Yield, growth and Fe uptake of cumin (Cuminum cyminum L.) affected by Fe-nano, Fe-chelated and Fe-siderophore fertilization in the calcareous soils.

Cumin (Cuminum cyminum L.) from the Apiaceae family and as an important medicinal plant is greatly used for food production and medicinal purposes. The plant requires macro- and micro-nutrients including iron (Fe), which is not available under calcareous conditions. Accordingly, it was hypothesized the proper source (including the new methods of fertilization) and concentration of Fe can provide cumin with its required amounts of Fe under calcareous soils. The objectives were to determine: 1) the most efficient source of Fe fertilization (by spraying) on cumin yield and Fe uptake, and 2) the most optimum Fe concentration for cumin growth, yield production and seed fortification. A field experiment, as a completely randomized block design, with three replicates was conducted in the city of Aligudarz, Lorestan province, Iran. The cumin plants were sprayed twice during the season, before and after flowering (with a 10 day interval) according to the manufacturing Company. Three different types of Fe fertilization including Fe-nano-chelated (Fe-N), Fe-chelated (Fe-C) and Fe-siderophore (Fe-S) with the concentrations of 0 (control), 0.5 and 1 g/l were used for the experiment. Different plant parameters including grain Fe, crop yield, weight of 1000 grains, grain length, root length and stem length were determined. The highest yield of single plant was resulted by Fe-N1 (250 mg). Fe-N1 (3.8 g) and Fe-C1 (4.0 g) resulted in the highest weight of 1000 grains. However, the highest Fe concentration was related to treatment Fe-S1 (9.4 mg/kg). Plants treated with Fe-N (24.9 cm) and Fe-C (25.0 cm) treatments had the highest plant height. The highest root length was resulted by the Fe-N (8.9 cm) and Fe-C (9.1 cm) treatments. The control treatment resulted in the highest rate of root length/stem length (0.41). Treating the plants with Fe-C treatments resulted in the highest and significantly different grain length (6.8 mm). The concentration of 1 g/l of nano, chelated and siderophores were the most effective, significantly enhancing cumin yield and grain fortification. The results indicated the significant effects of Fe-N on plant yield and Fe uptake followed by the Fe-C method. The findings of this research work indicated that the Fe-N and the Fe-C methods were the most efficient methods enhancing cumin growth and yield. However, the most efficient method for seed fortification was the Fe-S method. The findings are of great nutritional, environmental and economical significance.