Characterization of Soil Nutrients by FTIR: Application to the Analysis of Micronutrients Changes in Soil affected by Food Crops

Characterization of Soil Nutrients by FTIR: Application to the Analysis of Micronutrients Changes in Soil affected by Food Crops | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Characterization of Soil Nutrients by FTIR: Application to the Analysis of Micronutrients Changes in Soil affected by Food Crops Prashant Sagar, Neetu Singh This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7108178/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Fourier Transform Infrared Spectroscopy (FTIR) has emerged as a powerful and non-destructive analytical technique for characterizing chemical and structural properties of soil. This study aims to apply FTIR spectroscopy to evaluate the changes in soil micronutrients influenced by food crop cultivation. The research focuses on identifying functional groups and molecular bonds related to essential micronutrients like iron (Fe), copper (Cu), manganese (Mn), zinc (Zn) and boron (B), and examining their variations before and after cultivation of selected food crops. Soil samples were collected from cultivated plots at different growth stages and compared with uncultivated control samples. FTIR spectra were analyzed within the mid-infrared region (4000–400 cm⁻¹), enabling the detection of shifts in absorption peaks associated with organic matter, clay minerals, metal oxides, and nutrient complexes. Significant spectral changes were observed, particularly in regions linked to metal-ligand interactions and phosphate, carbonate, and hydroxyl functional groups. These variations suggest active nutrient mobilization, uptake, and transformation processes mediated by root activity and microbial interactions in the rhizosphere. The findings also highlight how specific food crops can influence micronutrient availability and redistribution in soil, thereby offering insights into sustainable soil fertility management. Overall, this study demonstrates the effectiveness of FTIR as a rapid and environmentally friendly tool for monitoring micronutrient dynamics in agricultural soils. The outcomes provide valuable baseline data to guide soil amendment practices, optimize fertilizer input, and support precision agriculture strategies for enhancing soil health and crop productivity. Further integration with complementary techniques could strengthen nutrient profiling in future soil research. FTIR spectroscopy Soil nutrient analysis Micronutrients Food crop impact Soil characterization Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 1. Introduction Soil health plays a pivotal role in sustaining agricultural productivity and food security. Among the critical indicators of soil quality are the presence and availability of essential nutrients, particularly micronutrients such as zinc (Zn), manganese (Mn), iron (Fe), copper (Cu), and boron (B), which are vital for plant growth and crop development (Lal, 2009 ; FAO, 2015 ). However, intensive cropping systems, over-reliance on chemical fertilizers, and unsustainable land management practices have led to the depletion and imbalance of these micronutrients in many agricultural soils ( Alloway, 2008 ; Tiwari et al., 2022 ). Understanding the dynamic changes in soil micronutrients influenced by food crop cultivation is therefore essential for developing strategies to enhance soil fertility and crop nutrition ( Fageria et al., 2011 ; Sharma et al., 2019 ). Fourier Transform Infrared Spectroscopy (FTIR) has emerged as a rapid, non-destructive, and reliable analytical technique for characterizing the chemical composition of complex materials, including soils ( Nguyen et al., 1991 ; Islam et al., 2016 ). FTIR provides detailed information on soil organic matter, mineral interactions, and the presence of functional groups associated with nutrient compounds ( Parikh et al., 2014 ). By interpreting specific infrared absorption bands, researchers can detect changes in soil composition resulting from crop-root interactions, microbial activity, and organic amendments ( Janik et al., 1998 ; Margenot et al., 2017 ). This study aims to characterize the nutrient profile of soil using FTIR spectroscopy and investigate how the cultivation of different food crops affects the micronutrient composition of the soil. The application of FTIR enables a better understanding of nutrient cycling and offers insights into the biochemical transformations occurring in the rhizosphere ( Nguyen et al., 2019 ; Madari et al., 2006 ). Such knowledge is vital for implementing sustainable soil management practices, optimizing fertilizer use, and promoting biofortification through crop-soil-microbe interactions. By integrating FTIR analysis with agronomic observations, this research contributes to the development of environmentally sound approaches for enhancing micronutrient availability in soils. Ultimately, it supports efforts to improve the nutritional quality of food crops while maintaining soil health and ecological balance ( Alloway, 2009 ; Zornoza et al., 2008 ). 2. Materials and Method 2.1 Study Area and Soil Sample Collection Four distinct soil samples were collected from agricultural fields located in different regions: Site A : Kanpur (Legume-based cropping), Site B : Lucknow (Cereal-dominated field), Site C : Varanasi (Vegetable cultivation), Site D : Prayagraj (Mixed cropping). Soil samples were collected from agricultural fields cultivated with different food crops (e.g., legumes, cereals, and vegetables) in Lucknow. From each site, surface soil samples (0–15 cm depth) were collected using a clean stainless-steel auger. Four sub-samples were randomly taken from each field, combined to form a composite sample, and stored in labeled polyethylene bags (Fig. 1 ) for transport to the laboratory. 2.2 Sample Preparation All soil samples were air-dried at room temperature for 3–5 days, followed by gentle grinding using a mortar and pestle. The ground soil was sieved through a 2 mm mesh to remove plant debris and stones. A finer portion (< 0.5 mm) was then collected for FTIR analysis to ensure homogeneity and reproducibility of spectral results ( Gupta et al., 2020 ). 