Projects - Z (Zhongchen) Yang MSc

PhD project: Impacts of antibiotic residues in manure on soil nitrogen cycling 

Circular agriculture aims to close elemental cycles which increases reliance on animal manure as soil fertilizer. However, veterinary antibiotics are still commonly used in animal husbandry to treat bacterial infections, leading to large amounts of antibiotics being excreted in manure. After applying manure containing antibiotics to soils, the fate and effects of these residues in soil have raised concerns regarding microbial antibiotic resistance and, more recently, nutrient cycling. Recent studies show that antibiotics in soil can potentially impair soil microorganisms and the physiology of plants. Since soil microorganisms and plants play crucial roles in soil nutrient cycling, the impacts of antibiotics on soil nutrient cycles, especially soil nitrogen (N) cycling, deserve further investigation.  

To address this, two incubation experiments were conducted: one to test the impacts of different antibiotics in the same soil and another to examine the effects of the same antibiotic in different soils. Additionally, the impacts of antibiotics on plant-soil interactions are not well understood. To fill this research gap, a greenhouse experiment was carried out. We investigated how antibiotics alter plant-microbe interactions of grassland species, soil N2O emissions, N fixation, and N mineralization. The results will support policy development for a circular agro-economy by identifying hidden risks of antibiotic residues in manure applied to soil.