• Irrigation - artificial application of water to soil throughout the crop period to assist in the production of crops
• Irrigation water is supplied to supplement the
water available from rainfall and ground
water.'
• In many areas of the world, the amount and
timing of the rainfall are not adequate to
meet the moisture requirements of crops.
• The pressure for survival and the need for
additional food supplies are causing the rapid
expansion of irrigation throughout the world.
Why Irrigation? Advantages of Water
Resource Development & Irrigation Facilities'
• Increase in food production
• Ensuring optimum growth in the field
• Elimination of mixed cropping
• Generation of Hydroelectric Power
• Inland Navigation
• Flood and Draught Control
• Soil Conservation
• Artificial Recharge of Ground Water
• Inter-basin transfer
• Domestic & Industrial Water Supply
Explanation
• Increase in food production – Exact quantity
required can be supplied as different crops
have different water requirements and the
same crop may have different water
requirements at different places, depending
on the variations in climate, types of soil,
methods of cultivation, useful rainfall etc.
• Ensuring optimum growth in the field –
Maximum yield is obtained only when sufficient
required quantity is supplied and the
corresponding moisture content is called as
Optimum Moisture Content.'
Elimination of Mixed Cropping –
Farmers have a tendency to cultivate more than one type of
crop in the same field such that even if one dies without the required amount of water, at least he would get the yield of the other. This reduces the overall production of the field.
• With assured water by irrigation, the farmer would go for only a single variety of crop in one field at anytime, which would increase the yield.
Please note that mixed farming and mixed cropping are being
used interchangebly in irrigation engineering. (REFER CLASS
for clarity in both definitions)
Domestic and industrial water supply – Some
water from the irrigation canals may be utilized for domestic and industrial water supply for nearby areas.
• Flood Control –
Provision of various techniques
such as flood cushioning, embankments and
dykes, flood plain zoning, flood proofing etc.
Generation of Hydroelectric Power –
Various Dams, Reservoirs and Multipurpose Projects
generates hydroelectric power. It is a clean,
renewable & reliable energy source.
• D ra u g h t C o n t r o l – Promoting S o i l
conservation, water harvesting practices,
minimization of evaporation losses, and
development of ground water including
recharging
Demerits of Irrigation
• Over irrigation may cause water logging which
reduces crop yield. The roots of most plants
require oxygen for respiration. Hence, full
saturation leads to restricted growth. Exception is
rice, jute etc. which requires standing water for
its growth and supply of oxygen to the roots is
made from leaves.
• Irrigation may lead to creation of conditions
which is favourable for the spread of diseases
like dengue and malaria.
• Irrigation may lead to seepage of nitrates into
the ground water table
