INTEGRATED NUTRIENT MANAGEMENT FOR PRODUCTIVITY AND QUALITY OF FCV TOBACCO ( NICOTIANA TABACUM ) IN IRRIGATED ALFISOLS

Abstract

A field experiment was conducted during the crop seasons of 2002-05, to find out the response of fluecured Virginia tobacco (Nicotiana tabacum L.) to integrated use of organic manures, biofertilisers and inorganic fertilizers in irrigated Alfisols (northern light soils) at Jeelugumilli in Andhra Pradesh. Results pooled over the years showed that addition of dual cultures of Azotobacter and Azospirillum along with co-inoculation of VAM fungi and PSB to tobacco grown after sunnhemp in situ green manuring (GM) with 8.7 kg P/ha and application of 90-8.7-99.9 kg NPK/ha followed by 0.2% MgSO4 spray + 0.2% ZnSO4 spray (T10) increased yields of green leaf by 1.46 t/ha (8.50%), cured leaf by 0.15 t/ha (6.78%) and grade index by 0.23 (14.47%); grade index/cured leaf by 5% and cured leaf production efficiency by 0.92 kg/ha/day compared with those of the recommended practice of fertilizer application i.e. sunnhemp with 8.7 kg P (in situ GM) + 110-17.599.9 kg NPK/ha (T3). Higher content of nicotine, total nitrogen and lower content of reducing sugars in tobacco leaf lamina; higher net returns, B:C ratio, profitability and higher soil available N were recorded in the treatment T10 compared to other treatments. Co-inoculation of VAM fungi + PSB cultures to tobacco grown with sunnhemp in situ GM saved 8.7 kg P/ha. Dual inoculation of free nitrogen fixing Azotobacter and Azospirillum to tobacco grown after sunnhemp in situ GM showed a saving of 20 kg N/ ha. Foliar spray of 0.2% ZnSO4 (T10) increased yields of green leaf by 0.75 t/ha (4.19%), cured leaf by 0.09 t/ha (3.96) and grade index by 0.12 (7.06%), grade index/ cured leaf by 2.2% and cured leaf production efficiency by 0.55 kg/ha/day compared with those of the treatment without foliar spray of ZnSO4 i.e. T9. It was concluded that treatment (T10) saved 8.7 kg P and 20 kg N/ha and produced higher cured leaf yield, grade index, better chemical quality in lamina, accrued higher net returns and improved soil available N.