Kraft Recycled Paper as an Eco-Friendly Mulching Strategy in Pepper Cultivation to Improve Soil Temperature Regulation, Weed Management, Water Use Efficiency, and Pepper Yield

Mulch helps control weeds, conserve water, and promote plant growth, yet research on the use of kraft recycled paper mulch in pepper cultivation remains limited. Field trials conducted in 2022 and 2023 investigated the effects of wheat straw and kraft recycled paper as biodegradable organic mulch, plus black polyethylene (BPE), transparent polyethylene (TPE), and bare soil (control), on pepper morphological parameters, weed management, irrigation water use efficiency (WUE), and soil temperature. Organic mulching improved soil temperature management; kraft paper and wheat straw reduced daily soil temperature ranges by 2–4 °C compared to bare soil at 5 and 10 cm depths. Mulch treatments significantly affected weed biomass and percentage, with BPE and kraft recycled paper providing the most effective weed control. Compared to bare soil, mulching enhanced root spread by 21–24% at 75 days after sowing, improving plant stability. Root development and fruit chemical quality were superior under organic mulches versus plastic or bare soil. Kraft paper achieved the highest yield and accelerated flowering. BPE and kraft paper recorded the highest WUE values, with no significant difference between them. These findings suggest that kraft recycled paper is a promising eco-friendly substitute for polyethylene mulch, effectively regulating soil temperature, suppressing weeds, and improving water use efficiency in pepper cultivation.