Soil Moisture Limits for Plant Growth
Soil Moisture Limits for Plant
Growth
Field Capacity
The
soil moisture content at which all the gravitational water has been drained out
of root zone. Usually the moisture content at 1/3 atmosphere tension is
considered to be field capacity that is usually to be attained approximately 2
to 3 days after irrigation.
Permanent Wilting Point
The
moisture content at which plant roots cease to extract soil moisture is called
permanent wilting point. Usually the soil moisture contents at 15 atmospheres
are considered to be permanent wilting point.
Available Moisture
The
difference in moisture content between field capacity and permanent wilting
point is considered available moisture. This is the moisture which plant can
utilize without going through stress and is given by the question.
Available Moisture = Field Capacity – Permanent Wilting Point
Net Available Moisture
It
is the difference in moisture content between the field capacity and actual
moisture when irrigation is to be applied under MAD (Management Allowed
Deficit). It is equivalent to the amount of moisture consumed by the plant
which must be replenished during irrigation application.