Research data for Effects of sample storage on the quantification of soil extracellular polymeric substances

Soil extracellular polymeric substances (EPS) are increasingly recognized as a critical microbially derived carbon with important roles in carbon cycling and soil structure. However, the impact of soil storage conditions on EPS quantification remains poorly constrained, limiting data comparability across studies. Here, we systematically evaluated seven common soil storage protocols across four distinct soil types short-term (two-month) and long-term (one-year) durations, utilizing mean-normalized root mean square deviation and cosine similarity to assess absolute and relative variations. Our results show that while polysaccharides (EPS-Poly) showed high variability and were largely restored to baseline levels through a 14-day preincubation, proteins (EPS-Prot) underwent an irreversible and substantial reduction (23%–97%) under all conditions. The carbon content of EPS remained relatively stable during long-term storage due to compensatory increases in EPS-Poly. Despite these strong effects on absolute concentrations, the relative variation in EPS components among soils was well preserved across all treatments. While stored soils remain suitable for comparative analyses, caution is warranted due to compositional shifts toward EPS-Poly. Overall, these findings highlight the necessity of standardized storage protocols and provide a robust methodological framework for future soil biogeochemical research.