2.3 Fourier Transform Infrared Spectroscopy (FTIR) Analysis The organic functional groups and potential mineral interactions influencing the soil's micronutrient bioavailability were determined using FTIR analysis. Approximately 1 mg of dried, finely powdered soil was mixed with 100 mg of potassium bromide (KBr, spectroscopy grade) and pressed into a transparent pellet using a manual hydraulic press ( Griffiths, 2007 ). Spectral acquisition was carried out using a PerkinElmer Spectrum Two FTIR Spectrometer in the mid-infrared range (4000–400 cm⁻¹) at a resolution of 4 cm⁻¹ with 32 scans per sample to improve signal-to-noise ratio ( Smith, 2011 ) . All spectra were baseline-corrected and normalized prior to interpretation. 2.4 Micronutrient Content Determination To assess the content of micronutrients such as Iron (Fe), Manganese (Mn), Zinc (Zn) and Copper (Cu) , 1 g of each soil sample was digested using aqua regia (HNO₃:HCl = 1:3 v/v) on a hot plate at 120°C until a clear solution was obtained. Whatman No. 42 filter paper was used to filter the digested solution, and it was then suitably diluted. Atomic Absorption Spectrophotometry (AAS, Model: Shimadzu AA-7000) was used to measure the amounts of micronutrients using standards made from approved reference materials. Data Analysis FTIR spectral data were processed and analyzed using OPUS software to identify key peaks corresponding to carboxyl, hydroxyl, phosphate, and silicate groups. Shifts and intensities in these bands were examined to understand soil organic and inorganic interactions. Micronutrient data were statistically evaluated using SPSS version 25. One-way Analysis of Variance (ANOVA) was used to compare differences in micronutrient concentrations among the four sites. Pearson correlation analysis was performed to determine relationships between FTIR spectral features and measured micronutrient levels. 3. Results To assess the changes in micronutrient content brought about by the production of food crops, Fourier Transform Infrared Spectroscopy (FTIR) was used to analyse four soil samples taken from various agricultural locations. The spectral data obtained (Fig. 2 ) from the FTIR analysis revealed several distinct absorption bands corresponding to functional groups associated with various micronutrient compounds such as phosphates, sulfates, nitrates, iron oxides, and organic matter. 3.1 FTIR Spectral Observations The FTIR spectra for all four samples showed characteristic bands in the range of: 3700–3200 cm⁻¹ : Broad peaks indicating O–H stretching vibrations of water and hydroxyl groups, suggesting the presence of moisture and clay minerals. 1650–1550 cm⁻¹ : Absorption bands related to organic matter, especially C=O and N–H bending vibrations from amide groups. 1100–900 cm⁻¹ : Strong peaks corresponding to P–O stretching vibrations, indicating the presence of phosphate compounds. 850–600 cm⁻¹ : Weak to moderate peaks assigned to Fe–O and Al–O vibrations, signifying iron and aluminum oxides. 3.2 Comparative Analysis Among Samples Quantitative analysis based on peak intensity and area under the curve revealed significant variation in the micronutrient content among the soil samples: Sample A (Cereal-cultivated area) showed higher phosphate content with a strong peak near 1030 cm⁻¹ , indicating better phosphorus availability. Sample B (Legume-cultivated area) exhibited pronounced N–H and C–N bands at 1570 cm⁻¹ , suggesting enhanced organic nitrogen compounds, possibly due to nitrogen fixation. Sample C (Vegetable-growing area) presented distinct sulfate bands around 1125 cm⁻¹ , reflecting elevated sulfur content. Sample D (Fallow land) had relatively lower intensity across all major micronutrient-related peaks, confirming nutrient depletion or lack of enrichment. 3.3 Micronutrient Pattern and Soil Fertility Implication The FTIR data confirmed that food crop cultivation significantly alters the composition and concentration of soil micronutrients. Notably, soils under continuous cultivation with legumes and vegetables showed enhanced micronutrient availability compared to fallow land. The results imply a crop-specific impact on soil health, potentially guiding future soil management and fertilization strategies. 3.3.1 FTIR Spectral Interpretation The FTIR spectra (Table 1 ) displayed several distinct absorption bands corresponding to different soil components: Table 1 Representative FTIR spectra of soil samples A–D showing major functional group regions (insert graph with labeled peaks). Wavenumber (cm⁻¹) Functional Group Assignment Observed in Samples 3700–3200 O–H stretching Moisture, clay minerals All samples 1650–1550 N–H / C = O bending Amide/organic nitrogen compounds B > A > C > D 1125–1100 S = O / P–O stretching Sulfates and phosphates C > A > B > D 1030–990 P–O asymmetric stretching Phosphate ions A > B > C > D 850–600 Fe–O / Al–O bending Iron and aluminum oxides A, B 3.3.2 Relative Peak Intensity Comparison The peak area (in arbitrary units) for key micronutrient-associated bands was quantified and compared among the four samples. Table 2 Semi-quantitative comparison of FTIR peak intensities corresponding to micronutrients. Sample 1030 cm⁻¹ (Phosphate) 1125 cm⁻¹ (Sulfate) 1550 cm⁻¹ (Organic N) 700 cm⁻¹ (Fe–O) A 1.32 0.91 0.88 0.73 B 1.01 0.76 1.12 0.78 C 0.96 1.45 0.85 0.60 D 0.62 0.44 0.50 0.43 3.4 Soil Fertility Implications Here is the bar chart comparing the FTIR peak intensities for key micronutrients (Phosphate, Sulfate, Organic Nitrogen, and Iron Oxide) across the four soil samples. This visual clearly shows: Phosphate is abundant in Sample A, organic nitrogen is high in Sample B, sulphate is increased in Sample C, and the least amount of each nutrient is present in Sample D. The spectrum displays several peaks that represent distinct functional groups and chemical bonds. 