International Journal of Horticulture, 2026, Vol.16, No.4, 206-213 http://hortherbpublisher.com/index.php/ijh 210 Table 4 Effect of mulching treatments on yield and yield-related parameters of onion (Allium cepaL.) at harvest Treatments Stem Dia. (cm) Bulb Wt. (g) Bulb length (cm) Bulb Dia. (cm) Root length (cm) Total yield (t/ha) Control 0.89c 61.72e 4.28c 5.21d 10.38a 18.42d Banana leaf mulch 1.11b 80.93cd 4.73bc 5.79cd 9.76a 22.14c Sawdust mulch 1.06b 76.58d 5.19a 5.91bc 10.09a 23.87c Rice straw mulch 1.28a 95.84b 4.97ab 6.53ab 10.68a 29.54b Plastic mulch 1.41a 111.47a 4.83b 7.08a 11.14a 35.27a LSD(p≤0.05) 0.19*** 9.7*** 0.33*** 0.61* 1.97ns 2.9*** CV(%) 5.92 6.24 3.82 5.17 10.91 5.86 Grandmean 1.15 85.31 4.80 6.10 10.41 25.85 Note: Means in a column followed by different lowercase letters differ significantly at p ≤ 0.05 (DMRT). * p ≤ 0.05; *** p ≤ 0.001; ns: not significant. LSD: least significant difference; CV: coefficient of variation; Stem Dia.: stem diameter; Bulb Wt.: bulb weight; Bulb Dia.: bulb diameter 3.4.1 Stem diameter Plastic mulch produced the widest stem diameter (1.41 cm), followed by rice straw mulch (1.28 cm), while the control recorded the smallest (0.89 cm). Pseudostem girth is closely correlated with overall plant vigor, vascular bundle density, and capacity for water and solute transport to the bulb (Ahmad et al., 2022). Banana leaf and sawdust mulches produced intermediate values (1.11 and 1.06 cm, respectively), reflecting their lower thermal insulation and slower nutrient contribution relative to plastic and straw mulches. 3.4.2 Bulb weight Fresh bulb weight differed significantly among treatments (p < 0.001). Plastic mulch achieved the highest value (111.47 g), followed by rice straw mulch (95.84 g), banana leaf mulch (80.93 g), sawdust mulch (76.58 g), and the control (61.72 g). The 80.7% increase in bulb weight under plastic mulch relative to the control underscores the critical importance of consistent moisture supply and thermal regulation during the bulbing phase. These results corroborate Islam et al. (2007) and Najafabadi et al. (2012), who documented substantial bulb weight advantages under polyethylene mulch. The competitive performance of rice straw mulch reflects the combined benefit of moisture conservation and gradual nitrogen supply during storage organ filling. 3.4.3 Bulb length and diameter Sawdust mulch produced the longest bulbs (5.19 cm), though statistically at par with rice straw mulch (4.97 cm). Elongated bulb form under sawdust is attributable to its high porosity and low bulk density when applied as mulch, improving aeration and reducing mechanical resistance to radial bulb expansion (Haque et al., 2003). Bulb diameter was greatest under plastic mulch (7.08 cm), followed by rice straw mulch (6.53 cm), and was lowest in the control (5.21 cm). Equatorial diameter is a primary determinant of commercial grade in onion markets, making the plastic mulch advantage economically significant (Najafabadi et al., 2012). 3.4.4 Total yield Total fresh yield showed the strongest treatment differentiation (Table 4). Plastic mulch yielded 35.27 t/ha 91.5% advantage over the control (18.42 t/ha)—and was significantly superior to all other treatments. Rice straw mulch (29.54 t/ha) was the next highest, statistically distinct from banana leaf mulch (22.14 t/ha), sawdust mulch (23.87 t/ha), and the control. The superior yield under plastic mulch is a cumulative outcome of consistently higher leaf area index, improved photosynthetic duration, enhanced nutrient uptake efficiency, and reduced weed competition across the entire growth cycle (Lamont, 2005; El-Beltagi et al., 2022). The yield hierarchy plastic > rice straw > sawdust > banana leaf > control is consistent with reports from comparable subtropical environments (Ramakrishna et al., 2006; Mutetwa and Mtaita, 2014).
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