Effect of Paddy Straw, Paddy Husk, and Cinnamon Residue as mulching in Turmeric (<em>Curcuma longa</em> L.) Cultivation in Low Country Wet Zone in Ultisols

An experiment was conducted to determine the most effective mulching material for maximizing turmeric (Curcuma longa L.) yield. The study was carried out in the low country wet zone of Sri Lanka, specifically in Ultisols, during 2021 and 2022, using locally available mulching materials, including paddy straw, paddy husk, and cinnamon residue. A control group was included, where turmeric was grown without any mulching material. The experimental setup followed a Randomized Complete Block Design, with three plots, each comprising thirty plants arranged in the rows of the plot at a spacing of 30X30 cm between plants. Plants at the edges of the beds were excluded from data collection. While there was no significant difference in per plant yield between turmeric plants grown with paddy husk and paddy straw mulching (1251 g and 1227 g), all three mulching materials resulted in significantly higher yields compared to the control group. Results revealed that turmeric plants grown with cinnamon mulching exhibited the highest yield (1523 g), suggesting cinnamon is also an effective mulching material for turmeric cultivation in Ultisols, the same as other mulching materials. Additionally, turmeric plants grown with cinnamon mulching showed significantly higher tuber dimensions, such as the number of mother rhizomes (5.97), primary fingers (31.10), and secondary fingers (134.1) compared to the control, further highlighting its effectiveness. However, mulching had no significant effect on the number of leaves, leaf blade length, and leaf petiole length in both control and treatment groups, suggesting other factors may play a more dominant role in determining these parameters. Cinnamon residue can also be an effective mulching material for achieving better turmeric yields in Ultisols.