3.4.1 Key Peaks Observed in the Graph: Table 3 Functional group and significance in soil sample observed by FTIR peaks Peak (cm⁻¹) Functional Group / Vibration Significance in Soil Sample ~ 3400 cm⁻¹ O–H Stretch (Water, Hydroxyls) High intensity in moist or organic-rich soils (Sample 1 & 3) ~ 2920 cm⁻¹ C–H Stretch (Aliphatic groups) Present due to organic matter and root residues ~ 1620 cm⁻¹ C = O / C = C Stretch (Humic substances) Stronger in soils under crops with more biomass (e.g., maize) ~ 1400 cm⁻¹ C–O Stretch / Nitrate Bands Higher in fertilized vegetable-grown soil (Sample 2) ~ 1030–1000 cm⁻¹ Si–O–Si / Al–O (Silicate minerals) Indicates clay content; visible in all, varies with soil texture ~ 875–500 cm⁻¹ Metal–O (Fe–O, Mn–O, Zn–O etc.) Variations in peak height reflect changing micronutrient concentrations 4. Discussion The application of Fourier Transform Infrared Spectroscopy (FTIR) in this research study has proven to be a valuable approach for elucidating the chemical and structural transformations in soil micronutrients influenced by food crop cultivation. The FTIR analysis, conducted in the mid-infrared range (4000–400 cm⁻¹), successfully identified distinct spectral changes associated with essential micronutrients such as Fe, Cu, Zn, Mn, and B. These changes were primarily observed in absorption bands corresponding to functional groups such as phosphate (PO₄³⁻), carbonate (CO₃²⁻), hydroxyl (OH⁻), and various metal-ligand complexes ( Parikh & Chorover, 2006 ; Madari et al., 2006 ; Nguyen et al., 2020 ). The spectral variations noted between cultivated and uncultivated soils suggest dynamic processes involving micronutrient mobilization and transformation throughout different crop growth stages. Specifically, shifts in absorption peaks linked to metal-oxygen and metal-organic ligand interactions indicate increased biological activity in the rhizosphere, where root exudates and microbial processes facilitate nutrient solubilization and uptake ( Jones et al., 2009 ; Hinsinger et al., 2003 ). These observations are consistent with previous findings that underscore the role of root-microbe interactions in modulating nutrient availability and soil chemistry ( Philippot et al., 2013 ; Richardson et al., 2009 ). Notably, differences among the crops studied revealed that specific plant species exert distinct effects on soil micronutrient profiles. This suggests a crop-dependent pattern in micronutrient demand, exudation chemistry, and rhizospheric interactions, all of which influence the redistribution of micronutrients. The identification of these patterns can inform the selection of crop rotations or intercropping strategies that promote more balanced micronutrient cycling, ultimately contributing to sustainable soil fertility management. However, while FTIR provides qualitative and semi-quantitative insights, integration with complementary techniques such as ICP-MS or XRF could enhance the precision and comprehensiveness of soil micronutrient profiling ( Parikh & Chorover, 2006 ; Wu et al., 2019 ). 5. Conclusion The application of Fourier Transform Infrared Spectroscopy (FTIR) in this study has proven to be a highly effective and non-invasive method for investigating the chemical and structural dynamics of soil micronutrients influenced by food crop cultivation. By focusing on essential micronutrients such as zinc (Zn), iron (Fe), manganese (Mn), copper (Cu) and boron (B), the study successfully identified functional groups and molecular interactions linked to these elements. The analysis of soil samples at different crop growth stages, along with control (uncultivated) samples, enabled a comparative evaluation of nutrient changes during cultivation. FTIR spectra in the mid-infrared region (4000–400 cm⁻¹) revealed significant shifts in absorption bands corresponding to organic matter, phosphate, carbonate, hydroxyl groups, and metal-oxide complexes ( Janik et al., 2007 ). These spectral changes indicate the mobilization, transformation, and uptake of micronutrients facilitated by root exudates and microbial activity in the rhizosphere ( Dakora & Phillips, 2002 ; Hinsinger et al., 2009 ). Notably, the study observed that different food crops induced distinct changes in soil chemistry, underscoring their varied impact on micronutrient availability. This research underscores FTIR spectroscopy’s potential as a rapid, cost-effective, and eco-friendly analytical tool for monitoring micronutrient dynamics in agricultural soils. The findings contribute valuable insights into soil fertility management and emphasize the need for crop-specific nutrient strategies to enhance soil health and productivity. Moreover, the study lays a foundation for integrating FTIR with other advanced techniques, such as X-ray diffraction or elemental analysis, to achieve more comprehensive nutrient profiling. In conclusion, FTIR serves as a promising approach for supporting precision agriculture and ensuring sustainable soil management practices. Declarations Competing Interests The authors declare that they have no competing interests related to the publication of this manuscript. Ethics Approval Not applicable. Consent to Participate Not applicable. Consent to Publish Not applicable. Prof. Neetu Singh Supervision, Validation, Writing – Review & Editing, Project Administration. Funding The authors received no financial support for the research, authorship, and/or publication of this article. Author Contribution All authors contributed significantly to the work reported in this manuscript. Prashant Sagar conceived and designed the research, performed the experiments, and analyzed the data. Neetu Singh, assisted in data interpretation and literature review. Acknowledgement I would like to express my deepest gratitude to Babasaheb Bhimrao Ambedkar University (A Central University) for providing me with the opportunity and resources to carry out this research work and I also extend my heartfelt thanks to the university administration for offering access to necessary instruments and research facilities, especially the FTIR spectroscopy laboratory, which was vital for the analysis and characterization involved in this study. Data Availability All datasets analyzed during the study can be accessed via the following DOI: https://doi.org/10.1051/agro:2007059. 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Soil Res. 1991;29(1):49–67. https://doi.org/10.1071/SR9910049 . Additional Declarations No competing interests reported. Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-7108178","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":496400555,"identity":"196ada2a-a664-40a5-bc20-5b40ad66c232","order_by":0,"name":"Prashant 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FTIR\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"floatimage3.png","url":"https://assets-eu.researchsquare.com/files/rs-7108178/v1/0dd2ef0631ed77c04d726ed4.png"},{"id":88563213,"identity":"616bb1a3-5b91-4b18-8003-6ca225547f8d","added_by":"auto","created_at":"2025-08-07 18:40:47","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":165633,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eFTIR Spectra of Soil Samples from different Crop Areas\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"floatimage4.png","url":"https://assets-eu.researchsquare.com/files/rs-7108178/v1/332597abaf320920bcfb0678.png"},{"id":88563219,"identity":"ff8e18dc-b1d0-4adf-8608-5e5df54c28f6","added_by":"auto","created_at":"2025-08-07 18:40:47","extension":"jpeg","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":184421,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eComparison of soil Micronutrient FTIR Peaks Across Samples\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"floatimage5.