Conclusions
Long-term implementation of reduced tillage on an organically
managed clay soil enhanced the density and biomass of
earthworms and microorganisms while also influencing their community
structures. Total and juvenile earthworm density and
biomass were increased along with higher cocoon numbers due
to prolonged use of reduced tillage. Hence, there is some evidence
that one of the key responses of the earthworm communities to
tillage practices is themodification oftheir reproduction behaviour.
In contrast to other field trials, endogeic earthworm species profited
mostfrom non-inverting tillage. Distinctincreases in microbial
biomass accompanied by a shift towards fungal-based decomposition
of organic matter in the top 10 cm of the soil with the use of
reduced tillage clearly underlined that a change in tillage management
can effectively enhance biological soil fertility. Accumulation
of carbon in the topsoil was greatly increased while perturbation
was reduced with non-inverting tillage. The assessed soil biota
showed little response to and no interaction with fertilization treatments
most likely due to small differences in overall nutrient input
to the treatments. It is concluded that reduced tillage reinforces
the beneficial effects of organic farming practices on soil biota
in a synergistic manner. Therefore the use of reduced tillage in
organic systems even on fine-textured soils provides an approach
for eco-intensification by not only reducing external inputs but
also enhancing inherent soil fertility and providing additional agroecological
services including soil conservation.