Hydrological Observation on the Water Budget at the Cornfield in Northern Kyushu, Japan
Abstract
If global warming will proceed constantly, we may face the crisis of decreasing available water. To use limited water resource for agriculture efficiently, it is important to understand the hydrological cycle and to analyze the water budget in agricultural land. Although there are various factors related to hydrological cycle in agricultural land, it is not well known how these factors contribute to the process of hydrological cycle. In order to reply to this problem, we observed the components on the water budget at the feed-crop cornfield in northern Kyushu, Japan. The study cornfield is on the pyroclastic flow deposits upland at the foot of Mt. Aso caldera. The observation period is from May to August, 2007 that corresponds to the period between seeding and harvesting of the corn. When corns were harvested, they were about 2.5m tall. During three months growing periods, it is thought that the content of the water budget was different at each growing stage. As corns grew taller and taller, corn leaves intercepted rainfall more and more to prevent the direct free-throughfall to the soil surface because of shapes of corn leaves. For this study, we defined three water budget equations. They were based on 1) distribution of gross rainfall through the corn canopy, 2) components of evapotranspiration, and 3) water budget around the soil surface, respectively. Because these equations must be correlated each other, we could evaluate the interception and the fluctuation of soil water content which are related above three water budget equations. Also we observed the fluctuation of soil water content during rainfall-infiltration process by using the electrical resistivity tomography (ERT). We also evaluate the water budget during the whole period between seeding and harvesting by using the all monitored hydrological elements; gross rainfall, throughfall, stem flow, interception loss, surface evaporation, transpiration, soil water content, surface flow, and infiltration.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2007
- Bibcode:
- 2007AGUFM.H51C0640S
- Keywords:
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- 1818 Evapotranspiration;
- 1865 Soils (0486);
- 1866 Soil moisture;
- 1876 Water budgets