International Journal of Horticulture, 2026, Vol.16, No.4, 206-213 http://hortherbpublisher.com/index.php/ijh 208 2.4 Observations and measurements Five representative plants were randomly selected from the central two rows of each plot and tagged after transplanting for recording growth observations. Plant height (measured from the soil surface to the tip of the longest leaf), leaf length (base to tip of the longest fully expanded leaf), and the number of leaves per plant were recorded at 30, 60, 90, and 120 days after transplanting (DAT). At harvest, stem diameter (measured 2 cm above the bulb neck), bulb fresh weight, bulb length, equatorial bulb diameter, and root length were measured using a digital Vernier caliper (±0.01 mm) and a digital balance (±0.1 g). Total bulb yield was determined from the fresh weight of all harvested bulbs in each plot and converted to tonnes per hectare (t/ha). 2.5 Statistical analysis The recorded data were subjected to analysis of variance (ANOVA) appropriate for a Randomized Complete Block Design (RCBD) using RStudio version 4.3.1. Before conducting ANOVA, the assumptions of normality and homogeneity of variance were verified using the Shapiro-Wilk and Levene's tests, respectively. Treatment means were compared using Duncan's Multiple Range Test (DMRT) at the 5% level of significance. The coefficient of variation (CV%) was calculated to assess the precision of the experiment. 3 Results and Analysis 3.1 Plant height Plant height increased progressively across all treatments from 30 to 90 DAT, with a characteristic decline at 120 DAT reflecting assimilate remobilization from foliar tissues to the developing bulb during senescence (Brewster, 2008). No significant treatment differences were detected at 30 DAT (Table 1). Significant effects were evident from 60 DAT onward. Table 1 Effect of mulching treatments on plant height (cm) of onion (Allium cepa L.) at 30, 60, 90, and 120 days after transplanting (DAT) Treatments Plant height (cm) 30DAT 60DAT 90DAT 120DAT Control 18.47b 35.62c 52.83d 48.91c Banana leaf mulch 19.53ab 38.74bc 58.16c 53.45bc Sawdust mulch 20.28ab 41.15b 61.42bc 58.07b Rice straw mulch 21.74a 44.58a 67.93a 63.41a Plastic mulch 21.19a 44.07a 65.28ab 61.83a LSD(p≤0.05) 2.94 3.51** 4.23** 4.01*** CV(%) 7.86 4.42 3.81 3.64 Grandmean 20.24 40.83 61.12 57.13 Note: Means in a column followed by different lowercase letters differ significantly at p ≤ 0.05 (DMRT). ** p ≤ 0.01; *** p ≤ 0.001. DAT: days after transplanting; LSD: least significant difference; CV: coefficient of variation Rice straw mulch recorded the tallest plants at 60 DAT (44.58 cm), 90 DAT (67.93 cm), and 120 DAT (63.41 cm), closely followed by plastic mulch (44.07, 65.28, and 61.83 cm, respectively). The control consistently produced the shortest plants across all stages. The superiority of rice straw mulch for plant height is attributable to its dual role in moisture retention and progressive release of nitrogen and other nutrients as decomposition proceeds, augmenting the inorganic fertilizer program (Baten et al., 1995; Ramakrishna et al., 2006). These findings are consistent with Islam et al. (2007) and Mutetwa and Mtaita (2014), who documented superior plant height responses under straw mulch compared with bare soil in Alliumcrops. 3.2 Number of leaves per plant Leaf count per plant was significantly influenced by mulching at all observation stages (Table 2). Plastic mulch consistently recorded the greatest leaf numbers: 4.73 (30 DAT), 7.00 (60 DAT), 9.27 (90 DAT), and 9.00 (120 DAT). The control produced the fewest leaves at every stage. Plastic mulch maintains stable, slightly elevated soil
RkJQdWJsaXNoZXIy MjQ4ODYzNA==