Aggregate stability under different treatments of soil salinity and organic materials in the presence of the anecic earthworm Lumbricus terrestris L. under greenhouse conditions

The influence of organic materials on soil aggregate stability in the presence of earthworms is of great importance for the maintenance of soil fertility and quality, which might be relatively different in saline than non-saline environments. The main objective of this study was to realize the interactive effects between soil salinity and organic materials on aggregate stability in a soil inoculated with an anecic earthworm (Lumbricus terrestris L.) The experiment was a 4×4 factorial consisting of three levels of salinity (2, 4, and 8 dSm-1) obtained using NaCl and a control soil, and three organic materials (alfalfa and corn residues, cow manure) with an unamended soil as the control arranged in a completely randomized design replicated three times under controlled greenhouse conditions. The experiment lasted 19 weeks. At the end of 19 weeks, wet aggregate stability was measured. The aggregate stability decreased consistently with increasing salinity levels from 0.1 to 24%. The results showed that organic materials added to saline and non-saline soils improved aggregate stability (1-53%). The influence of various organic materials on soil aggregate stability and subsequent soil structure is largely dependent on the level of soil salinization imposed. Briefly, salinity would reduce aggregate stability, and that the utilization of plant residues and animal manures in saline soils may reduce the negative effects of salinity on soil fauna resulting in enhanced microbial activities, probably through the stimulation of the microbial community and feeding earthworms.