Does the earthworm favor the survival and growth of Abies religiosa (Kunth) Schltdl. & Cham. seedlings in a nursery?

Introduction: In nurseries, irrigation inside plastic bags contributes to soil compaction, affecting plant growth.  Objective: To evaluate the effect of the earthworm Pontoscolex corethrurus Müller on the survival and growth of Abies religiosa (Kunth) Schltdl. & Cham. plants and on soil compaction in a nursery.  Materials and methods: The plants were subjected to three treatments (adult earthworm, two juvenile earthworms and no earthworms) in plastic bags (250 cc, 400 gauge) with 25 replicates. One year later, the height, cover, number of primary and secondary branches and biomass production (root, stems and branches) of the plants were recorded and soil compaction evaluated.  Results and discussion: The earthworm promoted an increase of 28 % in height and 44 % in root dry matter production (P < 0.05) without affecting survival, which was similar (86 ± 4.25 %; P > 0.05) in all three treatments. Compaction was significantly lower (48 %, P < 0.0001) in the earthworm treatments. Conclusion: P. corethrurus has the potential to improve the quality of plants grown in plastic bags in forest nurseries.