Biological soil properties in a long‐term tillage trial in Germany

After 37 years of different soil‐tillage treatments in a long‐term field experiment in Germany, a number of biological soil characteristics was measured. The field trial comprised six major treatments with different implements and various depths. In this paper, results from a comparison of long‐term use of a plow (to 25 cm depth), a chisel plow (to 15 cm depth), and no‐tillage are presented. The biological soil characteristics measured include the soil‐organic‐carbon (SOC) content, microbial biomass, enzyme activities, and the abundance and biomass of earthworms. Long‐term use of a chisel plow and no‐tillage increased the organic‐C content in the uppermost soil layer (0–10 cm) compared with the plow treatment. The microbial biomass and the enzyme activities arginine‐ammonification, β‐glucosidase, and catalase decreased with depth in all treatments. Arginine‐ammonification and catalase were higher in the plow treatment in soil layers 10 to 30 cm. Additionally, the chisel plow caused an increase in number and biomass of earthworms compared to both other tillage treatments. Differences in earthworm numbers and biomass between plowing and no‐tillage were not statistically significant.