A field experiment was conducted at Experimental Farm, Annamalai University to find out the effect of green manuring and nitrogen levels on soil health and yield of rice. The experiment was laid out in a split plot design with twenty five treatment combinations resulting from five age of sesbania as main treatments and five nitrogen levels as sub treatments, replicated thrice. Results of the investigation indicated that green manure help in the reduction processes leading to the change in pH, EC, higher content of organic carbon and available NPK. The microbial count, Actinomycetes, Azotobacter and Azospirillum
increased in soil when green manuring with Sesbania aculeata
was incorporated. Maximum grain and straw yield recorded in 60 days old Sesbania
and 90 kg N ha-1
beyond which the use of nitrogen was not economical with respect to nutrient uptake. Green manuring crop of Sesbania,
if incorporated in soil of an age 45-60 days period have provided more benefits to the rice crop. Maximum uptakes of nutrient were obtained if the rate of application of N was up to 60 kg ha-1
. There is improvement in soil organic carbon; available nutrients, microbial population and crop yield due to use of Sesbania
aculeata along with fertilizer N.