SOIL MOISTURE ESTIMATION BY THE NEUTRON METHOD IN BRITAIN

THE PROCEEDINGS OF AN INFORMAL NEUTRON GAUGE USERS' MEETING, RESULTS OF THE COMPARISONS AND A CONDENSED ACCOUNT OF THE MAIN DISCUSSION POINTS ARE REPORTED. A SERIES OF THREE TEST PROFILES WERE PRESENTED TO COMPARE THE INTERFACE EFFECTS AND THE RESOLUTION OF THE DIFFERENT GAUGES. IN COMPARING RESULTS OF THE VARIOUS EQUIPMENTS, IT IS POINTED OUT THAT THE SOURCE/DETECTOR GEOMETRY OF THE EQUIPMENT SHOULD BE CONSIDERED. MOISTURE VOLUME FRACTION CURVES ARE PRESENTED WHICH APPLY TO THE PROBES AS THEY ARE MARKETED. PROBLEMS IN DEFINITIONS, CALIBRATION AND STANDARDS, FIELD EQUIPMENT AND EQUIPMENT DESIGN ARE DISCUSSED. IT IS CONCLUDED THAT THE MAGNITUDE OF THE EFFECTS OF SOIL CHEMISTRY AND BULK DENSITY ON THE CALIBRATION CURVE ARE UNDERESTIMATED BY MANY USERS WHILE OTHERS ARE SO DISCONCERTED BY THE PROBLEM THAT THEY TEND TO IGNORE IT AND HOPE FOR THE BEST. FOR THE MEASUREMENT OF ABSOLUTE MOISTURE, VERY LARGE MOISTURE DIFFERENCE CHANGES, OR MOISTURE CHANGES WHERE VERY HIGH ACCURACY IS REQUIRED, DETAILED FIELD OR THEORETICAL CALIBRATIONS OF EACH SITE ARE UNAVOIDABLE. NEUTRON SUBSURFACE MOISTURE GAUGES WILL CONTINUE TO BE IMPROVED, BUT PRESENT MODELS WHEN OPERATED WITH CARE AND UNDERSTANDING OF THEIR LIMITATIONS ARE PRODUCING EXCELLENT RESULTS.

• Supplemental Notes:
  • Vol 7, No 4, PP 415-433, 6 FIG, 2 TAB, 7 REF
• Authors:
  • Bell, J P
  • Mcculloch, J S
• Publication Date: 1969-4

Media Info

• Serial:
  • Journal Hydrology /Neth/

Subject/Index Terms

• TRT Terms: Alternatives analysis; Calibration; Definitions; Measuring instruments; Moisture meters; Nuclear radiation; Sensors; Soil water; Standards
• Old TRIS Terms: Radiation counters /sensors/
• Subject Areas: Geotechnology; Highways; Materials;

Filing Info

• Accession Number: 00216836
• Record Type: Publication
• Files: TRIS
• Created Date: Jul 7 1994 12:00AM