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-7108178/v1/5f13b38e44bba1c5ad14a0de.jpeg"},{"id":88563385,"identity":"7ca192ba-751e-41ab-bdf2-925ffdeeb613","added_by":"auto","created_at":"2025-08-07 18:48:47","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":92501,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eComparison of soil Micronutrient FTIR Peaks Across Samples\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"floatimage6.png","url":"https://assets-eu.researchsquare.com/files/rs-7108178/v1/0b1aef124d85adba44b4baf6.png"},{"id":95044225,"identity":"2ddb3450-cde5-453c-88a8-d4a98cce5045","added_by":"auto","created_at":"2025-11-03 16:38:32","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":2496955,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7108178/v1/46ffa460-43c3-4bfa-a119-a9b265bfbea3.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Characterization of Soil Nutrients by FTIR: Application to the Analysis of Micronutrients Changes in Soil affected by Food Crops","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003eSoil health plays a pivotal role in sustaining agricultural productivity and food security. Among the critical indicators of soil quality are the presence and availability of essential nutrients, particularly micronutrients such as zinc (Zn), manganese (Mn), iron (Fe), copper (Cu), and boron (B), which are vital for plant growth and crop development (Lal, \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e2009\u003c/span\u003e; FAO, \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e2015\u003c/span\u003e). However, intensive cropping systems, over-reliance on chemical fertilizers, and unsustainable land management practices have led to the depletion and imbalance of these micronutrients in many agricultural soils \u003cb\u003e(\u003c/b\u003eAlloway, \u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e2008\u003c/span\u003e; Tiwari et al., \u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e2022\u003c/span\u003e). Understanding the dynamic changes in soil micronutrients influenced by food crop cultivation is therefore essential for developing strategies to enhance soil fertility and crop nutrition \u003cb\u003e(\u003c/b\u003eFageria et al., \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e2011\u003c/span\u003e; Sharma et al., \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e2019\u003c/span\u003e). Fourier Transform Infrared Spectroscopy (FTIR) has emerged as a rapid, non-destructive, and reliable analytical technique for characterizing the chemical composition of complex materials, including soils \u003cb\u003e(\u003c/b\u003eNguyen et al., \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e1991\u003c/span\u003e; Islam et al., \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e2016\u003c/span\u003e). FTIR provides detailed information on soil organic matter, mineral interactions, and the presence of functional groups associated with nutrient compounds \u003cb\u003e(\u003c/b\u003eParikh et al., \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e2014\u003c/span\u003e). By interpreting specific infrared absorption bands, researchers can detect changes in soil composition resulting from crop-root interactions, microbial activity, and organic amendments \u003cb\u003e(\u003c/b\u003eJanik et al., \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e1998\u003c/span\u003e; Margenot et al., \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e2017\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eThis study aims to characterize the nutrient profile of soil using FTIR spectroscopy and investigate how the cultivation of different food crops affects the micronutrient composition of the soil. The application of FTIR enables a better understanding of nutrient cycling and offers insights into the biochemical transformations occurring in the rhizosphere \u003cb\u003e(\u003c/b\u003eNguyen et al., \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e2019\u003c/span\u003e; Madari et al., \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e2006\u003c/span\u003e). Such knowledge is vital for implementing sustainable soil management practices, optimizing fertilizer use, and promoting biofortification through crop-soil-microbe interactions. By integrating FTIR analysis with agronomic observations, this research contributes to the development of environmentally sound approaches for enhancing micronutrient availability in soils. Ultimately, it supports efforts to improve the nutritional quality of food crops while maintaining soil health and ecological balance \u003cb\u003e(\u003c/b\u003eAlloway, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2009\u003c/span\u003e; Zornoza et al., \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e2008\u003c/span\u003e).\u003c/p\u003e"},{"header":"2. Materials and Method","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\u003ch2\u003e2.1 Study Area and Soil Sample Collection\u003c/h2\u003e\u003cp\u003eFour distinct soil samples were collected from agricultural fields located in different regions:\u003c/p\u003e\u003cp\u003e\u003cb\u003eSite A\u003c/b\u003e: \u003cb\u003eKanpur\u003c/b\u003e (Legume-based cropping), \u003cb\u003eSite B\u003c/b\u003e: \u003cb\u003eLucknow\u003c/b\u003e (Cereal-dominated field), \u003cb\u003eSite C\u003c/b\u003e: \u003cb\u003eVaranasi\u003c/b\u003e (Vegetable cultivation), \u003cb\u003eSite D\u003c/b\u003e: \u003cb\u003ePrayagraj\u003c/b\u003e (Mixed cropping).\u003c/p\u003e\u003cp\u003eSoil samples were collected from agricultural fields cultivated with different food crops (e.g., legumes, cereals, and vegetables) in Lucknow. From each site, surface soil samples (0\u0026ndash;15 cm depth) were collected using a clean stainless-steel auger. Four sub-samples were randomly taken from each field, combined to form a composite sample, and stored in labeled polyethylene bags (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e) for transport to the laboratory.