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parvin zolfaghary; Abutaleb Hezarjaribi; Mohamad Esmail Asadi; Ebrahim Amiri
Abstract
Rice is one of the important food products that is generally transplanted. The rice “dry seeding method (DSM)” is a new approach that has provided an opportunity to increase water productivity. In this research, changing the cultivation method from transplanting to DSM and using pressurized ...
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Rice is one of the important food products that is generally transplanted. The rice “dry seeding method (DSM)” is a new approach that has provided an opportunity to increase water productivity. In this research, changing the cultivation method from transplanting to DSM and using pressurized irrigation instead of flooding method was studied in 5 rice fields in Golestan Province. The field with flood irrigation method was considered as the control treatment. Other fields were cultivated in dry soil and irrigated by drip and sprinkler methods. The results showed that, in all parameters related to grain yield and yield components, the field with flood irrigation method had higher values. Economic study at the different growth stages with different irrigation methods showed that by changing the planting method and removing the puddling in rice field, 4000 to 7000 cubic meters of water can be saved. Comparison between different irrigation methods showed that the sprinkler irrigation had a higher average yield (4998 kg/ha) than drip irrigation) 4426 kg/ha(. With 30% yield reduction, this method saved 61% in water use, which is a significant amount. The highest and lowest physical (0.53 and 0.3 kg/m3) and economical productivity rates (141,791 and 82,704 Rials/m3) were related to sprinkler irrigation and flood irrigation, respectively, which show very low water productivity in the rice fields of the province. This shows the need to increase water productivity under the current climatic conditions of the country.
p sh; e a; s r; m a
Abstract
Today, even in humid areas, the water crisis is a major problem for agriculture and increasing the efficiency of water use is also one of the requirements for sustainable development. Regarding this, the use of plant growth simulation models as a tool for managing water crisis seems useful. In this study, ...
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Today, even in humid areas, the water crisis is a major problem for agriculture and increasing the efficiency of water use is also one of the requirements for sustainable development. Regarding this, the use of plant growth simulation models as a tool for managing water crisis seems useful. In this study, WOFOST model to simulate the performance of two soybean cultivars (DPX and SEPIDEH) under deficit irrigation was used in the Gorgan region. Using the measured plant yield and simulated water balance components from the model, the average productivity of evapotranspiration (Wp < sub>ET), based on seed yield, was obtained as 0.72 kg m-3. With increasing water stress, water use efficiency based on irrigation and precipitation series (Wp < sub>I+R) and water use efficiency based on irrigation (Wp < sub>I) increased in both cultivars, but the DPX water use efficiency under drought stress was higher than the SEPIDEH cultivar. According to the results and accuracy of WOFOST model, index of relative root mean square errors of seed yield and total biomass in both cultivars was less than 10%, the index of the coefficient of residual mass (CRM) was close to zero, the performance factor (EF) was 0.89, the coefficient of determination (R2) equaled 0.93, and the index of Willmott agreement (IOA) was about 0.89. Overall, based on the findings of this study, favorable performance of the model to simulate the growth process and water impact on soybean seed yield and water efficiency is confirmed and cultivar DPX is recommended for cultivation in the Golestan province.
Parisa Shahinrokhsar; Mohammadsmaeil Asadi
Abstract
Among the main causes of low water use efficiency are use of an improper irrigation method and applying excessive irrigation. To evaluate tape and furrow irrigation methods for soybean cultivation under different irrigation regimes, a field experiment was conducted in two years (2006-2007) at Gorgan ...
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Among the main causes of low water use efficiency are use of an improper irrigation method and applying excessive irrigation. To evaluate tape and furrow irrigation methods for soybean cultivation under different irrigation regimes, a field experiment was conducted in two years (2006-2007) at Gorgan Agricultural Research Station located in Golestan province in north of Iran. The experiment was laid out in a split plot design in the form of completely randomized blocks where each treatment was replicated three times. Irrigation systems of tape and furrow were set up as the main plots, and three irrigation regimes of 100%, 75% and 50% of total crop water requirement were allocated to the subplots. Comparison of water consumption (m3/ha) between the two systems showed that tape irrigation had 33 percent less water use than furrow irrigation. Results indicated that the soybean yield was not affected by irrigation systems. But, the different irrigation regimens had some impact on crop yield. Water use efficiency in the full irrigation (100 %) regime under drip tape irrigation was 1.6 times that of furrow irrigation system. In tape irrigation, mean water distribution uniformity (Ed) in full irrigation was 96% and in furrow irrigation it was 95%. Application efficiency (Ea) under tape irrigation was 84%, which was much higher than furrow irrigation. Also, based on the results, most of water losses in furrow irrigation systems were due to surface run off, while these losses were not observed in the tape irrigation. Overall, in drip tape irrigation, less water was consumed and water use efficiency increased compared to furrow irrigation