Viljelusviisi ja väetamise mõju vihmaussidele

Summary

Earthworms are the easiest detectable species to evaluate soil conditions on arable land. The aim of current study was to investigate conventional and organic farming practices, including different fertilization schemes effect on earthworms’ abundance, biomass and species diversity. Data were collected in autumn of 2012 from a 5-year crop rotation experiment (pea, potato, barley undersown with red clover, red clover and winter wheat), established near Tartu, at Eerika on sandy loam Albic Stagnic Luvisol in 2008. This rotation was managed under 5 farming systems, two conventional: Conventional I (not fertilized but with addition of chemical pesticides) and Conventional II (mineral fertilized plots with
a final fertilization rate of N150P25K95 and with the addition of chemical pesticides); and three organic: Organic 0 (without any fertilization), Organic I (with winter cover crops used lately as green manure) and Organic II (plots with the same cover crops plus a yearly
amendment of 40 t ha–1 of cattle manure). Earthworms were collected from humus layer of the soil, counted by species and weighted. The dominating species on all treatments were Aporrectodea caliginosa L. and Lumbricus rubellus L. Only some individuals of Aporrectodea
rosea L. were found under conventional farming in both fertilization treatment, but they were found almost on every plot under Organic I and II treatments. As it was expected, the highest number and biomass of earthworms was by using cattle manure. However, as the residues goes back into the soil in this experiment, there was no significant differences in earthworm abundance and biomass between highly fertilized conventional treatment
and organic treatments with cover crops. Earthworms favoured red clover and pea and less potato and barley. The results revealed slightly improving effect of organic farming on earthworms. However, the main factor on earthworms seems to be the availability of suitable food (plant residues, manure) than farming practice itself.