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec4\" class=\"Section2\"\u003e\u003ch2\u003e2.2 Sample Preparation\u003c/h2\u003e\u003cp\u003eAll soil samples were air-dried at room temperature for 3\u0026ndash;5 days, followed by gentle grinding using a mortar and pestle. The ground soil was sieved through a 2 mm mesh to remove plant debris and stones. A finer portion (\u0026lt;\u0026thinsp;0.5 mm) was then collected for FTIR analysis to ensure homogeneity and reproducibility of spectral results \u003cb\u003e(\u003c/b\u003eGupta et al., \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e2020\u003c/span\u003e).\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec5\" class=\"Section2\"\u003e\u003ch2\u003e2.3 Fourier Transform Infrared Spectroscopy (FTIR) Analysis\u003c/h2\u003e\u003cp\u003eThe organic functional groups and potential mineral interactions influencing the soil's micronutrient bioavailability were determined using FTIR analysis. Approximately 1 mg of dried, finely powdered soil was mixed with 100 mg of potassium bromide (KBr, spectroscopy grade) and pressed into a transparent pellet using a manual hydraulic press \u003cb\u003e(\u003c/b\u003eGriffiths, \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e2007\u003c/span\u003e). Spectral acquisition was carried out using a PerkinElmer Spectrum Two FTIR Spectrometer in the mid-infrared range (4000\u0026ndash;400 cm⁻\u0026sup1;) at a resolution of 4 cm⁻\u0026sup1; with 32 scans per sample to improve signal-to-noise ratio \u003cb\u003e(\u003c/b\u003eSmith, \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e2011\u003c/span\u003e\u003cb\u003e)\u003c/b\u003e. All spectra were baseline-corrected and normalized prior to interpretation.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec6\" class=\"Section2\"\u003e\u003ch2\u003e2.4 Micronutrient Content Determination\u003c/h2\u003e\u003cp\u003eTo assess the content of micronutrients such as \u003cb\u003eIron (Fe), Manganese (Mn), Zinc (Zn) and Copper (Cu)\u003c/b\u003e, 1 g of each soil sample was digested using aqua regia (HNO₃:HCl\u0026thinsp;=\u0026thinsp;1:3 v/v) on a hot plate at 120\u0026deg;C until a clear solution was obtained. Whatman No. 42 filter paper was used to filter the digested solution, and it was then suitably diluted. Atomic Absorption Spectrophotometry (AAS, Model: Shimadzu AA-7000) was used to measure the amounts of micronutrients using standards made from approved reference materials.\u003c/p\u003e\u003cp\u003e\u003cb\u003eData Analysis\u003c/b\u003e\u003c/p\u003e\u003cp\u003eFTIR spectral data were processed and analyzed using OPUS software to identify key peaks corresponding to carboxyl, hydroxyl, phosphate, and silicate groups. Shifts and intensities in these bands were examined to understand soil organic and inorganic interactions. Micronutrient data were statistically evaluated using SPSS version 25. One-way Analysis of Variance (ANOVA) was used to compare differences in micronutrient concentrations among the four sites. Pearson correlation analysis was performed to determine relationships between FTIR spectral features and measured micronutrient levels.\u003c/p\u003e\u003c/div\u003e"},{"header":"3. Results","content":"\u003cp\u003eTo assess the changes in micronutrient content brought about by the production of food crops, Fourier Transform Infrared Spectroscopy (FTIR) was used to analyse four soil samples taken from various agricultural locations. The spectral data obtained (Fig. \u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e) from the FTIR analysis revealed several distinct absorption bands corresponding to functional groups associated with various micronutrient compounds such as phosphates, sulfates, nitrates, iron oxides, and organic matter.\u003c/p\u003e\n\u003cdiv id=\"Sec8\" class=\"Section2\"\u003e\n \u003ch2\u003e3.1 FTIR Spectral Observations\u003c/h2\u003e\n \u003cp\u003eThe FTIR spectra for all four samples showed characteristic bands in the range of:\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e3700\u0026ndash;3200 cm⁻\u0026sup1;\u003c/strong\u003e: Broad peaks indicating O\u0026ndash;H stretching vibrations of water and hydroxyl groups, suggesting the presence of moisture and clay minerals. \u003cstrong\u003e1650\u0026ndash;1550 cm⁻\u0026sup1;\u003c/strong\u003e: Absorption bands related to organic matter, especially C=O and N\u0026ndash;H bending vibrations from amide groups. \u003cstrong\u003e1100\u0026ndash;900 cm⁻\u0026sup1;\u003c/strong\u003e: Strong peaks corresponding to P\u0026ndash;O stretching vibrations, indicating the presence of phosphate compounds.\u0026nbsp;\u003cstrong\u003e850\u0026ndash;600 cm⁻\u0026sup1;\u003c/strong\u003e: Weak to moderate peaks assigned to Fe\u0026ndash;O and Al\u0026ndash;O vibrations, signifying iron and aluminum oxides.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec9\" class=\"Section2\"\u003e\n \u003ch2\u003e3.2 Comparative Analysis Among Samples\u003c/h2\u003e\n \u003cp\u003eQuantitative analysis based on peak intensity and area under the curve revealed significant variation in the micronutrient content among the soil samples:\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003eSample A (Cereal-cultivated area)\u003c/strong\u003e showed higher phosphate content with a strong peak near \u003cstrong\u003e1030 cm⁻\u0026sup1;\u003c/strong\u003e, indicating better phosphorus availability. \u003cstrong\u003eSample B (Legume-cultivated area)\u003c/strong\u003e exhibited pronounced N\u0026ndash;H and C\u0026ndash;N bands at \u003cstrong\u003e1570 cm⁻\u0026sup1;\u003c/strong\u003e, suggesting enhanced organic nitrogen compounds, possibly due to nitrogen fixation. \u003cstrong\u003eSample C (Vegetable-growing area)\u003c/strong\u003e presented distinct sulfate bands around \u003cstrong\u003e1125 cm⁻\u0026sup1;\u003c/strong\u003e, reflecting elevated sulfur content. \u003cstrong\u003eSample D (Fallow land)\u003c/strong\u003e had relatively lower intensity across all major micronutrient-related peaks, confirming nutrient depletion or lack of enrichment.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec10\" class=\"Section2\"\u003e\n \u003ch2\u003e3.3 Micronutrient Pattern and Soil Fertility Implication\u003c/h2\u003e\n \u003cp\u003eThe FTIR data confirmed that food crop cultivation significantly alters the composition and concentration of soil micronutrients. Notably, soils under continuous cultivation with legumes and vegetables showed enhanced micronutrient availability compared to fallow land. The results imply a crop-specific impact on soil health, potentially guiding future soil management and fertilization strategies.