The Ministry of Agriculture and Farmers Welfare has announced sweeping amendments to the Fertiliser (Inorganic, Organic or Mixed) (Control) Order, 1985. The Fertiliser (Inorganic, Organic or Mixed) (Control) Fifth Amendment Order, 2025, seeks to ensure the quality, efficacy, and standardization of all fertilisers, including complex organic and mixed formulations.
This update introduces rigorous guidelines for bio-efficacy trials and establishes methodologies for testing a diverse array of components, marking a significant stride towards sustainable and productive farming practices.
The Fertiliser Control Order, 1985, has long served as the bedrock of quality regulation in India’s fertiliser industry, governing everything from manufacturing and import to pricing and distribution. However, with the advent of innovative organic and mixed fertiliser products, often incorporating biostimulants and novel compounds, there arose a critical need to update testing protocols and evaluation standards. The 2025 amendment aims to instill greater transparency, reliability, and scientific rigor in product assessment, ultimately benefiting millions of farmers who rely on these inputs for their livelihoods.
Strengthening Bio-efficacy Trials: A Scientific Approach to Field Performance
One of the most pivotal changes articulated in the amendment pertains to Clause 20C, Sub-clause (3), item B, which now dictates a revised framework for bio-efficacy trials. Previously, while trials were mandated, the specifics of their execution are now more prescriptive and scientifically robust.
Under the new order, all agronomic bio-efficacy trials are to be conducted exclusively within the institutions of the National Agricultural Research System (NARS). This includes research bodies under the Indian Council of Agricultural Research (ICAR) and State Agricultural Universities (SAUs). This centralization of trials within established research institutions ensures that evaluations are carried out by qualified experts, adhering to standardized scientific protocols, thereby minimizing variability and enhancing the credibility of results. The move is expected to curb unverified claims and ensure that only genuinely effective products reach the farmers.
Furthermore, the amendment specifies that bio-efficacy trials must now be conducted on the same crop using a minimum of three different doses for one season, across three distinct agro-ecological locations. This multi-dose and multi-location approach is critical. By testing products at varying concentrations, scientists can determine optimal application rates, preventing both under-application (leading to poor results) and over-application (causing waste and potential environmental harm). Conducting trials across diverse agro-ecological zones—regions with differing climate, soil types, and farming practices—ensures that the product’s efficacy is validated under a broader range of real-world agricultural conditions. This testing paradigm will provide farmers with more reliable information regarding product performance in their specific regions and for their particular crops, fostering informed decision-making and potentially leading to significant improvements in yield and crop health.
Unveiling the Science: Detailed Methodologies for Fertiliser Testing
Perhaps the most extensive addition within the new order is the complete substitution of Part D in Schedule VI, which now outlines a meticulously detailed “Methodology of Testing” for a wide array of fertiliser components. This section is a testament to the Ministry’s commitment to precision and comprehensiveness in quality control.
Beyond basic parameters like pH, specific gravity, bulk density, organic matter, and organic carbon (for which the order cross-references existing methodologies), the amendment introduces sophisticated procedures for various biologically active compounds and physical properties:
Estimation of Water Solubility
The order specifies a precise procedure involving analytical balance, rotary evaporator, magnetic stirrer, and constant temperature water bath. Samples are agitated at controlled temperatures (30°C and 20°C) for specific durations (24, 48, 72 hours) to ensure saturation. The filtered solution is then evaporated to dryness, and the residue’s mass is measured. Water solubility is crucial as it directly impacts nutrient availability to plants. A highly soluble fertiliser can release nutrients quickly, while a less soluble one might provide a sustained release.
Estimation of Total Dissolved Solids (TDS) or Total Soluble Solids (TSS)
This methodology focuses on determining the total mass of solid matter dissolved or suspended in a liquid or viscous sample. Using a rotary evaporator or hot plate, a known volume of liquid sample is heated to evaporate the solvent, and the constant weight of the remaining residue provides the TDS/TSS value. This is vital for liquid formulations, indicating the concentration of active ingredients and potential impurities.
