Effect of various mulching materials on different varieties of watermelon under eastern Nepal agro-climatic conditions

Abstract

Watermelon (Citrullus lanatus) production is often limited by soil moisture stress and low resource-use efficiency, making mulching an effective strategy for improving crop performance. This study evaluated the effects of different mulching materials on growth, yield, and fruit quality of two watermelon varieties under the agro-climatic conditions of eastern Nepal. The experiment was conducted in a two-factor factorial Randomized Complete Block Design (RCBD) with eight treatment combinations and three replications. Two varieties (Sweet Honey and Saraswati) were evaluated under three mulching materials (straw, sawdust, and black plastic mulch) along with a non-mulched control. Mulching significantly (p<0.05) affected plant height, number of leaves, number of branches, titratable acidity, and yield. Black plastic mulch recorded the highest plant height (3.44 m) and yield (22.35 t ha⁻¹), while straw mulch produced highest number of leaves (131.77) and branches (10.06). Among varieties, Saraswati showed higher firmness (9.03 kg cm⁻²) and leaf number (101.51), whereas Sweet Honey produced heavier fruits (2.74 kg). Significant interaction effects were observed for leaves, branches, titratable acidity, and firmness. The highest leaf number (138.75), branch number (11.75), and firmness (9.73 kg cm⁻²) were recorded in Sweet Honey × Straw mulch, Saraswati × Straw mulch, and Saraswati × Sawdust mulch, respectively. No significant effects were observed on pH, total soluble solids, node diameter, pulp weight, and fruit diameter. Therefore, black plastic mulch maximizes yield, while straw mulch enhances vegetative growth and provides a sustainable, low-cost alternative. Integration of suitable mulching practices with the Saraswati variety can improve watermelon productivity under eastern Nepal conditions.