ABE 1- MODULE 5 Flashcards
-the controlled application of water to arable lands in order to supply crops with the water requirements not satisfied by natural precipitation (NEH, 1991)
-the application of water to soil for the purpose of supplying the moisture essential for plant growth (Hansen, 1979)
IRRIGATION
-the application of water to soil for any of the following purposes (Hansen, 1979):
- provide crop insurance against short duration crops
- cool the soil and atmosphere, thereby making more
-favorable environment for plant growth
- washout or dilute salts in the soil
- soften tillage pans and clods
IRRIGATION
-the artificial application of water onto a piece of cropland in sufficient amount and proper time to
promote a favorable rootzone environment and to supply the optimum plant water requirement for good growth and yield
IRRIGATION
-a manmade water management system, which is required to fulfill the water demands of the crop during
less rainfall
-designed to maximize efficiencies and minimize labor and capital requirements
IRRIGATION SYSTEM
-consists of an intake structure or pumping station, a conveyance system, a distribution system, a field
application system, and a drainage system
IRRIGATION SYSTEM
-Soil type
-Slope and topography
-Climate
-Water (quality & quantity)
Natural conditions
Choosing an irrigation method:
-Natural conditions
-Type of crop
-Type of technology
-Required labor inputs
-Crop characteristics and compatibility
-Environmental requirements
Type of crop
never use sprinkler or drip method
high sediments
never use surface method and use overhead instead
high infiltration
never use surface method
high ET
never use sprinkler
strong wind
-Availability of the system
-Capital investment per capital per hectare
-Operation of the system (technical know-how)
-Maintenance of the system (technical know-how)
Type of technology
-Man-animal labor
-Man-machine labor
Required labor inputs
-Costs and benefits (financial)
-Previous experience with irrigation
-Social considerations
-Environmental considerations
water is applied on the soil surface (by flooding the entire area) and allowing the water to infiltrate in the soil
SURFACE IRRIGATION METHODS
- water is applied in the root zone
SUBSURFACE IRRIGATION METHODS
OVERHEAD IRRIGATION
1.watering can
2. hose pipe
3.Sprinkler
(drip or trickle)
MICRO IRRIGATION
-are horizontal, flat plots of
land, surrounded by small
dykes or bunds
-the banks prevent the water
from flowing to the
surrounding fields; water is
held in the basin at the
desired depth for the
required time
-commonly used for rice
grown on flat lands or in
terraces on hillsides
Basin
-the field to be irrigated is divided
into strips (also called borders or
borderstrips) by parallel dykes or
border ridges
-water is turned into each strip
through a head gate and flows
downhill the length of the strip
-requires that land be divided into
strips 10-20 m wide and 100-400 m
long
Border
-furrows are narrow ditches
dug on the field between the
rows of crops
-water runs along the
furrows as it moves down
the slope of the field narrow
ditch between row of plants
-widely used for row crops
Furrow/Corrugation
-water is flooded without much control
- usually used if there is excessive amount of water
Wild flooding
- Schemes of water distribution
- Rotational distribution
Schemes of water distribution
-water is supplied continuously to all the canals from the primary canal up to the farm ditches and the paddy fields
Simultaneous or continuous distribution
-the supply of water is rotated to the different areas of any of the following practices:
-rotation by section along the main canal
-rotation by section along the laterals
-rotation by section along the sublateral
Rotational distribution
Wherever or whenever water supplies are abundant, farmers are free to use water __________. The practice of supply at will is common in tropical and even in semi-arid countries during the rainy season – but is generally of little use in large-scale projects.
at will
If water is scarce, __________________, or ______________________is used to ensure equitable distribution. Where the flow pattern is
predictable and not too variable in the medium-term, say a few weeks, a common practice is to rotate the
flows among individuals or farmer groups.
-time sharing
-rationing
- water is applied in the root zone
SUBSURFACE IRRIGATION METHODS
natural subirrigation also known as…
(open ditches)