Glomalin, a soil protein produced by arbuscular mycorrhizal fungi (AMF) and quantified in soil as glomalin-related soil protein (GRSP), is a persistent component of soil organic matter with a potentially important influence on soil structure. Although changes with age of tallgrass prairie restoration in both soil structure and percent colonization of plant roots by AMF have been documented, GRSP has not been quantified in prairie restoration soils. We quantified GRSP in soil samples collected during July through September 2009 from a chronosequence of four tallgrass prairie restoration sites in northeastern Illinois, ranging in age from 3 to 30 years old. We hypothesized that soil GRSP concentration in soil would increase with age of restoration. A 5-cm diameter soil core sampler was used to collect soil samples from three random locations in each site at two depths: 0 – 15 cm and 15 – 30 cm. Glomalin was extracted from soil with sodium citrate, followed by autoclaving and centrifuging. Protein concentrations of extract supernatants were estimated using a Bradford assay, using BSA as the standard.
Results/Conclusions
Mean amount of GRSP extracted per site ranged from 1.57 ± 0.15 mg/g soil to 2.99 ± 0.44 mg/g soil, with the 30 year old site mean higher than those of the younger sites. Mean GRSP extracted was higher at the 0 -15 cm depth in the youngest site, but higher at the 15 – 30 cm depth in the oldest site. Results from this study suggest that AMF activity increases, and is associated with roots at deeper soil depths, as age of prairie restoration increases.
