Effects of Shading Methods and Harvesting Time on Leaf Quality and Wrapper Output Rate of Cigar Tobacco

In order to determine the suitable shading methods and harvesting time combinations for cigar tobacco leaves in Hainan, three harvesting times under top shading and full shading methods, with a total of six combination treatments from T₁ to T₆, were set to study their effects on the quality of tobacco leaves and output rate of wrappers. The results showed that the leaf length, leaf width, and leaf fresh weight of T₂ and T₃ treatment at leaf positions 1 to 4, 5 to 8, and 9 to 12 were all higher. The leaf thickness at leaf positions 5 to 8 decreased with the delay of harvesting time, while at leaf positions 9 to 12 with the same shading method, the leaf thickness was the lowest when harvested in the middle. The leaf SPAD values at leaf positions 5 to 8 and 9 to 12 were the lowest during the middle harvesting time treatments. The leaf magnesium contents at leaf positions 5 to 8 increased with delayed harvesting time, while the nitrogen, phosphorus, potassium and sulfur contents of T₄ at leaf positions 9 to 12 were the highest. The yield of cigar tobacco leaves reduced delayed harvesting time, but the yield and output rate of cigar wrappers of T₅ treatment were highest. After fermentation, the weighted scores of appearance quality of tobacco leaves of T₅ treatment at all leaf positions were the highest. In conclusion, the optimal treatment combination is the middle harvesting treatment with full shading (T₅). Therefore, the suitable harvesting times for Hainan cigar tobacco leaves at leaf positions 1 to 4, 5 to 8, and 9 to 12 under full shading are 70 days, 79 days, and 89 days after transplantation, respectively.