Effect of organic and inorganic sources of nitrogen on productivity, quality and economics of FCV tobacco (Nicotiana tabacum)

A field experiment was conducted during 2001–02 and 2002–03 at Rajahmundry, Andhra Pradesh to evaluate the response of FCV tobacco (Nicotiana tabacum L.) to doses of N fertilizer (20, 40 and 60 kg/ha) and its integration with organic N i.e. farmyard manure (FYM), groundnut [Arachis hypogaea (L.)] cake (GNC) and green leaf manuring (GLM) with Pillipesara [Vigna trilobata (L.) Verdc.]} in organic: fertilizer N of 0: 100, 25: 75 and 50: 50. Results showed that the net returns were higher by Rs 2,330 and Rs 850/ha with GLM when compared with GNC and FYM, respectively. Application of organic: inorganic N in 25: 75 ratio increased mean yields of cured leaf by 0.14 t/ha, and net returns by Rs 3,000/ha over fertilizer N alone. However, 50% each of organic: inorganic N registered higher soil fertility status (OC%, available N,P and K) after crop harvest. The highest mean leaf yields, leaf production efficiency and net returns (Rs 24,450) were recorded with 60 kg N/ha. Leaf lamina concentrations of N and nicotine increased while sugars, and sugars: nicotine ratio decreased with increase in the level of N from 20 to 60 kg/ha. Application of 60 kg N/ha, 25% through FYM or GLM and 75% through fertilizers improved the productivity, quality, economic returns of tobacco and soil fertility status. GLM with Pillipesara is a suitable alternative to FYM whenever its supply is limited in vertisols of Andhra Pradesh.