Effects of soil amendments on native and exotic grasses of the south Texas coastal plain (Paspalum setaceum, Dactyloctenium aegyptium, Dichanthium annulatum)

Many exotic plants are adapted to high soil N levels, while many native plants are adapted to low soil N, low pH levels, and vesicular-arbuscular mycorrhizal fungi (AMF). I tested the effects of 2 N treatments, 2 pH treatments, and 2 AMF inoculants on the growth of exotic and native grasses. In field experiments, both native and exotic grasses increased cover following urea fertilization. AMF inoculation had no effect on native or exotic grasses. In greenhouse experiments, the native grass Paspalum setaceum produced more biomass in the low pH and low N treatments while the exotic grass Dichanthium annulatum produced more biomass in the low N and control treatments and the high pH treatment. AMF Inoculation had no effect on biomass of either grass. Greenhouse studies indicate differences in exotic and native grass response to soil N and pH. However, these trends have not been corroborated in the field.