Abstract
Abstract The West Asia‐North Africa (WANA) region, with a Mediterranean‐type climate, has an increasing deficit in cereal production, especially bread wheat ( Triticum aestivum L.). Rainfed cropping coincides with the relatively cool, rainy winter season, usually from October to May. Cereal yields are low and variable in response to inadequate and erratic seasonal rainfall and associated management factors, such as lack of N and late sowing. In an area where water is limited, small amounts of supplemental irrigation (SI) water can make up for the deficits in seasonal rain and potentially produce satisfactory yields. This field study (1992–1993 to 1995–1996) on a deep clay soil (a Calcixerollic Xerochrept) in northern Syria was conducted for four growing seasons to assess the effects of SI (rainfed, 1/3, 2/3, and full irrigation) combined with N rate (0, 50, 100, and 150 kg ha −1 ) and sowing date (early, normal, and late) on one traditional (Mexipak 65) and three improved bread wheat cultivars (Cham 4, Cham 6, Gomam). Yields of rainfed wheat varied with seasonal rainfall and its distribution, with all main factors having significant effects. A delay in the sowing date from November to January consistently reduced yields and the response to both SI and N. With irrigation, crop responses were generally significant up to 100 kg N ha −1 , while optimum response for rainfed conditions was with 50 kg N ha −1 . An addition of only limited irrigation (1/3 full irrigation) significantly increased yields, but near maximum yields were obtained by 2/3 of full irrigation. Responses to N and SI were greatest for the higher‐yielding cultivars. Use efficiency for both water and N was greatly increased by SI. Thus, with minimum irrigation during the winter growing season combined with appropriate management, inputs, and varieties, wheat output could be substantially and consistently increased in the semiarid Mediterranean zone. Production functions developed from this dataset can help predict the effects of changing any of these parameters in other locations in the region.
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Claims 12
Claim · model-written summary
Rainfed wheat yields varied with seasonal rainfall and distribution.
- Taxon
- wheat
Triticum aestivume0 - Treatment
- seasonal rainfalle0
- Outcome
- Yields of rainfed wheate0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Yields of rainfed wheat varied with seasonal rainfall and its distribution”
Claim · model-written summary
The studied main factors significantly affected wheat yield.
- Taxon
- wheatTriticum aestivumt0
- Outcome
- significant effectse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“all main factors having significant effects”
t0“Wheat”
Claim · model-written summary
Delaying sowing from November to January reduced wheat yield.
- Taxon
- wheatTriticum aestivumt0
- Treatment
- Januarye0
- Outcome
- yieldse0
- Direction
- reducede0
- Comparator
- Novembere0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“A delay in the sowing date from November to January consistently reduced yields”
t0“Wheat”
Claim · model-written summary
Delayed sowing reduced wheat yield response to supplemental irrigation.
- Taxon
- wheatTriticum aestivumt0
- Treatment
- Januarye0
- Outcome
- response to both SI and Ne0
- Direction
- reducede0
- Comparator
- Novembere0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“A delay in the sowing date from November to January consistently reduced yields and the response to both SI and N”
t0“Wheat”
Claim · model-written summary
With irrigation, wheat response to nitrogen was generally significant up to 100 kg N ha −1.
- Taxon
- wheatTriticum aestivumt0
- Treatment
- 100 kg N ha −1e0
- Outcome
- crop responsese0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“With irrigation, crop responses were generally significant up to 100 kg N ha −1”
t0“Wheat”
Claim · model-written summary
Under rainfed conditions the optimum nitrogen response occurred at 50 kg N ha −1.
- Taxon
- wheatTriticum aestivumt0
- Treatment
- 50 kg N ha −1e0
- Outcome
- optimum responsee0
- Direction
- optimume0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“optimum response for rainfed conditions was with 50 kg N ha −1”
t0“Wheat”
Claim · model-written summary
One third full irrigation significantly increased wheat yield.
- Taxon
- wheatTriticum aestivumt0
- Treatment
- 1/3 full irrigatione0
- Outcome
- yieldse0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“limited irrigation (1/3 full irrigation) significantly increased yields”
t0“Wheat”
Claim · model-written summary
Two thirds full irrigation produced near maximum wheat yields.
- Taxon
- wheatTriticum aestivumt0
- Treatment
- 2/3 of full irrigatione0
- Outcome
- near maximum yieldse0
- Direction
- maximume0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“near maximum yields were obtained by 2/3 of full irrigation”
t0“Wheat”
Claim · model-written summary
Higher yielding cultivars responded most to nitrogen.
- Taxon
- wheatTriticum aestivumt0
- Material
- higher‐yielding cultivarse0
- Outcome
- Responses to Ne0
- Direction
- greateste0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Responses to N and SI were greatest for the higher‐yielding cultivars”
t0“Wheat”
Claim · model-written summary
Higher yielding cultivars responded most to supplemental irrigation.
- Taxon
- wheatTriticum aestivumt0
- Material
- higher‐yielding cultivarse0
- Outcome
- SIe0
- Direction
- greateste0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Responses to N and SI were greatest for the higher‐yielding cultivars”
t0“Wheat”
Claim · model-written summary
Supplemental irrigation increased water use efficiency.
- Taxon
- wheatTriticum aestivumt0
- Treatment
- SIe0
- Outcome
- Use efficiency for both watere0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Use efficiency for both water and N was greatly increased by SI”
t0“Wheat”
Claim · model-written summary
Supplemental irrigation increased nitrogen use efficiency.
- Taxon
- wheatTriticum aestivumt0
- Treatment
- SIe0
- Outcome
- Ne0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Use efficiency for both water and N was greatly increased by SI”
t0“Wheat”
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