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Ali Abdzad Gohari; Amir Nik Akhtar; Niazali Ebrahimipak; Arash Tafteh
Abstract
Soil and Water Research Institute (SWRI) has presented NIAZAB system to estimate and determine crops water requirement, water consumption, and irrigation planning at the scale of region, district, and plains in Iran. The current research was conducted in order to use NIAZAB system (including Tafteh, ...
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Soil and Water Research Institute (SWRI) has presented NIAZAB system to estimate and determine crops water requirement, water consumption, and irrigation planning at the scale of region, district, and plains in Iran. The current research was conducted in order to use NIAZAB system (including Tafteh, Pasquale and Reas methods) in determining the amount of water used for soybean cv. Williams, based on the inverse solution of the production function. The experimental treatments in this research included no fertilizer and application of of 150 kg N ha-1 and different irrigation treatments including 100%, 80%, 60%, and 40% of water requirement. Experimental design was split plot in the form of randomized complete blocks with three replications, and was conducted in Hajiabad Region, Hormozgan Province, in 2020 and 2021. The values estimated by the system and measured showed that, in the first year, the average relative error (ARE) in eatimation of evapotranspirationin by Tafteh, Pasquale and Reas methods were 7.49%, -0.05%, and 9.14%, respectively. In the second year, these values were 6.47%, -1.29%, and 9.06%, respectively. The ARE in the physical water productivity in the mentioned methods was -8.23%, -0.73%, and -10.08% in the first year, and -7.10%, 0.58%, and -10.07% in the second year, respectively. In Tafteh, Pasquale, and Reas methods, the root mean square error (RMSE) were 43, 35, and 49 mm, respectively, and the normalized root mean square error (RMSEn) were 0.093%, 0.076%, and 0.105%, respectively. Considering the results, NIAZAB system estimated the amount of irrigation water and evapotranspiration with acceptable approximation and it can be used for estimation of water consumption in the studied area.
Arash Tafteh; Niazali Ebrahimipak; Hossin Babazadeh; Fereydoon Kaveh
Abstract
Management of water distribution in the Qazvin Plain is planned on monthly intervals. Therefore, production functions which can accurately predict yield reduction under deficit irrigation on monthly basis are needed. This study was conducted with the following purpose: assessment of the production functions ...
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Management of water distribution in the Qazvin Plain is planned on monthly intervals. Therefore, production functions which can accurately predict yield reduction under deficit irrigation on monthly basis are needed. This study was conducted with the following purpose: assessment of the production functions using different methods including, minimum, average, multiplicative, Raes method, and product with yield response factor (Ky) power as applied by FAO and Najarchi yield response factors. To estimate tomato yield under different deficit irrigations and evaluation of empirical methods, a study was conducted by using randomized complete block design with irrigation interval treatments including T1, T2, T3, and T4 representing, respectively, 60, 90,120, and 150 mm evaporation from class A pan between consecutive irrigations. The study had three replications and was carried out at the Faizabad Agricultural Research Station, in Qazvin. The results showed that maximum water requirement of tomato plant was 1073 mm, T1 treatment had the maximum yield with 88500 kg/ha and T4 treatment had the minimum yield with 57000 kg/ha. Also, according to statistical comparisons, the proposed method that estimated the plant response factor based on monthly power had the minimum root mean square error (RMSE) and normal root mean square error (NRMSE), while it had the highest agreement index and coefficient of determination (R2).The plant yield response factors were determined in June, July, August, September, and October as, respectively, 0.7, 1.1, 1.1, 1.14 and 0.4. The value of this factor for initial growth, plant development satge, mid-season, and late-season were, respectively, 0.7, 1.1, 1.14, and 0.4, while the average for the whole growing period was determined as 0.89 by using the proposed method. As a result, the proposed method is suggested as a convenient method.