The effects of different application rates of oilcakes of neem (Azadirachta indica) and castor (Ricinus communis),
composted manure and urea on plant-parasitic, predatory and free-living nematodes and growth of pigeonpea (Cajanus
ca jan) in field trials were studied. Amendments to soil with these materials resulted in a significant decrease of
plant-parasitic nematodes, whereas predatory and free-living nematodes increased. Neem and castor oilcakes were the most
effective in reducing plant-parasitic nematodes. However, amendment to soil of composted manure and urea was found to be
beneficial in increasing free-living nematodes. As a consequence of suppression of plant-parasitic nematodes, plant growth
parameters improved. Increasing doses of the amendments were found to be effective in further reducing plant-parasitic
nematodes and increasing predatory and free-living nematodes