Improvement of Soil Ecosystem Multifunctionality by Dissipating Manure-Induced Antibiotics and Resistance Genes

Abstract

The application of animal manure containing antibiotic residues to farmlands as an organic fertilizer causes a long-term potential threat to the ecological environment of farmland. This study analyzed the effects of abating typical antibiotics and resistance genes (ARGs) applied with pig manure on farmland soil as well as on soil ecosystem multifunctionality (EMF) and its influencing factor. The results showed that Lolium multiflorum exhibited significantly stronger abatement of typical antibiotics and ARGs when combined with biochar than when used alone (p < 0.05). The dissipation of antibiotics significantly enhanced the soil functions (respiratory, ammonification, and nitrification activities) (p < 0.05). A structural equation model was established to explore the effects of abating antibiotics and ARGs in different treatment systems on soil EMF. The treatment of plant roots with ryegrass alone and in combination with biochar exerted direct positive effects on the physical structure and EMF (p < 0.001). The improvement in soil physical structure directly promoted the abatement of antibiotics and ARGs (p < 0.01). Soil pH and trace elements exerted weaker effects on antibiotics and ARGs after the application of biochar. Plant roots were the most important factor in promoting the EMF of soil containing antibiotics and ARGs.

Straw biochar strengthens the life strategies and network of rhizosphere fungi in manure fertilized soils

“…Results from these analyses indicated that ryegrass roots affect the life strategies and interactions of fungi through their own direct and indirect effects on soil pH, trace elements, soil structures, and antibiotics. Biochar addition enhanced the positive effect of soil pH in deceasing antibiotic concentrations (p < 0.01), indicating that pH variation may promote the degradation of antibiotics (Liang et al, 2017). Liang et al (2017) found that a combination of biochar and ryegrass treatment mitigates the effects of antibiotics more effectively than with ryegrass planting alone.…”

“…Biochar addition enhanced the positive effect of soil pH in deceasing antibiotic concentrations (p < 0.01), indicating that pH variation may promote the degradation of antibiotics (Liang et al, 2017). Liang et al (2017) found that a combination of biochar and ryegrass treatment mitigates the effects of antibiotics more effectively than with ryegrass planting alone. Following these observation, the rapid mitigation of antibiotics in the RS + biochar treatment significantly enhanced fungal inter-specific relationships and increased the number of positive correlations among fungal taxa abundances.…”

“…The sample geochemical variables were measured per sampling day, including: soil pH, nitrate (NO 3 --N), ammonium nitrogen (NH 4 + -N), available phosphorous, trace elements (Si, Al, Fe, K, Ca, Ti, S, Zr, Mn, V, Sr, Zn, Cr, Rb, Y and Nb), soil surface structural parameters (the surface area, micropore area, external surface area and micropore volume), and ryegrass root surface characteristics (the total length, total diameter, total surface area, total cross-sectional area, average length, average diameter, average surface area and average cross-sectional area). In addition, since the large amounts of residual antibiotics in manure fertilized soil can alter the fungi activity and community structures in soils (Hammesfahr et al, 2008), therefore, antibiotic concentrations were also determined from the collected rhizosphere soils, including chlortetracycline, doxycycline, tetracycline, sulfamethazine, enrofloxacin, lomefloxacin, ciprofloxacin and norfloxacin (Liang et al, 2017).…”

“…After biochar addition, ryegrass roots became the primary factor that affects fungal communities (r = 0.428, p < 0.05; Table S3). It has been observed that biochar addition benefits the growth of ryegrass in antibiotic-contaminated soils (Liang et al, 2017), and this stimulation may result from complex ecological interactions. For instance, biochar can modify the relationship between inter-rhizosphere microbes and plants and also affect competition between beneficial soil microbes and soiltransmitted pathogens, which then triggers plant system defenses against soil-transmitted pathogens.…”

Highly enhanced adsorption performance of tetracycline antibiotics on KOH-activated biochar derived from reed plants

“…3 Micro-levels of antibiotics in water do not usually cause acute toxicity; however, long-term exposure could lead to chronic toxicity for organisms in the environment. 4 In addition, widely-used antibiotics can induce the generation of antibiotic-resistant genes (ARGs) in microorganisms, [5][6][7] which can proliferate and widely disseminate in ecosystems, thereby posing a great danger to human health. 8 Experts have demonstrated that the emergence of "super bacteria" or "multi-drug resistant bacteria" may be associated with the environmental contamination of antibiotics and the killing of microbial communities.…”