Effects of Water Deficit on Water Consumption Characteristics of Pepper under Mulched Drip Irrigation in the Hexi Oasis Region

This study examined how varying degrees of water deficit influence the water consumption patterns of pepper under drip irrigation with mulch through a field trial. The experimental design included mild and moderate water deficits during the flowering and fruiting phases, as well as mild deficits during the full fruit and late fruiting stages. A fully irrigated treatment throughout the reproductive stage served as the control (CK). The findings revealed that across treatments, pepper water use characteristics — specifically water consumption modulus, rate, and total consumption — ranked as follows: full fruit stage > late fruiting stage > flowering and fruiting stage > seedling stage. Compared to CK, both water use intensity and total consumption generally declined as the severity of water deficit increased. Notably, mild water limitation at the seedling phase and water stress in the late fruiting stage had little effect on overall water use, whereas other deficit treatments significantly decreased total consumption by 9.90%-24.10% relative to CK. Overall, deficits during the seedling and late fruiting stages minimally influenced total water use, whereas reductions were most pronounced when stress occurred during the flowering and fruiting stage.