Effects of non-inverting deep tillage vs. conventional ploughing on collembolan populations in an organic wheat field

A study of the effect of different tillage methods on the soil system and crop yield in an organic agroecosystem has been carried out in Denmark as a joint effort of a team of soil scientists, microbiologists, zoologists and modellers. In this paper, the reaction of the collembolan community to two kinds of primary soil tillage in the autumn, i.e. deep tillage with a non-inverting tine subsoiler (modified Dutzi method) vs. conventional ploughing, is compared. A surprisingly high mean number of Collembola, i.e. more than 100,000 m–2, were present in the field before soil tillage. The abundance of total Collembola was strongly reduced 1 week after tillage with both methods and the sum of populations in four strata between the soil surface and 32 cm in depth showed no significant difference between the two tillage treatments. Conventional ploughing reduced the collembolan population more than the non-inverting tillage in the uppermost 4 cm stratum, while in the deepest stratum the immediate effect was opposite. When the whole soil horizon is considered, the two tillage treatments resulted in similar population changes for most collembolan species whereas significant differences were observed in individual strata. Especially strong effects were observed in epedaphic and hemiedaphic species.