Effect of acidified cattle slurry on a soil collembolan community: A mesocosmos study

The concept of soil health emphasizes the role of soil organisms in sustainable agriculture and relies on bioindicators to assess the impact of management options. This study employed Collembola, a key group of micro arthropods with intimate links to soil microbial activity, as bioindicators to reveal the sustainability of using acidified cattle slurry. While environmental and plant production benefits of acidification are well known, effect of acidified slurry on Collembola is undocumented. We added Collembola to sandy soil mixed with untreated or acidified cattle slurry labelled with N-15 and applied at two rates (corresponding to 30 and 90 Mg slurry ha(-1)). The collembolan community included two species for each vertical life-form: epedaphic (Sinella curviseta and Heteromurus nitidus), hemiedaphic (Proisotoma minuta and Hypogastrura assimilis) and euedaphic species (Folsomia fimetaria and Protaphorura fimata). Replicate mesocosmos were incubated for 28 or 56 days at 15 degrees C, 65% WHC and a 12 h light-dark cycle. The epedaphic species strongly declined at the end of the experiment, whereas P. minuta and F. fimetaria were positively affected by high rates of untreated and acidified slurry, respectively. The hemiedaphic P. minuta showed the highest abundances and accumulation of slurry-N-15, especially when high rate of untreated slurry was applied. We conclude that the impact on Collembola of low rates of untreated and acidified slurry applied to agricultural soils is marginal while higher rates of slurry may subsequently form a favourable habitat for euedaphic species.