Effect of Different Plant Spacing and Mulching Materials on the Growth and Yield Performance of Okra (Abelmoschus esculentus) in the Dry Zone of Sri Lanka

Okra (Abelmoschus esculentus) is a globally cultivated economically important crop where weed pressure and inadequate agronomic practices often limit its productivity. A field experiment was conducted at the Sri Lanka School of Agriculture, Palamunai, during the period from November 2024 to March 2025, with the objective of investigating suitable spacing and mulching material for growing okra (Haritha variety) in the dry zone of Sri Lanka. The experiment was laid out in a 3×4 factorial RCBD with three levels of spacing (90cm x 60cm, 75cm x 45cm, and 60cm x 60cm) as the first factor and four levels of mulching material (polythene, paddy straw, paddy husk, and no mulch) as the second factor. Each treatment combination was replicated four times. According to the ANOVA results of the experiment, there was no significant interaction effect (p>0.05) observed between plant spacing and mulching materials for the measured growth and yield parameters. Therefore, the main effects were analyzed independently. Spacing had no significant influence (p>0.05) on plant height, leaf number, pod length, or total yield, although the 60×60 cm spacing resulted in earlier flowering (31.1 days). With respect to the mulching material used, except for the days to 50% flowering, polythene mulch significantly enhanced leaf number (12.8 leaves at 8 WAP), average pod length (19.39 cm), and total yield per plant (322.38 g) outperforming organic mulches and the no-mulch control. Polythene mulch proved to be the most effective mulching material for improving okra productivity under dry-zone conditions. These results emphasize the necessity of adopting optimal mulching practices to maximize crop performance and resource-use efficiency.