Plantation forestry plays a vital role in meeting the raw material demand of wood based industries. Under such plantations a paradigm shift is essential from general sivicultural packages to site specific, management packages to harvest higher utilizable biomass at the shortest rotation period. To elucidate information on the above line a field experiment was conducted with Casuarina species viz., C. equisetifolia and C. junghuhniana from seed and clonal sources raised under two spacings and five nutrient levels with a common irrigation schedule. The study was taken up at Agricultural Research Station, Bhavanisagar during 2010-2012. The current study has thus clearly brought out that wider spacing of 1.5 m x 1.5 m with the seed source of C.equisetifolia under 25 % more of fertilizer applications over the soil test recommendation value of 93.75: 225: 100 of NPK kg ha-1 was the ideal combination for higher biomass production as well as for getting maximum profit for site specific conditions at Bhavanisagar tract in Tamil Nadu, India under need based irrigated condition.