Effect of organic and inorganic sources of nutrients in chewing tobacco (Nicotiana tabacum) and their residual effect on sunflower (Helianthus annuus) under different fertility levels

Abstract

A field experiment was conducted at the farm of Central Tobacco Research Institute-Regional Station, Vedasandur, during 200810, to evaluate the organic and inorganic sources of nutrients in chewing tobacco (Nic- otiana tabacum L.) and their residual effect on sunflower (Helianthus annuus L.) under different fertility levels. Three levels of organic manures, viz. sunhemp green-manuring and ploughing in-situ at 45 days, 75% of recom- mended farmyard manure (FYM), 100% of FYM with 2 levels of fertilizers, viz. 75% recommended dose of fertil- izer (RDF) and 100% RDF were tested in chewing tobacco. The residual effect of the organic manures and fertil- izers applied to chewing tobacco was tested in the succeeding sunflower. Three levels of fertilizers, viz. 50% RDF, 75% RDF and 100% RDF, were tested for sunflower. First-grade leaf yield and total cured leaf yield of chewing to- bacco increased significantly by 15% and 16%, respectively, with sunhemp green manuring over the 75% RFYM. The first grade leaf yield and total cured leaf yield recorded was 2.99 and 3.55 t/ha respectively. Recommended dose of fertilizer (RDF) at 100% level significantly increased the First-grade leaf yield (FGLY) and total cured leaf yield (TCLY) by 9 and 5%, respectively, over the 75% RDF. Sunhemp green manuring to chewing tobacco signifi- cantly increased the sunflower seed yield and oil yield by 18 and 25%, respectively, over the 75% recommended farmyard manure. The RDF at 100% level to sunflower increased the seed and oil yield by 16 and 25%, respec- tively, over the 75% RDF to chewing tobacco. The seed and oil yield recorded were 1.39 t/ha and 474 kg/ha. To- bacco-equivalent yield significantly increased by 16% over the 75% RFYM. The tobacco-equivalent yield (TEY) was 4.32 t/ha. Application of 100% RDF to tobacco significantly increased the net returns by 6% over the 75% RDF. The net returns recorded was 98,300/ha. The residual soil organic-C status varied between 0.48 and 0.53%. The phosphorus balance showed that the net gain of P was higher (2.02.2 kg/ha), when RDF was added to chewing tobacco as well as sunflower. The potassium balance showed that the net gain of K was higher (1216 kg/ha) with 100% recommended farmyard manure under various nutrient level.