Can Calcium and Sodium Help to Restore Prairie Soil Following Removal of an Invasive Tree?

Chinese Tallow (Triadica sebifera) is an invasive tree in the southeast US that rapidly outcompetes native grasses and shrubs, reduces biodiversity, and threatens grassland ecosystems. T. sebifera growth, however, has been shown to be sensitive to changes in soil salinity and suggests that micronutrients, like calcium and sodium, may be important factors that affect growth. Therefore, Ca and Na may help to improve restoration techniques by altering soil characteristics and preventing recolonization following removal of T. sebifera. To determine how Na and Ca affect soil characteristics following T. sebifera removal, we manipulated the amount of Ca and Na (by 10%, 25%, and 40% above ambient levels in a fully factorial designed experiment) in 3 meter by 3 meter plots. Each plot had one of four levels of invasion, those being remnant prairie (control), lightly invaded, moderately invaded, and heavily invaded areas. In total, this adds up to 16 treatments x 4 levels of invasion x 3 replicates + 12 additional controls = 204 plots. We collected soil samples from each plot with a soil auger in mid-July 2019 and these samples were frozen until analysis. We measured soil moisture, pH, conductivity, and bulk density. We found that calcium and sodium affect the soil characteristics differentially when added alone but have stronger effects when these micronutrients were added together. Additionally, the strength of the effect depended on the initial T. sebifera density, likely due to differences in plant biomass. These results suggest that micronutrients, Ca and Na, may be important for restoring soil characteristics like soil moisture, pH, and conductivity following invasion of T. sebifera, and may help to make coastal tallgrass prairies more resilient to invasion by this invasive tree.https://ecommons.udayton.edu/stander_posters/2779/thumbnail.jp