Enhancement of Grain Yield and Nutritional Composition of Faba Bean by Foliar Application of Cobalt | ||
| Egyptian Journal of Soil Science | ||
| Volume 65, Issue 3, September 2025, Pages 1653-1668 PDF (923.5 K) | ||
| Document Type: Original Article | ||
| DOI: 10.21608/ejss.2025.410124.2298 | ||
| Authors | ||
| Mahmoud Elshony1, 2; Ihab M. Farid1; Nader Habashy2; Mohamed H.H. Abbas* 1 | ||
| 1Soils and Water Department, Faculty of Agric., Benha University , Egypt | ||
| 2Soil, Water and Environment Res. Inst, Agric, Res. Center (ARC), Giza, Egypt | ||
| Abstract | ||
| Faba bean is a nutrient-rich winter legume in Egypt that improves soil fertility through biological nitrogen fixation (BNF). Cobalt (Co) can further increase its productivity and boost BNF. This nutrient has been recently listed as a micronutrient for fertilization in the Official Journal of the European Union, Regulation (EU) 2019/1009, but information on its foliar application remains limited. Probably, this foliar application at 35 days after sowing increase plant growth, and also indirectly enhance root nodulation during its peak activity because of its intermediate mobility in plant phloem. However, excess Co may impair plant growth and photosynthesis, though optimal concentrations should be decided to avoid growth inhibition. This study evaluates the effects of foliar application of Co (0, 5, 10, and 15 mg L⁻¹) in two forms (CoSO₄ and CoCl₂) on faba bean plants under field conditions for two successive years (2022/2023 and 2023/2024). Results revealed that foliar application of cobalt (Co) significantly enhanced morphological (e.g. plant height), physiological (e.g. chlorophyll content), biochemical (e.g. nutrient accumulation in shoots and biological nitrogen fixation), and yield-related traits in faba bean (100 grain weight, total seed yield and their contents of protein and carbohydrate). These applications also recorded significant indirect impacts on nodule biomass and nitrogenase activity within the rhizosphere, with optimal results at 10 mg Co L⁻¹. A higher Co dose (15 mg L⁻¹) further improved straw yield and chlorophyll levels, yet, its had adverse effects on grain yield-related parameters and negatively diminished biological nitrogen fixation. Probably, diluting Co concentrations through increasing the vegetative growth was survival strategy under stress; however, reproductive processes — such as flowering, grain formation, and filling require a balanced supply of nutrients and assimilates. Among the two sources of Co, CoSO₄ was more effective than CoCl₂ in increasing phosphorus, iron, manganese, and zinc uptake, whereas CoCl₂ favoured nitrogen accumulation, though potassium remained unaffected. Generally, seed yield and quality parameters were positively correlated with nutrient accumulation in shoots, chlorophyll content and nodulation. These findings highlight the importance of cobalt role in promoting the physiological performance and nutritional value of faba beans, with 10 mg L⁻¹ identified as the optimum level. Future research should focus on molecular and transcriptomic responses of cobalt under field conditions, including nutrient uptake regulations, its mobility within both plants and nodules, considering stress mitigation routes | ||
| Keywords | ||
| Vicia faba; Nutrient uptake; Chlorophyll; Nitrogenase; Co salts | ||
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