Oxytetracycline Contamination Alters the Effects of Phosphate Fertilization and Maize–Faba Bean Intercropping on Plant Growth and Uptake of Nitrogen and Phosphorus

ABSTRACT Background Veterinary antibiotics entering agricultural soil may inhibit crop growth and nutrient uptake. Aims This study explored whether oxytetracycline (OTC) would alter the effects of phosphate fertilization and intercropping on plant growth and nitrogen (N) and phosphorus (P) uptake. Methods A pot experiment was conducted to grow maize and faba bean with different P rates (50 and 200 mg kg −1 ) and with OTC (10 mg kg −1 ) or without OTC (0 mg kg −1 ) under either monoculture or intercropping. Plant dry mass, N and P concentrations, soil N and P concentrations, rhizosheath sugar and carboxylates, and soil alkaline phosphatase activity were determined and compared. Results The addition of OTC had different effects on the dry mass and N and P uptake of maize and faba bean. Specifically, adding OTC enhanced the promoting effect of intercropping on the shoot dry mass of maize but weakened the promoting effect of intercropping on the root dry mass of maize. Adding OTC weakened the promoting effect of P200 on shoot N and P concentrations of monocultured maize but enhanced the promoting effect of P200 on root P concentration of intercropped faba bean. Conclusions Adding OTC could enhance or weaken the promoting effects of P fertilization or intercropping on the growth and uptake of N and P in maize and faba bean.