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There are different climate classes in Iran where about 85% of the agricultural lands are located in arid and semi-arid regions. To mitigate or compensate effects of drought stress and increase crop fitting and yield, effects of micronutrient application have been studied by several researchers. Field experiments were conducted during the 2021–2022 and 2022–2023 crop seasons to investigate the effect of micronutrients on quantitative and qualitative characteristics of canola cultivars under late-season drought stress conditions. The experiments were arranged in a factorial split-plot design, with two irrigation treatments – normal irrigation (control) or restricted irrigation at flowering stage – and four foliar applications of Zn and Mn after rosette stage (F1: Water, F2: ZnSO4, F3: MnSO4 and F4: ZnSO4 + MnSO4) as the main factor. Winter canola cultivars, including Okapy, Hyola401 and Hyola308, as sub-factor. The results showed that limited irrigation at flowering reduced seed yield, oil percentage and fatty acids content in different canola cultivars. Most of the canola oil is composed of unsaturated fatty acids, and the occurrence of drought stress at the reproductive stage reduced oil quality. By contrast, the minimum yield loss was obtained from Hylon401 cultivar, an early mature cultivar. Overall, it is recommended Hylon401 cultivar for normal irrigation and Hylon308 cultivar for a drought environment when considered the acceptable seed yield in canola. In general, it is suggested that a suitable performance of canola seeds is achieved by foliar application of manganese and zinc. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the efficacy of different fertilizer management systems such as organic, chemical and integrated fertilizer systems in increasing total quality and quantity yields of canola and wheat in two rotations included canola–soybean–wheat and canola-wheat. In this experiment, the effects of zeolite incorporation with different organic and chemical fertilizers were investigated on the improvement of yield components, crop yield and nutrient uptake of canola and wheat in Iran during 2014–2018. Two crop rotations of canola-soybean-wheat and canola-wheat provided the whole-plot treatments with nine fertilization management (F1: urea, F2: urea + zeolite, F3: composted manure, F4: composted manure + zeolite, F5: urea + composted manure, F6: urea+ composted manure + zeolite, F7: urea+ azocompost, F8: urea+ azocompost + zeolite and F9: Control) providing the sub-plots. The highest yield of canola and wheat were observed under F6 and F8. Embedding soybean in the rotation was not significantly efficacious in increasing canola and wheat yields. Also, soybean did not reduce wheat and canola yield, it could fulfill its own requirements. Elemental composition of seeds in crops was affected by the treatments. Principal component analysis (PCA) perfectly displayed that organic fertilizers, especially composted manure accompanied with the application of 8 ton ha−1 zeolite and urea (F6) had the most predominant effect on yield and yield components in both wheat and canola. Crop rotation in the short-term programs might not produce desirable results, but it is expected to see the efficacy of crop rotation in long-term farming practices. [ABSTRACT FROM AUTHOR]

Optimum use of nitrogen (N) fertilizers is necessary to achieve maximum profitability by farmers and to minimize the risks of environmental pollution. In this study, we used three statistical models to predict the grain yield response of wheat, safflower, and canola to N fertilizer based on combined data from 38 field experiments. Meanwhile, based on the yield response functions and fertilizer-to-product price ratios, the economic optimum N fertilizer rate for each crop for 2009 (before targeting subsidies) and 2015 (after targeting subsidies) was estimated. According to quadratic, exponential, and square root models, 82.5, 90, and 76 kg N ha−1 was estimated to be required for maximum agronomic yield of safflower. More than 300 kg N ha−1 was estimated by all three models to obtain the maximum agronomic yield of canola. In contrast with the government policies for reducing N fertilizer application rates by farmers, due to low fertilizer-to-product price ratios, all application rates of N fertilizer were economic for wheat production even after targeting subsidies. According to the results, to achieve the optimum use of N fertilizers, a proper ratio of the fertilizer cost to the product value should be considered in fertilizer subsidy programs. [ABSTRACT FROM AUTHOR]

