How Does Tillage Affect Soil Microbiological Activity of Agricultural Soils in Austria?.

As one part of a research project about the influence of soil tillage on carbon dioxide emissions and soil carbon dynamics of Austrian cropland different parameters of soil microbiological activity are investigated at five different agricultural fields in Lower Austria and Styria. The study sites differ in climatic conditions, soil texture, slope and crop rotation. All fields belong to long-term tillage treatment experiments performed by agricultural schools. Three different tillage systems are investigated: Conventional tillage (CT), Reduced tillage (RT) and No-tillage (NT). RT and NT use cover crops during the winter period. Each tillage system is replicated three times per site.
In spring, summer and autumn 2007, soil samples were taken from each plot at different soil depths (0-10 cm, 10-20 cm, 20-30 cm). Samples were sieved (2 mm) and stored at 4°C in a refrigerator. Analyses of soil respiration, substrate-induced respiration, β-glucosidase activity and dehydrogenase activity were performed within one month after sampling. In addition, soil moisture, pH and carbon (C_org, C_inorg, C_tot) and nitrogen content of the soil samples were measured.
Preliminary results show that the amount of microbiological activity differs between the five sites. For all fields values change during the vegetation period. At three sites significant differences due to tillage system were observed. Microbiological activity is significantly higher in top layer than in deeper layers.