Page 48 - soil-plant-water relationship and water requirement

SOIL-PLANT-WATER RELATIONSHIP AND WATER REQUIREMENT

Main concerns of irrigation
 How to apply
 How much to apply
 When to apply

5.1.2 Benefit of Irrigation

Irrigation development has played a key role in

 Strenghtening economy
 Increasing employment opportinities
 Self sufficiency in food production
 Raise a crop where nothing would grow otherwise
 Grow a more profitable crop
 Increase the yield and/or quality of a given crop
 Increase the aesthetic value of a landscape

Other Benefits of Irrigation

 Leaching of salts
 Wind erosion control
 Multiple cropping during an year
 Provides jobs
 Reduces risk of crop failures
 Improve socioeconomic conditions

5.2 CROP WATER REQUIREMENT

Crop Water requirements means that water is supplied for its survival, growth,
development and to produce economic parts. In other words, crop water requirement
is total water demand for growing a crop. This requirement is applied either naturally
by precipitation or artificially by irrigation.

The crop water need (ET crop) is defined as the amount (or depth) of water needed to
meet the water loss through evapotranspiration

The crop water need mainly depends on
o The climate
o The crop types
o The growth stage of crop

Crop water requirement includes all losses like:

 Transpiration loss through leaves (T)
 Evaporation loss through soil surface in cropped area (E)

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