Document Type : Research Paper
Authors
1
Assistant Prof., Department of Soil Chemistry, Fertility and Plant Nutrition, Soil and Water Research Institute, Agricultural Research, Education and Extension Organization (AREEO), Karaj, Iran.
2
Researcher, On-Farm Water Management Department, Soil and Water Research Institute, Agricultural Research, Education and Extension Organization (AREEO), Karaj, Iran.
Abstract
This study aimed to evaluate the effects of humic acid, amino acid, fulvic acid, and seaweed extract on seed yield, oil content, and water use efficiency (WUE) of canola. Two irrigation treatments were considered: irrigation after 70–80 mm of cumulative evaporation (normal) and irrigation after 130–140 mm (drought stress). The experiment was conducted using a split-plot design, with three replications, in two years in Moghan area. Results showed that all bio-stimulant treatments outperformed the control in improving key agronomic traits, although their effectiveness varied depending on irrigation conditions. Under normal irrigation, humic acid led to the highest seed yield (3802 kg/ha), oil content (43.8 %), and WUE (1.17 kg m-3). Under drought stress, the amino acid treatment achieved the highest WUE (1.75 kg m-3) and a high seed yield (3682 kg/ha). Partial budgeting analysis showed that, under normal irrigation, humic acid was the most economically profitable treatment, while amino acid performed best under drought conditions. Multi-criteria decision analysis using the TOPSIS method revealed that the optimal treatment depended on the target criteria (yield, quality, or efficiency) and environmental conditions. Based on the farmer’s agricultural priorities, under normal conditions humic acid ranked first, while under drought conditions amino acids, and sometimes seaweed extract, had the highest priority. The results suggest that using organic growth stimulants, especially under limited water availability, can improve canola (rapeseed) yield, oil quality, and WUE, offering a sustainable and economically viable management strategy for semi-arid regions of Iran.
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