watershed; Soil water; Grazing pasture; 硝酸態窒素; 草地; 放牧; 火山

To reduce the nutrient outflow from mountain pasture, it needs to know the hydrological processes and chemical material transport within a watershed. The aim of this research is to clarify the variation of soil water and the formation of water chemistry on the landforms of hilly grassland within a small watershed. Experimental watershed was selected in a pasture of research station of NILGS, Nagano, Japan. Soils are Andisols. We traced the soil water condition and the nitrate-nitrogen content on convex ridge slope and concave valley bottom in the watershed. Soil water condition was measured by using tension meters as the matric potential. Water samples were collected by porous cup method.Rainwater on the ridge slope mostly infiltrated into soil. The gradient of matric potential is large between the layers of 20cm depth and 50cm depth. This shows the soil water moved laterally at the 20-40cm deep layer on the ridge slope. Matric potential of soil water on the valley bottom increases into deeper soil layers. Due to the high hydraulic conductivity and the abundant macro pore of valley bottom soil the soil water from surrounding areas accumulates and the water percolates into deeper soil-horizons.Nitrate-nitrogen concentration was below 1 mgN/L on the ridge slope. The concentration on the valley bottom was high over several mgN/L. The concentration increases almost linearly along the valley bottom in the fertilizer-applied area and decreases exponentially in the un-fertilized section. Along the valley bottom the increase of soil water pH also occurs. Thus the nitrogen decrease suggests that the denitrification processes within the valley-bottom reduce the concentration of nitrate-nitrogen.These results indicate that the nitrate-nitrogen accumulates into the valley bottom accumulated through the downward movement process from the 20-40cm deep zone of ridge slope in the fertilized area.

为了减少山地牧草的养分外流，需要了解流域内的水文过程和化学物质的运输。本研究的目的是阐明小流域丘陵草地地貌土壤水分的变化和水化学的形成。实验流域选择在日本长野NILGS研究站的一个牧场。土壤是土。对流域内凸脊坡和凹谷底的土壤水分状况和硝态氮含量进行了追踪。采用张力计作为基质电位测量土壤水分状况。水样采用多孔杯法采集。垄坡上的雨水大多渗入土壤。20cm ~ 50cm层间基质电位梯度较大。说明土壤水分在垄坡20 ~ 40cm深土层呈横向移动。谷底土壤水分的基质势向更深的土层增加。由于河谷底部土壤的高导水率和丰富的宏观孔隙，使得周围土壤水分积聚，并向较深的土层渗透。山脊坡面硝态氮浓度低于1 mgN/L。谷底浓度高达几mgN/L以上。在施肥区，浓度沿谷底几乎呈线性增加，而在未施肥区，浓度呈指数下降。沿着山谷底部，土壤水分pH值也会增加。因此，氮的减少表明谷底的反硝化过程降低了硝酸盐氮的浓度。这些结果表明，硝态氮从施肥区垄坡20 ~ 40cm深区通过向下运动过程积累到谷底。

项目成果

草地の土壌保全機能とその活用・回復

草原水土保持功能及其利用与恢复

• 发表时间: 2004
• 期刊: 日本草地学会誌 50(2)
• 作者: 黒木貴一;磯望;後藤健介;宗建郎;山本博;山本博;藤田 伸二;山本博;Shinji Fujita;山本博
• 通讯作者: 山本博

Characteristics of mountainous slope grasslands and Sustainable management

山坡草地特征及可持续管理

• 发表时间: 2004
• 期刊: Grassland Science 51(1)
• 作者: KANO;Shunpei;YAMAMOTO;Hiroshi;SAITO Yoshimitsu;KIDO Kyoko
• 通讯作者: KIDO Kyoko

草地の土地保全機能とその活用・回復

草原土地保护功能及其利用与恢复

• 发表时间: 2004
• 期刊: 日本草地学会誌 50・2
• 作者: 後藤健介;黒木貴一;磯 望;宗 建郎;百原 新(岡崎浩子ほか6名);山本 博
• 通讯作者: 山本 博

火山麓草地における地形曲率と地形構成物質の分布

火山脚草地地形曲率及地形成分分布

• 发表时间: 2004
• 期刊: 地形 25・3
• 作者: 黒木貴一;磯 望;後藤健介;宗 建郎;山本 博
• 通讯作者: 山本 博

火山麓草地における土壌中硝酸態窒素の低減

火山脚下草地土壤硝态氮的减少

• 发表时间: 2005
• 期刊: 土壌物理学会シンポジウム、第47回(講演要旨集)
• 作者: 黒木貴一;磯望;後藤健介;宗建郎;山本博;山本博;藤田 伸二;山本博
• 通讯作者: 山本博