ASHNA SUSAN JOSEPH2023-12-012023-12-012023-12-01https://krishikosh.egranth.ac.in/handle/1/5810202025Investigations were carried out during kharif and rabi seasons of 2018-19 and 2019- 20 at Agricultural Research Station, Dhadesugur, University of Agricultural Sciences, Raichur on “Studies on nutrient management approaches in rice-blackgram cropping system under different ecosystems” in order to quantify the distribution of nitrogen in different pools as well as to study the response of paddy crop to rice ecosystem, nutritional approaches and nitrogen sources. It was noticed that the release of NH4 +-N and NO3 --N started on the 5th day of N application when neem coated urea was the source of N for direct seeded rice and transplanted rice applied through SSNM approach for targeted yield of 7 t ha-1. It reaches on the peak at 8th and 12th day of N application when the NCU started releasing NH4 +-N and NO3 --N which also sustained until the last day of sampling and it matches the crop requirements at different intervals. The results of the field experiment had shown that the application of nutrients through SSNM approach for targeted yield of 7 t ha-1 along with neem coated urea for transplanted rice and its residual effect on blackgram had significantly increased the growth, yield attributes, grain/seed and straw/haulm, quality parameters and total uptake of nutrients favorably. In soils which possessed neem coated urea based on SSNM approach (6 and 7 t ha-1) under direct seeded rice and transplanted rice-blackgram recorded higher available N, K2O and S in soil. Among the different rice ecosystems, nutritional approaches and nitrogen sources, application of neem coated urea through SSNM approach for targeted yield of 7 t ha-1 under direct seeded rice and transplanted rice-blackgram cropping system. approach (7 t ha-1) for transplanted rice followed by blackgram had recorded higher rice-equivalent yield, gross returns, net returns and BC ratio. Thus, it was followed by the treatments applied with neem coated urea through SSNM approach for the yield target of 6 t ha-1 and STCR approach for targeted yield of 7 t ha-1 under direct seeded rice and transplanted rice-blackgram.EnglishThesis