Contribution of earthworms to nitrogen turnover in agricultural soils treated with different mineral N-fertilizers

Abstract

The effects of the earthworm Lumbricus terrestris on nitrogenous components in soil treated with different mineral-N fertilizers were studied in a replicated field experiment using artificial soil columns surrounded with mesh to confine the earthworms. The fertilizer treatments were urea, calcium nitrate and an unfertilized control and for comparison, the same experiment was carried out in the laboratory under standardized conditions in columns of soil within glass cylinders. Mineral N content was affected by the presence of L. terrestris, with enhancement of N mineralization in the field being greatest in the urea treatment and least in the calcium nitrate treatment. The results of the laboratory experiment were similar but with less pronounced differences between the effects of the earthworms on different fertilizer treatments.