PSS 1411 Irrigation Management
Why proper water management is essential
- a critical resource for sustainable agriculture - essential for agriculture, industry, domestic use - important component of environment with a significant impact on health and nature conservation
Sprinkler irrigation systems
- apply water through pressurized sprinkler heads - requires conduits (pipes) and pumps - common systems include: stationary sprinklers on risers and traveling overhead sprinklers
Flood, or furrow irrigation
- historical approach, remains widely used around the world - uses gravity flow and require nearly flat fields - generally inexpensive
supply problems of irrigation
- increased demand for irrigation - growing population - decreased availability of good-quality water
Cons of flood and furrow irrigation
- inefficient with respect to water use - associated with salinization concerns, as they can easily raise groundwater tables
Manual irrigation
- involves watering cans, buckets, garden hoses, inverted soda bottles, etc. - not suitable for large-scale agriculture - used in gardens and small-scale agriculture in underdeveloped countries
Subsurface drip irrigation systems
- lines and emitters are semi-permanently buried, tubing and emitters need to be close to the plant roots
advantages of drip/trickle irrigation systems
- main advantage: parsimonious use of water and the high level of control - relatively inexpensive, can be installed easily, use low pressure, low energy consumption
Changes in the planet make consistent water management evident
- rapid growth of population, increased irrigated agriculture, industrial development, and climate change - no "use and discard" methodology with water
drip, trickle irrigation systems
- use flexible or spaghetti tubing combined with regularly spaced emitters - can be surface or sub-surface
Pros/Cons of sprinkler irrigation systems
pros: more precise water application rates than flooding systems, and more efficient water use cons: require larger up-front investments and pumps use energy
increased irrigation efficiency
reduce water loss, reduce evaporation in fields, schedule irrigation based on soil moisture and plant needs, do not over-fertilize crops, control weeds that compete for water, time planting to take greatest advantage of natural precipation
Water sources
surface water, groundwater, and recycled wastewater
Economic problems
water rationing, increased cost of irrigation water, water available but not sufficient or available only at the wrong time
18% of irrigated cropland
40% of the world's food comes from...
71%
How much withdrawn freshwater is used for irrigation?
Irrigated fields yield more than dryland farms
U.S. avg. crop yields of irrigated farms > dryland farms (118% for wheat and 30% for corn)
Competing water demands
agriculture, residential, industrial/commercial use (i.e. bottled water for industry, tourism like hotels, fountains, golf, boating, etc.)
concerns with climate change
deficits and excesses of precipitation, increasing pressure for more irrigation and drainage
Efficiency of irrigation methods from least to most efficient
flood/furrow, sprinkle (center-pivot, wheel line), micro-irrigation (trickle/drip, above, below ground)
rivers and aquifers
Irrigation depletes
agriculture lands in southern and western U.S., other dry climates around the world, and horticulture crops in the U.S.
Irrigation is very important for the productivity of...