A new soil analysis method will help assess the role of microorganisms in plant nutrition

Phosphorus plays a key role in ensuring plant growth and food production. Since natural reserves of this element are limited, it is important for specialists to understand the processes of its storage, transformation, and release in the soil in order to maintain agricultural soil fertility and minimize environmental damage.

In a study published in the Journal of Agricultural and Marine Sciences, an international team of scientists from Sultan Qaboos University, the James Hutton Institute, the Environment Authority of Oman, and other organizations improved a laboratory method for determining DNA-bound phosphorus (DNA-P). This substance is part of the organic phosphorus pool associated with living microorganisms. This form of the element reflects the biologically active part of the soil phosphorus cycle, as microbes continuously uptake, transform, and release nutrients.

The updated procedure was tested on 32 different soil types collected across the UK. The modified approach retained the accuracy and sensitivity required for reliable measurements, while becoming less expensive and simpler to perform. The main change was the exclusion of enzyme treatments, which were previously used in the process but proved unnecessary. At the same time, the ultrafiltration step remained mandatory, as it is required to accurately separate DNA-bound phosphorus from other compounds.

The analysis showed that the concentration of DNA-P accounts for a small fraction of the total organic phosphorus in the soil, yet it is closely correlated with parameters such as pH level, organic matter content, soil water phosphorus, and microbial biomass phosphorus. The obtained data indicate that DNA-P is closely linked to living microorganisms and reflects the active phase of the phosphorus cycle.

The developed tool provides scientists with the opportunity to more effectively study active phosphorus in soils and investigate the impact of microbial communities on the availability of this element for plants. This approach may find application in further research on soil fertility, nutrient management systems, and sustainable food production.