In studies of soil moisture flux in the arid, alluvial basins of Nevada, drilling technologies have been developed to easily and economically install 15-cm diam. steel casing to depths of up to 100 m. Laboratory and field calibration of a low source strength (3.7 X 10(8) Bq or 10 mCi) neutron moisture meter was carried out to determine the impact of such large casing on tool performance. Both laboratory and field tests showed that a quadratic calibration equation relating returned thermal neutron counts (N) to the volumetric water content (theta) of the form N = b0 + b1 0 + b2 02 was acceptable to determine soil profile water content. The density of thermal neutrons returned to the detector was considerably reduced when compared to reported fluxes in traditional small diameter aluminum access pipe. This reduction is attributed to the increased air gap between the tool and the soil, and neutron capture by the steel casing.
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页码
v.890-892(3)
其它主题
Normalizacion; Caract morfologicas suelos
语言
英语
注释
references.
类型
Journal Article; Journal Part
来源
Soil-Science-Society-of-America-journal (USA). (May-Jun 1988). v. 52(3) p. 890-892.
团体作者
AgRISTARS Program (USA). Lyndon B. Johnson Space Center (USA).
2012-11-15
AGRIS AP