Soil DNA-Phosphorus: Method Optimisation and Application Across UK Soils

Despite growing recognition of rapid diester P turnover, quantitative data on soil DNA-P across soil types remain scarce due to methodological constraints. This study aimed to investigate the impact of changes in the analytical protocol of a soil DNA-P method developed by Paraskova et al. (2013) on DNA-P recovery and the use of the revised procedure on 32 UK soils on our understanding of DNA-P in soils. The steps of the Paraskova method were tested on two contrasting soils, and a revised version was developed and used to determine the DNA-P levels of 32 UK soils. These findings were then compared with 31P-Nuclear Magnetic Resonance (31P-NMR) speciation and other standard soil parameters for the same soils. The revised Paraskova method proved to be more cost-effective and simpler, while retaining precision and sensitivity, and DNA-P recovery could be obtained without the need for enzymes, but did require an ultrafiltration step. The DNA-P values for the 32 soils were considered small with respect to the total soil organic P. The DNA-P data obtained were significantly correlated with pH, microbial biomass P, organic matter content, and P concentration in water extracts, suggesting that the sampled DNA-P pool was associated with the living soil biota and not with stabilised soil P fractions. The modified Paraskova method can be used as an effective way to understand the biological relevance of this functionally important form of phosphorus.