Effect of vermicompost, FYM, crop residue and crop rotation on soil nematode densities in Rice ecosystem

A field trial was conducted in rice (Pusa Basmati 1121) ecosystem to evaluate the effect of vermicompost (VC), FYM, phosphate solubilising bacteria (PSB) and crop residue (CR) and crop rotation with mungbean (Vigna radiata) on plant-parasitic and bacterivorous nematodes. The rice root nematode, Hirschmanniella oryzae was the predominant plant-parasitic nematode (0–750/250cc soil), followed by Heterodera cajani juveniles (0–625/250cc soil) in mung plots, stunt nematode, Tylenchorhynchus sp. (0–150/250cc soil) and dorylaimids (0–540/250cc soil). The bacterial feeders varied from 50–1800/250cc soil. The population densities of the nematode were low in treatments with VC (T3), VC + CR (T5) and VC + CR + PSB (T7), indicating an antagonistic effect of vermicompost on the nematode. The highest densities of bacterivorous nematodes were observed in plots with vermicompost + crop residue (T5). The population densities of H. oryzae were significantly high (50–1110/250cc soil) in treatments with FYM (T2), or treatments with FYM + CR (T4) and treatments with FYM + CR + PSB (T6), indicating that both FYM and2crop residue did not have an antagonistic effect on the rice root nematode. The plant parasitic index was low in all treatments that had a high saprozoic nematode index.