Determination of Moisture and Ash in Soil (TGA801)

Significance of the Topic

Accurate determination of soil moisture and ash content is essential in agriculture, hydrology, and soil science. Soil water influences plant nutrient transport, microbial activity, and temperature regulation, directly impacting crop yield and ecosystem health. Ash measurement provides insight into organic matter content and supports corrections for soil constituents such as carbon, nitrogen, and sulfur.

Objectives and Study Overview

The study demonstrates a thermogravimetric analysis (TGA) method for simultaneous determination of moisture and ash in soil samples. Using the LECO TGA801 macro analyzer, the procedure follows ASTM D2974-13 standards to deliver reproducible results across reference materials and routine samples.

Methodology and Instrumentation

This approach employs a ceramic crucible and controlled heating steps under an air atmosphere. Key steps include:

• Moisture determination from 25 °C to 110 °C at 10 °C/min, held for 60 minutes.
• Ash measurement at 440 °C and 750 °C with 15 °C/min ramps and 60-minute holds.
• Mass constancy achieved within 0.0010 g over a 9-minute window.

The LECO TGA801 enables up to 19 concurrent analyses and uses custom calculations to convert mass changes into percentage moisture and ash values.

Main Results and Discussion

Analysis of certified reference soils revealed:

• Moisture content varied between 2.6 % and 9.5 %, with standard deviations below 0.03 %.
• Ash content at 440 °C ranged from 61 % to 98 %, and at 750 °C from 57.6 % to 96.8 %, with high repeatability (s<0.11 %).

These findings confirm the method’s precision and suitability for soil quality control and research applications.

Practical Benefits and Applications

The described protocol offers laboratories a robust tool for routine soil analysis, enabling data-driven irrigation management and organic matter assessments. Integration into quality assurance programs ensures reliable moisture correction for downstream analyses of soil nutrients.

Future Trends and Potential Applications

Advances in TGA instrumentation may incorporate automated sample handling and enhanced atmosphere control, expanding applications to volatile compound profiling and pollutant monitoring. Coupling TGA data with machine learning could further optimize soil management strategies and predictive modeling.

Conclusion

The LECO TGA801 method provides a standardized, high-throughput solution for precise moisture and ash determination in soils. Adherence to ASTM protocols and robust reproducibility make it a valuable asset for agricultural, environmental, and industrial laboratories.

Reference

• ASTM D2974-13 Standard Test Methods for Moisture, Ash, and Organic Matter of Peat and Other Organic Soils.