Synergistic effects of irrigation scheduling and mulching on growth, productivity, and quality attributes of chilli in a semi-arid agroecosystem

Abstract

An experiment was conducted during 2020-21 at the Department of Vegetable Science, Horticultural College and Research Institute (HC&RI), Periyakulam, Tamil Nadu, to evaluate the interactive effects of irrigation regimes and mulching practices on the growth, yield, fruit quality, soil moisture dynamics, and water use efficiency (WUE) in chilli (Capsicum annuum L.) under semi-arid conditions. The field trial was laid out in a split-plot design with three irrigation levels based on crop evapotranspiration (ETc) [80% (I₁), 100% (I₂), and 120% (I₃)] assigned to main plots, and three mulching types [no mulch (M₁), straw mulch (M₂), and black polyethylene mulch (M₃)] in sub-plots, replicated thrice. Results revealed that both irrigation and mulching had significant individual and interactive effects on chilli performance. Among all treatments, I₂M₃ (100% ETc + black polyethylene mulch) recorded the highest plant height (64.2 cm), primary branches (11.2), and leaf area index (2.25), along with early flowering (44.0 days). This treatment also produced the maximum number of fruits per plant (128), highest fruit yield (18.3 t/ha), fruit length (8.7 cm), girth (1.20 cm), and superior quality parameters, including capsaicin content (2.21 mg/g) and vitamin C (118.6 mg/100 g). Moreover, I₂M₃ showed the highest soil moisture retention across growth stages and a water use efficiency of 4.45 kg/m³. While I₁M₃ (80% ETc + black mulch) yielded slightly lower output, it recorded the highest WUE (4.73 kg/m³), suggesting potential for water-saving without substantial yield loss. Overall, the study highlights that the integration of 100% ETc-based irrigation with black polyethylene mulch is an effective strategy for improving chilli productivity, fruit quality, and water use efficiency in water-limited environments. These findings offer practical insights for optimizing input use and promoting climate-resilient chilli cultivation in semi-arid agroecologies.