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...