There are different climate classes in Iran where about 85% of the agricultural lands are located in arid and semi-arid regions. To mitigate or compensate effects of drought stress and increase crop fitting and yield, effects of micronutrient application have been studied by several researchers. Field experiments were conducted during the 2021–2022 and 2022–2023 crop seasons to investigate the effect of micronutrients on quantitative and qualitative characteristics of canola cultivars under late-season drought stress conditions. The experiments were arranged in a factorial split-plot design, with two irrigation treatments – normal irrigation (control) or restricted irrigation at flowering stage – and four foliar applications of Zn and Mn after rosette stage (F1: Water, F2: ZnSO4, F3: MnSO4 and F4: ZnSO4 + MnSO4) as the main factor. Winter canola cultivars, including Okapy, Hyola401 and Hyola308, as sub-factor. The results showed that limited irrigation at flowering reduced seed yield, oil percentage and fatty acids content in different canola cultivars. Most of the canola oil is composed of unsaturated fatty acids, and the occurrence of drought stress at the reproductive stage reduced oil quality. By contrast, the minimum yield loss was obtained from Hylon401 cultivar, an early mature cultivar. Overall, it is recommended Hylon401 cultivar for normal irrigation and Hylon308 cultivar for a drought environment when considered the acceptable seed yield in canola. In general, it is suggested that a suitable performance of canola seeds is achieved by foliar application of manganese and zinc. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the efficacy of different fertilizer management systems such as organic, chemical and integrated fertilizer systems in increasing total quality and quantity yields of canola and wheat in two rotations included canola–soybean–wheat and canola-wheat. In this experiment, the effects of zeolite incorporation with different organic and chemical fertilizers were investigated on the improvement of yield components, crop yield and nutrient uptake of canola and wheat in Iran during 2014–2018. Two crop rotations of canola-soybean-wheat and canola-wheat provided the whole-plot treatments with nine fertilization management (F1: urea, F2: urea + zeolite, F3: composted manure, F4: composted manure + zeolite, F5: urea + composted manure, F6: urea+ composted manure + zeolite, F7: urea+ azocompost, F8: urea+ azocompost + zeolite and F9: Control) providing the sub-plots. The highest yield of canola and wheat were observed under F6 and F8. Embedding soybean in the rotation was not significantly efficacious in increasing canola and wheat yields. Also, soybean did not reduce wheat and canola yield, it could fulfill its own requirements. Elemental composition of seeds in crops was affected by the treatments. Principal component analysis (PCA) perfectly displayed that organic fertilizers, especially composted manure accompanied with the application of 8 ton ha−1 zeolite and urea (F6) had the most predominant effect on yield and yield components in both wheat and canola. Crop rotation in the short-term programs might not produce desirable results, but it is expected to see the efficacy of crop rotation in long-term farming practices. [ABSTRACT FROM AUTHOR]

Optimum use of nitrogen (N) fertilizers is necessary to achieve maximum profitability by farmers and to minimize the risks of environmental pollution. In this study, we used three statistical models to predict the grain yield response of wheat, safflower, and canola to N fertilizer based on combined data from 38 field experiments. Meanwhile, based on the yield response functions and fertilizer-to-product price ratios, the economic optimum N fertilizer rate for each crop for 2009 (before targeting subsidies) and 2015 (after targeting subsidies) was estimated. According to quadratic, exponential, and square root models, 82.5, 90, and 76 kg N ha−1 was estimated to be required for maximum agronomic yield of safflower. More than 300 kg N ha−1 was estimated by all three models to obtain the maximum agronomic yield of canola. In contrast with the government policies for reducing N fertilizer application rates by farmers, due to low fertilizer-to-product price ratios, all application rates of N fertilizer were economic for wheat production even after targeting subsidies. According to the results, to achieve the optimum use of N fertilizers, a proper ratio of the fertilizer cost to the product value should be considered in fertilizer subsidy programs. [ABSTRACT FROM AUTHOR]