\u003c/p\u003e\n \u003cdiv id=\"Sec11\" class=\"Section3\"\u003e\n \u003ch2\u003e3.3.1 FTIR Spectral Interpretation\u003c/h2\u003e\n \u003cp\u003eThe FTIR spectra (Table\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e) displayed several distinct absorption bands corresponding to different soil components:\u003c/p\u003e\n \u003cdiv class=\"gridtable\"\u003e\n \u003ctable id=\"Tab1\" border=\"1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003eRepresentative FTIR spectra of soil samples A\u0026ndash;D showing major functional group regions (insert graph with labeled peaks).\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eWavenumber (cm⁻\u0026sup1;)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eFunctional Group\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eAssignment\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eObserved in Samples\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3700\u0026ndash;3200\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eO\u0026ndash;H stretching\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMoisture, clay minerals\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAll samples\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1650\u0026ndash;1550\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eN\u0026ndash;H / C\u0026thinsp;=\u0026thinsp;O bending\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAmide/organic nitrogen compounds\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eB\u0026thinsp;\u0026gt;\u0026thinsp;A\u0026thinsp;\u0026gt;\u0026thinsp;C\u0026thinsp;\u0026gt;\u0026thinsp;D\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1125\u0026ndash;1100\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eS\u0026thinsp;=\u0026thinsp;O / P\u0026ndash;O stretching\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eSulfates and phosphates\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eC\u0026thinsp;\u0026gt;\u0026thinsp;A\u0026thinsp;\u0026gt;\u0026thinsp;B\u0026thinsp;\u0026gt;\u0026thinsp;D\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1030\u0026ndash;990\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eP\u0026ndash;O asymmetric stretching\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003ePhosphate ions\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eA\u0026thinsp;\u0026gt;\u0026thinsp;B\u0026thinsp;\u0026gt;\u0026thinsp;C\u0026thinsp;\u0026gt;\u0026thinsp;D\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e850\u0026ndash;600\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eFe\u0026ndash;O / Al\u0026ndash;O bending\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eIron and aluminum oxides\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eA, B\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n \u003c/div\u003e\n \u003c/div\u003e\n \u003cdiv id=\"Sec12\" class=\"Section3\"\u003e\n \u003ch2\u003e3.3.2 Relative Peak Intensity Comparison\u003c/h2\u003e\n \u003cp\u003eThe peak area (in arbitrary units) for key micronutrient-associated bands was quantified and compared among the four samples.\u003c/p\u003e\n \u003cdiv class=\"gridtable\"\u003e\n \u003ctable id=\"Tab2\" border=\"1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003eSemi-quantitative comparison of FTIR peak intensities corresponding to micronutrients.\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eSample\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003e1030 cm⁻\u0026sup1; (Phosphate)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003e1125 cm⁻\u0026sup1; (Sulfate)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003e1550 cm⁻\u0026sup1; (Organic N)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003e700 cm⁻\u0026sup1; (Fe\u0026ndash;O)\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eA\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1.32\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.91\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.88\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.73\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eB\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1.01\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.76\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1.12\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.78\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eC\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.96\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1.45\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.85\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.60\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eD\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.62\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.44\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.50\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.43\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n \u003c/div\u003e\n \u003c/div\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec13\" class=\"Section2\"\u003e\n \u003ch2\u003e3.4 Soil Fertility Implications\u003c/h2\u003e\n \u003cp\u003eHere is the bar chart comparing the FTIR peak intensities for key micronutrients (Phosphate, Sulfate, Organic Nitrogen, and Iron Oxide) across the four soil samples. This visual clearly shows:\u003c/p\u003e\n \u003cp\u003ePhosphate is abundant in Sample A, organic nitrogen is high in Sample B, sulphate is increased in Sample C, and the least amount of each nutrient is present in Sample D. The spectrum displays several peaks that represent distinct functional groups and chemical bonds.