Document Type : Research Paper
Authors
1 Department of Soil Science and Engineering, Faculty of Agriculture, University of Zanjan, Zanjan, Iran
2 Department of Soil Science, Faculty of Agriculture, University of Zanjan. Zanjan, Iran.
3 Farhikhtegan Zarnam Industrial Research Group, Alborz Province, Hashtgerd City, Iran.
Abstract
Keywords
Main Subjects
Iron deficiency is one of the main factors limiting plant growth and plays an important role in crop yield, food quality, and human nutritional health. Although iron is an abundant element in soil, its availability to plants is generally very low (Zuluaga et al., 2023). Therefore, iron deficiency is one of the most important limiting variables affecting crop yield, food quality, and human nutrition. Currently, iron fertilization is the most common approach adopted in agriculture to prevent or correct iron chlorosis. For soil applications, iron fertilizers are based on iron chelated with synthetic amino carboxylate ligands (e.g. HEDTA, EDTA, DTPA, EDDHA), which are effective in retaining iron in the soil solution, even in alkaline soils, thereby increasing its bioavailability for plant uptake (Zuluaga et al., 2023). Among these chelates, the significant increase in plant iron yield and nutritional value confirms the usefulness of Fe-EDDHA application in calcareous soils (Schenkeveld et al., 2008). Along with synthetic iron chelates, the use of organic fertilizers is one of the most effective methods of plant nutrition in order to increase yield, be environmentally friendly, and achieve sustainable agricultural goals. Organic materials and fertilizers increase soil quality by improving soil structure, nutrient retention, and biological activity. Organic fertilizers have residual effects in soils and may be able to enhance plant growth and increase iron availability, making them a suitable alternative to expensive chemical iron fertilizers (Widowati et al., 2012). Accordingly, the present study was designed and implemented in a calcareous soil with the aim of investigating and comparing the effects of various types of liquid organic fertilizers enriched with different sources of iron and their different levels of application on the concentration of nutrients in corn plants and soil after harvest.
A factorial greenhouse experiment with two factors—fertilizer type and application rate—was conducted in a completely randomized design using fertigation, with three replications under controlled conditions, in the greenhouse of the Farhikhtegan Zarnam Industrial–Research Group during the winter of 2024. The treatments included: control (C); 3% iron-containing ferrous sulfate solution (S); organic fertilizer without iron enrichment (O); separate application of organic fertilizer without iron and 3% ferrous sulfate (OS); organic fertilizer enriched with 3% iron from ferrous sulfate (A); organic fertilizer enriched with 1.5% iron from Fe-EDTA and 1.5% from ferrous sulfate (AE); organic fertilizer enriched with 1.5% iron from Fe-DTPA and 1.5% from ferrous sulfate (AD); and organic fertilizer enriched with 1.5% iron from Fe-EDDHA and 1.5% from ferrous sulfate (AH). These fertilizers were applied via fertigation at two levels, 50 and 100 L ha⁻¹, corresponding to 80 and 160 mg Fe per 3 kg of soil, respectively.
The results of this study showed that the application of organic fertilizers, especially liquid organic fertilizer enriched with Fe-EDDHA, significantly improved the absorption of nutrients in the aerial parts of corn plants, which, considering the increase in fresh and dry weight, indicates that this treatment improved the yield and absorption of nutrients by the plant. The AH treatment at the level of 100 liters per hectare (AH100) showed the best efficiency, as it increased the concentration of iron, nitrogen, phosphorus, potassium, calcium, magnesium and copper compared to the control treatment in the aerial parts of the plant and the soil after harvest. The results indicated that the AH100 and AH50 treatments led to the highest iron concentrations in both soil and plant shoots, with increases of 57.7% and 45.6% in the soil and 54.3% and 38.9% in the shoots, respectively, compared to the control. Zinc concentration in the soil reached a maximum value of 1.71 mg/kg under the AH100 treatment, which was significantly higher than the control (1.58 mg/kg). Similarly, zinc accumulation in the aerial parts of corn was enhanced by fertilizer application, particularly in AH100 and AH50, showing increases of 16.2% and 14.7% over the control. Nitrogen concentration in the shoots was also highest in AH100 and AD100 treatments, with increases of 17.7% and 12%, while soil nitrogen content significantly increased under AH100. The highest available phosphorus level was also recorded in the AH100 treatment, with an 11.1% increase relative to the control. In addition, the AH100 treatment resulted in the highest soluble potassium concentration in the soil (0.0274%), representing an 8.8% increase over the control, and the highest shoot potassium contents (2.27%, 2.23%, and 2.22% for AH100, AH50, and AD100, respectively). Similarly, calcium concentration in both soil and shoots reached its maximum under AH100, showing significant differences from the control, with average shoot values of 0.339%, 0.335%, and 0.314% for AH100, AH50, and AD100 treatments, respectively. Moreover, all fertilizer treatments enhanced the fresh and dry weights of corn shoots compared to the control, although not all increases were statistically significant. The greatest fresh shoot biomass was achieved in the AH100, AH50, and AD100 treatments, with averages of 199.26, 186.25, and 183.45 g per pot, representing 35.8%, 26.9%, and 25% increases compared with the control, respectively.
The use of liquid organic fertilizer enriched with Fe-EDDHA significantly improved the growth and nutritional status of corn, which is attributed to the increased absorption of iron and other nutrients in the plant and soil. In addition, due to the composition of this fertilizer, which contains organic matter and amino acids, it can help improve the physical, chemical and biological properties of the soil, including stimulating the activity of beneficial microorganisms. However, due to the potted nature of the experiment, the present results reflect the plant response under controlled conditions and cannot be directly generalized to field conditions. Therefore, providing a definitive recommendation regarding this treatment requires conducting field trials to assess the stability of its effects and its efficiency under real production conditions.
This article was conducted with the financial and spiritual support of the University of Zanjan.
The authors' contributions to the article extracted from the thesis should be approximately as follows:
A, Ahmadvand: Student: Preparation and preparation of samples, conducting experiments and collecting data, performing calculations, statistical analysis of data, analyzing and interpreting information and results, preparing a draft of the article.
A, Golchin: Thesis supervisor, research design, supervising the stages of research, reviewing and controlling the results, revising, reviewing and finalizing the article.
M, Jafari Asl: Thesis advisor, participation in research design, research supervision, reading and reviewing the article.
S, Amanifar: Thesis advisor, participation in research design, research supervision, reading and reviewing the article.
The authors did not use artificial intelligence tools to write this article.
Data available on request from the author.
The authors would like to thank Zanjan Universities and Farhikhtegan Zarnam Research & Industrial Group (Zar Grain Refinery) for providing all the needed facilities.
The authors avoided data fabrication, falsification, and plagiarism, and any form of misconduct.
The authors declare no conflict of interest.
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