Inoculation and amendment strategies influence switchgrass establishment in degraded soil

Highlights

• Microcosm experiment undertaken to evaluate biomass productivity of switchgrass in degraded soil.

• Among ten types of amendments, arbuscular mycorrhizal fungi (AMF) performed the best.

• Significant enhancement in terms of dry weight of aboveground and belowground biomass recorded.

• Root phenotyping confirmed that AMF and AMF with vermicompost influenced the root architecture.

• Hierarchical clustering and principal component analyses showed a strong correlation between root traits and treatments used.

Abstract

Bioenergy feedstock production on degraded land can serve as a means for modulating land competition for food versus energy. Due to little or no agricultural value of degraded soil, fortification of the soil with an organic amendment or inoculum will improve biomass productivity. However, as farmers struggle to rejuvenate their degraded land, there is a need for a quick screening strategy to select the best method of enhancing cellulosic (switchgrass, SG) biomass production in degraded soil. The goal of this study is to evaluate the effects of soil amendment and inoculation strategies on biomass productivities of SG in a reclaimed surface-mined soil (RMS). Experiments were conducted in the greenhouse using moisture replacement microcosms (MRM) to screen strategies for enhancing biomass productivities of SG in a RMS. Strategies included soil amendment with organic by-products (poultry litter, paper mill sludge, and vermicompost), inorganic nutrients (nitrogen and phosphorus fertilizers), or a commercial preparation of endomycorrhizae fungi (AMF, BioVam). Experiments were implemented with ten (10) treatments with six replicates for each treatment. After eight weeks of incubation in MRM systems, inoculation of RMS with AMF produced the highest aboveground and total biomass (0.9 g and 1.77 g per microcosm container) at p < 0.05. The total biomass of commercial AMF significantly (p < 0.05) outperformed all other treatments in the order of AMF > AMF + VC > PMS + N > VC = PMS = PL > PMS + AMF > N + P > ASL > Control. This microcosm screening experiment served as a quick screening to establish that soil enhancement and inoculation strategies can enhance biomass productivities of SG in degraded soil.