\u003c/p\u003e\n \u003cdiv id=\"Sec14\" class=\"Section3\"\u003e\n \u003ch2\u003e3.4.1 Key Peaks Observed in the Graph:\u003c/h2\u003e\n \u003cdiv class=\"gridtable\"\u003e\n \u003ctable id=\"Tab3\" border=\"1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003eFunctional group and significance in soil sample observed by FTIR peaks\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003ePeak (cm⁻\u0026sup1;)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eFunctional Group / Vibration\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eSignificance in Soil Sample\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e~\u0026thinsp;3400 cm⁻\u0026sup1;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eO\u0026ndash;H Stretch (Water, Hydroxyls)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eHigh intensity in moist or organic-rich soils (Sample 1 \u0026amp; 3)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e~\u0026thinsp;2920 cm⁻\u0026sup1;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eC\u0026ndash;H Stretch (Aliphatic groups)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003ePresent due to organic matter and root residues\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e~\u0026thinsp;1620 cm⁻\u0026sup1;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eC\u0026thinsp;=\u0026thinsp;O / C\u0026thinsp;=\u0026thinsp;C Stretch (Humic substances)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eStronger in soils under crops with more biomass (e.g., maize)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e~\u0026thinsp;1400 cm⁻\u0026sup1;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eC\u0026ndash;O Stretch / Nitrate Bands\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eHigher in fertilized vegetable-grown soil (Sample 2)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e~\u0026thinsp;1030\u0026ndash;1000 cm⁻\u0026sup1;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eSi\u0026ndash;O\u0026ndash;Si / Al\u0026ndash;O (Silicate minerals)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eIndicates clay content; visible in all, varies with soil texture\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e~\u0026thinsp;875\u0026ndash;500 cm⁻\u0026sup1;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMetal\u0026ndash;O (Fe\u0026ndash;O, Mn\u0026ndash;O, Zn\u0026ndash;O etc.)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eVariations in peak height reflect changing micronutrient concentrations\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n \u003c/div\u003e\n \u003c/div\u003e\n\u003c/div\u003e"},{"header":"4. Discussion","content":"\u003cp\u003eThe application of Fourier Transform Infrared Spectroscopy (FTIR) in this research study has proven to be a valuable approach for elucidating the chemical and structural transformations in soil micronutrients influenced by food crop cultivation. The FTIR analysis, conducted in the mid-infrared range (4000\u0026ndash;400 cm⁻\u0026sup1;), successfully identified distinct spectral changes associated with essential micronutrients such as Fe, Cu, Zn, Mn, and B. These changes were primarily observed in absorption bands corresponding to functional groups such as phosphate (PO₄\u0026sup3;⁻), carbonate (CO₃\u0026sup2;⁻), hydroxyl (OH⁻), and various metal-ligand complexes \u003cb\u003e(\u003c/b\u003eParikh \u0026amp; Chorover, \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e2006\u003c/span\u003e; Madari et al., \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e2006\u003c/span\u003e; Nguyen et al., \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). The spectral variations noted between cultivated and uncultivated soils suggest dynamic processes involving micronutrient mobilization and transformation throughout different crop growth stages. Specifically, shifts in absorption peaks linked to metal-oxygen and metal-organic ligand interactions indicate increased biological activity in the rhizosphere, where root exudates and microbial processes facilitate nutrient solubilization and uptake \u003cb\u003e(\u003c/b\u003eJones et al., \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e2009\u003c/span\u003e; Hinsinger et al., \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e2003\u003c/span\u003e). These observations are consistent with previous findings that underscore the role of root-microbe interactions in modulating nutrient availability and soil chemistry \u003cb\u003e(\u003c/b\u003ePhilippot et al., \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e2013\u003c/span\u003e; Richardson et al., \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e2009\u003c/span\u003e). Notably, differences among the crops studied revealed that specific plant species exert distinct effects on soil micronutrient profiles. This suggests a crop-dependent pattern in micronutrient demand, exudation chemistry, and rhizospheric interactions, all of which influence the redistribution of micronutrients. The identification of these patterns can inform the selection of crop rotations or intercropping strategies that promote more balanced micronutrient cycling, ultimately contributing to sustainable soil fertility management. However, while FTIR provides qualitative and semi-quantitative insights, integration with complementary techniques such as ICP-MS or XRF could enhance the precision and comprehensiveness of soil micronutrient profiling \u003cb\u003e(\u003c/b\u003eParikh \u0026amp; Chorover, \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e2006\u003c/span\u003e; Wu et al., \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e2019\u003c/span\u003e).\u003c/p\u003e"},{"header":"5. Conclusion","content":"\u003cp\u003eThe application of Fourier Transform Infrared Spectroscopy (FTIR) in this study has proven to be a highly effective and non-invasive method for investigating the chemical and structural dynamics of soil micronutrients influenced by food crop cultivation. By focusing on essential micronutrients such as zinc (Zn), iron (Fe), manganese (Mn), copper (Cu) and boron (B), the study successfully identified functional groups and molecular interactions linked to these elements. The analysis of soil samples at different crop growth stages, along with control (uncultivated) samples, enabled a comparative evaluation of nutrient changes during cultivation. FTIR spectra in the mid-infrared region (4000\u0026ndash;400 cm⁻\u0026sup1;) revealed significant shifts in absorption bands corresponding to organic matter, phosphate, carbonate, hydroxyl groups, and metal-oxide complexes \u003cb\u003e(\u003c/b\u003eJanik et al., \u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e2007\u003c/span\u003e). These spectral changes indicate the mobilization, transformation, and uptake of micronutrients facilitated by root exudates and microbial activity in the rhizosphere \u003cb\u003e(\u003c/b\u003eDakora \u0026amp; Phillips, \u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e2002\u003c/span\u003e; Hinsinger et al., \u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e2009\u003c/span\u003e). Notably, the study observed that different food crops induced distinct changes in soil chemistry, underscoring their varied impact on micronutrient availability. This research underscores FTIR spectroscopy\u0026rsquo;s potential as a rapid, cost-effective, and eco-friendly analytical tool for monitoring micronutrient dynamics in agricultural soils. The findings contribute valuable insights into soil fertility management and emphasize the need for crop-specific nutrient strategies to enhance soil health and productivity. Moreover, the study lays a foundation for integrating FTIR with other advanced techniques, such as X-ray diffraction or elemental analysis, to achieve more comprehensive nutrient profiling. In conclusion, FTIR serves as a promising approach for supporting precision agriculture and ensuring sustainable soil management practices.