Drainage and Drainage Properties of Soils
It is the removal of excess water, from the surface or below surface of farm land so as to create favourable soil conditions for plant growth.
Drainage Properties of Soils:
A soil may need artificial drainage for i) a high water table that should be lowered, ii) Removing excess water that cannot move downward.
Following properties of soils affects the artificial drainage-
A permeable soil seldom needs artificial drainage, except when the soil has a high water table.
Slowly permeable soils often needs artificial drainage, especially when the land surface is level and rainfall is high.
The texture or particle size affects pore size distribution. The finer the texture , the smaller size of pores and greater the need for artificial drainage.
Conversely, the need for removal of excess water by artificial drainage is reduced as particle sixe, increase from clay to silt to loam to sandy loam to sand.
3. Soil Structure:
The arrangement of soil particles, i.e soil structure affects the drainage properties of soil.
Soils having platy structure or aggregate with horizontal axis loner than vertical have poor drainage than granular structure.
Infiltration characteristics of soil surface greatly affects the drainage of soils, if infiltration rate of soil is poor we need artificial drainage.
5. Soil Colour:
Permeable soils that don’t require drainage are uniform in colours throughout the profile. Yellow sub soils usually intermediate permeability.
Grey clay sub soils in humid regions indicate very slow permeability that needs artificial drainage.