Effects of rhizosphere soil microorganisms and soil nutrients on competitiveness of Bidens pilosa with different native plants

Abstract

The invasive plant Bidens pilosa has caused losses to agriculture and livestock. We studied the effects of B. pilosa on rhizosphere soil microorganisms and soil nutrients of different native species. The soil microbial species were examined using phospholipid fatty acid (PLFA), and the concentrations of soil nutrients and the activities of soil enzyme activities were measured. Correlation analysis of soil microbial, soil nutrients, and soil enzyme activities was used in Canoco 4.5. Results showed that B. pilosa had a strong ability to aggregate soil microorganisms such as gram-positive bacterium (G(+)), gram-negative bacterium (G(-)), and arbuscular mycorrhizal fungi (AMF). The microbial species in the rhizosphere soil of B. pilosa was closely related to the native plant species. Bidens pilosa significantly increased the concentration of organic carbon, while decreasing the concentration of ammonium. The concentrations of available potassium, available phosphorus, and nitrate were strongly related to the native plant species. Correlation analysis showed that 16:00 and 16:1 omega 5c had a significant influence on the concentration of ammonium. The concentrations of 16:00 and 16:1 omega 5c in the rhizosphere soil of B. pilosa were significantly higher than that in the soil of the control, which may lead to the decrease of the concentration of ammonium in the rhizosphere soil of B. pilosa. The concentrations of 15:1 anteiso A and 18:1 omega 5c were significantly positively correlated with the concentration of available potassium, and its content were significantly greater than the other treatments in Setaria viridis. The concentration of available potassium in the competition treatment between B. pilosa and S. viridis was significantly higher than the other treatments. The above results show that the invasive plant B. pilosa affected soil enzyme activities and soil nutrients via altering microbial communities, and these changes impacted the native plant species.