Measurement of soil moisture

IGKV CET JRF Physical Science

Measurement of soil moisture:

• Indirect method (on the basis of tension):

a. Tensiometer/irrometer:

• Tensiometers ale sensitive up to 0.85 bar of soil moisture
• Suitable for sandy soil in which most of the available water
below 1 bar tension.
• Not suitable for clay soil.
• Tensiometers are vrAN.7 useful in scheduling irrigation to
frequently irrigated crop.

b. Electrical resistance/bouyoueous moisture meter/gypsum
block:

• Based on conductivity of electricity low resistance at field
capacity and high at PWP
• Gypsum block perform satisfactory measurement in dry soil
• Not suitable for saline soil as salt in soil increase
conductivity.

▪ It is used for measuring soil moisture tension up to 0-15 bar
and for scheduling irrigation of crops of delayed intervals.

C.Neutron moisture meter:

• Rapid method used for Field or in situ measurement of soil
moisture from large volume of soil based on the measurement
of number of 1-1+nuclei present in a unit volume of soil.
• This is best method at present available for quantities
estimation of changes in soil moisture. (ARS-05)

D . Pressure member and pressure plate apparatus:

• Used for laboratory measurement of soil moisture potential.
• Generally used for estimating FC, PWP and moisture content
at different pressures.
• Suitable for measuring soil moisture tension: 0-15 bar.

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