Native soil amendments combined with commercial arbuscular mycorrhizal fungi increase biomass of Panicum amarum

Noah C Luecke,Austin J Mejia,Kerri M Crawford

doi:10.1038/s41598-021-97307-2

Abstract

Coastal dune restorations often fail because of poorly performing plants. The addition of beneficial microbes can improve plant performance, though it is unclear if the source of microbes matters. Here, we tested how native soil amendments and commercially available arbuscular mycorrhizal (AM) fungi influenced performance of Panicum amarum, a dominant grass on Texas coastal dunes. In a greenhouse experiment, we manipulated the identity of native soil amendments (from P. amarum, Uniola paniculata, or unvegetated areas), the presence of soil microbes in the native soil amendments (live or sterile), and the presence of the commercial AM fungi (present or absent). Native soils from vegetated areas contained 149% more AM fungal spores than unvegetated areas. The commercial AM fungi, when combined with previously vegetated native soils, increased aboveground biomass of P. amarum by 26%. Effects on belowground biomass were weaker, although the addition of any microbes decreased the root:shoot ratio. The origin of native soil amendments can influence restoration outcomes. In this case soil from areas with vegetation outperformed soil from areas without vegetation. Combining native soils with commercial AM fungi may provide a strategy for increasing plant performance while also maintaining other ecosystem functions provided by native microbes.

Highlights

Coastal dune restorations often fail because of poorly performing plants
The presence of commercial arbuscular mycorrhizal (AM) fungi increased the aboveground biomass of P. amarum by 13.6% ( F1,274 = 5.21, P = 0.02, Table 1), but the degree of increase depended on the identity of the native soil amendment (F2,274 = 4.78, P = 0.01, Table 1, Fig. 1)
When commercial AM fungi were added to soils from U. paniculata aboveground biomass of P. amarum increased by 35.5%

Summary

Introduction

Coastal dune restorations often fail because of poorly performing plants. The addition of beneficial microbes can improve plant performance, though it is unclear if the source of microbes matters. We tested how native soil amendments and commercially available arbuscular mycorrhizal (AM) fungi influenced performance of Panicum amarum, a dominant grass on Texas coastal dunes. In addition to mutualists, including nitrogen-fixing bacteria and arbuscular mycorrhizal (AM) fungi, soils contain decomposers that can increase soil nutrient quantity and pathogens that decrease plant performance. While host-specific pathogens may play an important role in promoting plant d iversity[23,24], they may be detrimental to the early stages of restoration, especially if only one or two species is planted. To consider plant identity when collecting soil amendments for restoration, because there may be a build-up of species-specific pathogens that makes it unadvisable to collect soil near the species that is being restored

Methods

Results

Conclusion