1、Towards precise nitrogen fertilizer management for sustainable

Testing-based methods rely on in-season, real-time assessments of crop and soil conditions, while modeling-based approaches use historical spatial and temporal performance data, following the pattern of diminishing returns.

2、Fertilizers and soil conditioners — Determination of total nitrogen by

Fertilizers and soil conditioners — Determination of total nitrogen by combustion

3、Testing Methods for Fertilizers (2018)

“The Official Methods of Analysis of Fertilizers” stipulated by the Ministry of Agriculture, Forestry and Fisheries is the only analysis method to assess main components and harmful components in fertilizers in Japan and contributes to maintaining quality and securing safety of fertilizers.

Method evaluation in total Nitrogen in solid fertilizers

Following an IFA internal membership request, the IFA Method Harmonization Working Group embarked on the process of identifying methods for recommendation as best practice on determination of Nitrogen content for nitrogen containing solid fertilizers.

Comparison of Dumas Combustion Method and Kjeldahl

Abstract: To evaluate the applicability of Dumas combustion method and Kjeldahl nitrogen determination method in determining the total nitrogen content of different types of fertilizers,20 different types of nitrogen⁃containing fertilizers and 4 standard samples were selected as experimental objects.Dumas combustion method and ...

Fertilizer Testing Methods

Fertilizer raw materials must be identified by appropriate methods such as visual observation, detection of active ingredients by qualitative tests, and confirmation by equipment. In order to ensure the quality and fair trade of fertilizers, specific analytical methods have been developed.

Total Nitrogen Determination in Liquid Fertilizers

This application note compares the nitrogen determination in different samples of fertilizer by using NDA 701 Dumas Nitrogen Analyzer and UDK 159 Automatic Kjeldahl Analyzer.

ISO 20620:2026

While the fertilizers analysed in this international ring study were mineral fertilizers, previous studies have shown that total nitrogen by combustion is suitable for use with many non-mineral, nitrogen-containing fertilizers.

Testing Methods for Fertilizers (2026)

Testing Methods for Fertilizers (2024) Incorporated Administrative Agency Food and Agricultural Materials Inspection Center Note: This is an unofficial translation. Only the original Japanese texts have effect and the translation is to be used solely as reference material.

Determination of nitrogen in solid and liquid fertilisers

In the Dumas method, the nitrogen contained in the sample is oxidized to nitrogen oxides in an oxygen atmosphere, at high temperatures and in the presence of a catalyst.

The principle of industrial methods for testing nitrogen fertilizers primarily relies on chemical analysis techniques, particularly titration. This method determines the nitrogen content in fertilizers by measuring the nitrogen concentration in a solution. Below are the detailed steps and underlying principles:

1. Sample Preparation: A specific amount of soil or fertilizer sample, typically ranging from several grams to tens of grams, is taken. The sample is then ground into a powder to ensure thorough mixing with water.

2. Sample Dissolution: The powdered sample is added to a beaker containing an appropriate amount of water and stirred with a glass rod until fully dissolved. During dissolution, some precipitates (usually inorganic salts) may form, which do not affect the subsequent titration process.

3. Sample Dilution: To improve titration accuracy, the sample solution is diluted using deionized water or distilled water, reducing its concentration to a suitable range for titration. The volume of the diluted solution is measured accurately.

4. Indicator Selection: Appropriate indicators (e.g., phenolphthalein, bromocresol green) are chosen to signal the endpoint of the titration. These indicators undergo color changes during the reaction, helping to identify the titration endpoint.

5. Titration Process: A standard solution of known concentration (typically 0.1 mol/L hydrochloric acid) is added dropwise to the sample solution. As the reaction progresses, the solution’s color changes, indicating the titration endpoint.

6. Result Calculation: The nitrogen concentration in the sample solution is calculated based on the volume of titrant consumed and the color change observed. The nitrogen content in the fertilizer is then determined using the sample’s mass.

7. Precautions:

   • Ensure representative and accurate sampling.
   • Strictly control experimental conditions (e.g., temperature, humidity).
   • Select appropriate indicators to accurately determine the endpoint.
   • Avoid operational errors during titration.
   • Regularly calibrate instruments to maintain measurement accuracy.

industrial methods for testing nitrogen fertilizers use titration to measure nitrogen concentration in samples, thereby determining the nitrogen content in fertilizers. This approach is widely applied in agriculture, forestry, and other sectors due to its simplicity, speed, and accuracy.