Depar tment o f AGRONOMY

Un ive rs i ty Co l l ege o f Agr i cu l tu re , Un ivers i t y o f Sa rgodha , Sa rgodha

Noraiz Hamid Umer Farooq Adnan Ashraf Malik Attique-Ur-

Rehman Sohaib Chattha Ali Raza

Group Member

Topic Name

Instrumental Methods to Measure Soil Moisture

Soil moisture is a key variable in controlling the exchange of water and heat energy between the land surface and the atmosphere through evaporation and plant transpiration.

As a result, soil moisture plays an important role in the development of weather patterns and the production of precipitation.

What is Soil Moisture?

Soil composition by Volume and Mass, by phase: air, water, void (pores filled with water or air), soil, and total. 

Water content or moisture content is the quantity of water contained in a material, such as soil(called soil moisture), rock, ceramics, fruit, or wood.

Soil Moisture Content

Physical and chemical properties of soil vary with moisture content.

Measurement of soil water content needed in every type of soil study.

Hydrology, agrology, plant science and

Civil engineering all require soil moisture data.

Instrumental Methods to Measure Soil Moisture

The feel method involves estimating soil-water by feeling the soil.

Feel Method

Soil moisture is determined by taking a soil sample from the desired soil depth, weighing it, drying it in an oven for 24 hours and 220 degrees F.

Then reweighing the dry sample to determine how much water was lost.

Gravimetric Method

Sealed, airtight, water-filled tube (barrel) with a porous tip on one end and a vacuum gauge on the other.

Tensiometer measures soil water suction (negative pressure), which is usually expressed as tension.

Tensiometer

Consists of two electrodes enclosed in a blocks of porous material.

Electrode are connected to insulated lead wires that extend upward to the soil surface.

Electrical Resistance Block

Uses a radiation source to measure soil-water.

An empty tube (access tube) with a 2-inch inside diameter must be installed vertically in the soil at each field location where the soil- water is to be measured.

Neutron probe

Works on the principle that a soil conducts heat in relation to its water content.

Be measuring the heat conducted from a heat source and calibrating the conductance versus water content for a specific soil, the Phene cell can be used reliably to determine soil-water content.

Phene Cell

TDR is a new device developed to measure soil-water content.

Two parallel rods or stiff wires are inserted into the soil to the depth at which the average water content is desired.

Time Domain Reflectometer

AQUAFLEX SOIL MOISTURE SENSOR AUGERS BENTONITE ENVIROPRO SOIL MOISTURE AND EC

PROBE These are less in usage.

Other instruments