Some problems associated with the use of the neutron probe in swelling/shrinking clay soils
Jarvis, N.J.
Some problems associated with the use of the neutron probe in swelling/shrinking clay soils - 1987 - Printed
Comparisons of neutron probe count rate ratios measured at 10 cm depth, withbulk soil water contents measured 3-5 m away from the access tubes, confirmed that in swelling/shrinking clay soils, recharge may be overestimated. This is due to the drying soil shrinking from the access tube, creating an air gap and radial cracks which allow preferential re-wetting of the soil near the access tube. Installation of access tubes into dry soil was only a short-term answer. Comparison of results obtained for bulk soil and for small clods shows that calibrating the neutron probe using small diameter cores may lead to serious under estimates of changes in
English
Clay soils
Measuring instruments
Radiations
Shrinkage
Soil chemicophysical properties
Soil testing
Soil water content
Some problems associated with the use of the neutron probe in swelling/shrinking clay soils - 1987 - Printed
Comparisons of neutron probe count rate ratios measured at 10 cm depth, withbulk soil water contents measured 3-5 m away from the access tubes, confirmed that in swelling/shrinking clay soils, recharge may be overestimated. This is due to the drying soil shrinking from the access tube, creating an air gap and radial cracks which allow preferential re-wetting of the soil near the access tube. Installation of access tubes into dry soil was only a short-term answer. Comparison of results obtained for bulk soil and for small clods shows that calibrating the neutron probe using small diameter cores may lead to serious under estimates of changes in
English
Clay soils
Measuring instruments
Radiations
Shrinkage
Soil chemicophysical properties
Soil testing
Soil water content