Effect of foliar application of different forms of iron fertilizer on yield and forage properties of hairy vetch (Vicia villosa Roth) under drought stress conditions

Results and discussion The results showed that the main effect of irrigation and foliar spraying on all investigated traits was significant. Results revealed that the interaction effect of irrigation with iron fertilizer foliar application on chlorophyll index, plant height, digestibility percentage, cell wall NDF, fiber percentage, and ash percentage was a significant, In our study dry conditions, compared to the treatment of two times of irrigation, decreased the wet fodder yield and dry fodder yield and the protein content of fodder by 71.65, 50.16, and 58.58%, respectively, and increased the insoluble fibers in the acidic cell (ADF) by 48.15%. Also, under iron nano chelate treatment of fresh and dry fodder yield, the protein content of the fodder and the content of soluble carbohydrates increased by 84.35, 40.19, 22.90 and 64.08, respectively, and the insoluble fibers in the neutral cell wall (NDF) decreased by 11.60%. Among the interaction treatments of irrigation with the iron foliar application, the highest chlorophyll content (133.45 and 131.04 mg/g fresh weight respectively), plant height (23.81 and 23.43 cm respectively), fodder digestibility percentage (72 42.42 and 77.10% respectively), fiber percentage (37.75 and 40.98 respectively) and fodder ash percentage (19.37 and 21.01% respectively) And the lowest NDF of the cell wall (21.78 and 26.93% respectively) was recorded in the treatment of iron chelate (Fe-EDTA) and iron nano chelate with two times of irrigation. The results of the interaction treatments also showed that iron chelate (Fe-EDTA) under the one-time irrigation treatment could significantly increase the leaf chlorophyll content, the percentage of forage digestibility and the percentage of forage fiber compared to the control treatment. Conclusion It can be concluded that foliar application of iron fertilizer from sources of iron chelate (Fe-EDTA) and nano-iron chelate (Khizra) with two times of irrigation to achieve the maximum quantitative and qualitative characteristics of the fodder of the cluster flower is recommended, therefore it can be stated that supplementary irrigation and foliar application of iron fertilizer can be a solution to improve the quantitative and qualitative characteristics of fodder in vetch.