Long-term effects of three different continuous tillage practices on Collembola populations

Published source details Sabatini M.A., Rebecchi L., Cappi C., Bertolani R. & Fratello B. (1997) Long-term effects of three different continuous tillage practices on Collembola populations. Pedobiologia, 41, 185-193.
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Summary

This experiment tested the effects of minimum tillage and reduced nitrogen fertilizer input on springtails (Collembola) and mites (Acarina) in the soils of cereal fields at an experimental farm in the Po Valley, northern Italy.

Three tillage practices were tested in arable fields growing sugar beet, winter wheat and maize in rotation: minimum tillage to less than 10 cm; conventional ploughing to 25 cm and conventional ploughing to 50 cm. There were two replicates of each tillage treatment.

Each plot was divided, and half given one third as much nitrogen fertilizer (urea) as the other. Reduced and conventional fertilizer application rates were 100 and 300 kg N/ha/yr for maize, 75 and 225 kg N/ha/yr for winter wheat and 50 and 150 kg N/ha/yr for sugar beet.

The experiment was started in 1976. Microarthropods were extracted from four soil cores (7 cm diameter, 25 cm deep) taken in each treatment in July 1991, October 1991 and July of 1992, 93 and 94.

Reduced fertilizer did not significantly affect mite numbers and only affected springtail numbers in one of the five sampling dates (July 1993, under a sugar beet crop). On this date, there were more springtails at the higher nitrogen level.

Reduced tillage only affected total springtail numbers in one of the five sampling dates (July 1992 under maize), when there were more springtails in the plot ploughed to 50 cm than in the minimum tillage plot. When shallow soil (0-12.5 cm depth) was considered separately, there were more springtails in the minimum tillage treatment in July 1993.

Reduced tillage plots had significantly more mites than ploughed plots on two of the five sampling dates - July 1993 and 1994. In 1994, the effect was only in the upper layer of soil (0-12.5 cm depth).

Some springtail species, such as Isotoma notabilis were consistently more abundant under reduced tillage. Others, such as Onychiurus insubrarius were more abundant in ploughed plots. Thirty five springtail species were recorded and the diversity of springtails was not consistently greater under reduced tillage or reduced fertilizer use.

Two springtail species - Isotomurus palustris and Megalothorax minimus were more abundant in plots with reduced fertilizer, but several species were more abundant in conventionally fertilized plots.

Note: If using or referring to this published study, please read and quote the original paper. This was not available online at the time of writing. The journal can be found at: http://www.sciencedirect.com/science/journal/00314056