Enhancing soil hydrothermal efficiency through spectral-selective mulching and drip irrigation in broccoli (Brassica oleracea var. italica L.)

Water scarcity and declining soil fertility necessitate the adoption of sustainable agricultural practices that enhance crop productivity while maintaining soil health. Mulching is an effective strategy for regulating soil temperature, conserving soil moisture, and improving crop performance. This study was conducted during the 2022 Rabi season at the experimental farm of Sher-e-Kashmir University of Agricultural Sciences and Technology of Kashmir (SKUAST-K) to evaluate the effects of different mulching materials on soil temperature, soil moisture dynamics, growth, and yield of broccoli ( Brassica oleracea var. italica L.). The experiment was laid out in a randomized complete block design with three replications, comprising five mulching treatments (control, white plastic, black plastic, silver plastic, and organic mulch), with soil measurements recorded at three depths (5, 10, and 15 cm). Silver plastic mulch significantly improved soil moisture retention (30.61% at 15 cm), curd weight (791.99 g plant⁻¹), head diameter (17.97 cm), and total yield (52.80 t ha⁻¹), while also promoting earlier head initiation at 25 days after transplanting. Black plastic mulch produced the highest soil temperature (24.67 °C at 5 cm), whereas organic mulch enhanced soil organic carbon (1.3%) and organic matter content (2.24%). The HYDRUS-1D model was employed to simulate soil water content and heat transport under mulched and non-mulched conditions, showing strong agreement between observed and simulated values (RMSE: 0.718–1.161; R²: 0.8995–0.9445). Silver plastic mulch is the most effective treatment for improving broccoli yield and water use efficiency, whereas organic mulch contributes to long-term soil health. HYDRUS-1D proved to be a reliable tool for simulating root water uptake and soil heat dynamics under different mulching conditions.