Effect of composted coir pith, nitrogen and irrigation on chewing tobacco (Nicotiana tabacum)

A field experiment was conducted from 2001–02 to 2003–04 at Vedasandur to study the effect of coconut (Cocos nucifera L.) coir pith compost at three levels (10.0, 12.5 and 15.0 t/ha) in comparison with municipal compost at 25 t/ha, three levels of irrigation (0.5, 0.75 and 1.0 ETc) and three levels of nitrogen (50, 75 and 100 kg N/ha) on the yield and quality of chewing tobacco (Nicotiana tabacum L.). The yields of first-grade leaf and total cured-leaf of chewing tobacco with municipal compost at 25 t/ha were comparable with that of composted coir pith at 10 t/ha. Irrigation at 1.0 ETc significantly increased the yields of first-grade leaf and total cured leaf by 19 and 17% respectively compared with that at 0.5 ETc. Nitrogen at 100 kg/ha significantly increased the yield of first-grade leaf and total cured leaf by 15 and 19% respectively than at 75 kg N/ha. Water-use efficiency was higher with 0.5 ETc and 100 kg N/ha. Net returns increased by 4% with composted coir pith at 10 t/ha than with municipal compost at 25 t/ha, 12% with 1.0 ETc than with 0.5 Etc, and 6% with 100 kg N/ha over 50 kg N/ha. Soil available P, lamina P and K uptake were higher with municipal compost at 25 t/ha than composted coir pith at 10 t/ha. Soil-organic C and nutrient uptake of lamina improved with 1.0 ETc and 100 kg N/ha than with 0.5 ETc and 50 kg N/ha, respectively. Nicotine increased with 0.5 ETc and decreased with 1.0 ETc. Composted coir pith at 10 t/ha, irrigation at 1.0 ETc and nitrogen 100 kg/ha were found optimum for increased yields of first-grade leaf and total cured leaf, net returns and benefit: cost ratio.