M N; B GH; K D; A A; H D; A T
Abstract
In order to evaluate the role of a limited irrigation and agronomic management scenarios on improving yield and rain water productivity (WP) of rainfed wheat, a field study was conducted at multiple farms of Honam (Lorestan Province) in the upper Karkheh River Basin (KRB), Iran. The calibrated and validated ...
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In order to evaluate the role of a limited irrigation and agronomic management scenarios on improving yield and rain water productivity (WP) of rainfed wheat, a field study was conducted at multiple farms of Honam (Lorestan Province) in the upper Karkheh River Basin (KRB), Iran. The calibrated and validated AquaCrop model was used to define the best management scenario in order to enhance yield and WP of rainfed wheat in upper KRB in 2013-2014. In the next step, the best management scenarios were carried out in three research fields of rainfed wheat in 2014-2015. In field experiments, the treatments included two main management (traditional and advanced management) and two levels of limited irrigation (rainfed, single irrigation of 60 mm at spring time). According to the best scenario of AquaCrop model, spring single irrigation with constant depth of 60 mm was applied at three times (the first, middle and end of flowering period). The result shows that under rainfed conditions, by using the advanced management, rain water productivity of wheat increased by 36% as compared to traditional management. The results of this study showed that a single irrigation application at spring time (during flowering stage) increased the average total water productivity of wheat to 0.70 kg m-3, an increase of 74% as compared to the traditional management. The optimum program was obtained by a combination of advanced agronomic management package with single irrigation of 60 mm at the middle of flowering stage, which increased yield and WP of rainfed wheat to 176% and 134%, respectively, as compared to traditional management. Results of field experiments were in good agreement with the proposed scenarios by AquaCrop model.
Ali Reza Tavakoli
Abstract
In order to improve irrigation water productivity and to allocate the saved water to limited irrigation of the adjacent areas, different deficit irrigation methods were studied under surface and sprinkler irrigation systems for two wheat cultivars (Pishtaz and Shiraz), during 2006-07, in Selseleh region ...
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In order to improve irrigation water productivity and to allocate the saved water to limited irrigation of the adjacent areas, different deficit irrigation methods were studied under surface and sprinkler irrigation systems for two wheat cultivars (Pishtaz and Shiraz), during 2006-07, in Selseleh region located in Lorestan province, Iran. The objectives of this study were to find the optimum water depth in sprinkler irrigation and non-effective irrigation in surface irrigation. Different levels of irrigation water were studied under sprinkler irrigation by using a single source. The treatments of surface irrigation included full irrigation, withholding the first irrigation in spring, withholding the first and third irrigation in spring time. The grain yield, irrigation water use, and water productivity were measured in different treatments. Under sprinkler irrigation, optimum level of deficit irrigation was realized with 29.4% of full irrigation treatment (220.5 mm). Under surface irrigation, withholding of the first spring irrigation (78 percent of full irrigation) was the optimum treatment. Under surface irrigation, deficit irrigation led to 22% irrigation water saving and 3.3% increase in grain yield. Root expansion in the deficit irrigation treatments and, consequently, increase in effective soil moisture availability limited grain yield reduction. Under deficit irrigation, deep root expansion was 10.5 percent more than full irrigation condition. Increasing the effective soil depth prevented yield decline. Water saving by deficit irrigation can be used for single irrigation of adjacent rainfed areas (at planting time or critical stages of spring time), which increases total water productivity by 9.3%.