RESUMO
Effects of organic fertilizers with and without the application of chemical fertilizers for seven years as part of a wheat-pearl millet cropping sequence on soil chemical properties and the establishment of nitrogen fixing bacteria in the rhizosphere were examined. The application of farmyard manure, poultry manure, and sugarcane filter cake alone or in combination with chemical fertilizers improved the soil organic C, total N, P, and K status. Larger populations of Azotobacter chroococcum and Rhizobium leguminosarum biovar trifolii in the rhizosphere of wheat and Egyptian clover respectively, were maintained in soils receiving organic fertilizers either alone or in combination with chemical fertilizers than in soils given chemical fertilizers alone.
