Specific response of fungal and bacterial residues to one-season tillage and repeated slurry application in a permanent grassland soil

• Published in: Applied soil ecology : a section of Agriculture, ecosystems & environment Vol. 72; pp. 31 - 40
• Main Authors: Murugan, Rajasekaran, Loges, Ralf, Taube, Friedhelm, Joergensen, Rainer Georg
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 01.10.2013; Elsevier
• Subjects: Agronomy. Soil science and plant productions; Bacteria; Biochemistry and biology; Biological and medical sciences; Chemical, physicochemical, biochemical and biological properties; Cropping systems. Cultivation. Soil tillage; ergosterol; field experimentation; Fundamental and applied biological sciences. Psychology; General agronomy. Plant production; grassland soils; grasslands; Microbial biomass; Microbial residues; Microbiology; nitrogen content; One-season tillage; Organic matter; Physics, chemistry, biochemistry and biology of agricultural and forest soils; plowing; sampling; Saprotrophic fungi; slurries; soil fungi; Soil organic C; soil organic carbon; Soil science; Soil tillage; Tillage. Tending. Growth control; Microbial residues; Soil organic C; Saprotrophic fungi; Microbial biomass; One-season tillage; Organic carbon; Soil tillage; Ecology; Permanent grassland; Saprobiosis; Fungus; Residue; Bacteria; Soil science; Microorganism; Grassland soil
• ISSN: 0929-1393; 1873-0272
• DOI: 10.1016/j.apsoil.2013.05.018

•Tillage decreased stocks of SOC and total N in 2 years but also 5 years after tillage.•Microbial biomass C showed some recovery in the long term – 5 years after tillage.•Tillage promoted saprotrophic fungi at the expense of AMF and bacteria.•Slurry application decreased the saprotrophic fungi and the fungal C-to-bacterial C ratio.•Fungal C/bacterial C exhibited a positive relationship with ergosterol/microbial biomass C. The dynamics of fungal and bacterial residues to a one-season tillage event in combination with manure application in a grassland soil are unknown. The objectives of this study were (1) to assess the effects of one-season tillage event in two field trials on the stocks of microbial biomass, fungal biomass, microbial residues, soil organic C (SOC) and total N in comparison with permanent grassland; (2) to determine the effects of repeated manure application to restore negative tillage effects on soil microbial biomass and residues. One trial was started 2 years before sampling and the other 5 years before sampling. Mouldboard ploughing decreased the stocks of SOC, total N, microbial biomass C, and microbial residues (muramic acid and glucosamine), but increased those of the fungal biomarker ergosterol in both trials. Slurry application increased stocks of SOC and total N only in the short-term, whereas the stocks of microbial biomass C, ergosterol and microbial residues were generally increased in both trials, especially in combination with tillage. The ergosterol to microbial biomass C ratio was increased by tillage, and decreased by slurry application in both trials. The fungal C to bacterial C ratio was generally decreased by these two treatments. The metabolic quotient qCO2 showed a significant negative linear relationship with the microbial biomass C to SOC ratio and a significant positive relationship with the soil C/N ratio. The ergosterol to microbial biomass C ratio revealed a significant positive linear relationship with the fungal C to bacterial C ratio, but a negative one with the SOC content. Our results suggest that slurry application in grassland soil may promote SOC storage without increasing the role of saprotrophic fungi in soil organic matter dynamics relative to that of bacteria.