.
Furrow
irrigation is not the most efficient irrigation method, but it is cheap and
low-technique.
Probably
one of the oldest methods of irrigating fields is furrow irrigation, where
farmers flow water down small trenches running through their crops. It is one
type of flood irrigation. Early man did not have any mechanized
spray irrigation systems
On
the one hand, less water is lost to evaporation than in spray irrigation, but
on the other hand, more water can be lost from runoff at the edges of the
fields.
After use, much of this
water cannot be reused because so much of it evaporates
and transpires in the fields.
Here are some things that farmers are doing
to be more efficient:
1.
Leveling of fields: Furrow irrigation uses gravity to
transport water, and, since water flows downhill, it will miss a part of the
field that is on a hill, even a small hill. Farmers are using leveling
equipment, some of which is guided by a laser beam, to scrape a field flat
before planting. That allows water to flow evenly throughout the fields.
2.
Surge flooding: Traditional flooding involved just releasing
water onto a field. In using surge flooding, water is released at prearranged
intervals, which reduces unwanted runoff.
3.
Capture and reuse of runoff: A large amount of
furrow-irrigation water is wasted because it runs off the edges and back of the
fields. Farmers can capture the runoff in ponds and pump it back up to the
front of the field where it is reused for the next cycle of irrigation.