Why measuring soil phosphorus matters

Phosphorus is essential for plant growth and food production, but the world’s natural phosphorus reserves are limited. Understanding how nutrients are stored, transformed, and released in soil is therefore important for maintaining fertile agricultural land while reducing waste and environmental damage.

A simpler way to measure DNA-bound phosphorus

In a study published in Agricultural and Marine Science Magazine, an international team including researchers from Sultan Qaboos University, the James Hutton Institute, and the Oman Environment Agency refined a laboratory method for measuring DNA-bound phosphorus, or DNA-P, in soil.

DNA-P is part of an organophosphorus pool associated with living microorganisms. Because microorganisms continuously take up, transform, and release nutrients, DNA-P can provide insight into the biologically active part of the soil phosphorus cycle.

The researchers tested and modified an existing analytical procedure using 32 different soil types from across the UK. The updated method is easier and cheaper to perform while maintaining the accuracy and sensitivity needed for reliable measurements.

Removing unnecessary steps from the soil analysis

One of the main improvements was the removal of an enzymatic treatment that had previously been included in the process. The researchers found that these treatments were unnecessary, allowing the procedure to become simpler and less expensive.

One important step was still required: ultrafiltration. This process separates phosphorus bound to DNA from other phosphorus-containing compounds. Without that separation, DNA-P measurements would be less accurate.

DNA-P may be linked to living soil microorganisms

DNA-P accounted for only a small portion of the total organic phosphorus in the soils studied. However, its concentration showed a strong relationship with several important soil properties, including pH, phosphorus in microbial biomass, organic matter content, and dissolved phosphorus in soil water.

These associations suggest that DNA-P is more closely connected with living soil microorganisms than with long-term, stable phosphorus reserves. Measuring DNA-P may therefore offer a useful view of the more active parts of the phosphorus cycle influenced by microbial life.

What the improved method could mean for sustainable agriculture

The improved method gives scientists a more practical tool for studying biologically active phosphorus in soil. It could also help researchers investigate how microbial communities affect the amount of phosphorus available to plants.

More accurate phosphorus measurements may become increasingly important as pressure grows to use limited phosphorus resources efficiently. The method could support future research into soil fertility, nutrient management, and more sustainable food production systems.