Agriculture Reference
In-Depth Information
Fig. 3.6
Lysimeter and cen-
ter pivot irrigation rig
Irrigation Management
The Problem of Water Scarcity and Resources
Irrigated agriculture is a major consumer of water, accounting for about two thirds
of the total fresh water diverted to human uses (Fereres and Evans
2006
) (Fig.
3.6
).
The predicted climate change coupled with increasing number of drought events
for many areas of the world is exacerbating the problem of water scarcity (Petit
et al.
1999
; Anon
2001
; Luterbacher et al.
2006
). The rising demands on water re-
sources and limited availability makes water an increasingly valuable commodity.
This is true for several southern regions of the U.S., such as Texas, which is heavily
dependent on underground water resources. In Egypt, where farming is confined
to less than 3 % of the total land area near the Delta, irrigation is mainly based on
pumping of the Nile water from Lake Nasser and mixing it with underground water
(Mason
2003
). A much more complex scenario occurs in central and southern-des-
ert areas of Israel, where the main water source for vegetable irrigation comes from
a combination of water reservoirs, saline water, recycled sewage water and more
recently, desalinated water.
Water Conservation and Deficit Irrigation
Water conservation and crop water-use efficiency (WUE) is a matter of great con-
cern among researchers, vegetable growers and government agencies. The WUE
in the agricultural sector has been improving by the use of drought tolerant culti-
vars and by the utilization of efficient cultivation and irrigation practices (Chaves
et al.
2003
; Condon et al.
2004
). The development of drip or “trickle” irrigation in
Israel during the 1960's together with the adoption of the plasticulture technology
on raised beds have been two major technological “milestones” for vegetable pro-
duction. These systems are now widely used for fresh market vegetable production