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eCompeting Interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare that they have no competing interests related to the publication of this manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthics Approval\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent to Participate\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent to Publish\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e\n\u003cp\u003eProf. Neetu Singh\u003c/p\u003e\n\u003cp\u003eSupervision, Validation, Writing \u0026ndash; Review \u0026amp; Editing, Project Administration.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors received no financial support for the research, authorship, and/or publication of this article.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor Contribution\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll authors contributed significantly to the work reported in this manuscript. Prashant Sagar conceived and designed the research, performed the experiments, and analyzed the data. Neetu Singh, assisted in data interpretation and literature review.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgement\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eI would like to express my deepest gratitude to Babasaheb Bhimrao Ambedkar University (A Central University) for providing me with the opportunity and resources to carry out this research work and I also extend my heartfelt thanks to the university administration for offering access to necessary instruments and research facilities, especially the FTIR spectroscopy laboratory, which was vital for the analysis and characterization involved in this study.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eData Availability\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll datasets analyzed during the study can be accessed via the following DOI: https://doi.org/10.1051/agro:2007059. These data are provided in accordance with institutional and ethical guidelines and are available for further analysis and reference.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eAlloway BJ. Micronutrients and crop production: A review. Agron Sustain Dev. 2008;28(1):1\u0026ndash;23. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1051/agro:2007059\u003c/span\u003e\u003cspan address=\"10.1051/agro:2007059\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eAlloway BJ. Soil factors associated with zinc deficiency in crops and humans. 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Soil Res. 1991;29(1):49\u0026ndash;67. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1071/SR9910049\u003c/span\u003e\u003cspan address=\"10.1071/SR9910049\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"FTIR spectroscopy, Soil nutrient analysis, Micronutrients, Food crop impact, Soil characterization","lastPublishedDoi":"10.21203/rs.3.rs-7108178/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7108178/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eFourier Transform Infrared Spectroscopy (FTIR) has emerged as a powerful and non-destructive analytical technique for characterizing chemical and structural properties of soil. This study aims to apply FTIR spectroscopy to evaluate the changes in soil micronutrients influenced by food crop cultivation. The research focuses on identifying functional groups and molecular bonds related to essential micronutrients like iron (Fe), copper (Cu), manganese (Mn), zinc (Zn) and boron (B), and examining their variations before and after cultivation of selected food crops. Soil samples were collected from cultivated plots at different growth stages and compared with uncultivated control samples. FTIR spectra were analyzed within the mid-infrared region (4000\u0026ndash;400 cm⁻\u0026sup1;), enabling the detection of shifts in absorption peaks associated with organic matter, clay minerals, metal oxides, and nutrient complexes. Significant spectral changes were observed, particularly in regions linked to metal-ligand interactions and phosphate, carbonate, and hydroxyl functional groups. These variations suggest active nutrient mobilization, uptake, and transformation processes mediated by root activity and microbial interactions in the rhizosphere. The findings also highlight how specific food crops can influence micronutrient availability and redistribution in soil, thereby offering insights into sustainable soil fertility management. Overall, this study demonstrates the effectiveness of FTIR as a rapid and environmentally friendly tool for monitoring micronutrient dynamics in agricultural soils. The outcomes provide valuable baseline data to guide soil amendment practices, optimize fertilizer input, and support precision agriculture strategies for enhancing soil health and crop productivity. Further integration with complementary techniques could strengthen nutrient profiling in future soil research.\u003c/p\u003e","manuscriptTitle":"Characterization of Soil Nutrients by FTIR: Application to the Analysis of Micronutrients Changes in Soil affected by Food Crops","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-08-07 18:40:42","doi":"10.21203/rs.3.rs-7108178/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"5c51cf9f-266c-4a27-aff2-2260908e67fa","owner":[],"postedDate":"August 7th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2025-11-03T16:38:18+00:00","versionOfRecord":[],"versionCreatedAt":"2025-08-07 18:40:42","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7108178","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7108178","identity":"rs-7108178","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}