Babu Mathew, TRaji S, PrasadKAU2019-06-242019-06-242007http://krishikosh.egranth.ac.in/handle/1/5810109790PGA field experiment was carried out in both kharif and rabi seasons during 2004-2005 at Cropping System Research station, Karamana to find out the effect of long term integrated nutrient supply system on soil health and productivity of rice ( Oryza sativa L) –rice sequential cropping system. The experiment was laid out in RBD with 12 treatments in 4 replications and treatments in kharif and rabi together form one set of treatment. The treatments included control , 50% ,75% and 100% levels of RDF in kharif and rabi and 50% or 25% substitution of recommended dose of nitrogen in kharif substituted by organic manure viz. FYM , crop residues and green manure. The treatments exerted profound influence in majority of growth characters and yield attributes. Application of 25% or 50% substitution of RDF through organic manure along with 75% or 100% RDF in rabi through chemicals produced remarkable influence in growth and yield attributes. In grain and straw yield of rabi and kharif , the highest values were given by those treatments which supplied either 50% or 25% of RDF through FYM or crop residues in kharif and 100% or 75% of RDF through inorganic fertilizers in rabi .Since these treatments were on par with each other, the best treatment is that which supply 25% RDF through organic manure in kharif and 75% of RDF through inorganic fertilizers in rabi since25% of the chemical fertilizers are saved there. The highest NPK contents in grain and straw in both kharif and rabi were recorded and mostly in those treatments with 50% or 25% of RDF through organic manures in kharif along with 100% or 75% of RDF through in organics in rabi The highest NPK uptake in all the crop stages in both kharif and rabi were also higher observed in plots those receive 50% or 25% of RDF through organic manures in kharif along with 100% or 75% of RDF through in organics in rabi The soil available P and K values did not vary remarkably in both Kharif and rabi .However soil available nitrogen in soil varied profoundly before and after rabi seasons and the maximum available nitrogen was observed before rabi in those plots which supply 25% RDF through crop residues in kharif and 100% RDF through chemical fertilizers in rabi and 50% RDF through green manure in kharif and 100% RDF through chemical fertilizers in rabi. The physical properties like bulk density and water holding capacity were also significantly influenced by the treatments before and after the experiment in which lower bulk density values were exhibited by organics applied plots in kharif and they also showed significantly higher water holding capacity compared to those treatments which were supplied with organic matter in kharif . Soil chemical properties like organic carbon and CEC remarkably improved in organic manure applied plots along with inorganics in rabi. The population count studies of bacteria, fungi, and actinomycetes revealed the positive influence of the collective application of organic matter and inorganic fertilizers on soil biological properties and its subsequent influence on soil health when compared with control. As per the economic analysis of the cultivation the maximum benefit cost ratio was exhibited by the treatment which received 25% of RDF in kharif through crop residues and 75% of RDF through in organics in rabi .ennullThesis