Detection and Quantification of Alginic Acid
Recognizing the growing importance of seaweed extracts as biostimulants, the order introduces a detailed method for alginic acid using a High-Performance Liquid Chromatography with Refractive Index Detector (HPLC-RID) system. The procedure includes preparing a series of sodium alginate standards, precise sample preparation (including vortexing and centrifugation for solid samples), and specific chromatographic conditions (e.g., Rezex RHM Monosaccharide H+ LC Column, 65°C column temperature, 0.05% acetic acid mobile phase). Alginic acid, a polysaccharide from brown algae, is known for its role in improving soil structure, water retention, and nutrient uptake.
Estimation of Carrageenan
Another key component from seaweed, carrageenan, will now be quantified using a spectrophotometer-based method involving Toluidine Blue-O (TBO). This involves preparing TBO and κ-Carrageenan standards, careful mixing of samples/standards with TBO solution, and measuring absorbance at 630 nm. Carrageenan, a sulfated polysaccharide, contributes to plant immunity and stress tolerance.
Detection and Quantification of Fucoidan
Fucoidan, another bioactive compound from brown seaweed, will also be detected and quantified using the HPLC-RID system, following a procedure similar to that for alginic acid. A critical note in the methodology highlights the need to add 2% CaCl2 solution prior to sample preparation to precipitate out alginates, thereby preventing their interference with fucoidan estimation. This ensures accurate measurement of this valuable compound, known for its plant growth-promoting properties.
Estimation of Mannitol
The order provides a method for mannitol estimation using an HPLC-RID system, with specific column and detector parameters. Similar to alginic acid and fucoidan, it involves precise standard and sample preparation protocols. Mannitol, a sugar alcohol, acts as an osmoprotectant and energy source in plants.
Estimation of Total Poly-phenols
This procedure utilizes the well-established Folin-Ciocalteu Reagent method with spectrophotometric detection at 765 nm. It involves extracting samples with 80% aqueous methanol, preparing gallic acid (or phloroglucinol) standards, and reacting the extract with Folin-Ciocalteu reagent and sodium carbonate. Results are expressed as milligrams of Gallic Acid Equivalent (GAE) per gram of sample. Polyphenols are potent antioxidants and play a significant role in plant defense mechanisms and overall plant health.
Estimation of Humic Acid and Fulvic Acid
This is arguably the most intricate and crucial new methodology, reflecting the growing use of humic substances as soil conditioners and biostimulants. The multi-stage procedure involves:
Alkaline Extraction
For solid and granular materials, this includes crushing samples, determining moisture content, and extracting humic substances with 0.1 M Sodium Hydroxide. For liquid materials, density measurement and precise aliquot addition are required.
Flocculation
Humic acid is flocculated by carefully adjusting the pH to 1.0 ± 0.05 with concentrated hydrochloric acid.
Separation of Humic Acid
Precipitated humic acid is separated via centrifugation, dried to constant weight, and its ash content is determined (combustion at 500°C in a muffle oven) to calculate the true organic content.
Separation of Fulvic Acid
The remaining fulvic acid-containing extract is passed through a Supelco Superlite DAX-8 resin column to selectively adsorb fulvic acid, while other acid-soluble compounds are discarded. The fulvic acid is then desorbed by back elution with 0.1 M Sodium hydroxide.
Protonation and De-ashing of Fulvic Acid
The desorbed fulvic acid is further purified by repeatedly passing it through Amberlite IR 20 strong cation exchange resin until the electrical conductivity indicates sufficient purity.
Concentration and Quantification
The purified fulvic acid is concentrated using a rotary evaporator, dried to constant weight, and its ash content determined.
The methodology also details column regeneration procedures for both DAX-8 and Amberlite resins, ensuring reusability and efficiency. Humic and fulvic acids are vital for nutrient chelation, microbial activity, and improving soil structure, directly impacting nutrient uptake and plant vitality.
These amendments by the Ministry of Agriculture and Farmers Welfare signify a progressive shift towards ensuring the quality, authenticity, and effectiveness of fertilisers in India. Rigorous bio-efficacy trials and advanced testing methodologies for a wide range of components, empower farmers with reliable products, stimulate innovation in the fertiliser industry, and ultimately contribute to enhanced agricultural productivity and sustainable farming practices nationwide.
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