Innovations in Dryland Agriculture

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In the 2012 growing season, the application of deficit supplemental irrigation at
50 % CWR (353 mm rainfall + 162 mm irrigation) increased fruit yield by 2460 kg
ha−^1 (33 %) for Sorani and 3900 kg ha−^1 (96 %) for Jlout compared with the rainfed
treatment (Table 1 ). At 100 % CWR (353 mm rainfall + 325 mm irrigation), fruit
yield increased by a further 2030 kg ha−^1 (25 %) for Sorani and 1250 kg ha−^1 (13 %)
for Jlout. In terms of percentage oil extracted from fruit, Sorani produced the high-
est values when grown under 50 % CWR (24 %).
In the 2011 growing season, for 50 % CWR treatment, fruit yields increased by
as much as 113 % (4375 kg ha−^1 vs. 9360 kg ha−^1 ) when 115 mm of irrigation was
applied (in addition to 316 mm rainfall) to rainfed Sorani. A further increase of
2652 kg/ha (28 %) over 113 % achieved with 50 % CWR treatment, was achieved
by applying an additional 115 mm of irrigation (100 % CWR) in addition to the
rainfall. Year 2013 was wetter and hotter than 2012 and 2011. Yields of 50 % CWR
treatment increased by as much as 77 % (4836 kg ha−^1 vs. 8580 kg ha−^1 ) when
142 mm of irrigation was applied (in addition to 416 mm rainfall) to rainfed Sorani.
For the same cultivar, a further increase of 1404 kg/ha (16 %) was achieved by
applying additional 142 mm of irrigation (100 % CWR) in addition to the rainfall.
Presently, 695,711 ha are planted to rainfed olives in Syria. Based on the above
results, if 25 % of this area applies supplemental irrigation, yields will increase by
approx. 90 % for Jlout and 100 % for Sorani. At US$0.70/kg olive, this translates to
about US$646 million additional income for farmers growing Jlout and US$670
million for farmers growing Sorani.

2.2 Iraq

Wheat is one of the most important food crops in areas of West Asia such as in the
Kurdistan Region of Iraq (IKR). Bread (Triticum aestivum L.) and durum (Triticum
durum L.) wheat are cultivated in Kurdistan where consumption is high, and yields

Table 1 Results summary of research on supplemental irrigation of olive trees in Darra, Syria

Year Treatment

Water applied

(mm)

Olive yield (kg ha−^1 )

Water productivity (kg m−^3

applied)

Sorani Jlout Sorani Jlout

2011 100 % CWR 546 12,012 9282 5.18 4.03

50 % CWR 431 9360 7644 8.12 6.63

Rainfed 316 4375 – – –

2012 100 % CWR 678 11,076 9984 1.63 1.47

50 % CWR 515 9828 7956 1.91 1.54

Rainfed 353 7368 4056 2.09 1.15

2013 100 % CWR 700 9984 8892 1.42 1.27

50 % CWR 558 8580 7332 1.53 1.31

Rainfed 416 4836 4056 1.16 0.98

Supplemental Irrigation: A Promising Climate-Resilience Practice for Sustainable...