Studies on the Role of Arbuscular Mycorrhizal Fungal Enhancement on Soil Aggregate Stability

Arbuscular Mycorrhizal (AM) fungi isolated from various crop rhizosphere of sodic soil sites were purified and selected for inoculation along with two standard strains namely, Glomus intraradices and Scutellospora calospora in a pot culture experiment with maize as host crop to study their influence on soil aggregation. Analysis on soil parameters responsible for improving soil aggregation after a period of 24 weeks showed influence of AM fungal inoculations on root colonization (93 %), soil spore load (620 spores 100 g-1 soil), particulate organic matter (60 mg g-1 soil), microbial count (9.7 x 105 of bacteria, 10.3 x 104 of fungi and 1.4 x 103 of actinobacteria), micronutrient contents (4.96 ±0.06, 0.83±0.05 and 3.52±0.20 ppm of iron, copper and zinc respectively) soil organic carbon (0.37 %), total glomalin production (62 µg of protein g-1 of soil) as well as the water soluble carbohydrate content (0.67 mg g-1 soil). Therefore the aggregate stability of the soil has been increased to 53 % where, the standard strains ranked the highest followed by the sodic soil isolates, Glomus mosseae (TRY 3) and Scutellospora sp. (TRY 2). Overall results showed the positive influence of AM fungi on soil aggregation.