EARTHWORM (Aporrectodea longa) EFFECTS ON SOME PHYSICAL PROPERTIES OF COMPACTED CLAY AND LOOSE SANDY SOILS

Abstract

to evaluate the effect of earthworm Aporrectodea longa (the black-headed worm) individuals application on improving some physical properties of compacted clay soil (losing of compaction and improved the movement of water and air) and loose sandy soil (stabilization of aggregates and increase of moisture retention). The results showed that the addition of earthworm (Aporrectodea longa) individuals had a marked effect for improving soil physical properties of both soils under investigation (compacted clay and loose sandy soils). Where it seen that the compaction of clay soil was reduced, which appear which the soil bulk density values was decreased and subsequently, total porosity was increased. On this concern, the hydraulic conductivity was increased, indicating a marked improvement of the pore size distribution. The results showed that aggregate size distribution and mean weight diameter affected by addition of earthworm (Aporrectodea longa) individuals, where the percentage of macro-aggregates increased and the micro-aggregates decreased. According to this the results indicated that mean weight diameter values increased compared to the control treatment of both soils. The same trend was observed either soil bulk density or total porosity of the loose sandy soil. This is contrast in case of both pore size distribution and hydraulic conductivity. Where the hydraulic conductivity was decrease by application of earthworm (Aporrectodea longa) treatments.