Leaf water potential for surface and subsurface drip irrigated bell pepper under various deficit irrigation strategies

Increased water scarcity necessitates the implementation of water-conserving irrigation management practices to sustain crop production, especially in water-limited areas. Field experiments were conducted to evaluate midday leaf water potential (LWP) of bell pepper (Capsicum annuum L. var. annuum) irrigated differentially using surface drip (DI) and subsurface drip irrigation (SDI) systems during 2016 and 2017 growing seasons in the eastern Mediterranean environmental conditions. The treatments considered were deficit irrigations (I-50, I-75), regulated deficit irrigation (RDI), partial root-zone drying (PRD50) and full irrigation (I-100) under DI and SDI systems. The experimental design was completely randomized in a split-plot system with four replicates per treatment. Deficit irrigation treatments of I-75 and I-50 received 75% and 50% I-100, respectively; RDI was supplied with 50% I-100 during vegetative growth stage until flowering, then received 100% of crop water requirement; PRD50 plots received 50% I-100. Bell pepper plant water status was estimated by LWP. Higher LWP values were determined in I-100 for two drip systems than the I-75, I-50, and PRD50; LWP correlated significantly (P < 0.01) and negatively with fresh pepper yield, DM yield, leaf area index (LAI), and mean soil water content and all these relations are best described with the curvilinear equations. In conclusion, bell pepper should be irrigated at mean LWP values between -0.89 and -0.95 MPa without any yield reduction. It is also concluded that RDI and I-75 treatments appear to be good alternatives to I-100 for sustainable bell pepper production under the Mediterranean environmental conditions.