Microbial population and biomass in rhizosphere as influenced by continuous intensive cultivation and fertilization in an inceptisol

Abstract

The population of bacteria, fungi and actinomycetes was affected significantly with different treatments in all the three crops (finger millet, maize, cowpea fodder) of the cropping system. Bacteria, fungi and actinomycetes proliferated well under continuous applications of NPK and FYM treatments. Among the microbes, bacterial population was the highest compared to fungi and actinomycetes in the soil after all crops of cropping sequence. The application of 100% N alone and control recorded lower values of microbial population. Higher grain and straw yields of finger millet, maize and cowpea were recorded by the application of 10 t FYM ha−1 along with 100% NPK continuously followed by 150% NPK. There was a gradual increase in biomass C and N content of the soil for the graded levels of NPK from 50 to 150%. Application of 100% NPK + FYM recorded significantly the highest biomass C and N followed by 150% NPK application, whereas 100% N alone and control treatments recorded lower values in the soil.