Nematode population dynamics and trophic structure in a soil profile under the canopy of the desert shrub Zygophyllum dumosum

Average soil nematode population densities obtained at the 0-10 cm depth were significantly higher than those obtained at 10-20 and 20-30 cm (3.7 × 10⁵, 3.2 × 10⁵ and 2.3 × 10⁵ ind m^-2, respectively). The distribution of nematode trophic groups was almost identical at all three depths; a higher percentage of plant parasites was obtained, followed by the bacteria feeders > fungal feeders > omnivore-predators. Fungal feeding nematode numbers were significantly higher at 0-10 cm than at the other two depths. A significant depth and soil water effect was obtained at 0-10 cm. the higher moisture level enhanced root and fungal growth, resulting in an increase of fungal feeding nematodes. -from Authors