title: Improvement of the soil nitrogen content and maize growth by earthworms and arbuscular mycorrhizal fungi in soils polluted by oxytetracycline.
abstract: Interactions between earthworms (Eisenia fetida) and arbuscular mycorrhizal fungi (Rhizophagus intraradices, AM fungi) have been suggested to improve the maize nitrogen (N) content and biomass and were studied in soils polluted by oxytetracycline (OTC). Maize was planted and amended with AMF and/or earthworms (E) in the soil with low (1mgkg(-1) soil DM) or high (100mgkg(-1) soil DM) amounts of OTC pollution in comparison to soil without OTC. The root colonization, shoot and root biomass, shoot and root N contents, soil nitrogen forms, ammonia-oxidizing bacteria (AOB) and archaea (AOA) were measured at harvest. The results indicated that OTC decreased maize shoot and root biomass (p<0.05) by mediating the soil urease activity and AOB and AOA abundance, which resulted in a lower N availability for maize roots and shoots. There was a significant interaction between earthworms and AM fungi on the urease activity in soil polluted by OTC (p<0.05). Adding earthworms or AM fungi could increase the maize biomass and N content (p<0.05) in OTC polluted soil by increasing the urease activity and relieving the stress from OTC on the soil N cycle. AM fungi and earthworms interactively increased maize shoot and root biomass (p<0.05) in the OTC polluted soils through their regulation of the urease activity and the abundance of ammonia oxidizers, resulting in different soil NH4(+)-N and NO3(-)-N contents, which may contribute to the N content of maize shoots and roots. Earthworms and AM fungi could be used as an efficient method to relieve the OTC stress in agro-ecosystems.
authors: College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China; Beijing Key Laboratory of Biodiversity and Organic Farming, China.
authors: Jia
authors: J
authors: Cao
authors: College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China; Beijing Key Laboratory of Biodiversity and Organic Farming, China; Key Laboratory of Plant-Soil Interactions, Ministry of Education, China. Electronic address: wangchong@cau.edu.cn.
authors: Chong
authors: C
authors: Wang
authors: College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China; Beijing Key Laboratory of Biodiversity and Organic Farming, China.
authors: Dingge
authors: D
authors: Ji
mesh_terms: D000641:Ammonia / Q000378:metabolism; D000818:Animals; D000900:Anti-Bacterial Agents / Q000378:metabolism; D001105:Archaea / Q000378:metabolism; D001419:Bacteria / Q000378:metabolism; D038821:Mycorrhizae / Q000378:metabolism*; D009584:Nitrogen / Q000032:analysis / Q000378:metabolism*; D009835:Oligochaeta / Q000378:metabolism*; D010084:Oxidation-Reduction; D010118:Oxytetracycline / Q000378:metabolism*; D012987:Soil / Q000737:chemistry; D012988:Soil Microbiology; D012989:Soil Pollutants / Q000378:metabolism*; D003313:Zea mays / Q000254:growth & development*
chemical_list: D000900:Anti-Bacterial Agents; D012987:Soil; D012989:Soil Pollutants; D000641:Ammonia; D009584:Nitrogen; D010118:Oxytetracycline
keywords: AOA and AOB abundance; OTC polluted soil; Shoot and root N content; Shoot and root biomass; Soil urease