Interaction Effects of Organic Matters, Earthworm and Compaction on Pore Size Distribution and Moisture Coefficients of Two Fine and Coarse-textured Soils

The aim of this research was comparison of the interactions of Eisenia fetida earthworm and organic matters on some hydraulic properties of two fine and coarse-textured soils under two compaction levels. A factorial experiment was conducted as the completely randomized design with 24 treatments and three replications under growth room conditions during six months. The factors were two soil textural classes (sandy loam and clay loam), three organic matter levels (0, 20 g kg-1 of both wheat straw and cow manure), and two compaction levels (1.3 and 1.45 g cm-3) with or without earthworm. The results showed that the both used organic matters averagely increased the soil field capacity (4.1%), permanent wilting point (2.4%) and available (8.78%) moistures values, meso騧pores volume (4.3%), while decreased the macropores volume (11.75%) in the both textural classes. Also, the highest available water content was observed in straw and clay loam soil treatments. Soil compaction decreased the soil saturated moisture value (11.6%) and macropores volume (29.5%) and increased meso騧pores volume (12%), while earthworm increased the mean of saturated moisture value (8.1%) and macropores volume (17%) and decreased meso騧pores volume (5%), averagely. The results of this study indicate that inoculating soil with earthworm can improve hydraulic quality of fine and coarse-textured soils under compaction condition even with using minimum organic matter.