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3.8 Deficit Irrigation and Crops Production
Several studies have been done in Egypt on the assessment of deficit irrigation
effects on crop productivity, as well as the amount of saved irrigation water.
3.8.1 Effect of Deficit Irrigation on Winter Crops
3.8.1.1 Wheat
Skipping the last irrigation event for wheat at flowering stage cultivated in clay soil
under surface irrigation resulted in high yield losses fluctuated between 28% for cv.
Misr2 and 7% for cv. Misr1 (Elhag 2017). Abdelkhalek et al. (2015) indicated that
skipping the last irrigation applied for wheat in loamy clay soil under surface irrigation resulted in 12% saving in the applied water, with 6% yield losses. Ouda et al.
(2007) indicated that skipping the last irrigation for wheat at maturity stage reduced
yield by 13%, whereas this percentage was reduced to 7% under spraying MgCO 3
as an anti-transpirant compound during vegetative stage and skipping the last irrigation at maturity stage.
Taha and Ouda (2016) indicated that application of deficit irrigation to wheat
grown in sandy soil under sprinkler system and fertigation in 80% of irrigation time,
where 11% saving in the applied water resulted in 2% yield losses. Whereas, fertigation in 60% of irrigation time resulted in saving the same amount of irrigation
water with higher yield losses, namely 8%. The low percentage of yield losses under
fertigation in 80% of irrigation time was resulted from increasing fertilizer use efficiency. Furthermore, Abdelraouf et al. (2013) indicated that application of 75% of
wheat water requirements under sprinkler irrigation in sandy soil resulted in only
3% reduction in wheat yield as a result of applying 100% of NPK via fertigation
pump. This technology resulted in reduction in fertilizer leaching, and improved
plants growth and reduced yield losses.
Noreldin et al. (2015) tested the effect of reducing the applied irrigation water by
25 and 20% to wheat irrigated with either drip or sprinkler systems, respectively
grown in sandy soil. They found that wheat yield was reduced by 20 and 18%,
respectively. Because these yield losses were high under either system, they simulated the effect of reducing only 10% of the applied water under either system on
wheat yield using CropSyst model (Stockle et al. 1994). Under these circumstances,
yield losses became 3 and 4%, under drip and sprinkler systems respectively.
Abdrabbo et al. (2013) indicated that saving 20% of the applied water to wheat in
clay soil resulted in 8% yield losses under clay soil. Karrou et al. (2012) revealed
that application of 78% of full irrigation of wheat grown in clay soil under surface
irrigation resulted in 5% yield losses.
Simulation of deficit irrigation effects was also done. Ouda et al. (2015) simulated the effect of deducting 5% of full irrigation of wheat with fresh water
3 Egypt Faces Water Deficiency, and Food Insufficiency
3.8 Deficit Irrigation and Crops Production
Several studies have been done in Egypt on the assessment of deficit irrigation
effects on crop productivity, as well as the amount of saved irrigation water.
3.8.1 Effect of Deficit Irrigation on Winter Crops
3.8.1.1 Wheat
Skipping the last irrigation event for wheat at flowering stage cultivated in clay soil
under surface irrigation resulted in high yield losses fluctuated between 28% for cv.
Misr2 and 7% for cv. Misr1 (Elhag 2017). Abdelkhalek et al. (2015) indicated that
skipping the last irrigation applied for wheat in loamy clay soil under surface irrigation resulted in 12% saving in the applied water, with 6% yield losses. Ouda et al.
(2007) indicated that skipping the last irrigation for wheat at maturity stage reduced
yield by 13%, whereas this percentage was reduced to 7% under spraying MgCO 3
as an anti-transpirant compound during vegetative stage and skipping the last irrigation at maturity stage.
Taha and Ouda (2016) indicated that application of deficit irrigation to wheat
grown in sandy soil under sprinkler system and fertigation in 80% of irrigation time,
where 11% saving in the applied water resulted in 2% yield losses. Whereas, fertigation in 60% of irrigation time resulted in saving the same amount of irrigation
water with higher yield losses, namely 8%. The low percentage of yield losses under
fertigation in 80% of irrigation time was resulted from increasing fertilizer use efficiency. Furthermore, Abdelraouf et al. (2013) indicated that application of 75% of
wheat water requirements under sprinkler irrigation in sandy soil resulted in only
3% reduction in wheat yield as a result of applying 100% of NPK via fertigation
pump. This technology resulted in reduction in fertilizer leaching, and improved
plants growth and reduced yield losses.
Noreldin et al. (2015) tested the effect of reducing the applied irrigation water by
25 and 20% to wheat irrigated with either drip or sprinkler systems, respectively
grown in sandy soil. They found that wheat yield was reduced by 20 and 18%,
respectively. Because these yield losses were high under either system, they simulated the effect of reducing only 10% of the applied water under either system on
wheat yield using CropSyst model (Stockle et al. 1994). Under these circumstances,
yield losses became 3 and 4%, under drip and sprinkler systems respectively.
Abdrabbo et al. (2013) indicated that saving 20% of the applied water to wheat in
clay soil resulted in 8% yield losses under clay soil. Karrou et al. (2012) revealed
that application of 78% of full irrigation of wheat grown in clay soil under surface
irrigation resulted in 5% yield losses.
Simulation of deficit irrigation effects was also done. Ouda et al. (2015) simulated the effect of deducting 5% of full irrigation of wheat with fresh water
3 Egypt Faces Water Deficiency, and Food Insufficiency