Control of plant-parasitic nematodes with organic and inorganic amendments in agricultural soil

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 cajan) 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.